Scandinavian Journal of Work, Environment & Health

About the journal

Publisher: Nordic Association of Occupational Safety and Health
Published: 1975 to the present, Finland
Language: English
ISSN: 0355-3140 (print), 1795-990X (electronic)
Merged from: Nordisk Hygienisk Tidskrift
Merged from: Work, Environment, Health
Its record in the NLM Catalog

2020s

Occupational exposure to carcinogenic substances in night versus day shift jobs. J. Parks, U. Zanif, P. Bhatti. 2026;52(4):434-441. PubMed · Publisher · Free full text

Abstract

Objectives: This study aimed to determine whether night shift work was associated with exposure to carcinogenic hazards, independent of occupation and industry.

Methods: We conducted a cross-sectional analysis of 16 250 job records reported by 7023 participants. Participants provided lifetime job histories, including shift schedules and exposures to hazardous agents. Carcinogenic agents included established carcinogens classified by the International Agency for Research on Cancer, as well as broader exposure categories that may potentially contain carcinogenic constituents. Jobs involving ≥1 and ≥7 night shifts/month were compared with day-shift jobs. Occupations and industries were coded using National Occupational Classification (2016) and North American Industry Classification System (2017) codes. Generalized linear mixed models with random intercepts for participant, occupation code (2-digit level), and industry code (2-digit level) were used to estimate odds ratios (OR) for exposures associated with night- versus day-shift work, adjusting for biological sex and job start year.

Results: Night shifts were associated with greater odds of any hazardous exposure [≥1 night shift/month: OR 3.1, 95% confidence interval (CI) 2.6-3.8; ≥7 night shifts/month: OR 3.1, 95% CI 2.5-3.8]. Significant associations were observed for multiple agents, including asbestos, degreasing agents, diesel engine exhaust, gasoline engine exhaust, ionizing radiation, mineral/cutting/lubricating oil, paints/stains/varnish, welding fume, and wood dust.

Conclusions: Night-shift work was associated with an increased likelihood of self-reported exposure to multiple potentially carcinogenic agents, independent of broad occupational and industry groupings. Future research with more granular task-level information and quantitative exposure assessment will be important for clarifying the mechanisms underlying these differences.
Detailed mapping of mesothelioma cases in Denmark to identify areas with elevated risk: a nationwide population-based study. H.S. Christensen, R.H. Jensen, L.H. Nielsen, et al. 2025;51(5):449-453. PubMed · Publisher · Free full text

Abstract

Objectives: Previous studies mapping pleural mesothelioma in Denmark have found that the risk varies between Danish regions. However, evaluating disease risk for such relatively large geographical units ignores any heterogeneity within the unit and can thus diminish more local spikes in risk, missing smaller areas of excess risk. In this study, we examined the distribution of pleural mesothelioma in Denmark on an unprecedented detailed scale, mapping cases to each of the Danish parishes.

Methods: We identified individuals diagnosed with pleural mesothelioma between 1990 and 2021 in the Danish Cancer Registry. Considering age- and sex-standardized incidence rate ratios (IRR), we used a conditional autoregressive random effects model to smooth IRR across parishes. Parishes with a smoothed parish-to-national IRR >1.25 or >2.0 with a posterior probability of >95% were flagged as parishes with an excess risk of pleural mesothelioma.

Results: We identified 3105 incident cases of pleural mesothelioma in the study period. A total of 74 and 14 parishes were flagged with IRR significantly above 1.25 and 2.0, respectively. These parishes had posterior mean smoothed IRR of 1.82-4.13.

Conclusions: We provided a detailed mapping of pleural mesothelioma cases in Denmark and found five distinct areas, each covering several parishes, with a significantly elevated risk. All these areas were in the proximity of previous asbestos-using industries.
Asbestos and disease - a public health success story?. B. Järvholm, A. Burdorf. 2024;50(2):53-60. Review PubMed · Publisher · Free full text

Abstract

Objective: This paper discusses the failure and success of society to decrease the adverse health effects of asbestos exposure on workers' health in relation to scientific knowledge.

Methods: The findings are based on a narrative literature review.

Results: Early warnings of the adverse health effects of workplace exposure to asbestos were published already in the 1930s. Serious health effects, such as malignancies and fibrosis due to occupational asbestos exposure, were highlighted in major medical journals and textbooks in late 1960s. New technologies could detect also asbestos fibers in the lung of non-occupational exposed persons in the 1970s. The first bans for using asbestos came in the early 1970s, and more general bans by authorities came in the 1980s and continue until today.

Conclusions: The rather late recognition of adverse effects of asbestos exposure in the general population and measures to decrease the exposure through more general bans came rather late. However, the very strong measures such as general bans in many countries have been a success. A Swedish study showed that the general ban and other measures have decreased the risk of malignancies due to occupational exposure. The effect of the bans on adverse effects in the general population has yet to be studied. Analysis of fibers in the lungs of persons born after the bans could be an efficient method.
The asbestos-asbestosis exposure-response relationship: a cohort study of the general working population. I.B. Iversen, J.M. Vestergaard, J. Ohlander, et al. 2024;50(5):372-379. PubMed · Publisher · Free full text

Abstract

Objectives: The association between asbestos exposure and asbestosis in high-exposed industrial cohorts is well-known, but there is a lack of knowledge about the exposure-response relationship for asbestosis in a general working population setting. We examined the exposure-response relationship between occupational asbestos exposure and asbestosis in asbestos-exposed workers of the Danish general working population.

Methods: We followed all asbestos-exposed workers from 1979 to 2015 and identified incident cases of asbestosis using the Danish National Patient Register. Individual asbestos exposure was estimated with a quantitative job exposure matrix (SYN-JEM) from 1976 onwards and back-extrapolated to age 16 for those exposed in 1976. Exposure-response relations for cumulative exposure and other exposure metrics were analyzed using a discrete time hazard model and adjusted for potential confounders.

Results: The range of cumulative exposure in the population was 0.001 to 18 fibers per milliliter-year (f/ml-year). We found increasing incidence rate ratios (IRR) of asbestosis with increasing cumulative asbestos exposure with a fully adjusted IRR per 1 f/ml-years of 1.18 [95% confidence interval (CI) 1.15- -1.22]. The IRR was 1.94 (95% CI 1.53-2.47) in the highest compared to the lowest exposure tertile. We similarly observed increasing risk with increasing cumulative exposure in the inception population.

Conclusions: This study found exposure-response relations between cumulative asbestos exposure and incident asbestosis in the Danish general working population with mainly low-level exposed occupations, but there is some uncertainty regarding the exposure levels.
Cancer incidence in sites potentially related to occupational exposures: 58 years of follow-up of firefighters in the Norwegian Fire Departments Cohort. N. Marjerrison, J. Jakobsen, T.K. Grimsrud, et al. 2022;48(3):210-219. PubMed · Publisher · Free full text

Abstract

Objectives: Firefighters are exposed to a variety of known and suspected carcinogens through their work. However, the association with cancer risk has limited evidence. We examined cancer incidence among firefighters in the newly established Norwegian Fire Departments Cohort restricted to sites with established associations with carcinogens encountered during firefighting. This included sites within the respiratory, urinary, and lympho-hematopoietic systems, and the skin and all sites combined.

Methods: Male firefighters (N=3881) in the cohort were linked to the Cancer Registry of Norway for incident cancer cases occurring during the period 1960-2018. We calculated standardized incidence ratios (SIR) with rates for the national male population as reference, and stratified SIR analyses by period of first employment, duration of employment, and time since first employment.

Results: Elevated risk was seen for all sites combined (SIR 1.15, 95% confidence interval 1.07-1.23). Elevated risk of urinary tract cancer was observed among firefighters who began working before 1950, and with observation ≥40 years since first employment. Risk of mesothelioma and laryngeal cancer were elevated with ≥40 years since first employment and with ≥30 years employment duration.

Conclusions: The observed associations between firefighting and urinary tract cancer, laryngeal cancer, and mesothelioma have been observed in some studies previously, and our results suggest the observed elevated risks are related to carcinogenic occupational exposures. Differences in risk by period of employment potentially reflect changes in exposures from improved quality and use of personal protective equipment.
Authors' response: Mezei et al's "Comments on a recent case-control study of malignant mesothelioma of the pericardium and the tunica vaginalis testis". A. Marinaccio, D. Consonni, C. Mensi, et al. 2021;47(1):87-89. Letter · Comment PubMed · Publisher · Free full text
Comments on a recent case-control study of malignant mesothelioma of the pericardium and the tunica vaginalis testis. G. Mezei, E.T. Chang, F.S. Mowat, et al. 2021;47(1):85-86. Letter · Comment PubMed · Publisher · Free full text

Summary

In this letter, the authors commented on the 2020 case-control study by Marinaccio et al of malignant mesothelioma of the pericardium and the tunica vaginalis testis (mTVT) in Italy, arguing that it had several methodological problems. Comparing the published tables, they reported that the distributions of male cases (pericardial or mTVT) and controls by period of birth were clearly different (P<0.001). These differences remained in a sensitivity analysis restricted to subjects born before 1950, so in their view cases and controls were not matched on birth cohort. Cases came from across Italy, but controls came from only six regions, and the regional distribution of controls differed from that of person-time observed. On exposure ascertainment, they noted that case information was presumably obtained at registration (1993–2015), whereas the two control sets were interviewed in 2014–2015 and 2014–2016, and one set had participation below 50%. They asked for results for each control set separately, for separate analyses of definite occupational exposure, for clearer exposure classification, and for details on the 12 of 80 registered mTVT cases that were not analysed. They also questioned treating agriculture as an asbestos-exposed sector. They concluded that the reported association of occupational exposure with mTVT and male pericardial mesothelioma might be spurious, resulting from control-selection bias and deficient exposure assessment. All authors stated they were Exponent, Inc. employees who had worked as consulting and testifying experts in asbestos litigation.

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Association between asbestos exposure and pericardial and tunica vaginalis testis malignant mesothelioma: a case-control study and epidemiological remarks. A. Marinaccio, D. Consonni, C. Mensi, et al. 2020;46(6):609-617. PubMed · Publisher · Free full text

Abstract

Objectives The purposes of this study are to describe the epidemiology of pericardial and tunica vaginalis testis mesothelioma and assess the role of asbestos exposure for these rare diseases. Methods Based on incident pericardial and tunica vaginalis testis mesothelioma cases collected from the Italian national mesothelioma registry (ReNaM) in the period 1993-2015, incidence rates, survival median period and prognostic factors have been evaluated. A case-control study has been performed to analyze the association with asbestos exposure (occupational and non-occupational) for these diseases. Results Between 1993 and 2015, 58 pericardial (20 women and 38 men) and 80 tunica vaginalis testis mesothelioma cases have been registered with a mean annual standardized (world standard population as reference) incidence rates of 0.049 (per million) in men and 0.023 in women for the pericardial site, and 0.095 for tunica vaginalis testis mesothelioma. Occupational exposure to asbestos was significantly associated with the risk of the diseases [odds ratio (OR) 3.68, 95% confidence interval (CI) 1.85-7.31 and OR 3.42, 95% CI 1.93-6.04 in pericardial and tunica vaginalis testis mesothelioma, respectively]. The median survival was 2.5 months for pericardial and 33.0 months for tunica vaginalis testis mesotheliomas. Age was the main predictive factor for survival for both anatomical sites. Conclusions For the first time in an analytical study, asbestos exposure was associated with pericardial and tunica vaginalis testis mesothelioma risk, supporting the causal role of asbestos for all anatomical sites. The extreme rarity of the diseases, the poor survival and the prognostic role of age have been confirmed based on population and nationwide mesothelioma registry data.
Cancer incidence among seafarers and fishermen in the Nordic countries. K. Ugelvig Petersen, E. Pukkala, J.I. Martinsen, et al. 2020;46(5):461-468. PubMed · Publisher · Free full text

Abstract

Objectives Maritime workers may be exposed to several occupational hazards at sea. The aim of this study was to assess cancer incidence among seafarers and fishermen in the Nordic countries and identify patterns in morbidity in the context of existing studies in this field. Methods A cohort of 81 740 male seafarers and 66 926 male fishermen was established from census data on 15 million citizens in the five Nordic countries. Using personal identity codes, information on vital status and cancer was linked to members of the cohort from the national population and cancer registries for the follow-up period 1961-2005. Standardized incidence ratios (SIR) were calculated applying national cancer incidence rates for each country and pooling results. Results The overall incidence of cancer was increased among the male seafarers [SIR 1.22, 95% confidence interval (CI) 1.19-1.23]. Significant excesses were observed for multiple cancer sites among the seafarers, while results for the fishermen were mixed. Lip cancer incidence was increased among both maritime populations. For mesothelioma (SIR 2.17, 95% CI 1.83-2.56 seafarers) and non-melanoma skin cancer (SIR 1.23, 95% CI 1.14-1.32 seafarers), incidence was increased among the seafarers. Conclusion In our cohort, seafaring was associated with a higher overall incidence of cancer compared to the general population. While the majority of cancers could not be linked to specific occupational factors, increases in mesothelioma, lip and non-melanoma-skin cancer indicate previous exposure to asbestos, ultraviolet radiation and potentially also chemicals with dermal carcinogenic properties at sea.
Not just a research method: If used with caution, can job-exposure matrices be a useful tool in the practice of occupational medicine and public health?. M. Fadel, B.A. Evanoff, J.H. Andersen, et al. 2020;46(5):552-553. Letter · Comment PubMed · Publisher · Free full text

Summary

In this letter to the editor, the authors responded to an editorial by Susan Peters that had described the strengths and limitations of job-exposure matrices (JEM) in occupational epidemiology research. They argued that JEM may also be useful in compensation and surveillance in occupational health. In compensation, JEM could support the assessment of exposures relevant to specific health conditions. They cited work examining a JEM as a decision tool for compensating work-related musculoskeletal disorders. Because occupational diseases are often under-recognized, they suggested that JEM could be used to screen for occupational exposures as part of health surveillance. They noted that using JEM to screen for asbestos and wood dust exposure in the clinical setting had shown promising results. JEM could also help policy-makers set priorities and help practitioners target prevention and exposure measurement. The authors described the JEMINI (JEM InterNatIonal) initiative, which began with physical (biomechanical) exposures and had started homogenizing job coding systems and comparing available JEM. They cautioned that estimating differences in exposure between countries would require much more work, without guaranteed success. The limitations they listed were the source of exposure data, job coding that is time-consuming and error-prone, and job-level averages that lose individual variation. They concluded that JEM cannot replace professionals in individual exposure assessment but might be used as a public health tool, provided their limitations are properly taken into account.

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2010s

Non-occupational exposure to asbestos is the main cause of malignant mesothelioma in women in North Jutland, Denmark. V. Panou, M. Vyberg, C. Meristoudis, et al. 2019;45(1):82-89. PubMed · Publisher

Abstract

Objectives Diffuse malignant mesothelioma (MM) is mainly caused by asbestos inhalation. The malignancy is rare among women and studies of the prevalence and causative role of non-occupational asbestos exposure among women with MM are scarce. This observational study aimed to elucidate the asbestos exposure patterns among women with MM. Methods All histological and cytological specimens from women diagnosed with MM between 1974-2015 at the Institute of Pathology, Aalborg University Hospital in Denmark, were re-evaluated. Occupational and habitation information were obtained from Danish registries and medical journals based on record linkage via the unique person ID. The number of MM cases in each parish in the region of North Jutland was determined and the incidence density in parishes was used to calculate the spatial relative risk (RR) of MM among women. Results Diagnosis of MM was confirmed in 91 women. Exposure types were classified as occupational (9%), domestic (10%), environmental (22%), combination of domestic and environmental (34%) and unknown (25%). Twenty continuous parishes formed a MM "hotspot" around the asbestos-consuming industries in the city of Aalborg. Of these, the maximum RR was found in a parish housing an asbestos factory [RR 10.5, 95% confidence interval (CI) 5.5-19.4, environmental exposure in particular RR 2.9, 95% CI 0.7-6.1]. Conclusion Non-occupational asbestos exposure is the main cause of MM and may account for up to 66% of MM cases among women in North Jutland, Denmark.
Proportion of mesothelioma attributable to living in industrially contaminated areas in Italy. R. Pasetto, A. Zona, L. Fazzo, et al. 2019;45(5):444-449. PubMed · Publisher

Abstract

Objectives The aim of this study was to estimate the attributable proportion (AP) of mesothelioma resulting from living in or close to major Italian industrially contaminated areas. Methods For populations living close to 39 sites of "national priority for remediation", incident mesothelioma cases were extracted from the Italian National Mesothelioma Registry (ReNaM) in the period 2000‒2011. Each site was classified in one of seven asbestos risk groups (RG) on the basis of the type of industrial plants. RG were ranked by the a priori evidence on asbestos risk. The AP for each RG was calculated as the meta-analytic estimate of AP of sites of the same group by gender and age class (0-64, 65-74, ≥75 years). The sex ratio (men/women) was computed for each RG. Results Among men, the AP by age class had the same gradient in each RG, with the highest values in the age class 0-64 years and the lowest in the ≥75 class; in the age class 0-64 years, the AP was positive in each RG, >90% in the presence of asbestos cement factories and harbors with shipyards. Among women, the overall AP decreased by RG, with negative values in the last two ranked RG; the AP by age class was variable without a definite gradient. The sex ratio was close to one only in the RG "only asbestos-cement factories"; the highest value (9.6) was observed in the age class 0-64 years in the RG "harbors with shipyard". Conclusions The integration of a geographic- and case-based approach provides valuable insights into occupational and environmental determinants of mesothelioma risk in industrially contaminated sites.
DNA damage and genomic instability among workers formerly and currently exposed to asbestos. M. Milić, M. Neri, M. Ceppi, et al. 2018;44(4):423-431. PubMed · Publisher

Abstract

Objectives Despite an asbestos ban in the European Union, exposure to asbestos still represents an occupational risk. Biomarkers of DNA damage and genomic instability in groups exposed to asbestos may contribute to the identification of subgroups/subjects at higher risk. Methods A cross-sectional study was conducted on 468 male individuals (80 working in occupational settings with potential exposure to asbestos fibers, 202 retired workers with past exposure, and 186 non-exposed controls) to compare genomic instability, cell proliferation and differentiation level using the non-invasive micronucleus buccal cytome assay. Data on demographic variables, lifestyle, and occupational history were collected with a standardized questionnaire. Micronuclei (MN) and other biomarkers of DNA damage and genomic instability were scored in a minimum of 2000/1000 cells per individual, respectively. Results Univariate and multivariate analysis showed opposite associations of MN frequency with current and former exposure. Compared to unexposed controls, workers with current potential exposure to asbestos had 55% lower MN frequency [95% confidence interval (CI) 71-29%, P<0.001] while those with past exposure had 34% higher MN frequency (95% CI 1-77%, P<0.001). The frequency of cells with condensed chromatin and binucleated cells was elevated among formerly exposed workers. The multivariate analysis did not reveal any actual confounders, although lower MN frequency was observed among subjects eating fresh fruit or vegetables every day or taking vitamin supplements. Conclusions Active workers with potential exposure to asbestos fibers did not show increased genomic damage. On the contrary, workers exposed in the past experienced a persistently elevated genomic instability, which may be used for risk assessment at subgroup or individual level.
Mesothelioma incidence and asbestos exposure in Italian national priority contaminated sites. A. Binazzi, A. Marinaccio, M. Corfiati, et al. 2017;43(6):550-559. PubMed · Publisher

Abstract

Objectives This study aimed to (i) describe mesothelioma incidence in the Italian national priority contaminated sites (NPCS) on the basis of data available from the Italian National Mesothelioma Registry (ReNaM) and (ii) profile NPCS using Bayesian rank analysis. Methods Incident cases of mesothelioma and standardized incidence ratios (SIR) were estimated for both genders in each of the 39 selected NPCS in the period 2000-2011. Age-standardized rates of Italian geographical macro areas were used to estimate expected cases. Rankings of areas were produced by a hierarchical Bayesian model. Asbestos exposure modalities were discussed for each site. Results In the study period, 2683 incident cases of mesothelioma (1998 men, 685 women) were recorded. An excess of mesothelioma incidence was confirmed in sites with a known past history of direct use of asbestos (among men) such as Balangero (SIR 197.1, 95% CI 82.0-473.6), Casale Monferrato (SIR 910.7, 95% CI 816.5-1012.8), and Broni (SIR 1288.5, 95% CI 981.9-1691.0), in sites with shipyards and harbors (eg, Trieste, La Spezia, Venice, and Leghorn), and in settings without documented direct use of asbestos. The analysis ranked the sites of Broni and Casale Monferrato (both genders) and Biancavilla (only for women) the highest. Conclusions The present study confirms that asbestos pollution is a risk for people living in polluted areas, due to not only occupational exposure in industrial settings with direct use of asbestos but also the presence of asbestos in the environment. Epidemiological surveillance of asbestos-related diseases is a fundamental tool for monitoring the health profile in NPCS.
Asbestos in toys: an exemplary case. S. Silvestri, F. Di Benedetto, C. Raffaell, et al. 2016;42(1):80-5. Historical article PubMed · Publisher

Abstract

Objectives: DAS was an artificial clay which, once molded, hardened at room temperature. It was largely used as a toy between 1963 and 1975 in Italy, Netherlands, Germany, UK and Norway. This case report describes and reports the presence of asbestos in DAS.

Methods: We investigated the presence of asbestos in DAS using light and electron microscopy on samples of the original material. We searched administrative documents at the State Archive of Turin and conducted interviews with past employees on annual production, suppliers, and purchasers.

Results: The analytical tests confirmed the presence of asbestos fibers in DAS: about 30% of its composition. The documents found at the State Archive confirmed the annual purchase of hundreds tons of raw asbestos from the Amiantifera di Balangero, the Italian asbestos mine. DAS was found to be used also within craftsmanship.

Conclusions: Asbestos fibers in DAS may have caused exposure to production workers and a variety of users, including artists, teachers, and children. Over 13 years, about 55 million packs of DAS were produced and sold. The number of users is difficult to estimate but may have been in the order of millions. In Italy, a specific question on the use of DAS has been included in a routinely used mesothelioma questionnaire. As DAS was exported to other countries, our findings suggest that mesothelioma patients should be asked about their past use of DAS, in particular individuals not reporting a clear past asbestos exposure. Additionally, this discovery shows the incompleteness of records on asbestos uses and suggests to test items, including toys, imported from countries where asbestos is not forbidden.
Collegium Ramazzini response to 'Asbestos, asbestosis, and cancer, the Helsinki criteria for diagnosis and attribution 2014: recommendations'. Collegium Ramazzini. 2016;42(1):91-4. Letter · Comment PubMed · Publisher
Response by the organizers of the Helsinki criteria updates 2014: Criteria for asbestos-related diseases need periodic updates. H. Wolff, T. Vehmas, P. Oksa, et al. 2016;42(1):95-6. Letter · Comment PubMed · Publisher
The 18th Collegium Ramazzini statement: The global health dimensions of asbestos and asbestos-related diseases. Collegium Ramazzini. 2016;42(1):86-90. PubMed · Publisher

Abstract

The Collegium Ramazzini reaffirms its long-standing position that responsible public health action is to ban all extraction and use of asbestos, including chrysotile. This current statement updates the Collegium's earlier statements with a focus on global health dimensions of asbestos and asbestos-related diseases (ARD). The ARD epidemic will likely not peak for at least a decade in most industrialized countries and for several decades in industrializing countries. Asbestos and ARD will continue to present challenges in the arena of occupational medicine and public health, as well as in clinical research and practice, and have thus emerged as a global health issue. Industrialized countries that have already gone through the transition to an asbestos ban have learned lessons and acquired know-how and capacity that could be of great value if deployed in industrializing countries embarking on the transition. The accumulated wealth of experience and technologies in industrialized countries should thus be shared internationally through global campaigns to eliminate ARD.
The 2-phase case-control design: an efficient way to use expert-time. P. Wild, W. Schill, E. Bourgkard, et al. 2016;42(2):162-9. PubMed · Publisher

Abstract

Objectives: The objective of this paper is to show the benefits of using a 2-phase case-control (2PCC) design in identifying dose-response relationships between cumulative occupational exposure as assessed by experts and lung cancer incidence in an actual study.

Methods: A population-based case-control study including 246 cases and 531 controls was conducted in an area with high lung cancer rates in Northeast France. Detailed occupational and personal risk factors were obtained in face-to-face interviews. Cumulative expert-based exposure scores were obtained from a subset of 215 cases and 269 controls stratified on smoking and a prior algorithmic exposure score for asbestos, crystalline silica, and polycyclic aromatic hydrocarbons (PAH) in the framework of a 2PCC design. This subset deliberately under-sampled large strata among controls but not among cases. Logistic regression models adapted to 2PCC studies were applied and corresponding computations of attributable fractions and their confidence intervals developed.

Results: Based on this 2PCC design, statistically significant dose-response relationships were obtained for asbestos, crystalline silica, PAH, and diesel motor exhaust. Simulations within this study showed that 2PCC studies were always more powerful than random samples.

Conclusion: The 2PCC design may be the design of choice when resources allow only a limited number of subjects with a full expert-based exposure assessment.
Asbestos, asbestosis, and cancer, the Helsinki criteria for diagnosis and attribution 2014: recommendations. H. Wolff, T. Vehmas, P. Oksa, et al. 2015;41(1):5-15. Consensus statement · Guideline PubMed · Publisher
Eligibility for low-dose computerized tomography screening among asbestos-exposed individuals. N.R. Fitzgerald, W.M. Flanagan, W.K. Evans, et al. 2015;41(4):407-12. PubMed · Publisher

Abstract

Objectives: The study aimed to incorporate an estimate of risk for asbestos exposure in the Canadian Cancer Risk Management Lung Cancer (CRMM-LC) microsimulation model.

Methods: In CRMM-LC, a 3-year probability of developing lung cancer can be derived from different risk profiles. An asbestos-exposed cohort was simulated and different scenarios of low-dose computerized tomography (LDCT) screening were simulated.

Results: As annual LDCT screening among non-asbestos-exposed individuals is less cost-effective than biennial screening, all the scenarios modeled for an asbestos-exposed cohort were biennial. For individuals with a two-fold risk of asbestos-induced lung cancer to be eligible for biennial LDCT screening, a smoking history of ≥15 pack-years would be necessary. For non-smokers with asbestos exposure resulting in a relative risk (RR) for lung cancer, it is not cost-effective to screen those with a RR of 5, but it is cost-effective to screen those with a RR of 10 (the heavily exposed).

Conclusion: Asbestos-exposed individuals with an estimated two-fold or more risk of lung cancer from asbestos-exposure are eligible for LDCT screening at all ages from 55-74 years if they have a cigarette smoking history of ≥15 pack-years. Asbestos-exposed individuals who are lifelong non-smokers are eligible for LDCT screening at all ages from 55-74 years if they have accumulated a degree of asbestos exposure resulting in an estimated risk of lung cancer of ≥10.
Epidemics of asbestos-related diseases--something old, something new. H. Vainio. 2015;41(1):1-4. Editorial · Comment PubMed · Publisher
Re: Fitzgerald et al. "Eligibility for low-dose computerized tomography screening among asbestos-exposed individuals". A. Descatha, S. Ollivier, T. Despreaux. 2015;41(4):417-8. Letter · Comment PubMed · Publisher
Occupational asbestos exposure and risk of oral cavity and pharyngeal cancer in the prospective Netherlands Cohort Study. N.S. Offermans, R. Vermeulen, A. Burdorf, et al. 2014;40(4):420-7. PubMed · Publisher

Abstract

Objectives: The evidence for an association between occupational asbestos exposure and pharyngeal cancer (PhC) is limited, while for oral cavity cancer (OCC) the literature is even sparser. We studied OCC and PhC risk both separately and combined (OCPC) in relation to occupational asbestos exposure, specifically addressing the influence of potential confounders, the existence of an exposure-response relation, and the presence of interaction between asbestos and smoking.

Methods: Using the prospective Netherlands Cohort Study (N=58 279 men, aged 55-69 years), we estimated asbestos exposure by linkage to a general population job-exposure matrix (DOMJEM) and a Finnish job exposure matrix (FINJEM). After 17.3 years of follow-up, 58 OCC and 53 PhC cases were available for analysis.

Results: No association between asbestos and risk of OCC was observed for either JEM. Hazard ratios (HR) of PhC and OCPC increased after adjusting for confounders, particularly alcohol consumption and socioeconomic status. For PhC, a multivariable-adjusted increased HR was observed for "ever" versus "never" exposed to asbestos [HR 2.20, 95% confidence interval (95% CI) 1.08-4.49] when using FINJEM, but a trend of increased risks with higher cumulative exposure could not be demonstrated for either JEM. Results for OCPC showed patterns similar to those observed for PhC. None of the cancers showed a significant interaction between asbestos and smoking.

Conclusions: This prospective population-based study showed no convincing evidence of an association between asbestos and risk of OCC, PhC, and OCPC as an exposure-response relation was lacking, and results were not robust against the use of different JEM. However, the potentially increased HR of PhC and OCPC observed in this and previous studies warrant further research.
Mortality attributable to occupational exposure in Sweden. B. Järvholm, C. Reuterwall, J. Bystedt. 2013;39(1):106-11. PubMed · Publisher

Abstract

Objectives: The objective of this study was to estimate the mortality from cancer, cardiovascular, and respiratory diseases attributable to occupational exposure in Sweden.

Methods: Estimates were calculated for men and women separately, and we considered only deaths between 25-74 years of age. We considered cancer exposures/sites classified as I or 2a according to the International Agency for Research on Cancer (IARC). Acute myocardial infarction was the only included cardiovascular disease. Respiratory diseases comprised chronic obstructive pulmonary disease (COPD) asthma, pneumoconiosis and alveolitis. All deaths of pneumoconiosis and alveolitis were considered work-related. Estimates were based on the Swedish mortality in 2007.

Results: In total, we estimate that there are about 800 work-related deaths per year in the studied causes. The majority are due to acute myocardial infarction, with 126 deaths among women and 337 deaths among men attributable to job strain, shift work, exhaust gases, combustion products, or environmental tobacco smoke (ETS). There are 99 respiratory disease-related deaths, the vast majority from COPD (N=92). In total, 270 cancer deaths are estimated to be work-related. For men, half of the cases are attributed to asbestos exposure.

Conclusions: Our results indicate that preventive measures to decrease occupational mortality should consider factors associated with myocardial infarction such as job strain, shift work and exhaust gases from vehicles and combustion products. Exposures to factors associated with COPD, such as dust, also seem important to prevent.

2000s

Exposure to iron and welding fumes and the risk of lung cancer. S.S. Siew, T. Kauppinen, P. Kyyrönen, et al. 2008;34(6):444-50. PubMed · Publisher

Abstract

Objectives: Exposure to iron fumes and dust and welding fumes is widespread and may increase the risk of lung cancer. The aim of this study was to identify associations between exposure to iron and welding fumes and the incidence of lung cancer among Finnish men.

Methods: The cohort of all economically active Finnish men, born in 1906-1945, who participated in the national census in 1970 was followed through the Finnish Cancer Registry for lung cancer cases (N=30,137) during 1971-1995. Their census occupations in 1970 were converted to estimates of cumulative exposure to iron and welding fumes with the Finnish job-exposure matrix on the basis of likelihood, average level, and estimated duration of exposure. Relative risk estimates for categorized cumulative exposure were defined by a Poisson regression, adjusted for smoking, socioeconomic status, and exposure to asbestos and silica dust.

Results: The relative risks for lung cancer increased as the cumulative exposure to iron and welding fumes increased. Relative risks in the highest exposure category was 1.35 [95% confidence interval (95% CI) 1.05-1.73] for iron and 1.15 (95% CI 0.90-1.46) for welding fumes. The respective relative risks estimated for squamous-cell carcinoma of the lungs were 1.94 (95% CI 1.35-2.78) and 1.55 (95% CI 1.08-2.24). There was no excess risk of small-cell carcinoma in any exposure category.

Conclusions: Occupational exposure to iron and welding fumes was associated with an increase in lung cancer risk, mainly that of squamous-cell carcinoma. The simultaneous exposure to both of these agents and other potential work-related carcinogens complicates the interpretation of the independent roles of the risk factors.
Incidence trends and gender differences in malignant mesothelioma in New South Wales, Australia. R.A. Hyland, S. Ware, A.R. Johnson, et al. 2007;33(4):286-92. PubMed · Publisher

Abstract

Objectives: Features of malignant mesothelioma reportedly differ between men and women, including occupational asbestos exposure, histological subtype, and median survival. In this study, incidence trends and clinical features for malignant mesothelioma were compared between genders in New South Wales (NSW), where notification of malignant mesothelioma to the Central Cancer Registry is a statutory requirement.

Methods: Notifications to the Central Cancer Registry were compared with those to the registry of the NSW Workers' Compensation (Dust Diseases) Board. The latter includes occupational and clinical data.

Results: Of the 3090 cases of malignant mesothelioma reported to the Central Cancer Registry between 1972 and 2004, 456 (15%) were female. Altogether 1995 malignant mesotheliomas were compensated between 1969 and 2004, of which 105 (5%) occurred among women. The incidence increased for both genders by approximately 15-fold. Median survival was similar for the men and women for all of the cases (7 versus 6 months), but was better among the women who received compensation (8.5 versus 10.4 months, P<0.0001). The mean disease latency (42.8 years) increased over the study period (P<0.001).

Conclusions: In New South Wales over the last 30 years, the total number of malignant mesotheliomas and the number of compensated cases of malignant mesothelioma have risen for both genders. The mean latency is increasing, and increasing numbers of "nonoccupational" cases are being reported. Survival remains poor.
Risk of lung cancer according to mild steel and stainless steel welding. A.R. Sørensen, A.M. Thulstrup, J. Hansen, et al. 2007;33(5):379-86. PubMed · Publisher

Abstract

Objectives: Whether the elevated risk of lung cancer observed among welders is caused by welding emissions or by confounding from smoking or asbestos exposure is still not resolved. This question was addressed in a cohort with a long follow-up and quantified estimates of individual exposure to welding fume particulates.

Methods: Male metal workers employed at least 1 year at one or more Danish stainless or mild steel industrial companies from 1964 through 1984 were enrolled in a cohort. Data on occupational and smoking history were obtained by questionnaire in 1986. Welders in the cohort who started welding in 1960 or later (N=4539) were followed from April 1968 until December 2003, when information on cancer diagnosis was obtained from the Danish Cancer Registry. During the follow-up, 75 cases of primary lung cancer were identified. Lifetime accumulated exposure to welding fume particulates was estimated by combining questionnaire information and more than 1000 welding-process-specific measurements of fume particulates in the Danish welding industry.

Results: The standardized incidence ratio (SIR) for lung cancer was increased among the welders [SIR 1.35, 95% confidence interval (95% CI) 1.06-1.70)]. Among the stainless steel welders, the risk increased significantly with increasing accumulative welding particulate exposure, while no exposure-response relation was found for mild steel welders, even after adjustment for tobacco smoking and asbestos exposure.

Conclusions: The study corroborates earlier findings that welders have an increased risk of lung cancer. While exposure-response relations indicate carcinogenic effects related to stainless steel welding, it is still unresolved whether the mild steel welding process carries a carcinogenic risk.
Imputation of individual cancer cases to occupational causes. S. Vandentorren, L.R. Salmi, S. Mathoulin-Pélissier, et al. 2006;32(1):32-40. Case report PubMed · Publisher

Abstract

Objectives: Many potential occupational causes of cancer have been documented. Imputation of an individual cancer to occupational or other causes is, however, difficult. A method based on the Bayes theorem is proposed for assessing causal relationships at the individual level.

Methods: Causality assessment, dealing with four types of persons defined by exposure and the occurrence of cancer, was linked with imputation, only dealing with persons who have cancer and were exposed. Imputation was then formulated using the Bayes theorem, relating epidemiologic information regarding causes, a patient's exposure history, and the posterior odds that the cancer was caused by a suspected occupational exposure. Data needed to apply a Bayesian method were defined in terms of relative risks, proportion of people exposed in populations, and the frequency of a positive relevant characteristic for persons without cancer. A relevant characteristic was defined using a formal consensus between experts. The method was then illustrated with cases of mesothelioma and lung cancer in possible relation to asbestos.

Results: Experts defined the relevant characteristics as being qualification of occupational exposure, intensity of exposure, latency, disease characteristics, and presence of causal agent in the body. Application to mesothelioma and lung cancer cases illustrated the potential usefulness of the method.

Conclusions: The importance of occupational exposure in the formulation of imputation underscores the need for available and reliable data sources on occupational exposures. The proposed method could become a powerful tool for the expert assessment of causes of cancer cases, provided data become available in individual files and the literature.
Occupational exposures and head and neck cancers among Swedish construction workers. M.P. Purdue, B. Järvholm, I.A. Bergdahl, et al. 2006;32(4):270-5. PubMed · Publisher

Abstract

Objectives: Occupational exposures in the construction industry may increase the risk of head and neck cancers, although the epidemiologic evidence is limited by problems of low study power and inadequate adjustment for tobacco use. In an attempt to address this issue, the relationship between selected occupational exposures and head and neck cancer risk was investigated using data from a large cohort of Swedish construction workers.

Methods: Altogether 510 squamous cell carcinomas of the head and neck (171 in the oral cavity, 112 in the pharynx, 227 in the larynx) were identified during 1971-2001 among 307 799 male workers in the Swedish construction industry. Exposure to diesel exhaust, asbestos, organic solvents, metal dust, asphalt, wood dust, stone dust, mineral wool, and cement dust was assessed using a semi-quantitative job-exposure matrix. Rate ratios (RR) and 95% confidence intervals (95% CI) were calculated for head and neck cancers in relation to occupational exposure, using Poisson regression with adjustment for age and smoking status.

Results: Asbestos exposure was related to an increased laryngeal cancer incidence (RR 1.9, 95% CI 1.2-3.1). Excesses of pharyngeal cancer were observed among workers exposed to cement dust (RR 1.9, 95% CI 1.2-3.1). No occupational exposures were associated with oral cavity cancer. These findings did not materially change upon additional adjustment for cigarette pack-years.

Conclusions: These findings offer further evidence that asbestos increases the risk of laryngeal cancer. The observation of a positive association between cement dust exposure and pharyngeal cancer warrants further investigation.
Update of a meta-analysis on lung cancer and welding. D. Ambroise, P. Wild, J.J. Moulin. 2006;32(1):22-31. Meta-analysis PubMed · Publisher

Abstract

Objectives: This study is an update, over the period 1954-2004, of a previous meta-analysis completed in 1994. It was aimed at assessing lung cancer risk among welders, while addressing heterogeneity, publication bias, and confounding issues.

Methods: Combined relative risks (CRR) and their variances were calculated using fixed and random effects models. Heterogeneity was tested using the Q statistic. The publication bias was estimated using funnel plots, and Egger's regression and partially controlled by excluding studies with positive reporting bias.

Results: The literature provided 60 studies eligible for the meta-analysis. No heterogeneity was observed. The fixed effect CRR for all of the welders and all of the studies was 1.26 (95% CI 1.20-1.32) after partial control of publication bias. No difference was observed according to welding activities. Smoking did not appear to be a marked confounder in the relationship between lung cancer and welding, but the effect of asbestos could not be assessed.

Conclusions: The meta-analysis showed a 26% excess of lung cancer for welders without any difference according to welding activities.
Asbestos hazard in the Swedish construction industry--recent trends in mesothelioma incidence. G. Engholm, A. Englund. 2005;31 Suppl 2:27-30. PubMed

Abstract

Objectives: The aim of this study was to analyze the incidence of pleural tumors among various categories of Swedish construction workers and to determine to what extent its change over time differs from that of the general male population.

Methods: Traditional methods have been used to study cancer incidence through 1998 in a cohort comprising 370 165 male workers examined in 1971-1992 by Bygghälsan, an organization at the time providing nationwide occupational health service. Incidence was assessed by linkage to the national cancer register.

Results: Swedish construction workers, particularly those heavily exposed to asbestos, had an excess incidence of pleural tumors in 1975-1998 [standardized incidence ratio (SIR) 3.16, 95% confidence interval (95% CI) 2.55-3.88]. The excess declined with subsequent follow-up periods and birth cohorts with the exception of the most recent period (SIR 3.83, 95% CI 2.64-5.38) and those borne in the 1930s.

Conclusions: A possible decline in pleural tumors among men following the cessation of asbestos use 25 years earlier in the population at large may not be applicable to an end-user sector like construction work. In occupations charged with repairing and refurbishing work, there may even have been an increase lately.
Impairment of lung function in asbestos-exposed workers in relation to high-resolution computed tomography. P. Piirilä, M. Lindqvist, O. Huuskonen, et al. 2005;31(1):44-51. PubMed · Publisher

Abstract

Objectives: The aim of the study was to determine the causes of impairment of ventilatory function and diffusing capacity in smoking asbestos-exposed workers (N=590) showing radiological pleural thickenings or pulmonary fibrosis.

Methods: High-resolution computed tomography (HRCT) and spirometry were performed, and diffusing capacity was measured. The workers were divided into five groups based on the HRCT scoring: pleural disease (N=190), pulmonary fibrosis (N=68), emphysema (N=148), combined fibrosis and emphysema (N=74), and marked adhesions (N=110). The graded lung function impairment was compared between the groups.

Results: Moderate impairment of forced expiratory volume in 1 second [odds ratio (OR) 2.72, 95% confidence interval (95% CI) 1.31-5.57] and forced vital capacity (OR 2.81, 95% CI 1.05-6.89) was associated with the persons with combined fibrosis and emphysema. Marked impairment of diffusing capacity was associated with the combined fibrosis and emphysema (OR 4.94, 95% CI 2.48-9.77) but not with pleural disease (OR 0.21, 95% CI 0.09-0.45) or pulmonary fibrosis (OR 0.36, 95% CI 0.08-1.05). For the persons with combined fibrosis and emphysema, the mean fibrosis score did not differ between normal, slightly reduced, or markedly reduced diffusing capacity, but the emphysema score was significantly higher for the patients with marked impairment than for those with normal diffusing capacity (P < 0.01).

Conclusions: Different profiles of asbestos- and smoking-induced pulmonary or pleural disease were found. The results indicate that the most important factor determining the degree of functional impairment in smoking asbestos-exposed workers is the presence of pulmonary emphysema.
National job-exposure matrix in analyses of census-based estimates of occupational cancer risk. E. Pukkala, J. Guo, P. Kyyrönen, et al. 2005;31(2):97-107. PubMed · Publisher

Abstract

Objectives: The aim of this study was to increase the understanding of the alternative exposure metrics and analysis methods in studies applying job-exposure matrices in analyses of health outcomes, the association between crystalline silica and cancer being used as an example.

Methods: Observed and expected numbers of cancer cases during 1971-1995 among Finns born in 1906-1945 were calculated for 393 occupational categories, as defined in the 1970 population census. According to the Finnish Cancer Registry, there were 43 433 lung and 21 444 prostate cancer cases. The Finnish job-exposure matrix (FINJEM) provided estimates of the proportion of exposed persons and the mean level of exposure among the exposed in each occupation.

Results: The most comprehensive exposure metric included period- and age-specific estimates of exposure and an estimate of occupational stability, but also remarkably simpler metrics gave significantly elevated estimates of the risk ratio (RR) between 1.36 and 1.50 for lung cancer for occupations with the highest estimated cumulative silica exposure (> or = 10 mg/m3-years), allowing a lag time of 20 years. It proved important to adjust the risk ratios at least for the socioeconomic status and occupational exposure to asbestos. The risk ratios for prostate cancer were close to 1.0 in every model.

Conclusions: The results showed that the FINJEM-based analysis was able to replicate the well-known association between exposure to crystalline silica and lung cancer. The FINJEM-based method gives valid results, and it can be used to analyze large sets of register-based data on health outcomes.
Pleuropulmonary lesions, ergotamines and asbestos exposure. G. Hillerdal, A. Rask-Andersen. 2005;31(6):459-64. PubMed · Publisher

Abstract

Objectives: This study investigated the possibility of pleuropulmonary lesions, which can occur as rare but serious side effects of different ergot drugs, occurring more commonly in persons earlier exposed to asbestos.

Methods: All reports of pleuropulmonary side effects of the ergot drugs used in Sweden in the Swedish side effect registry from 1985 to 2003 were studied. In addition, the literature was reviewed.

Results: In the registry, 47 men and 3 women were found. Of the men, 24 were exposed to asbestos, and 2 denied such exposure; 2 of the 3 women were exposed. In the literature, 111 patients were found--32 had confirmed exposure and 15 denied it. For most of the patients, it was not possible to determine exposure.

Conclusions: Enough evidence exists to postulate that earlier asbestos exposure in combination with the intake of ergot drugs can cause pleuropulmonary lesions.
Cancer mortality and morbidity among Lithuanian asbestos-cement producing workers. G. Smailyte, J. Kurtinaitis, A. Andersen. 2004;30(1):64-70. PubMed · Publisher

Abstract

Objectives: This study investigated the incidence of cancer and cause-specific mortality among workers in the two Lithuanian asbestos-cement factories.

Methods: The study included 1887 asbestos-cement workers, 1285 men and 602 women, and 37000 person-years. The two factories were active from 1956 (A) and 1963 (B), and the workers were observed from 1978 to 2000. The analysis was based on a comparison between the observed and expected numbers of cancer and causes of death. The observed numbers of cancer were obtained through linkage with the national cancer registry. The date and causes of death were obtained from two different sources. The expected numbers were calculated on the basis of gender- and age-specific incidence and mortality rates in 5-year periods from the whole country. Standardized incidence ratios (SIR) and standardized mortality ratios (SMR) and 95% confidence intervals (95% CI) were calculated. Duration of employment and time since first exposure were used as indicators of exposure.

Results: During the follow-up, 1978-2000. 473 deaths were observed versus 489 expected. There was no excess risk of deaths from nonmalignant respiratory diseases, except for an elevated risk of mortality in relation to the digestive organs other than cancer, 18 observed versus 12.2 expected (95% CI 0.9-2.3). There was no excess risk for any types of cancer, except for colorectal cancer in men, 17 observed cases (SIR 1.6, 95% CI 1.6-2.6) and one case of mesothelioma in a woman.

Conclusions: This study on asbestos-exposed workers did not show any excess risk of respiratory cancer or deaths of pneumoconiosis.
Electromagnetic fields and health effects--epidemiologic studies of cancer, diseases of the central nervous system and arrhythmia-related heart disease. C. Johansen. 2004;30 Suppl 1:1-30. Review PubMed

Abstract

This epidemiologic investigation comprised separate studies of the risk of cancer, cause-specific mortality rates, risks for neurodegenerative diseases, and the risk of arrhythmia-related heart disease among employees exposed to extremely low-frequency (50-Hz) electromagnetic fields (EMF) in the Danish utility industry. All the employees in this industry were followed-up in several registers. The risk of disease was analyzed in relation to occupational exposure to EMF, latency, and duration of employment. A specific job-exposure matrix was developed and validated by comparison with direct measurements of EMF during a workday. Linkage with the Danish Cancer Register did not identify increased risks for the cancers suggested a priori to be associated with exposure to EMF, including leukemia, brain tumors, and breast cancer. Significantly increased risks for lung cancer and mesothelioma were identified for workers highly exposed to asbestos. Linkage with the National Mortality Register revealed a significantly increased overall mortality rate from amyotrophic lateral sclerosis (ALS), with an increasing trend with duration of employment and EMF exposure. In addition, a significantly increased mortality rate from electric accidents was observed. It was hypothesized that the observation of increased mortality from ALS was associated with exposure to EMF or electric shocks. No increased mortality rate from cardiovascular or cerebrovascular disease was observed. Linkage with the National Hospital Register also revealed an increased risk of ALS and, thereby confirmed the finding of an increased mortality rate for this disease in the previous study. Linkage of the cohort with the Multiple Sclerosis Register revealed an increased risk of multiple sclerosis, which was not, however, significant. Linkage with the Pacemaker Register showed no increased risk of severe arrhythmia-related heart disease. The second part of the study included the establishment of a large, nationwide cohort of mobile phone subscribers comprising some 420 000 persons. No increased risk was observed for the cancers considered a priori to be possibly associated with the radiofrequency fields emitted by mobile phones, which were brain tumors, including acoustic neuroma, salivary gland tumors, and leukemia. The data were analyzed by duration of phone use, latency, system used (NMT, GSM or both) and age at first subscription. A study of the incidence of ocular malignant melanoma in comparison with the annual increase among the mobile phone subscribers showed a highly stable incidence rate for this rare cancer in Denmark over close to 50 years of registration. On the basis of these studies and the scientific literature, it is concluded that occupational exposure to 50-Hz EMF is not associated with an increased risk of cancer, but that these fields, electric shocks, or some other unknown factor related to alternating current electricity may be associated with the risk of ALS. There is no clear evidence that 50-Hz EMF is associated with other neurodegenerative or cardiovascular diseases. At present, there is little, if any, evidence that the use of mobile phones is associated with cancer in adults, including brain tumors, acoustic neuroma, cancer of the salivary glands, leukemia, or malignant melanoma of the eye.
Factors associated with early-stage pulmonary fibrosis as determined by high-resolution computed tomography among persons occupationally exposed to asbestos. C. Paris, J. Benichou, C. Raffaelli, et al. 2004;30(3):206-14. PubMed · Publisher

Abstract

Objectives: Asbestosis remains difficult to diagnose, particularly in its early stages. The aim of this study was to determine criteria for independently associated features of pulmonary fibrosis in high-resolution computed tomograms among persons occupationally exposed to asbestos.

Methods: Retired persons with documented occupational asbestos exposure and no known asbestos-related diseases were assessed for occupational, clinical, functional respiratory, and chest X-ray criteria. In addition, they all underwent high-resolution computed tomography (HRCT) in the prone position.

Results: Altogether 51 (7.2%) of the 706 enrolled participants had features of pulmonary fibrosis consistent with asbestosis in the HRCT. Among those with small irregular opacities of <1/0 according to the 1980 International Labour Office Classification (ILO-C) in their X-rays, 5% had asbestosis in the HRCT. In a multivariate analysis, only age [odds ratio (OR) per year 1.08, 95% confidence interval (95% CI) 1.02-1.14], cumulative-exposure index (CEI) for asbestos (OR 6.4, 95% CI 1.5-28.4 for a CEI of > or =100 fibers/ml x years), and the presence of small irregular X-ray opacities of > or =1/0 ILO-C (OR 3.0, 95% CI 1.6-6.0) were independently associated with HRCT asbestosis. No combinations of these criteria simultaneously yielded high sensitivity and specificity for the diagnosis of early-stage HRCT asbestosis. Moreover, only 2% of the persons with a CEI of <25 fibers/ml x years had HRCT asbestosis, the finding confirming the low incidence of asbestosis for such low exposure, as previously reported on the basis of X-ray data.

Conclusions: Additional research is needed to better identify the persons most likely to benefit from HRCT screening for asbestosis.
Ovarian cancer and occupational exposure among pulp and paper employees in Norway. H. Langseth, K. Kjaerheim. 2004;30(5):356-61. PubMed

Abstract

Objectives: A cohort study of female pulp and paper workers in Norway has shown a significantly increased risk of ovarian cancer. Other than the involvement of hormonal and reproductive factors, little is known of the etiology of ovarian cancer. Asbestos and talc are two agents hypothesized to influence the development of the disease. The present study aimed to investigate the association between ovarian cancer and occupational exposure to asbestos, talc, and total dust among Norwegian pulp and paper workers.

Methods: Forty-six cases of ovarian cancer, with four controls each, were included in the study. Occupational exposure was assessed by combining work histories from personnel files, questionnaire information about production processes, and exposure assessments from the mills. To obtain information about possible confounders, cases and controls were invited to participate in a personal interview.

Results: The odds ratio for asbestos exposure was 2.02, 95% confidence interval 0.72-5.66. For talc exposure, the odds ratio was 1.10, and for ever exposure to total dust, it was below 1.00. The risk estimates did not essentially differ after adjustment for possible confounding variables.

Conclusions: The results do not confirm an association between exposure to asbestos, talc, and total dust and ovarian cancer among Norwegian pulp and paper workers. However, the odds ratio for asbestos exposure was doubled, and control for established nonoccupational risk factors did not change the estimate. Therefore, the possibility that exposure to substances in the work environment contributes to the elevated risk cannot be rejected.
Diffuse pleural fibrosis--an unreliable indicator of heavy asbestos exposure?. K.A. Smith, L.J. Sykes, C.R. McGavin. 2003;29(1):60-3. PubMed · Publisher

Abstract

Objectives: This study aimed at testing the hypothesis that diffuse pleural fibrosis is associated with a heavier exposure to asbestos than that of benign pleural plaques, and hence diffuse pleural fibrosis can be used as a marker of heavy exposure.

Methods: Asbestos burden was estimated for 192 naval dockyard workers (96 with diffuse pleural fibrosis, 96 with plaques) by calculating the exposure ratings from the trade and the years spent in that trade. In 53 cases the diffuse pleural fibrosis was bilateral.

Results: No difference was found in the mean estimated asbestos burden between all diffuse pleural fibrosis and plaques, nor between plaques and unilateral and bilateral diffuse pleural fibrosis, analyzed separately by a one-factor analysis of variance. The mean asbestos burden was significantly greater for bilateral than for unilateral diffuse pleural fibrosis. A wide spread of asbestos exposure was noted among the men with diffuse pleural fibrosis.

Conclusions: Diffuse pleural fibrosis may arise after widely varying exposure to asbestos. The mean exposure ratings for diffuse pleural fibrosis do not differ from those for pleural plaques, although the ratings are significantly higher for men with bilateral diffuse pleural fibrosis than for those with unilateral diffuse pleural fibrosis. Diffuse pleural fibrosis cannot be used as a reliable marker of heavy asbestos exposure.
Incidence of cancer among the participants of the Finnish Asbestos Screening Campaign. K. Koskinen, E. Pukkala, K. Reijula, et al. 2003;29(1):64-70. PubMed · Publisher

Abstract

Objectives: Cancer risk has been estimated for asbestos production workers or other heavily exposed asbestos workers in numerous studies. The bulk of the asbestos epidemic results come, however, from past intermittent exposures during asbestos product use. This study concentrated on estimating the risk of cancer in such a population.

Methods: Altogether 23285 men and 930 women invited to a nationwide screening campaign for benign asbestos-related diseases in 1990-1992 were followed for cancer through the Finnish Cancer Register up to 1998. Standardized incidence ratios (SIR) were calculated in comparison with the total Finnish population.

Results: Altogether 1392 cases of cancer were found among the men. The risk was slightly, but significantly elevated for lung cancer [SIR 1.14, 95% confidence interval (95% CI) 1.01-1.26), mesothelioma (SIR 2.77, 95% CI 1.66-4.31), and prostate cancer (SIR 1.21, 95% CI 1.09-1.34). The risk of lung cancer was slightly higher among the invited nonparticipants (SIR 1.48, 95% CI 1.20-1.79) than among the participants (SIR 1.02, 95% CI 0.88-1.17). About 98% of the lung cancers occurred in current or ex-smokers.

Conclusions: In a population of long-term construction workers, the risk of lung cancer and mesothelioma was increased, but considerably lower than among insulators, asbestos sprayers, or patients with asbestosis. As it was not possible to follow most of the invited nonparticipants in the original screening study, selection bias by smoking or other life-style factors possibly correlated to the individual's decision to participate in the health screening cannot be excluded.
Lung function impairment in relation to asbestos-induced pleural lesions with reference to the extent of the lesions and the initial parenchymal fibrosis. J. Lebedová, B. Dlouhá, L. Rychlá, et al. 2003;29(5):388-95. PubMed · Publisher

Abstract

Objectives: The study focused on the effect of pleural lesions on the lung function of asbestos-exposed workers.

Methods: A clinical check-up, chest radiography, high-resolution computed tomography (HRCT), and lung function testing were performed on 162 asbestos-exposed workers without any sign of parenchymal fibrosis on their chest radiographs. According to the HRCT scans, two subgroups were delineated, 97 subjects with pleural lesions and 65 referents without pleural lesions. Four categories of pleural lesions were specified according to the extent. Parenchymal changes, if identified on the HRCT scans, were recorded.

Results: The radiographic sensitivity and specificity for pleural lesion detection when compared with that of HRCT were 64.9% and 98.5%, respectively. The HRCT scans showed parenchymal abnormalities in 46.3% of the participants, more frequently in those with pleural lesions (67.0% versus 15.4%, P<0.0001). After the effect of parenchymal fibrosis was taken into account, pleural lesions were found to have a significant effect on the decrease in total lung capacity, forced vital capacity, and forced expiratory volume in 1 second, if being classified into category 2 or higher.

Conclusions: Pleural lesions proved to have a negative effect on lung function, depending on their extent. The effect of the initial parenchymal fibrosis detectable in the HRCT scans only was also significant. A normal chest radiograph does not exclude the presence of pleural lesions or initial parenchymal fibrosis, with a possible negative effect on lung function.
Cancer incidence among workers in the asbestos-cement producing industry in Norway. B. Ulvestad, K. Kjaerheim, J.I. Martinsen, et al. 2002;28(6):411-7. PubMed · Publisher

Abstract

Objectives: The incidence of cancer among employees of a Norwegian asbestos-cement factory was studied in relation to duration of exposure and time since first exposure. The factory was active in 1942-1968. Most of the asbestos in use was chrysotile, but for technical reasons 8% amphiboles was added.

Methods: For the identification of cancer cases, a cohort of 541 male workers was linked to the Cancer Registry of Norway. The analysis was based on the comparison between the observed and expected number of cancer cases. Standardized incidence ratios (SIR) and 95% confidence intervals (95% CI) were estimated. Period of first employment, duration of employment, and time since first employment were used as indicators of exposure. Poisson regression analysis was used for the internal comparisons.

Results: The standardized incidence ratio was 52.5 (95% CI 31.1-83.0) for pleural mesothelioma, on the basis of 18 cases. The highest standardized incidence ratio was found for workers first employed in the earliest production period (SIR 99.0, 95% CI 51.3-173). No peritoneal mesothelioma was found. The standardized incidence ratio for lung cancer was 3.1 (95% CI 2.14.3), but no dose-response effect was observed. The ratio of mesothelioma to lung cancer cases was 1:2.

Conclusions: This study showed a high incidence of mesothelioma and a high ratio of mesothelioma to lung cancer among asbestos-cement workers. The high incidence of mesothelioma was probably due to the fact that a relatively high proportion of amphiboles was used in the production process.
Occupational dust exposure and the risk of laryngeal cancer in Turkey. O.C. Elci, M. Akpinar-Elci, A. Blair, et al. 2002;28(4):278-84. PubMed · Publisher

Abstract

Objectives: A hospital-based case-referent study was conducted to identify occupational risk factors for laryngeal cancer. In a previous report an association was found between laryngeal cancer and occupations with potential dust exposure; a job-exposure matrix was developed to aid further evaluation of laryngeal cancer risks from five occupational dust exposures.

Methods: Among 7631 cancer cases from the Okmeydani Hospital, Istanbul, between 1979 and 1984, 958 larynx cancer cases were identified among men. After exclusions, 940 laryngeal cancer cases and 1519 referents were available. A standardized questionnaire was used to obtain basic information on the patients. Seven-digit standard occupational and industrial codes were created to classify the job and industrial titles. A job-exposure matrix was developed for occupational dusts, including silica, asbestos, wood, cotton, and grain, and age-, smoking-, and alcohol-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate risks of laryngeal cancer.

Results: An excess of laryngeal cancer occurred for workers potentially exposed to silica and cotton dust, particularly for supraglottic cancer (OR 1.8, 95% CI 1.3-2.3, for silica and OR 1.6, 95% CI 1.1-2.5, for cotton dust), and there was a significant dose-response relationship with silica exposure. No relationship was found between laryngeal cancer and asbestos, grain, or wood dust exposures.

Conclusion: Laryngeal cancer, especially supraglottic tumors, is associated with silica and cotton dust exposures in Turkey.
Ten-year update on mortality among mild-steel welders. K. Steenland. 2002;28(3):163-7. PubMed · Publisher

Abstract

Objectives: This study is an update on the lung cancer risk of mild-steel welders with no asbestos exposure using a cohort of nonwelders for comparison.

Methods: The subjects came from three United States (US) plants that manufactured heavy equipment. The follow-up was extended from 1988 to 1998. The welders were not exposed to asbestos (typical of shipyard welders) or to chromium or nickel (present in stainless steel).

Results: There were 108 lung cancer deaths among the welders and 128 such deaths among the nonwelders (double the previous number of lung cancer deaths). The standardized mortality ratio (SMR) for lung cancer was 1.46 [95% confidence interval (95% CI 1.20-1.76] for the welders and 1.18 (95% CI 0.98-1.40) for the nonwelders, both in comparison with the US general population. Direct comparison between the welders and nonwelders yielded a rate ratio of 1.22 (95% CI 0.93-1.59). Analyses using a 15-year lag time did not differ greatly from those of an unlagged analysis. There were no marked trends for lung cancer risk by duration of exposure or latency. Evidence from cross-sectional data from a sample of the cohort indicated that the welders smoked somewhat more than the US population and more than the nonwelders. An approximate adjustment of the rate ratios for possible confounding by smoking suggested that smoking may have accounted for about half of the excess lung cancer observed among the welders versus that of either reference population. CONCLUSIONS These data provide suggestive but not conclusive evidence of a modest lung cancer risk from mild-steel welding.
Association between pleural plaques and coronary heart disease. O. Korhola, A. Hiltunen, A. Karjalainen, et al. 2001;27(2):154-5. PubMed · Publisher

Abstract

Objective: The aim of this study was to verify a clinical impression that patients with coronary heart disease disproportionately frequently have calcified pleural plaques.

Methods: Chest X-rays were collected from 148 patients referred consecutively to the Helsinki University Central Hospital for coronary angiography and from 100 consecutive lung cancer patients seen at the same hospital. The radiographs were analyzed for the presence of calcified pleural plaques according to the classification the International Labour Office. A generalized linear model with binomial distribution and log link was used to estimate the relative risks and their 95% confidence intervals (95% CI).

Results: The prevalence of calcified pleural plaques was 35% for the coronary patients and 19% for the lung cancer patients. Calcified pleural plaques were more common among the men than the women, and the risk increased with age. The relative risk of calcified pleural plaques, adjusted for age and gender, was 2.19 (95% CI 1.44-3.32) for the coronary patients as compared with the lung cancer patients.

Conclusions: Further studies with better information on past exposure to asbestos and other potential risk factors are warranted to confirm the observations and to examine whether the association between coronary heart disease and calcified pleural plaques is related to an etiologic or an individual susceptibility factor common to both of these conditions.
Association between pleural plaques and coronary heart disease. B. Sjögren. 2001;27(6):420-1. Comment · Letter PubMed · Publisher
Cohort cancer incidence among pulp and paper mill workers in British Columbia. P.R. Band, N.D. Le, R. Fang, et al. 2001;27(2):113-9. PubMed · Publisher

Abstract

Objectives: A study was conducted to investigate cancer risks in a cohort of pulp and paper workers.

Methods: All male workers with > or =1 years of employment in 14 pulp and paper mills in 1950-1992 were studied. Standardized incidence ratios (SIR) were used to compare the cancer incidence of the cohort with that of the Canadian male population. Record linkage with the National Cancer Registry was performed using the generalized iterative record linkage method.

Results: Altogether 1756 cancer cases were observed in the entire cohort. For > or =15 years of work, the entire cohort had significantly increased SIR values for pleural and prostate cancer and skin melanoma; there was also a significantly increased risk for skin melanoma among workers in the kraft process only, rectal cancer among workers in the sulfite process only, and stomach and prostate cancer and all leukemias combined among workers in both the kraft and sulfite processes. A separate analysis comparing workers in pulping and papermaking with those in the pulping process only did not reveal any difference in cancer risk and hence did not modify the results. The SIR values for skin melanoma were not significantly increased in a comparison using the British Columbia male population. Nine of 10 pleural cancers were mesotheliomas, which likely reflect past asbestos exposure.

Conclusions: The results suggest that long-term work in the pulp and paper industry is associated with excess risks of prostate and stomach cancers and all leukemias for work in both kraft and sulfite processes and of rectal cancer for work in the sulfite process only.
Epidemiologic estimate of the proportion of fatalities related to occupational factors in Finland. M. Nurminen, A. Karjalainen. 2001;27(3):161-213. PubMed · Publisher

Abstract

Objectives: This study attempts to estimate the proportion of annual deaths related to occupational factors in Finland and considers related methodological issues and associated uncertainties.

Methods: Statistics on causes of death, numbers of subjects exposed, and risk ratios obtained from the epidemiologic literature were used to estimate the population attributable fraction and disease burden for causes of death from work-related diseases. Gender-, age- and disease-specific numbers of deaths were provided by Statistics Finland for 1996. Information on the size of the population, broken down by gender, age, occupation, and industry, was acquired from population censuses. A Finnish job-exposure matrix supplied data on the prevalence of exposure for specific agents and the level of exposure among exposed workers.

Results: The attributable fraction of work-related mortality in the relevant disease and age categories was estimated to be 7% (10% for men and 2% for women), and for all diseases and ages the fraction was 4%. For the main cause-of-death categories, the attributable fraction became 12% for circulatory system diseases, 8% for malignant neoplasms, 4% for respiratory system diseases, 4% for mental disorders, 3% for nervous system diseases, and 3% for accidents and violence. The following estimates were obtained for specific important diseases: 24% for lung cancer, 17% for ischemic heart disease, 12% for chronic obstructive pulmonary disease, and 11% for stroke. Based on these fractions, the total number of work-related deaths that occurred in Finland in 1996 was calculated to be on the order of 1800 (employed work force of 2.1 million); 86% involved men.

Conclusions: High-quality epidemiologic studies and national survey data are essential for obtaining reliable estimates of the proportion of deaths attributable to occupational factors. The magnitude of work-related mortality is an insufficiently recognized contributor to total mortality in Finland, especially from circulatory diseases and other diseases caused by exposure to agents other than asbestos.
High-resolution computed tomography classification of lung fibrosis for patients with asbestos-related disease. O. Huuskonen, L. Kivisaari, A. Zitting, et al. 2001;27(2):106-12. Case report PubMed · Publisher

Abstract

Objectives: This study tested a new high-resolution computed tomography (HRCT) scoring method for asbestos-induced parenchymal changes in the lung.

Methods: HRCT scans of 602 asbestos-exposed workers and 49 referents were reviewed by 3 radiologists. Structured forms were filled out for a semiquantitative HRCT fibrosis score based on several specified parenchymal abnormalities scored separately. Observer agreement was studied with the use of the quadratic-weighted kappa (kappaqw). The HRCT fibrosis score (from 0 to V with definitions and index images given retrospectively) was compared with the radiographic classification of the International Labour Office (ILO) for the same patients. Receiver-operating characteristic (ROC) curves were computed to compare the tests for diagnosing asbestosis.

Results: Good inter- and intraobserver agreements were achieved (kappaqw = 0.64 and 0.72, respectively) as regards the HRCT fibrosis score. All the specified computed tomography findings explained 86% of the variance in the HRCT fibrosis score. Age and occupational group were significant predictors of fibrosis. The area under the ROC curve was significantly greater for the HRCT fibrosis score (0.89) than for the ILO radiographic classification (0.76). The sensitivity (70%) and specificity (91%) of the HRCT fibrosis score (classes I/II-V representing asbestosis) were better than those of the classification published by the International Labour Office (51% and 89%, respectively, score > or = 1/0 representing asbestosis).

Conclusions: The examined HRCT scoring method proved to be a simple, reliable, and reproducible method for classifying lung fibrosis and diagnosing asbestosis also in large populations with occupational disease, and it would be possible to use it as a part of an international classification.
Occupational exposure to carcinogens in Estonia, Latvia, Lithuania and the Czech Republic in 1997. T. Kauppinen, B. Pajarskiene, Z. Podniece, et al. 2001;27(5):343-5. PubMed · Publisher

Abstract

Objectives: The aim of the study was to estimate the numbers of workers exposed to carcinogens in Estonia, Latvia, Lithuania, and the Czech Republic.

Methods: CAREX is an international information system on occupational exposure to 139 known and suspected carcinogens. It provides exposure data and estimates of the numbers of exposed workers by country, carcinogen, and industry. The CAREX method, which has been previously applied in the member states of the European Union, was applied in the present study to the exposure situation in Estonia, Latvia, Lithuania, and the Czech Republic in 1997. The preliminary estimates generated by CAREX were reviewed and revised by national experts mainly for asbestos, benzene, and lead, which were of special interest for this project.

Results: The numbers of workers exposed to carcinogens covered by CAREX in 1997 were about 180,000 (29% of employed persons) in Estonia, 260,000 (28% of employed persons) in Latvia, 470,000 (28% of employed persons) in Lithuania, and 1,400,000 (28% of employed persons) in the Czech Republic. The most common exposures were solar radiation (7-13% exposed at least 75% of the worktime), environmental tobacco smoke (4-5% exposed at least 75% of the worktime), wood dust (3-5% exposed), crystalline silica (2-3% exposed), diesel exhaust (2-3% exposed), radon and its decay products (2% exposed), benzene (0.9-1.7% exposed), and lead and inorganic lead compounds (0.8-1.4% exposed). Exposure to asbestos was slightly less prevalent (0.3-1.1% exposed).

Conclusions: These preliminary results indicate that a substantial proportion of the workers in the studied countries were exposed to carcinogens.
Asbestos-exposed blood monocytes--deoxyribonucleic acid strand lesions in co-cultured bronchial epithelial cells. K. Kienast, C. Kaes, K. Drumm, et al. 2000;26(1):71-7. PubMed · Publisher

Abstract

Objectives: In lungs of asbestos-exposed persons alveolar and interstitial macrophages are able to release genotoxic substances such as reactive oxygen intermediates. It is unknown whether reactive oxygen intermediates released by macrophages are able to induce DNA (deoxyribonucleic acid) strand lesions in neighboring bronchial epithelial cells.

Methods: A co-culture (transwell) system was established which allows exposure of human blood monocytes cultured on a polycarbonate membrane within a distance of 1 mm of a monolayer of the bronchial epithelial cell line BEAS-2B.

Results: Exposure of blood monocytes to chrysotile B (100 microg/10(6)cells) caused an up to 2.8-fold increase in DNA strand lesions in co-cultured BEAS-2B cells measured by alkaline elution when compared with the levels of control cells after 1, 3, 24, and 48 hours. The main DNA damage thus occurred as early as within 1 hour of incubation, corresponding to the time course of the release of reactive oxygen intermediates by blood monocytes determined by chemiluminescence. The maximum release of reactive oxygen intermediates (3.2-fold increase over control values) was measured after 30 minutes of exposure of blood monocytes to chrysotile B. The addition of catalase (200 U/ml) or desferoxamine (100 microM) to the culture medium blocked almost completely the induction of DNA strand lesions in this system (maximum 85%).

Conclusions: Exposure of blood monocytes to chrysotile B results in an increase in the release of reactive oxygen intermediates and induces DNA strand lesions in neighboring bronchial epithelial cells.
Cancer incidence among male pulp and paper workers in Norway. H. Langseth, A. Andersen. 2000;26(2):99-105. PubMed · Publisher

Abstract

Objectives: The study investigated cancer incidence among 23,718 male pulp and paper workers employed continuously for at least 1 year between 1920 and 1993 in Norway.

Methods: The name, date of birth, personal identification number, dates of hire and termination for all employment periods, specific department, and job categories were registered for each worker. Six subcohorts were established (sulfite mill, sulfate mill, paper mill, maintenance department, administrative staff and other departments). Data on the cohort were linked with data in the Norwegian Cancer Register. The follow-up period for cancer incidence, date of death, or emigration was from 1953 through 1993.

Results: An excess incidence of lung cancer was found among both short- and long-term employees [standardized incidence ratio (SIR) 1.5, 95% confidence interval (95% CI) 1.13-2.03 and SIR 1.2, 95% CI 1.09-1.34, respectively], especially for workers with the longest latency (SIR 1.3, 95% CI 1.08-1.44) and for sulfite mill workers (SIR 1.5, 95% CI 1.09-1.99). The risk for pleural mesothelioma was also increased (SIR 2.4, 95% CI 1.45-3.75), especially among maintenance workers. The results also showed an increased risk for malignant melanoma (SIR 1.3, 95% CI 1.04-1.60), an unexpected finding.

Conclusions: Almost all the increased risk for lung cancer can be explained by a combination of smoking habits and asbestos use. although an effect of other work-related exposures (sulfur and chloride compounds, wood dust) cannot be excluded. Most of the cases of pleural mesothelioma occurred in departments where asbestos was used. There is no clear explanation for the excess of malignant melanoma, and the finding may be a chance occurrence.
Incidence rates of malignant mesothelioma in Denmark and predicted future number of cases among men. J. Kjaergaard, M. Andersson. 2000;26(2):112-7. PubMed · Publisher

Abstract

Objectives: This study analyzed the incidence rates of malignant mesothelioma in Denmark in order to predict the future number of cases that will occur among Danish men.

Methods: The 1912 cases of malignant mesothelioma reported to the Danish Cancer registry in 1943-1993 were analyzed in order to describe current incidence rates. By a Poisson regression model the relative risks of synthetic birth cohorts were estimated and used in the prediction of the future number of cases that will occur among Danish men.

Results: The incidence rate increased to 1.33 per 100000 person-years in 1983-1987 among men and to 0.51 in 1973-1977 among women. From the Poisson regression model, the risk for birth cohorts of men, relative to the 1940-1944 cohort, peaked in the 1940-1944 cohort and decreased to 0.57 in the 1950-1954 cohort. The age-specific incidence rate peaked at 246 per 100000 person-years in the age group 80-84 years. The future annual number of mesothelioma cases is expected to peak around 2015 with 93 cases among men born before 1955.

Conclusions: The fit of the models was not ideal, but with careful interpretation of the results, it was concluded that a further increase in the number of mesothelioma cases can be expected, and the effect of regulating the environmental exposure to asbestos cannot be expected within the next 10-15 years.
International expert meeting on new advances in the radiology and screening of asbestos-related diseases. A. Tossavainen. 2000;26(5):449-54. Consensus statement · Review PubMed
Past occupational exposure to asbestos among men in France. M. Goldberg, A. Banaei, S. Goldberg, et al. 2000;26(1):52-61. PubMed · Publisher

Abstract

Objectives: This study aimed at reconstructing changes in the frequency and levels of occupational asbestos exposure in France over the past century.

Methods: Work histories were collected during 11 population-based case-referent studies recently carried out in France, and an asbestos-specific job-exposure matrix including 10 625 jobs was used to estimate indices of past occupational asbestos exposure. The results were estimated from a sample of 4287 subjects, bootstrapped 200 times.

Results: The distribution of socioeconomic categories within the sample was compared with that of the general population in 1954, 1962, 1968, 1975, and 1982. The proportion of blue-collar workers was similar. The highest proportion of exposed subjects was found between 1950 and 1980. Around 10% of each 10-year age class was exposed to asbestos. For those born in 1930-1939, 15.2% was exposed between the ages of 20 and 29 years. For each age class born in 190-1939, the proportion exposed at least once by 60 years of age ranged from 18.2% to 24.5 % and, of those exposed, the cumulative duration of exposure ranged from 11.3 to 15.4 years by the age of 60 years. A population exposure index showed that the heaviest exposure occurred between 1960 and 1970 and that the age classes born between 1920 and 1929 were the most heavily exposed. Time trends showed that the mean value of this index for the men aged 20-59 years reached a peak in the 1960s and then decreased.

Conclusions: This study presents data of reasonable validity about occupational asbestos exposure in France and its trends over the past century; the data are being used to forecast the development of male mortality from mesothelioma in France.

1990s

Call for an international ban on asbestos. 1999;25(6):633-5. PubMed
Magnetic resonance appearance of asbestos-related benign and malignant pleural diseases. P. Boraschi, S. Neri, G. Braccini, et al. 1999;25(1):18-23. PubMed · Publisher

Abstract

Objectives: This study describes the magnetic resonance findings of benign and malignant pleural diseases in asbestos-exposed subjects.

Methods: Thirty patients with a history of asbestos exposure and pleural lesions in chest X-rays and computed tomography scans were examined with a 0.5- and a 1.5-T magnetic resonance unit. The examination protocol included cardiac-gated proton density and T2-weighted images, unenhanced and enhanced (Gd-DTPA; 0.1 mmol/ kg) T1-weighted images in the axial plane and sometimes in another orthogonal plane (sagittal or coronal or both). All the magnetic resonance images were reviewed by 3 experienced observers, who visually evaluated morphologic features, signal intensity, and contrast enhancement of pleural lesions. The diagnosis was established by means of percutaneous biopsy, thoracotomy, and combined clinical and radiological follow-up for at least 3 years.

Results: Eighteen patients affected with multiple pleural plaques showed low signal intensity on both unenhanced and enhanced T1-weighted and proton density and T2-weighted images. In 2 of these patients an acute pleural effusion was observed. All the malignant lesions (11 mesotheliomas) and a solitary benign pleural plaque revealed high signal intensity on the proton density and T2-weighted images and inhomogeneous contrast enhancement in the postcontrast T1-weighted images. The sensitivity, specificity, and diagnostic accuracy of the magnetic resonance imaging in classifying a lesion as suggestive of malignancy were 100%, 95% and 97%, respectively.

Conclusions: The results point out 2 magnetic resonance signal intensity patterns for asbestos-related pleural lesions: (i) low-signal intensity on unenhanced and enhanced T1-weighted and proton density and T2-weighted images for benign plaques and (ii) nonhomogeneous hyperintensity in T2-weighted and enhanced T1-weighted images for malignant mesotheliomas.
Occupational exposure and cancer incidence among workers from an aluminum smelter in western Norway. A. Rønneberg, T. Haldorsen, P. Romundstad, et al. 1999;25(3):207-14. PubMed · Publisher

Abstract

Objectives: This study investigated the associations between specific cancers and occupational exposure to polycyclic aromatic hydrocarbons (PAH), asbestos, electromagnetic fields, and heat in a cohort of workers from a Norwegian aluminum smelter.

Methods: Cancer incidence between 1953 and 1993 was observed for 2647 male short-term workers and 2 cohorts of men with at least 4 years' employment (2888 production workers and 373 maintenance workers). Standardized incidence ratios (SIR) were calculated from the national male cancer incidence, and associations with cumulative exposure were investigated by stratified analysis. Cumulative exposure in 15-year time windows was used as an alternative dose indicator.

Results: Investigation of the a priori hypotheses in the production cohort revealed a positive association between bladder cancer and PAH exposure 30 years or more before observation. The results also suggested an association between PAH and pancreatic cancer, although not statistically significant. No association was seen between exposure to PAH and cancers of the lungs or between magnetic field exposure and lymphatic and hematopoietic cancer. In the maintenance cohort there was a positive association between employment as an electrician and lymphatic and hematopoietic cancer and a statistically nonsignificant association between PAH and lung cancer. The short-term workers showed a statistically significant excess of lung cancer.

Conclusions: The results support previous findings of an association between exposure to PAH and bladder cancer.
Occupational risk factors for lung cancer among young men. M. Kreuzer, H. Pohlabeln, W. Ahrens, et al. 1999;25(5):422-9. PubMed · Publisher

Abstract

Objectives: This study evaluated whether occupational exposure plays a role for lung cancer at a very young age.

Methods: In a pooled analysis of 2 German case-referent studies including 3498 incident cases among men and 3541 male population referents, a group of men (187 cases and 202 referents) aged > or =45 years was compared with a group of 2186 cases and 2146 referents aged 55-69 years. Occupational exposure to known (A list) or suspected (B list) lung carcinogens was assessed using job and industry codes, and exposure to asbestos was assessed using job-specific supplementary questionnaires. A conditional logistic regression was used to calculate the odds ratios (OR) and to control for smoking.

Results: Asbestos exposure showed an odds ratio (OR) of 2.39 [95% confidence interval (95% CI) 1.41-4.04] for the younger group and 1.46 (95% CI 1.24-1.72) for the older group. Having ever worked in a job belonging to the A list as compared with never working in an A- or B-list job was associated with a significantly increased risk for the younger (OR 2.06, 95% CI 1.03-4.12) and older (OR 1.35, 95% CI 1.10-1.65) groups, adjusted for asbestos. Lung cancer risk for those working in A-list jobs at a very young age (under 16 years) was increased in the younger group (OR 6.14, 95% CI 1.41-28.01) in contrast to the older group (OR 1.19, 95% CI 0.91-1.63).

Conclusion: Occupational risk factors play an important role for lung cancer among young men. Early age at first exposure may favor an early age of the onset of lung cancer.
Work-related cancer in the Nordic countries. A. Andersen, L. Barlow, A. Engeland, et al. 1999;25 Suppl 2:1-116. Review PubMed

Abstract

This report presents 20 years' of cancer incidence data by occupational group for the Nordic populations. The study covers the 10 million people aged 25-64 years at the time of the 1970 censuses in Denmark, Finland, Norway, and Sweden, and the 1 million incident cancer cases diagnosed among these people during the subsequent 20 years. The project was undertaken as a cohort study with linkage of individual records based on the personal identification numbers used in all the Nordic countries. In the 1970 censuses, information on occupation for each economically active member of the household was provided in free text in self-administered questionnaires. The data were centrally coded and computerized in the statistical offices. Norway, Sweden, and Finland used the Nordic Classification of Occupations, while Denmark used a national coding scheme. However, all the data could be reclassified into 53 occupational groups and 1 group of economically inactive persons. Person-years at risk were accumulated from 1 January 1971 until the date of emigration, date of death or 31 December 1987 in Denmark, 1989 in Sweden, 1990 in Finland, and 1991 in Norway. The 4 countries all had nationwide registration of incident cancer cases during the entire study period. All incident cancer cases during the individual risk periods were included in the analysis. Despite minor differences between the countries, the International Classification of Diseases, 7th revision, formed the core basis for the diagnostic coding in all 4 countries. For the present study the incident cancer cases have been classified into 35 broad diagnostic groups. The observed number of cancer cases in each group of persons defined by country, gender, and occupation was compared with the expected number calculated from the age-, gender-, and period-specific person-years and the incidence rates for the national population. The result has been presented as a standardized incidence ratio (SIR), defined as the observed number of cases divided by the expected number and multiplied by 100. In the tables of this report, all the SIR values for which the upper limit of the 95% confidence interval is below 100 are printed in green and all those for which the lower limit of the confidence interval is above 100 are printed in red. For all cancers combined, the study showed a wide variation among the men, from an SIR of 79 for farmers to 159 for waiters. The occupations with the highest SIR values also included seamen and workers producing beverages and tobacco. Among the women the SIR values varied from 83 for gardeners to 129 for tobacco workers. Low SIR values were found for farmers and teachers. Outdoor workers such as fishermen and gardeners had the highest risk of lip cancer, while the lowest risk was found among indoor workers such as physicians and artistic workers. Almost all pleural cancers are associated with asbestos exposure. Accordingly, plumbers, welders, mechanics, and seamen were the occupations with the highest risk. There was also an excess risk of pleural cancer in the occupational group of technical, chemical, physical, and biological workers, including, among others, engineers and chemists potentially exposed to asbestos. The wood workers included in the present study had the highest risk of nasal cancer. Most studies of nasal cancer have shown increased risks associated with exposure to wood dust, both for those in furniture making and for those exposed exclusively to soft wood. Nickel refinery workers are also known for their high risk of nasal cancer. In the present study they were included in the occupational group of smelting workers. Lung cancer was the most frequent cancer among men in the present study. Tobacco smoking is the major risk factor for this disease, but occupational exposures also play an important role. Waiters and tobacco workers had the highest risk of lung cancer. Miners and quarry workers also had a high risk of lung cancer, which may be related to
Anthophyllite exposure and endemic pleural plaques in Kumamoto, Japan. T. Hiraoka, M. Ohkura, K. Morinaga, et al. 1998;24(5):392-7. PubMed · Publisher

Abstract

Objectives: This study explored the high prevalence of pleural plaques in the town of Matsubase in Kumamoto, Japan.

Methods: Small-size chest X-ray film was used for screening, and all persons with pleural plaques were confirmed by computed tomography (CT). The prevalence rate of pleural plaques in the 4 districts of Matsubase and its surrounding towns and cities were also examined. The age-adjusted mortality rate for lung cancer in this town was compared with that of its surrounding towns and cities.

Results: Pleural plaques were found in 1357 persons (724 men and 633 women) among the inhabitants who were more than 20 years of age in Matsubase between 1988 and 1993. CT scans ascertained 938 cases with pleural plaques among the 11 14 persons who participated. Thus at least 9.5% of the inhabitants over 20 years of age in this town had pleural plaques. The neighboring towns had a higher rate than the more distant towns. A large-scale open-cast asbestos mine and mill had been in operation in Matsubase between 1883 and 1970. Mineral analysis revealed anthophyllite fibers. Most of the plaques were found in persons who had never worked in the mine or mill.

Conclusions: The high prevalence of pleural plaques in Matsubase was due to anthophyllite exposure, mainly environmental. No mesotheliomas were found, however. These findings agree with those from an earlier study from Finland.
Occupational risk factors of lung cancer in São Paulo, Brazil. V. Wünsch-Filho, J.E. Moncau, D. Mirabelli, et al. 1998;24(2):118-24. PubMed · Publisher

Abstract

Objectives: This study estimated the risk of occupational exposure for lung cancer in the metropolitan region of São Paulo, the largest urbanized and industrialized area in Brazil.

Methods: In this hospital-based case-referent study of 398 cases and 860 referents, the cases were matched to referents according to age, gender, and hospital and personally interviewed for information on lifetime job history, smoking habits, passive smoking exposure, cancer in relatives, socioeconomic status, and migratory history. The analysis concerned industrial titles and occupational categories. With the use of a job-exposure matrix, exposure to asbestos, polynuclear aromatic hydrocarbons, arsenic, dust, nickel and chromium was assessed.

Results: For the men in the 56 industrial and 122 occupational categories examined, an excess risk of lung cancer was found in the machinery industry [odds ratio (OR) 1.62, 95% confidence interval (95% CI) 1.02-2.55). In pottery manufacturing the risk (OR 2.21, 95% CI 1.00-4.87) was increased for workers exposed > or = 10 years (OR 6.43, 95% CI 1.12-37.01). Textile workers employed for > or = 10 years with a latency of > or = 40 years had an elevated risk (OR 21.93, 95% CI 1.96-245.0). In the analysis using the job-exposure matrix no risk was detected for the specific lung cancer carcinogens examined. For the women, no significantly elevated risk was observed.

Conclusions: The results of this study revealed risks of lung cancer for men in the machinery industry and for pottery and textile workers with long-term exposure.
Radiographic abnormalities among Finnish construction, shipyard and asbestos industry workers. K. Koskinen, A. Zitting, A. Tossavainen, et al. 1998;24(2):109-17. PubMed · Publisher

Abstract

Objectives: The prevalence of asbestos-related radiographic abnormalities was surveyed among Finnish construction, shipyard, and asbestos industry workers.

Methods: The radiographic screening focused on active and retired workers who were under the age of 70 years and had been employed for at least 10 years in construction or for at least 1 year in shipyards or in the asbestos industry. In 1990-1992, 18,943 people participated in an X-ray examination of the lungs and an interview on work history and exposure. The criteria for a positive radiological finding were (i) small irregular lung opacities clearly consistent with interstitial pulmonary fibrosis (ILO 1/1 or higher), (ii) lung opacities indicating mild pulmonary fibrosis (ILO 1/0) with unilateral or bilateral pleural plaques, (iii) marked adhesions with or without thickening of the visceral pleura, or (iv) findings consistent with bilateral pleural plaques.

Results: Fulfilling the criteria were 4133 workers (22%) (22% from construction, 16% from shipyards, and 24% from the asbestos industry). The radiological findings included signs of pulmonary fibrosis (3%), changes in the visceral pleura (7%), bilateral plaques (17%), and unilateral plaques (10%). Occupational disease was diagnosed according to the Finnish insurance regulations for three-fourths of those referred for further examinations, 96% being abnormalities in the pleura and 4% being asbestosis.

Conclusions: Exposure to asbestos dust has been common in ordinary construction work, and, consequently, radiographic abnormalities (mostly pleural) occur frequently among active and retired construction workers.
Towards the coordination of European research on the carcinogenic effects of asbestos. P. Boffetta, A. Burdorf, M. Goldberg, et al. 1998;24(4):312-7. PubMed
A meta-analysis of epidemiologic studies of lung cancer in welders. J.J. Moulin. 1997;23(2):104-13. Meta-analysis PubMed · Publisher

Abstract

Objective: A meta-analysis of epidemiologic studies was carried out on lung cancer risk among shipyard, mild steel, and stainless steel welders, and the role of asbestos exposure and smoking was considered.

Methods: The meta-analysis consisted of calculating combined relative risks (RR) and their variances through a logarithm transformation of published RR values and a weighing using the inverted variance of each RR.

Results: The literature provided 18 case-referent and 31 cohort studies. The combined RR values were 1.38 [observed 1028, 95% confidence interval (95% CI) 1.29-1.48] for "all or unspecified welding categories", 1.30 (observed 305, 95% CI 1.14-1.48) for shipyard welders, and 1.35 (observed 173, 95% CI 1.15-1.58) for nonshipyard welders. Similar combined RR values (RR) were observed for mild steel welders (combined RR 1.50, observed 137, 95% CI 1.18-1.91) and stainless steel welders (combined RR 1.50 observed 114, 95% CI 1.10-2.05). No significant heterogeneity was discerned between studies of any welding or study design category. A marked healthy worker effect may also lead to an underestimation of the standardized mortality ratio for lung cancer among stainless steel welders. Furthermore, welders of any category are likely to be exposed to asbestos. Welders also seem to smoke more than the general male population, and therefore the hypothesis of tobacco overconsumption among welders could not be discarded.

Conclusions: A 30-40% increase in the RR of lung cancer among welders cannot be explained by hexavalent chromium and nickel exposure among stainless steel welders. The combination of the carcinogenic effects of asbestos exposure and smoking may account for part of the lung cancer excess observed.
Asbestos, asbestosis, and cancer: the Helsinki criteria for diagnosis and attribution. 1997;23(4):311-6. Consensus statement · Review PubMed
Asbestos, asbestosis, pleural plaques and lung cancer. G. Hillerdal, D.W. Henderson. 1997;23(2):93-103. Review PubMed · Publisher

Abstract

Inhalation of asbestos fibers increases the risk of bronchial carcinoma. It has been claimed that asbestosis is a necessary prerequisite for the malignancy, but epidemiologic studies usually do not have enough statistical strength to prove that asbestos-exposed patients without asbestosis are without risk. Several recent studies do actually indicate that there is a risk for such patients. In addition, case-referent studies of patients with lung cancer show an attributable risk for asbestos of 6% to 23%, which is much higher than the actual occurrence of asbestosis among these patients. Thus there is an increasing body of evidence that, at low exposure levels, asbestos produces a slight increase in the relative risk of lung cancer even in the absence of asbestosis. Consequently, all exposure to asbestos must be minimized.
Asbestos--a continuing concern. A. Karjalainen. 1997;23(2):81-2. Editorial PubMed · Publisher
Fibrosis of the lung and pleura and long-term exposure to wollastonite. H.O. Koskinen, H.L. Nordman, A.J. Zitting, et al. 1997;23(1):41-7. PubMed · Publisher

Abstract

Objectives: The purpose of this study was to determine whether long-term exposure to wollastonite causes fibrosis of the lung and pleura in humans.

Methods: Forty-nine workers (mean exposure 25 years) in a Finnish limestone-wollastonite mine and mill were examined. Their work histories and symptoms of chronic bronchitis were recorded. The chest radiographs were classified according to the classification of the International Labour Office (1980); a radiographic follow-up from 1981 to 1990 was included. Spirometry and diffusion capacity were measured. Four workers underwent high-resolution computed tomography (HRCT) and bronchoalveolar lavage (BAL). Lung tissue specimens were available for 2 workers. Mineral fibers and asbestos bodies were analyzed from the BAL fluid and lung tissue specimens, which were also analyzed for lung fibrosis.

Results: Two workers (4%) had small irregular lung opacities (ILO 1/0), 1 worker (2%) ILO 0/1 of the s/t type. HRCT revealed no parenchymal fibrosis in the 2 workers with the ILO 1/0 classification. Of the 9 workers (18%) with pleural plaques, 5 had been exposed to asbestos. Multivariate logistic regression analyses revealed no association of plaques with the duration of wollastonite or asbestos exposure. Wollastonite fibers or bodies were not found in any of the 4 workers who underwent BAL, nor in either of the workers whose lung tissue specimens were available.

Conclusions: No evidence was found that long-term exposure to wollastonite causes parenchymal fibrosis of the lung and pleura. Furthermore, the findings indicate that wollastonite fibers are poorly retained in human lungs.
Relationship between asbestos bodies in sputum and the number of specimens. F. Sulotto, E. Capellaro, A. Chiesa, et al. 1997;23(1):48-53. PubMed · Publisher

Abstract

Objectives: This study investigated the relationship between asbestos body identification and the number of sputum specimens obtained from each subject.

Methods: The presence of asbestos bodies in sputum was studied in 142 asbestos workers with former low-exposure levels; the number of specimens collected during 1-3 weeks varied from 2 to more than 4. Furthermore the persistence of asbestos bodies in the sputum of 15 asbestos workers was studied during a long-time follow-up.

Results: Asbestos bodies were present in at least 1 specimen in 44.4% of the 142 subjects. The cumulative percentage of asbestos body presence increased linearly, from 20% to 68%, as the number of specimens increased.

Conclusions: Five specimens did not seem to be sufficient to obtain satisfactory sensitivity in a group with low exposure to asbestos. Neither the type of exposure (to chrysotile only or to chrysotile plus amphibole) nor the presence of an asbestos-related disease clearly influenced the probability of finding asbestos bodies.
Surveillance and intervention studies on respiratory cancers in asbestos-exposed workers. E. Merler, E. Buiatti, H. Vainio. 1997;23(2):83-92. Systematic review PubMed · Publisher

Abstract

A systematic review of the literature on the surveillance of workers at presumed increased risk for respiratory cancer because of their exposure to asbestos revealed surveillance programs at the national, population, industrial, and factory (workplace) levels. Furthermore, 3 randomized chemoprevention trials involving workers exposed to asbestos were found. The nationwide programs to survey problems related to occupational exposure to asbestos were conducted in Europe. Some of the countries have policies for the surveillance of workers exposed either currently or formerly to asbestos. The results of the chemoprevention trials suggest that there are, as yet, no practical tools for efficient, safe chemoprevention of asbestos-induced respiratory malignancies.
Trends in mesothelioma incidence and occupational mesotheliomas in Finland in 1960-1995. A. Karjalainen, E. Pukkala, K. Mattson, et al. 1997;23(4):266-70. PubMed · Publisher

Abstract

Objectives: The study analyzed the recent trend in the incidence of mesothelioma in Finland and evaluated the coverage of reporting work-related mesothelioma.

Methods: The incidence of mesothelioma in 1960-1995 was retrieved from the Finnish Cancer Registry, and the number of asbestos-associated work-related mesotheliomas were taken from the Finnish Register of Occupational Diseases.

Results: The annual number of mesotheliomas increased rapidly in 1975-1990. In the 1990s, the age-adjusted incidence remained relatively stable for Finnish men. The annual number of cases still increased among men over 65 years of age, but decreased slightly among men under 55 years of age and among women. About 35 annual cases were diagnosed among men and 10-15 among women in the mid-1990s. The reporting of work-related mesotheliomas improved during the Finnish asbestos program in 1987-1992. In 1993-1995 about 30 annual cases (ie, about 90% of all pleural and 50% of the peritoneal mesotheliomas in men) were reported to be work-related.

Conclusions: The increasing trend in the incidence of mesothelioma in Finland has slowed down in the 1990s, and the maximum of asbestos-related cases in the early 2000s will probably be clearly less than the 100 annual cases estimated in the early 1990s. If the observed trend continues up to 2010, about 40-50 cases among men and 10-20 among women will then be diagnosed annually. Altogether 40-50 of these cases would be related to occupational asbestos exposure.
Occupation and the risk of lung cancer in Uruguay. E. De Stefani, M. Kogevinas, P. Boffetta, et al. 1996;22(5):346-52. PubMed · Publisher

Abstract

Objectives: The purpose of this study was to provide more information regarding the risk of lung cancer associated with asbestos, and other exposures in the Uruguayan work force.

Methods: This multisite case-referent study was part of a large project designed for evaluating the role of occupational exposures in cancer risk in Uruguay. According to the design employed, cases were a subset of the data base corresponding to a particular site (in this instance lung cancer), and they were compared with all other sites combined (referents).

Results: Significant increases in risk associated with workers in the construction industry were mainly observed for squamous-cell carcinoma. Asbestos, silica dust, and DDT (dichlorodiphenyltrichloroethane) exposure were also associated with increases in the risk of lung cancer. Pipefitters, bakers, and textile workers were also at increased risk of developing lung cancer.

Conclusions: Workers employed in the construction industry, as well as those exposed to DDT may have an excess risk of lung cancer. These findings are particularly important in showing that developing countries like Uruguay display risk patterns of similar magnitude as those observed in developed communities.
Pulmonary asbestos bodies and asbestos fibers as indicators of exposure. A. Karjalainen, M. Nurminen, E. Vanhala, et al. 1996;22(1):34-8. PubMed · Publisher

Abstract

Objectives: The aim of the study was to analyze the correlation between pulmonary concentrations of asbestos bodies and asbestos fibers and to characterize asbestos body counts from lung tissue of Finnish patients occupationally exposed and unexposed to asbestos.

Methods: Ninety-nine surgically treated lung cancer patients were investigated. The number of asbestos bodies in iron-stained 5-micrometers histological lung tissue sections was determined by optical microscopy, and the pulmonary concentration of asbestos fibers was assessed by scanning electron microscopy. The correlation between asbestos body and asbestos fiber counts was calculated with linear regression. The asbestos body and asbestos fiber concentrations were also compared with exposure history according to a personal interview of the patients.

Results: The average number of asbestos bodies ranged from < 0.1 to 750 asbestos bodies per tissue section. All the cases with definite exposure showed an average of at least one asbestos body per tissue section. An average of at least one asbestos body per section was, however, detected in 34% of the patients with unlikely exposure. The regression equation log (AF) = -0.429 + 0.600.log (AB) was found to predict the concentration of asbestos fibers (AF, 10(6) fibers.g-1) corresponding to a given number of asbestos bodies (AB) in a section of lung tissue.

Conclusions: The background level of asbestos bodies in the lungs of patients with no specific asbestos exposure seems to be higher in Finland than in other countries. In medicolegal cases, the methodological variation involved in asbestos fiber and asbestos body counting must be recognized and all available exposure data should be used to produce the best possible estimate of the exposure.
Ubiquitous fiber exposure in selected sampling sites in Europe. T. Schneider, G. Burdett, L. Martinon, et al. 1996;22(4):274-84. Case report PubMed · Publisher

Abstract

Objectives: This study evaluates personal exposure to respirable inorganic and organic fibers during normal human lifetimes and assesses the order of magnitude of the contribution of inorganic fibers other than asbestos to total fiber exposure from man-made and natural sources.

Methods: Four groups (suburban schoolchildren, rural retired persons, office workers, and taxi drivers), with five persons per group, were monitored for 24 h four times during one year. Personal sampling pumps collected airborne dust on gold-precoated Nuclepore filters. The fibers were analyzed for fiber sizes specified by the World Health Organization.

Results: The geometric mean concentrations ranged from 9000 fibers.m-3 (office workers) to 20000 fibers.m-3 (schoolchildren) for organic fibers, and from 600 fibers.m-3 (taxi drivers) to 4000 fibers.m-3 (schoolchildren) for gypsum fibers. For other inorganic fibers the concentrations were around 5000 fibers.m-3. The contribution of fibers with an elemental composition similar to that of man-made vitreous fibers (MMVF) was less than about one-quarter of the content of other inorganic fibers. The fiber size distributions were uniform across the groups, and the organic fibers were the longest and thinnest nonasbestos fibers.

Conclusions: Lifetime exposure to fibers can be ranked as organic fibers > other inorganic fibers > fibers with an elemental composition similar to MMVF > MMVF. Information on the biological effects of fibers is difficult to interpret for use in assessing the health risk from exposure to low levels of ubiquitous fibers, and there is a lack of knowledge on the effects of organic fibers.
Does welding stainless steel cause cancer?. F. Marini, M.P. Ferré, H. Gross, et al. 1995;21(1):65-8. Letter PubMed · Publisher
Occupational and environmental mesotheliomas due to crocidolite mining activities in Wittenoom, Western Australia. A. Rogers, M. Nevill. 1995;21(4):259-64. PubMed · Publisher

Abstract

Objectives: The aim of the study was to review existing cases, calculate rates, and predict future numbers of occupational and environmental mesotheliomas from Wittenoom.

Methods: On the basis of information contained in occupational and environmental histories, Wittenoom cases were extracted from national records collected since 1979. Occupational and residential population estimates were obtained from company and government records. The proportional latency method was used to predict the numbers of mesotheliomas prior to and after the data collection phase. Airborne fiber monitoring was used to calculate risk due to current levels of contamination in the mine and town environments.

Results: During 1979-1994, Wittenoom cases (N = 176) comprised approximately 6% of the mesothelioma cases recorded in Australia. Of these 122 were employed directly in the mining and milling activities, another 18 were involved in the transport of raw fiber or tailings, and 34 were town residents or visitors. Due to past exposures, additional occupational (N = 301) and environmental (N = 83) cases can be expected. Dependent on residential time, existing levels of contamination may result in a risk of between < 1 to 57 per million of the population.

Conclusions: Latency effects will result in considerable numbers of mesotheliomas appearing over the next 10-20 years in Wittenoom. The cessation of mining activities and major clean up of the town will result in reduced mesothelioma cases.
Pleural mesothelioma in oil refinery workers. O. Wong. 1995;21(4):301-9. Comment · Letter PubMed · Publisher
Preliminary analysis of proportional mortality in a cohort of British pottery workers exposed to crystalline silica. J.C. McDonald, N. Cherry, R. McNamee, et al. 1995;21 Suppl 2:63-5. PubMed

Abstract

A cohort of 7020 male pottery workers born in 1916-1945 was identified from all employees in dust-exposed trades, subject to medical surveillance by the Benefits Agency Medical Service of the Department of Social Security in Stoke-on-Trent in the United Kingdom. All but 256 (3.6%) were traced, 1016 (15.0%) had died by 30 June 1992, and death certificates were obtained for 940 (92.5%) of the fatalities - 122 from respiratory cancer. After the exclusion of any recorded asbestos exposure, the proportional mortality ratio (PMR) for lung cancer was 1.22 when calculated against national rates (P < 0.02), but the PMR against local rates was 1.04. Logistic regression analyses based on 75 nested case-referent pairs for which the required information was available showed that lung cancer mortality was dominated by smoking and significantly affected by past asbestos exposure. However, for 47 pairs in which both the case and referent had a history of smoking, there was also significant evidence that the risk was related to duration of silica dust exposure in pottery work but not to radiological score.
Radiographic small lung opacities and pleural abnormalities as a consequence of asbestos exposure in an adult population. A.J. Zitting, A. Karjalainen, O. Impivaara, et al. 1995;21(6):470-7. PubMed · Publisher

Abstract

Objectives: The purpose of this study was to estimate the role of past asbestos exposure as a cause of radiographic small lung opacities and pleural abnormalities in the Finnish adult population.

Methods: The study was conducted in 1978-1981 and was based on a population sample (N = 8000) representative of the Finnish population aged 30 years or over. Full-size chest radiographs and a complete job title history were available for 3811 women and 3274 men. The radiographs were classified according to the 1980 classification of radiographs of pneumoconioses published by the International Labour Office and the work histories according to the probability of occupational asbestos exposure. Age- and smoking-adjusted relative risks of radiographic parenchymal and pleural abnormalities were calculated with the analysis of covariance according to the probability of asbestos exposure.

Results: About 13% of the men and 0.8% of the women were classified as probably exposed to asbestos. There was more than 90% agreement in the repeated work history evaluations. The risk of small lung opacities was significantly increased among the probably exposed men [risk ratio (RR) 1.7 for ILO profusion category 1/1 or more and RR 1.6 for profusion category 1/0]. The risk of pleural plaques was increased both among the men (RR 3.0) and the women (RR 4.8) with probable exposure. The risk of thickened horizontal interlobar fissure was also increased among the probably exposed men (RR 1.7). Among the men, the etiologic fraction attributable to occupational asbestos exposure was about 30% for small lung opacities, about 40% for pleural plaques, and about 20% for thickened horizontal fissure. Among the women the etiologic fractions for asbestos were similar for pleural abnormalities, but much lower for parenchymal ones.

Conclusions: Occupational asbestos exposure has been common among Finnish men, and it plays a significant role in the etiology of both pleural and parenchymal abnormalities also at the level of the general population.
Asbestos exposure and pulmonary fiber concentrations of 300 Finnish urban men. A. Karjalainen, E. Vanhala, P.J. Karhunen, et al. 1994;20(1):34-41. PubMed · Publisher

Abstract

Objectives: The aim of the study was to determine the pulmonary concentrations of mineral fibers in the Finnish male urban population and to evaluate the analysis of pulmonary fiber burden by scanning electron microscopy (SEM) as an indicator of past fiber exposure.

Methods: The pulmonary concentration of mineral fibers was determined by SEM and compared with occupational history for a series of 300 autopsies of urban men aged 33 to 69 years.

Results: The concentration of fibers (f) longer than 1 micron ranged from < 0.3 to 163.10(6) per gram of dry tissue (f.g-1). Asbestos fiber concentrations exceeding 1.10(6) f.g-1 were observed in 33% of the cases with probable occupational exposure to asbestos and 1% of the cases with unlikely occupational exposure. Even asbestos fiber concentrations of 0.3 to 1.10(6) f.g-1, especially of crocidolite-amosite fibers, were rare among the men with unlikely occupational exposure. Fiber concentrations exceeding or equaling 1.10(6) f.g-1 were 10 times more frequent among the men more than 60 years of age as compared with those less than 40 years of age. Inorganic fibers other than asbestos had a weaker correlation with occupational history and age. Smoking habits had no significant effect on the pulmonary fiber counts.

Conclusions: Asbestos fiber concentrations exceeding 1.10(6) f.g-1 are highly indicative of past occupational exposure to asbestos. The distribution of fiber concentrations in the different age groups of this study indicated decreasing asbestos exposure in Finland since the 1970s.
Asbestos exposure and the risk of lung cancer in a general urban population. A. Karjalainen, S. Anttila, E. Vanhala, et al. 1994;20(4):243-50. PubMed · Publisher

Abstract

Objectives: The aim of the study was to investigate the asbestos-associated risk of lung cancer according to histological type of cancer, lobe of origin, pulmonary concentration, and type of amphibole fibers and also to estimate the etiologic fraction of asbestos for lung cancer.

Methods: The pulmonary concentration of asbestos fibers in 113 surgically treated male lung cancer patients and 297 autopsy cases among men serving as referents was determined by scanning electron microscopy. The age- and smoking-adjusted odds ratios of lung cancer were calculated according to pulmonary fiber concentration for all lung cancer types, squamous-cell carcinoma, and adenocarcinoma and for the lower-lobe and the upper- and middle-lobe cancers.

Results: The risk of lung cancer was increased according to the pulmonary concentration of asbestos fibers (f) of 1.0 to 4.99 x 10(6) f.g-1 [odds ratio (OR) 1.7] and > or = 5.0 x 10(6) f.g-1 (OR 5.3). The odds ratios associated with fiber concentrations of > or = 1.0 x 10(6) f.g-1 were higher for adenocarcinoma (OR 4.0) than for squamous-cell carcinoma (OR 1.6). The asbestos-associated risk was higher for lower lobe tumors than for upper lobe tumors. The risk estimates for anthophyllite and crocidolite-amosite fibers were similar, except for the risk of squamous-cell carcinoma. An etiologic fraction of 19% was calculated for asbestos among male surgical lung cancer patients in the greater Helsinki area.

Conclusions: Past exposure to asbestos is a significant factor in the etiology of lung cancer in southern Finland. The asbestos-associated risk seems to be higher for pulmonary adenocarcinoma and lower-lobe tumors than for squamous-cell carcinoma and upper-lobe tumors.
Is there an association between pleural plaques and lung cancer without asbestosis?. M. Nurminen, A. Tossavainen. 1994;20(1):62-4. PubMed · Publisher

Abstract

Objectives: A recent review or meta-analysis of epidemiologic studies concluded that persons with asbestos-related pleural plaques do not have an increased risk of lung cancer in the absence of parenchymal asbestosis. The reviewer inferred that this conclusion provided indirect supportive evidence for the proposition that asbestosis is a necessary precursor of asbestos-related lung cancer. The objective of the present communication is to contest these claims.

Methods: Finnish epidemiologic data and population statistics were used to estimate the apparent risk ratio of lung cancer associated with radiographic signs of pleural plaques. Power calculations were applied to compute the needed population sizes to demonstrate that the association is statistically significant.

Results: Unrealistically large population studies would be needed to observe the statistical relation between pleural plaques and lung cancer, quantitated as a risk ratio of 1.1, resulting from relatively low levels of environmental asbestos exposure. In realistic and valid epidemiologic studies on heavily exposed subpopulations, a two- or threefold risk can be identified.

Conclusions: Uninformative studies should not be interpreted as providing suppressive evidence that pleural plaques are a noncausal risk indicator of lung cancer. Even for the null hypothesis, the inference that asbestosis is a necessary causal link between asbestos and lung cancer is illogical.
Mechanisms of the combined effect of asbestos and smoking in the etiology of lung cancer. H. Vainio, P. Boffetta. 1994;20(4):235-42. Review PubMed · Publisher

Abstract

The joint effects of exposure to two known lung carcinogens, tobacco smoking and asbestos, are reviewed. The variable pattern of interaction--ranging from supramultiplicative to less than additive--may reflect the fact that both asbestos and smoking are complex carcinogens which can affect more than one stage of lung carcinogenesis. The joint effect of two such agents will depend on the relative magnitude of the effects at each stage. The epidemiologic evidence from studies of insulation workers with high exposures suggests an interaction that approximates the multiplicative model, indicating that each of the two factors has an independent action on the multistage process of carcinogenesis. Very limited information is available on the interaction between these two agents in causing specific histological types of lung cancer. Both tobacco smoke and asbestos fibers can be genotoxic and cytotoxic and cause proliferative lesions in the lungs. Tobacco smoke is known to contain carcinogens that bind to critical genes in DNA (deoxyribonucleic acid) and cause mutations. Asbestos fibers may cause chronic inflammation of the lungs, which releases various cytokines and growth factors, and therefore may provide a possible selective growth advantage for mutated cells.
Occupational risk factors for renal-cell carcinoma in Denmark. A. Mellemgaard, G. Engholm, J.K. McLaughlin, et al. 1994;20(3):160-5. PubMed · Publisher

Abstract

Objectives: Risk factors for renal-cell carcinoma, the most frequent type of kidney cancer, remains enigmatic. Time trends in incidence and changes in the regional distribution of this cancer are suggestive of environmental risk factors. This study reports on occupational risk factors for renal-cell carcinoma in Denmark.

Methods: In a population-based study, 365 persons with histologically verified renal-cell carcinoma and 396 referents were interviewed. Information was collected on occupation, education, and occupational exposure to a number of suspected substances, including hydrocarbons, asbestos, and radiation.

Results: Risk of renal-cell carcinoma was found to be associated with employment as a truck driver, exposure to gasoline, other hydrocarbons, and insecticides and herbicides. The risk of renal-cell carcinoma was higher in the lower socioeconomic strata for both the men and the women. Nonsignificantly elevated risks were observed for employment in oil refineries, gasoline stations, and the iron and steel industry. No association was found for exposure to radiation or for employment in industries such as leather manufacturing and health care, which have previously been linked to an increased risk of renal-cell carcinoma.

Conclusions: The risk of renal-cell carcinoma is increased in lower socioeconomic strata, and previously identified or suspected risk factors do not explain the excess in risk. This study adds additional support to the hypothesis of a link between renal-cell carcinoma and hydrocarbons and also demonstrates the need for further studies on occupational risk factors for renal-cell carcinoma.
Pleural mesothelioma and asbestos exposure among Italian oil refinery workers. V. Gennaro, M. Ceppi, P. Boffetta, et al. 1994;20(3):213-5. PubMed · Publisher

Abstract

Objectives: The association between asbestos exposure and risk of mesothelioma was studied among workers from two oil refineries located in the northern Italian cities of Genoa and La Spezia, given that previous cohort analyses revealed two clusters of mesotheliomas and that international cohort studies have so far not reported an excess of this neoplasm among oil refinery workers.

Methods: Men (N = 2300) who had been employed between 1914 and 1988 in two oil refineries located in northern Italy were studied. The follow-up covered the mortality of 639 white-collar and 1661 blue-collar from 1950 to 1991.

Results: Among the cases, the median duration of employment was 14.5 years, and the median time since first employment was 27.5 years. The job titles of the 10 men with pleural mesothelioma were maintenance worker (seven men), electrician (one man) and unspecified blue-collar worker (two men). Blue-collar workers experienced a significantly increased risk of pleural neoplasms, five deaths in each plant, in respect to both the provincial [standardized mortality ratio (SMR) 266] and national (SMR 1663) reference populations. The SMR, based on eight deaths, was 320 for workers with more than 10 years of employment and 20 years since first exposure.

Conclusions: The results uphold the notion that exposure to asbestos in oil refineries causes pleural mesotheliomas. This is the first study to find an excess of pleural mesotheliomas among oil refinery workers exposed to asbestos.
Pleural mesothelioma in a cigarette filter factory worker. M. Huncharek. 1994;20(2):146-7. Case report PubMed · Publisher

Abstract

The incidence of pleural mesothelioma is increasing. Over the past two decades many new occupational and nonoccupational risk groups have been identified. This paper reports a case of pleural mesothelioma in an office worker employed in a cigarette filter factory. Both secondary occupational and domestic asbestos exposure may have occurred. Only one prior report describes the potential asbestos health risks of this occupational group.
Prevention of lung cancer through the use of knowledge on asbestos and other work-related causes--Norwegian experiences. S. Langård. 1994;20 Spec No:100-7. Review PubMed

Abstract

This review attempts to estimate the contribution of different known work-related causes of lung cancer in the Norwegian male population in order to predict the potential of prevention of work-related cases. The presented estimates are based on data from epidemiologic studies made in Norway, but may be of significance for other countries with a similar work-force structure. Over the past decade asbestos-related lung cancer appears to have contributed about two-thirds of the lung cancers that have been related to work exposure in Norway, for example, possibly 125-175 of the 1100 cases that occurred among Norwegian men in 1987. The potential for prevention is, however, greater due to synergism. To a less extent compounds of nickel and chromium have also contributed, along with exposure to polycyclic aromatic hydrocarbons, radon daughters, seafaring work, and other, less significant specific and nonspecific determinants of lung cancer.
Association between asbestos-related pleural plaques and resting hyperventilation. Z. Dujić, D. Eterović, J. Tocilj. 1993;19(5):346-51. PubMed · Publisher

Abstract

This study reports an association between pleural plaques and resting hyperventilation in a group of workers exposed to asbestos. Information on exposure level, pack-years of cigarette smoking, chest radiographs, ventilation parameters, single-breath diffusing lung capacity, and arterial gases were obtained for 344 workers. After the exclusion of 37 workers for isolated parenchymal fibrosis, combined pleuroparenchymal fibrosis, or diffuse pleural thickening, 55 subjects with isolated pleural plaques were evaluated against 252 no-plaque workers. A quantitative pleural score revealed mild pleural disease. Forty-four workers with plaques (80%) had hypocapnia induced by resting hyperventilation. The quantitative pleural score correlated significantly with the partial pressure of carbon dioxide in arterial blood (correlation coefficient = 0.7). A decrement in forced vital capacity was associated with plaques, whether controlled for age, smoking, and exposure or not. It was concluded that the resting hyperventilation observed in some asbestos-exposed subjects is related to the presence of mild pleural plaques and a restrictive disorder.
Lobe of origin of lung cancer among asbestos-exposed patients with or without diffuse interstitial fibrosis. A. Karjalainen, S. Anttila, L. Heikkilä, et al. 1993;19(2):102-7. PubMed · Publisher

Abstract

The effect of asbestos exposure and asbestos-associated fibrosis on the lobe of origin of lung cancer was studied among 108 lung cancer patients. The asbestos-exposed patients had significantly more lower lobe tumors than the unexposed patients. Similar results were obtained when occupational history or lung fiber concentration was used as an indicator of past occupational exposure to asbestos. The predominance of lower lobe tumors occurred even among exposed patients with no histological signs of asbestosis in their lung specimens. Both bronchial and peripheral cancers showed a lower lobe predominance among the exposed patients. Smoking history did not affect the lobar distribution of the tumors. No significant differences occurred for the histological cell types of the tumors between the exposed and unexposed patients. Patients with asbestosis had, however, more adenocarcinomas than the unexposed patients. The results indicate that asbestos may increase the risk of lung cancer even in the absence of asbestosis.
Lung cancer among textile workers in the Prato area of Italy. M. Zappa, E. Paci, A. Seniori Costantini, et al. 1993;19(1):16-20. PubMed · Publisher

Abstract

The association between lung cancer and occupational exposure in the textile industry was investigated in a population-based case-referent study conducted in the Prato area of the province of Florence (Italy) where there is a concentration of textile factories. A complete response to a postal questionnaire was obtained for 207 cases (85.1%) and 440 referents (76.1%). Those who had ever worked in the textile industry had an odds ratio (OR) of 1.45 [95% confidence interval (95% CI) 1.0-2.1]; when nine different textile job titles were considered, an increased OR was observed only for rag sorters (OR 2.2, 95% CI 1.3-3.8) and weavers (OR 1.7, 95% CI 1.1-2.7). Analysis by different "time windows" showed an OR of 3.0 (95% CI 1.6-5.8) for rag sorters at work in the 1950s and an OR of 2.8 (95% CI 1.5-5.0) for weavers at work in the 1970s. This result supports the suggestion of two different carcinogenic exposures in the Prato textile industry (asbestos and mineral oils).
Occupational airborne exposure of the general population of a Norwegian county. P. Bakke, V. Baste, R. Hanoa, et al. 1992;18(1):44-51. PubMed · Publisher

Abstract

Occupational airborne exposure was examined for a stratified sample (N = 1275) of the general population aged 18-73 years in Hordaland County, Norway. The subjects identified all jobs of more than six months since leaving school and stated whether they had been occupationally exposed to specific agents and work processes potentially harmful to the lungs. The prevalence in the population ever having been exposed was 18% for asbestos, 9% for quartz, 5% for aluminum dust, 6% for wood dust, 12% for metal gases, 12% for welding, 9% for soldering, and 1% for hairdressing. According to occupational title (last job), 3% of the population had held a job with a high degree of airborne exposure, 26% a job with moderate exposure, and 70% a job with no airborne exposure. During their worklife both the men and the women tended to leave polluted jobs more often than unpolluted jobs. Occupational exposure to airborne pollutants potentially harmful to the lungs is widespread in this Norwegian general population.
Occupational exposure to sulfuric acid in southern Ontario, Canada, in association with laryngeal cancer. C.L. Soskolne, G.S. Jhangri, J. Siemiatycki, et al. 1992;18(4):225-32. PubMed · Publisher

Abstract

A case-referent study, designed to test associations between asbestos, nickel, and the development of laryngeal cancer, was conducted in southern Ontario in 1977-1979. The cases were individually matched to neighborhood referents for gender and age. This constituted the primary study. Personal interviews had secured tobacco, alcohol, and detailed work histories. To 183 of the male pairs was added retrospective assessments of sulfuric acid exposure for each job, blind of disease status; this constituted the data base for an augmented secondary analysis. Logistic regression revealed statistically significant odds ratios when tobacco and alcohol were controlled. Exposure-response gradients were strongly positive with odds ratios in the range of 1.97 [95% confidence interval (95% CI) 0.63-6.13] for short duration-low level exposure through 6.91 [95% CI 2.20-21.74] for long duration-higher level exposure employing progressively more specific definitions of exposure. Asbestos as a confounder and the interaction terms examined were nonsignificant. These findings are corroborative of those of other studies.
Primary liver cancer and occupational exposure. T. Kauppinen, R. Riala, J. Seitsamo, et al. 1992;18(1):18-25. PubMed · Publisher

Abstract

In a dynamic population-based case-referent study on primary liver cancer and occupational exposure, the work histories of 344 cases and 861 referents, derived from the follow-up of the whole Finnish population in 1976-1978 and 1981, were analyzed by industry, occupation, and agent. After adjustment for alcohol consumption, elevated odds ratios were found for the categories other agricultural workers (mainly milkmaids), clerical workers, persons exposed to welding fumes and those exposed to other inorganic dusts (mainly silica). One possible explanation for the excess among milkmaids was exposure to dust from cattle feed contaminated with aflatoxins. The excess among clerical workers was probably due to nonoccupational factors or chance because occupational exposure was generally rare. The excesses for welding fumes and inorganic dusts, although compatible with occupational etiology, contradict the results of many previous studies carried out among workers exposed to silica dust and welders.
Screening for occupational cancer. M.S. Huuskonen. 1992;18 Suppl 1:110-4. Review PubMed

Abstract

The main strategy for preventing occupational cancer is an environmentally based approach or primary prevention. However, it should be combined with screening, early diagnosis, and treatment. This review discusses screening for occupational cancer but not from the point of view of medical screening. Instead it focuses on asbestos exposure and asbestos-related cancer in Finland and the role screening plays in the current Finnish asbestos program. For example it is the feeling in Finland that screening is a very effective way of preventing further occupational exposure to asbestos and of organizing antismoking campaigns. An individually oriented strategy in cancer prevention should include the modification of exposures by behavioral change, the monitoring of early effects of exposures, and health examinations. The termination of exposure, antismoking campaigns, improved diagnostics, and careful attention to compensation issues combined with the study of other opportunities for prevention are seen as the key issues in screening.
Effects of asbestos-related pleural disease on pulmonary function. S.P. Kouris, D.L. Parker, A.P. Bender, et al. 1991;17(3):179-83. PubMed · Publisher

Abstract

The relationship between loss of pulmonary function and the presence of asbestos-related pleural disease was evaluated for 913 Minnesota asbestos workers. Asbestos-related pleural disease was categorized as circumscribed plaques or diffuse thickening. Compared with workers with normal pleura, workers with plaques had a decreased mean percentage for predicted forced vital capacity (FVC) and predicted forced expiratory volume in 1 s (FEV1.0). Diffuse thickening was associated with more profound decreases in FVC and FEV1.0. No relationship was seen between FEV % [(100 x FEV1.0)/FVC)] and either type of pleural disease. Dyspnea was associated with diffuse thickening more so than plaques. These results remained after control for pack-years of smoking, extent of parenchymal disease, and the presence of pulmonary disease history. Pleural plaques and diffuse pleural thickening were considered independent risk factors for the loss of lung function.
Evaluation of serum aminoterminal propeptide of type III procollagen as an early marker of the active fibrotic process in asbestos-exposed workers. A. Cavalleri, F. Gobba, L. Bacchella, et al. 1991;17(2):139-44. PubMed · Publisher

Abstract

In an evaluation of the possibility of type III procollagen N-terminal propeptide (PIIINP) being an early marker of the active fibrotic process in asbestos-exposed workers, 91 asbestos workers had higher serum PIIINP concentrations than 108 referents. In 24 workers exposed to low levels of airborne asbestos, the serum PIIINP was higher than in the referents but lower than in an exposed group with higher exposure; furthermore a significant correlation (r = 0.63) was found between serum PIIINP and individual cumulative exposure. These data suggest a dose-effect relationship between asbestos exposure and PIIINP serum concentration. In addition workers with a reduced pulmonary function had higher PIIINP values than the referents or the exposed workers with normal pulmonary function. The serum PIIINP levels were related to asbestos exposure even at low airborne concentrations and may represent an early biological marker of impending fibrotic process induced by asbestos.
Relative risk of mesothelioma associated with different levels of exposure to asbestos. T. Tuomi, M.S. Huuskonen, M. Virtamo, et al. 1991;17(6):404-8. PubMed · Publisher

Abstract

The relative risk of mesothelioma associated with different levels of exposure to asbestos was evaluated. The exposure was assessed from work histories of 51 mesothelioma cases and 51 sarcoidosis referents. The lung fiber concentration of the mesothelioma patients was compared with that of two reference groups (13 random autopsy cases and 43 male lung cancer patients). When the categories definite and probable were used as an estimated probability of occupational exposure, an odds ratio of 17.7 [90% confidence interval (90% CI) 3.4-253] and 3.0 (90% CI 0.9-10.6), respectively, was obtained. A lung fiber concentration of greater than 1 million fibers/g of dry tissue as an indicator of accumulated exposure gave an odds ratio of 14.4 (90% CI 2.5-178) for the men in comparison with the autopsy cases and 3.1 (90% CI, 1.3-7.5) in comparison with the lung cancer patients. Elevated risk of mesothelioma was shown to be associated with a lung fiber concentration of greater than 1 million fibers/g of dry tissue.
Lung cancer and exposure to diesel exhaust among bus garage workers. P. Gustavsson, N. Plato, E.B. Lidström, et al. 1990;16(5):348-54. PubMed · Publisher

Abstract

Mortality and cancer incidence was investigated among the 695 bus garage workers employed as mechanics, servicemen, or hostlers for at least six months in five bus garages in Stockholm between 1945 and 1970. The exposure to diesel exhaust and asbestos was estimated by industrial hygienists. A small excess of lung cancer mortality was found in the cohort when occupationally active men in Stockholm were used as the reference group. A case-referent study was performed within the cohort, six referents being selected for each of the 20 lung cancer cases. The lung cancer risk increased with increasing cumulative exposure to diesel exhaust, but not with cumulative asbestos exposure. The relative risk for lung cancer among the highly exposed men was 2.4 (95% CI 1.3-4.5) as compared with those with low exposure. The study indicates that exposure to diesel exhaust increases the risk for lung cancer.
Reporting of occupational cancer in Denmark. T. Skov, S. Mikkelsen, O. Svane, et al. 1990;16(6):401-5. PubMed · Publisher

Abstract

Many patients with occupational diseases fail to obtain compensation because their disease is not recognized as occupational and reported to the authorities. The present study examined the reporting of pleural mesotheliomas and sinonasal adenocarcinomas--cancers with well-known associations with occupational exposures to asbestos and wood dust--in Denmark in 1983-1987. The estimated underreporting was around 50%. Examination of the medical records of patients who had not been reported in 1986-1987 revealed that in most cases the medical records did not contain sufficiently detailed information about occupational exposures. It was recommended that a formal screening interview be carried out whenever a diagnosis is made of a potential occupational cancer. Medical associations may play a major role by issuing guidelines addressing occupational diseases within the fields of their expertise.
Smoking habits and lifetime occupational exposure to gases or dusts, including asbestos and quartz, in a Norwegian community. P. Bakke, A. Gulsvik, G.E. Eide, et al. 1990;16(3):195-202. PubMed · Publisher

Abstract

Past or present occupational airborne exposure was recorded with a self-administered questionnaire sent to a random sample (N = 4992) of the 15- to 70-year-old population of Hordaland County, Norway. Completed questionnaires were returned by 90% of the sample. The respondents comprised 39% smokers, 20% ex-smokers, and 41% nonsmokers. Altogether 46% of the men and 12% of the women had a history of occupational gas or dust exposure. Occupational asbestos exposure was reported by 10% of the men and 0.4% of the women, and quartz exposure had been experienced by 8% of the men and 0.4% of the women. Smokers with a history of asbestos exposure represented 5% of the male population. Thirty percent of the smokers reported having been advised to stop smoking by a physician. The asbestos-exposed smokers had not received such advice more often than the smokers not exposed to asbestos. The findings indicate that airborne occupational exposure is widespread in the Norwegian County of Hordaland.

1980s

Amosite mesothelioma in a cohort of asbestos workers. J. Ribak, H. Seidman, I.J. Selikoff. 1989;15(2):106-10. PubMed · Publisher

Abstract

A cohort of 820 asbestos workers with a short duration of exposure to amosite between 1941 and 1945 was followed. These men were alive five years after starting work and were observed until 1988. Seventeen cases of malignant mesothelioma (eight pleural, nine peritoneal) were found. The mean age at the onset of exposure was 33 years for men with pleural mesothelioma and 30 years for those with peritoneal mesothelioma. Chest pain was the main symptom in pleural mesothelioma and abdominal pain in peritoneal mesothelioma. Open lung biopsy was the most useful diagnostic approach for pleural mesothelioma, whereas for peritoneal mesothelioma it was exploratory laparotomy. Pleural patients died of pulmonary insufficiency, and peritoneal patients of wasting and inanition. In both groups the death certificate diagnosis was less accurate than the clinical diagnosis at death. The mean survival was 12.5 months from first symptom to death for the pleural group and 5.4 months for the peritoneal group.
Incidence of cancer among welders and other workers in a Norwegian shipyard. A. Melkild, S. Langård, A. Andersen, et al. 1989;15(6):387-94. PubMed · Publisher

Abstract

The incidence of cancer among 4778 male shipyard workers, including 783 mild steel welders, was investigated in a historical cohort study. The workers had been employed for at least three months between 1 January 1946 and 31 March 1977. The incidence of cancer was observed from 1 January 1953 through 1986. The loss during follow-up was only 0.9%. There were 53 observed cases of lung cancer in the whole cohort versus 31.3 expected on the basis of the national rates for men. There was an increased incidence of lung cancer among the welders, with seven observed cases versus 3.2 expected. Twenty-two cases of bladder cancer were observed versus 15.2 expected. Two malignant mesotheliomas had occurred (0.7 expected). Smoking was likely to be a confounder in the present study. Due to concomitant exposure to asbestos, the results are inconclusive concerning the possible relationship between exposure to welding fumes and lung cancer.
Mesothelioma among Swiss furniture workers. G. Schüler, J.R. Rüttner. 1989;15(6):440-2. Comment · Letter PubMed · Publisher
Mortality of auto mechanics. A ten-year follow-up. E.S. Hansen. 1989;15(1):43-6. PubMed · Publisher

Abstract

This study was set up to investigate whether work in car repair workshops is associated with an increased risk of ischemic heart disease and specific malignant neoplasms. For this purpose, a cohort of auto mechanics has been followed through 10 years with regard to cause-specific mortality. Comparisons were made with another cohort of skilled male workers who were not exposed to asbestos or petrochemical substances. The auto mechanics' mortality was increased for ischemic heart disease [standardized mortality ratio (SMR) 121, 95% confidence interval (95% CI) 102-145], other cardiovascular diseases (SMR 112, 95% CI 82-150), cancer (SMR 115, 95% CI 97-136), other diseases (SMR 119, 95% CI 94-149), and external causes (SMR 131, 95% CI 113-153). For specific cancer sites, increases were seen for pancreatic cancer, urinary cancer outside the bladder, and pleural mesothelioma.
Re: "Malignant Pleural Mesothelioma Among Swiss Furniture Workers: A New High-Risk Group" by CE Minder, J.P Vader. Scand J work Environ Health 1988;14:252-6. E. Merler, P. Ricci. 1989;15(6):439-40. Comment PubMed · Publisher
Respiratory cancer mortality among workers employed in thermoelectric power plants. F. Forastiere, N. Pupp, E. Magliola, et al. 1989;15(6):383-6. PubMed · Publisher

Abstract

A historical cohort study of 406 workers was undertaken to evaluate the possible health hazards of employment in traditional electric power plants with particular regard to cancer mortality. The total mortality was below that expected [observed 40, standardized mortality ratio (SMR) 87] on the basis of national rates. Cancer mortality was slightly increased (SMR 112), mainly because of an excess of respiratory cancer (observed 9, SMR 171, 90% CI 89-299). Lung cancer deaths were higher than expected among those less than 60 years of age and among those with a duration of exposure and a latency period since first employment of over 10 years (observed 7, SMR 184). Furthermore, the increase was more pronounced among maintenance workers and workers in general services. Previous data indicated that there had been past exposure to some known respiratory carcinogens (ie, asbestos, polycyclic aromatic hydrocarbons). This study suggests that a possible lung cancer risk from traditional electricity generating plants should be considered and further studied.
An 11-year longitudinal study of the occupational dust exposure and lung function of polyvinyl chloride, cement and asbestos cement factory workers. A. Siracusa, A. Forcina, R. Volpi, et al. 1988;14(3):181-8. PubMed · Publisher

Abstract

Standardized questionnaires and lung function tests were administered in 1973, 1980, and 1984 to 126 workers occupationally exposed to polyvinyl chloride (PVC) dust, to cement dust, or to asbestos cement dust until 1974-1978 and to PVC thereafter. The workers in the last group were assigned to two asbestos exposure categories (heavy and slight). The decline in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1.0) was analyzed with regard to the length of time since the data of first employment. After adjustment for age, height, and smoking status at the date of first employment, the decline in FVC and FEV1.0 among the nonsmokers-light smokers was slightly accelerated with length of employment in the PVC and slight asbestos exposure groups and markedly accelerated with time since first employment in the heavy asbestos exposure group. The heavy smokers in all the exposure groups had FVC and FEV1.0 predicted values that were lower than those of the nonsmokers-light smokers; these differences remained constant with length of employment. Cessation of asbestos exposure for about 10 years did not seem to change lung function decline.
Comment on the interpretation of Jäppinen et al concerning increased incidence among board mill workers. K. Thorén, B. Järvholm, S. Hagberg. 1988;14(1):52. Letter PubMed · Publisher
Further evidence of nonasbestos-related mesothelioma. A review of the literature. P.V. Pelnar. 1988;14(3):141-4. Review PubMed · Publisher

Abstract

Asbestos is not the only cause of malignant mesothelioma. An updated review of the literature is presented with reports on mesothelioma with unknown causes (spontaneous cases) in animals and humans and on mesothelioma in man in association with exposure to erionite-zeolite, exposure to ionizing radiation, and chronic inflammation and in animals in association with biological (viral), chemical, physicochemical, and physical agents.
Mesothelioma in Great Britain in 1968-1983. R.D. Jones, D.M. Smith, P.G. Thomas. 1988;14(3):145-52. PubMed · Publisher

Abstract

The British mesothelioma register records deaths in Great Britain when the word "mesothelioma" is on the death certificate. In 1968-1983 the mesothelioma deaths among men increased from 114 to 467, while those among women increased from 38 to 90. In 1983 the crude mesothelioma death rates were 17.5 per million and 3.2 per million for the men and women, respectively. The Northern region had the highest crude rates. At the county level, the highest crude deaths rates in 1976-1983 were recorded for the men in Devon and for the women in Lancashire. Marked differences occurred in the ratio of deaths among men to deaths among women for mesothelioma of the pleura (4.6:1) and for mesothelioma of the peritoneum (2:1). The age-specific death rates for men and women diverged markedly for pleural mesothelioma but not for peritoneal mesothelioma. Trends in the use of asbestos and in age- and sex-specific death rates suggest that the annual number of mesothelioma deaths will continue to increase, possibly until the turn of the century. This increase will be concentrated among the men as the main asbestos exposure of women occurred during the war and the annual deaths due to this exposure may have already peaked.
Mortality and cancer incidence among marine engineers and machinists in Iceland. V. Rafnsson, S.G. Jóhannesdóttir, H. Oddsson, et al. 1988;14(3):197-200. PubMed · Publisher

Abstract

A retrospective cohort study of mortality and cancer morbidity was carried out among 295 marine engineers and 182 machinists with special regard to cancer of the lung. The cohort was defined as all graduates from engineering and machinists school in Iceland during 1936-1955. During vocational training, as well as in their professional lives, marine engineers and machinists are exposed to asbestos, different kinds of mineral oils, and exhaust gases with marked individual variation as regards mode and magnitude of exposure. For deaths occurring between 1951 and 1982 information was obtained from the Statistical Bureau of Iceland. Significantly increased standardized mortality ratios were determined for cancer of the trachea, bronchus, and lung for the entire cohort. Record linkage with the Cancer Register revealed 36 cancers in the period 1955-1982. No statistically significant excess was found for the overall cancer incidence or for the incidence of cancer at any particular site. A special survey of smoking status showed that cigarette smoking was not as common among the subjects of the cohort as among the general male population in Reykjavik. These results support the suggestion that the increased mortality of lung cancer in the study group had a causal relationship to occupational exposure, particularly to asbestos exposure.
Abnormalities of pulmonary function and pleural disease among titanium metal production workers. D.H. Garabrant, L.J. Fine, C. Oliver, et al. 1987;13(1):47-51. PubMed · Publisher

Abstract

The authors conducted a cross-sectional survey of respiratory disease among 209 titanium metal production workers. Work in areas where there was exposure to titanium tetrachloride and titanium dioxide particulates was associated with reductions in ventilatory capacity. Pleural disease (plaques and diffuse thickening) was present in the chest radiographs of 17% of the subjects and was associated with the duration of work in titanium manufacturing. It was also associated with past asbestos exposure. After control for asbestos exposure, it remained associated with titanium manufacturing. The findings are consistent with the hypothesis that titanium tetrachloride and titanium dioxide particulates may be associated with a reduction in ventilatory capacity and that the overall process of titanium manufacturing may be associated with unexpected pleural disease.
Asbestos-associated lung effects in car mechanics. K. Marcus, B.G. Järvholm, S. Larsson. 1987;13(3):252-4. PubMed · Publisher

Abstract

In a study of the possible impact of asbestos exposure on car mechanics, 925 car mechanics and 109 referents (office workers in car-repair firms) were examined. They took part in a health screening in 1977-1981. The forced expiratory volumes in 1 s and the forced vital capacities of the car mechanics were close to the predicted values and did not differ from the findings of the referents. Pleural plaques were found in 41 of the mechanics but in none of the referents. Only minor changes were detected in the chest radiographs ie, 1/1 or less according to the ILO-U/C classification. It is concluded that asbestos exposure can generally cause pleural plaques in car mechanics but no substantial impairment of lung function.
Preliminary results on smoking patterns for workers attending an asbestos abatement course. J.H. Lange, D.A. Weyel, L.M. Rosato, et al. 1987;13(5):459. Letter PubMed · Publisher
A case-referent study of lung cancer, occupational exposures and smoking. I. Comparison of title-based and exposure-based occupational information. H. Kjuus, R. Skjaerven, S. Langård, et al. 1986;12(3):193-202. PubMed · Publisher

Abstract

The role of occupational exposures and smoking in the development of lung cancer has been studied among 176 male incident lung cancer cases and 176 referents admitted to two county hospitals in southeast Norway during 1979-1983. After the allocation of all occupational titles in the Nordic Classification of Occupations into three exposure groups according to potential exposure to respiratory carcinogens and other contaminants, each subject was classified according to exposure status of main occupation and number of years in each exposure category. An excess risk of lung cancer was observed both among those in possibly exposed occupations and among those definitely exposed. A more than threefold excess risk was observed among subjects with more than 30 years in exposed occupations. Exposure to 22 agents/processes was further assessed by a separate questionnaire and estimated simultaneously in a logistic regression model. Elevated risks were associated with exposure to asbestos and several other agents/processes, which largely correlated to each other. Smoking was strongly associated with all histological subtypes of lung cancer, while for occupational exposures the risk ratio was highest for small cell carcinoma and lowest for adenocarcinoma. Very high risk ratios for lung cancer were observed among heavy smokers in exposed occupations.
A case-referent study of lung cancer, occupational exposures and smoking. II. Role of asbestos exposure. H. Kjuus, R. Skjaerven, S. Langård, et al. 1986;12(3):203-9. PubMed · Publisher

Abstract

In a hospital-based case-referent study of 176 incident lung cancer cases, ascertained during a five-year period from two county hospitals, the role of asbestos exposure and smoking has been studied. Information on asbestos exposure was obtained from personal interviews, and allocated to four exposure categories, according to the intensity and duration of the exposure. Twenty-five percent of the cases and 10% of the referents had been moderately to heavily exposed to asbestos during their working career. A statistically significant trend in risk ratio related to the degree of exposure was observed, with a more than fourfold risk among the heavily exposed. The strongest association was found between asbestos exposure and small cell carcinoma, and the weakest association between asbestos exposure and adenocarcinoma. Very high risk ratios were observed among asbestos-exposed subjects who were heavy smokers, and the interaction observed between asbestos and smoking conformed more closely to a multiplicative model than to an additive one. The results suggest that the observed association between lung cancer and occupational exposures in this study was, to a large extent, due to asbestos exposure. Information on such exposure was missing in 90% of the medical records of these patients.
A case-referent study of lung cancer, occupational exposures and smoking. III. Etiologic fraction of occupational exposures. H. Kjuus, S. Langård, R. Skjaerven. 1986;12(3):210-5. PubMed · Publisher

Abstract

The proportion of lung cancer related to occupational exposure to respiratory carcinogens and other workplace contaminants has been studied in a hospital-based case-referent study of 176 incident cases and 176 referents, recruited from the medical ward of two county hospitals in southern Norway. On the basis of job title and exposure information, three different approaches for the estimation of etiologic fraction were used, all based upon a trichotomous categorization of the exposure variable. Among the definitely exposed subjects, the etiologic fraction for lung cancer related to occupational exposure factors was from 22 to 35%, increasing to 37-47% when the "possibly exposed" categories were included. When asbestos was the only factor to be eliminated, the etiologic fraction estimate suggested a 23% reduction in the lung cancer incidence in the study population. More than 90% of the lung cancer cases would theoretically have been prevented if smoking had been completely removed. The relative merits of preventing one or several of the study factors simultaneously is discussed.
Asbestos-related findings in chest radiographs of the male population of the county of Telemark, Norway--a cross-sectional study. B. Hilt, J.T. Lien, P.G. Lund-Larsen, et al. 1986;12(6):567-73. PubMed · Publisher

Abstract

In order to investigate the prevalence of asbestos-related diseases, a cross-sectional population study was conducted among 28,216 men aged 40 years in nine municipalities of the county of Telemark, Norway. In a primary radiographic screening 10 X 10-cm chest radiographs were taken of 21,483 persons. In two independent readings of the radiographs, pleural changes were observed in 6.9 and 8.5% of the study subjects. Radiographic findings in the primary screening led to 1,431 subjects being selected for a reexamination. On the basis of occupational histories and 40 X 40-cm chest radiographs, it was concluded that 470 of these subjects (2.2% of the screened population) had radiographic changes consistent with an asbestos-related disorder. Among these, 86 had lung fibrosis (82 in combination with pleural plaques) and 384 had pleural plaques only. There were marked differences in the occurrence of asbestos-related disorders between the seven urban and two rural communities studied, and agreement was observed between the occurrence of such disorders and the degree and duration of the reported asbestos exposure. The study presents evidence that asbestos-related disorders may be more prevalent in the general male population than has been recognized earlier.
Past exposures to airborne fibers and other potential risk factors in the European man-made mineral fiber production industry. J. Cherrie, J. Dodgson. 1986;12 Suppl 1:26-33. PubMed

Abstract

A historical environmental investigation was undertaken in European man-made mineral fiber factories (MMMF). The aim was to assess past exposures to MMMF and other environmental risk factors (asbestos, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, formaldehyde, and arsenic). A self-administered questionnaire completed by each plant management and an interview of the respondents were used. Addition of oil to the MMMF, change in the nominal fiber size of the bulk MMMF, and elimination of early discontinuous production techniques were identified as principal changes. The absence of oil, small nominal size, and labor-intensive production have been judged to be associated with higher airborne fiber levels. It was concluded that for epidemiologic purposes the subdivision of the history of each plant into an early, intermediate, and late technological phase based on the aforementioned changes would be appropriate. Corresponding time periods were identified for asbestos usage, use of bitumen as a binder, and production of slag wool. Two factories were singled out for specific attention: one where asbestos was used in calcium silicate brick production and one where olivine, used as a raw material, may have been contaminated with natural mineral fibers and where the production process would have exposed workers to coal-tar pitch volatiles.
Previous asbestos exposure and smoking habits in the county of Telemark, Norway--a cross-sectional population study. B. Hilt, S. Langård, P.G. Lund-Larsen, et al. 1986;12(6):561-6. PubMed · Publisher

Abstract

A cross-sectional population study. Scand J Work Environ Health 12 (1986) 561-566. In order to study the number of persons previously exposed to asbestos in the general population, an investigation with a self-administered questionnaire and a screening with 10 X 10-cm chest radiographs was conducted among 28,216 men aged 40 years and over in nine municipalities in the county of Telemark, Norway. Among the 21,453 subjects who answered the questionnaire in the primary screening, 3,888 (18.1%) reported previous occupational exposure to asbestos. Of the exposed subjects 2,368 (61.4%) were less than 60 years of age, and 2,611 (69.9%) had been exposed for the first time after 1950. In regard to the degree of exposure, 77.7% considered their previous exposure to be light. Past and present smoking habits were recorded for all the subjects, and a high-risk group of 1,734 subjects with past exposure to asbestos and present smoking was identified. Approximately 270 incident cases of lung cancer can be expected among the 21,453 study subjects during the next 10 years, and it is estimated that about 110 of these cases will occur in the high-risk group with combined asbestos-cigarette exposure.
Analysis of asbestos fibers and asbestos bodies in tissue samples from human lung. An international interlaboratory trial. B. Gylseth, A. Churg, J.M. Davis, et al. 1985;11(2):107-10. PubMed · Publisher

Abstract

In order to compare methods of counting asbestos fibers in lung tissue, seven laboratories participated in an interlaboratory trial in which tissue samples from five human lungs were analyzed. In some laboratories, fiber concentrations were assessed with the light microscope and, in others, with either scanning or transmission electron microscopes. Within each laboratory the ranking of the results was similar, but there were marked differences in the absolute values obtained by the different laboratories. It is concluded that the laboratories participating in this trial appear to produce internally consistent results, but there is difficulty in directly comparing results from one laboratory to the next.
Lung function studies of asbestos workers. M.L. Wang, P.L. Lu. 1985;11 Suppl 4:34-42. PubMed

Abstract

Pulmonary function tests have been conducted on 155 asbestos workers and 130 referents. It was found that the lung function impairment in asbestos workers is predominantly a restrictive ventilatory defect appearing even when radiographic changes are not detectable. There was, however, no evidence of airway obstruction. As the disease progressed, all the pulmonary function indices, including vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), maximal ventilation volume (MVV), total lung capacity (TLC), and pulmonary diffusing capacity (DLCO), were reduced dramatically, with the exception of FEV1.0/FVC(%). It is suggested that both radiographic examination and pulmonary function tests should be used as early detection measures of asbestos-induced lung disorders. VC, FVC, and FEV1.0 are the simplest, most reproducible, and most valid indices for the health surveillance of asbestos workers, while the FVC test is the most valuable for epidemiologic study. With stepwise regression analysis a quantitative relationship between dust exposure and pulmonary function was demonstrated. There was no significant difference in the small airway function of the exposed workers and the referents. Further study is needed to investigate the possibility of asbestos-induced small airway obstruction and to estimate the roles played by cigarette smoking and air pollution.
Occupational cancer. Where now and where next?. F.J. Roe. 1985;11(3 Spec No):181-7. PubMed · Publisher

Abstract

For each kind of occupationally associated cancer, there are three distinct stages in the development of the problem: recognition of a possible problem, confirmation, and the introduction of preventive measures. In the past, recognition of a possible problem depended heavily on chance and on the powers and observation of dedicated physicians and surgeons. Confirmation consisted of the collection of further anecdotal evidence and the conduct of case-referent (case-control) or other studies. The introduction of preventive measures often lagged woefully behind confirmation that a problem existed. Recently, the power of epidemiology as a primary investigative tool has grown to the point where unsuspected associations between occupation and cancer risk may be the first hint that a problem exists. However, it is important to recognize that investigative epidemiology is capable of constructing misleading pictures. In the future there is bound to be continuing pressure to reduce maximal permissible exposure to proven carcinogens. For chemicals for which there is no more than suspicion based on laboratory tests, one must ensure that regulatory action is based on good science, sound judgement, and common sense, rather than on the machinations of those with vested interests, of ambitious lawyers, or of the lunatic fringe. Less than 10% of all cancers are likely to be due to occupational factors. Therefore, even turning the world upside down with safety precautions against actual and suspected carcinogens would only marginally affect the present human cancer burden.
Cancer mortality among workers in a thermoelectric power plant. G. Cammarano, P. Crosignani, F. Berrino, et al. 1984;10(4):259-61. PubMed · Publisher

Abstract

At a thermoelectric power plant in Turbigo (Milan, Italy), an analysis of the technological process has shown the presence of exposure to several carcinogens: polycyclic aromatic hydrocarbons, asbestos, hydrazine, polychlorinated biphenyls, chromium, nickel, and beryllium. An epidemiologic study was carried out to quantify the effect of the detected exposures on the workers, and the cancer mortality of the cohort was compared with the corresponding rates from the closest town and with cancer register data from a nearby province. Excess mortality was found for workers with 10 or more years of employment; the median latency time was about 20 years.
Mortality among asbestos-exposed workers in a railroad workshop. C.G. Ohlson, B. Klaesson, C. Hogstedt. 1984;10(5):283-91. PubMed · Publisher

Abstract

The mortality experience of a cohort of 3 297 railroad maintenance shopworkers exposed to asbestos was investigated. The study period was 1951-1980, and the vital status was assessed for 99.6% of the men. Individual estimates of cumulative asbestos exposure were based on detailed records on work tasks and divisions. Dust measurements were scanty in earlier decades, and estimates of average fiber levels were therefore based on information on the amount and kind of asbestos used, job descriptions, and interviews with older workers. The overall mortality was lower than expected from the national death rates (standardized mortality ratio = 82). The mortality from lung cancer increased as cumulative exposure increased in consistent dose-response relationships. Employment times of less than 30 years in workplaces with moderate levels of mainly chrysotile asbestos was not associated with any apparent increase in the risk of lung cancer. A subgroup exposed for more than 30 years in workplaces repairing steam engines, where amphiboles were used as well, had a standardized mortality ratio of 192 for lung cancer. This figure may be an underestimation due to healthy worker selection and fewer smokers than normal. The "true" standardized mortality ratio was estimated to be about 300. Five cases of mesothelioma were observed.
Mortality and morbidity of Swedish insulation workers. A. Sandén, B. Järvholm, P.E. Näslund. 1984;10(3):207. Letter PubMed
Occupational asbestos exposure, lung-fiber concentration and latency time in malignant mesothelioma. G. Mowé, B. Gylseth, F. Hartveit, et al. 1984;10(5):293-8. PubMed · Publisher

Abstract

Mineral fiber concentration in lung tissue was analyzed by scanning electron microscopy in 73 males with malignant mesothelioma and in 36 referents who died of cardio- or cerebrovascular diseases. The investigation showed apparent differences in the median lung-fiber concentration between occupational groups with different levels of asbestos exposure, as judged from their occupational history. Thus the mineral fiber content in human lung tissue provides a useful indicator of cumulative asbestos exposure. There was also a statistically significant difference between the median lung-fiber concentration among mesothelioma cases with unlikely or unknown occupational asbestos exposure and the reference group. The latency times in 42 of the cases with definite or probable occupational asbestos exposure showed a log-normal distribution with a median of 37 years and a range of 19-68 years. No statistically significant correlation was found between the logarithm of the latency time and the logarithm of the lung-fiber concentration.
Pleural changes and exposure to fibrous minerals. G. Hillerdal. 1984;10(6 Spec No):473-9. PubMed · Publisher

Abstract

The pleura is a main target for various reactions related to asbestos exposure. However there are great radiological and clinical differences between the various reactions, and there is also increasing evidence that they have different prognoses. The main reactions are pleural plaques on the one hand and acute pleurisy and diffuse pleural fibrosis on the other. In a population with a low mesothelioma risk, the anthophyllite-exposed population of Northern Karelia in Finland, there are very few reactions of the second type, while plaques are very common. In Turkey, where the exposure is to erionite, the mesothelioma level is extremely high, and reactions of type two are very common in the exposed population. Thus it seems that careful discrimination of the various pleural changes can have prognostic value. There are also indications that plaques do not have any relation to a disturbed immunologic system, while pleurisy and diffuse pleurisy have.
Lung function of sheet metal workers exposed to fiber glass. R. Sixt, B. Bake, G. Abrahamsson, et al. 1983;9(1):9-14. PubMed · Publisher

Abstract

Out of 532 registered and contacted sheet metal workers, 251 responded, but only seven pairs were acceptable for the present study due to the following requirement: no history of smoking, pleural plaques or asbestos exposure. Seven of these workers were exposed daily to fiber glass, and seven were almost never exposed. In a second step nine additional exposed workers were included. Ordinary spirometry, lung volumes, closing volumes and the slope of the alveolar plateau, the maximum expiratory flow in air and after helium-oxygen breathing, and the elastic recoil pressures were measured. No evidence of small airway dysfunction or restrictive or obstructive ventilatory impairment was found, but the elastic recoil pressures of the exposed group were slightly increased. Fiber glass can conceivably cause a corresponding faint and probably harmless fibrous reaction in the lung parenchyma.
Nasal and sinonasal cancer. Connection with occupational exposures in Denmark, Finland and Sweden. S. Hernberg, P. Westerholm, K. Schultz-Larsen, et al. 1983;9(4):315-26. PubMed · Publisher

Abstract

A joint Danish-Finnish-Swedish case-referent investigation was initiated in 1977 in order to study the connection between nasal and sinonasal cancer and various occupational exposures. All new cases of nasal and sinonasal cancer were collected from the national cancer registers (Finland and Sweden) or from the hospitals (Denmark). Those still alive who agreed to an interview (N = 167) were individually matched for age and sex with patients with colonic or rectal cancer. A detailed telephone interview was made according to standardized forms. Both cases and referents thought that their condition was the one under study. The exposures were coded blindly by an industrial hygienist. The results showed associations between nasal and sinonasal cancer and exposure to (i) hardwood or mixed wood dust (discordant pairs 14: 2), (ii) softwood dust alone (13:4), (iii) chromium (16: 6), (iv) nickel (12: 5, not significant), (v) welding, flame-cutting and soldering (17: 6), and (vi) lacquers and paints (14: 0). The last finding was probably due to confounding from wood dust exposure. Hardwood dust exposure was associated with adenocarcinoma. Softwood dust exposure alone was associated with epidermoid and anaplastic carcinomas. No associations were found for a number of exposures, including agricultural chemicals, textile dust, asbestos, quartz dust, organic solvents and leather work. Possible exposure to formaldehyde was evenly distributed between the cases and referents.
Nasal cancer and occupational exposures. Preliminary report of a joint Nordic case-referent study. S. Hernberg, Y. Collan, R. Degerth, et al. 1983;9(2 Spec No):208-13. PubMed · Publisher

Abstract

Nasal and sinus paranasal cancers have been associated with several occupational exposures, for example, dust from hardwood, nickel and unspecific agents occurring in the boot and shoe industry. A joint Danish-Finnish-Swedish case-referent investigation was initiated in 1977 to study further the connection between nasal and sinus paranasal cancers and various occupational exposures. All new cases of these cancers were collected from the national cancer registers (Finland & Sweden) or from hospitals (Denmark). Those still alive who agreed to the interview (N = 167) were individually matched for age and sex with patients with colonic or rectal cancer. A detailed telephone interview was performed according to a standardized procedure. Both the cases and referents thought that their condition was the one under study. The exposures were coded blindly by an experienced industrial hygienist. The results showed associations between nasal or sinus paranasal cancer and exposure to hardwood or mixed wood dust (discordant pairs 14/2); softwood dust alone (13/4); chromium 16/6); nickel (12/5, not significant); welding, flamecutting, and soldering (17/16); and lacquers and paints (12/0). Hardwood dust exposure showed a connection with adenocarcinoma. Softwood dust exposure alone was associated with epidermoid and anaplastic carcinomas. No associations were found for a number of exposures, including agricultural chemicals, textile dust, asbestos, quartz dust, organic solvents, and leather work. Possible exposure to formaldehyde was evenly distributed between the cases and referents.
Pathology standards for asbestosis. F.H. Green, M. Attfield. 1983;9(2 Spec No):162-8. PubMed · Publisher

Abstract

Pathology standards for asbestos-associated diseases of the lungs and pleural cavities were recently developed by the Pneumoconiosis Committee of the United States College of American Pathologists under contract to the US National Institute for Occupational Safety and Health (NIOSH). The purpose of the contract was to develop standardized criteria for the pathological diagnosis of these diseases and to develop a system for grading the severity and extent of asbestosis. The results of a preliminary reading trial and the NIOSH statistical analysis of the trial are presented. These results indicate that the proposed grading schema has acceptable inter- and intra-observer variability. The variability is similar to that observed for radiologists in radiographic reading trials.
Preliminary results from a cohort of workers exposed to wollastonite in a Finish limestone quarry. M.S. Huuskonen, J. Järvisalo, H. Koskinen, et al. 1983;9(2 Spec No):169-75. Case report PubMed · Publisher

Abstract

Wollastonite metasilicate fibers are rather similar in form, length, and diameter, but mineralogically different, to amphibole asbestos fibers. We have studied immunologic findings from 46 men exposed to wollastonite at a limestone quarry for at least 10 years. These workers showed a higher prevalence of positive serum rheumatoid factors than blood donors did. This finding resembles the one detected among asbestos workers. The group of wollastonite workers with radiological signs of pulmonary fibrosis had activities of serum angiotensin-converting enzyme that were similar to those of wollastonite workers without fibrosis. A mortality study of 238 quarry workers with 5,769 person-years was, as expected, nonpositive. It was interesting that one woman with 20 years of exposure to wollastonite and with no other known exposure to fibers revealed a malignant retroperitoneal mesenchymal tumor 30 years after the initial exposure. This kind of very rare tumor is difficult to distinguish from mesothelioma. However, this is only one case, and it is impossible to draw any definite conclusions.
Statistical methods for analyzing effects of temporal patterns of exposure on cancer risks. D.C. Thomas. 1983;9(4):353-66. PubMed · Publisher

Abstract

Two approaches to the inclusion of temporal factors in the analysis of exposure-response relations are compared: (i) multivariate logistic analysis incorporating simple exposure indices, together with additional temporal variables and their interactions, and (ii) direct fitting to models of the disease process. These approaches are illustrated on case-referent data relating lung cancer to asbestos and smoking. From approach i average age at exposure, age at risk, and duration of exposure were found to contribute direct or interaction effects. Two models of carcinogenesis were fit. In a two-stage initiation-latency model the median latency period was estimated at 11.0 years overall, but was somewhat longer for asbestos-induced and shorter for smoking-induced tumors. When this difference was allowed for, latency periods seemed to be inversely related to the average intensities of both asbestos and smoking. In the multistage model, the best fit was obtained with asbestos acting at the fourth and smoking at the fifth of six stages. Lifetime risks of lung cancer are projected under the different models.
A cohort study on mortality among long-time employed Swedish chimney sweeps. C. Hogstedt, K. Andersson, B. Frenning, et al. 1982;8 Suppl 1:72-8. PubMed

Abstract

A cohort study on mortality among all members of the Swedish Chimney Sweeps Union who were active in 1950 or later and have been members for at least 10 a has been performed; 2,071 chimney sweeps fulfilled the criteria and the loss in the follow-up was less than 1 %. The observed numbers of death before the age of 80 were compared with sex-, calendar year-, and age class specific expectancy values from the national statistics of 1951-1979. Two hundred and thirty deaths were observed versus 197.6 expected. This result was due to a significant excess of deaths from tumors, particularly lung and esophageal cancer, and from nonmalignant chronic respiratory diseases. The multifold increased risk from these diseases could hardly be explained by extreme smoking or alcohol habits but rather by exposure to polycyclic aromatic hydrocarbons, nitrogen compounds, arsenic, and asbestos in combination with exposure to sulfur dioxide. The excess mortality had occurred in spite of favorable selection factors as demonstrated in different subcohorts. Preventive actions to diminish inhalation of soot and combustion gases should be taken.
Analysis of a follow-up study: an example from asbestos-exposed insulation workers. M.J. Campbell, J.H. Langlands. 1982;8 Suppl 1:43-7. PubMed

Abstract

An 11-a follow-up study was carried out on a working population of asbestos insulation workers to investigate the possible progression of symptoms and signs. A total of 166 men had repeat radiology, and the 43 men who had progressed in radiography category of profusion of small irregular opacities (as determined by the ILO U/C International Classification of Radiographs of Pneumoconioses, 1980) comprised 37 (32%) of the 117 smokers, 3 (17%) of the 18 exsmokers, and 3 (10%) of the 31 nonsmokers. For 148 men over 20 a of age at the time of original study, and with lung function measured in both surveys, smoking was associated with a significantly reduced transfer factor (TLCO). For smokers in category 0 at first survey, a low TLCO was associated with subsequent progression to higher radiographic categories.
Effects of approximation in exposure assessments on estimates of exposure- response relationships. B.G. Armstrong, D. Oakes. 1982;8 Suppl 1:20-3. PubMed

Abstract

Information on exposure in cohort studies of occupational groups is often very incomplete. If assessments of exposure level are attempted, they are inevitably subject to random error. Even when unbiased, such measurement error can give rise to bias in an estimate of an exposure-response relationship. Since practical techniques exist to account for this effect only in certain situations where response may be measured on a continuous scale, a technique suitable for mortality studies needs developing. In the present report a procedure is described for reducing the bias due to random error in the estimated exposure-response relationship from a cohort mortality study. This procedure is based on a mechanism for adjusting exposure assessments, taking into account the distribution of exposures, and the independently estimated distribution of measurement errors. The initial bias and its reduction through analysis is shown for some simulated data sets. The results of applying this technique to a cohort mortality study of asbestos workers are presented.
Follow-up respiratory measurements in Quebec chrysotile asbestos miners and millers. M.R. Becklake, D. Thomas, F. Liddell, et al. 1982;8 Suppl 1:105-10. PubMed

Abstract

In 1974 changes in dyspnea, lung function, and pneumoconiotic radiographic abnormalities were recorded among the 1,015 Quebec chrysotile miners and millers surveyed in 1967-1968. The aim was to relate these changes to dust exposure--age, smoking, and earlier health status being taken into account. Dyspnea and lung function were assessed in 722 men, and for 277 recent radiographs were read separately by three experts for changes in the parenchyma and pleura. Each measure was analyzed independently for men without any abnormality when first seen (eligible for "attack") and for others (eligible for progression/regression). Age significantly influenced the rate of attack of pleural abnormality and the rates of attack and progression of dyspnea and lung function decline. Smoking had comparatively minor effects. The only associations with exposure were for progression of parenchymal change (one reader), and for progression of dyspnea. These essentially negative findings are similar to those obtained in a previous longitudinal survey of radiographs from the same workforce.
Malignant mesothelioma in Turkish immigrants residing in Sweden. G. Boman, V. Schubert, B. Svane, et al. 1982;8(2):108-12. Case report PubMed · Publisher

Abstract

Mesothelioma is a rare neoplasm in the general population, but it is strongly associated with previous asbestos exposure. The endemic occurrence of this disease in two villages in central Turkey has raised the question of whether the inhalation of naturally occurring zeolite dust may also be a factor in the development of mesothelioma. During the past few years a large portion of the inhabitants of one of the two villages of concern has immigrated to Sweden. This report presents three cases of malignant pleural mesothelioma and the results of a chest radiographic survey among these immigrants. Mineralogical analysis of lung tissue specimens from two of the cases revealed the presence of both zeolite and asbestos minerals and therefore suggested a synergistic effect involving both types of minerals. The importance of close medical surveillance of this high-risk population is emphasized, as is the possibility that similar cases appear in other countries because of increased migration.
Mesothelioma and the fiber type in three American asbestos factories - preliminary report. A.D. McDonald, J.S. Fry. 1982;8 Suppl 1:53-8. PubMed

Abstract

Preliminary findings are reported from three cohort studies in two asbestos factories (A and B) where chrysotile only was processed and a third (C) where chrysotile, amosite, and crocidolite were used. A total of 10,763 men and 3,118 women has been studied, of whom 97% and 89%, respectively, have been traced and 36% and 16% have died. Death certificates have so far been obtained and coded for 89% of the deaths. The standardized mortality ratios (SMRs) for persons employed less than a year varied greatly between plants. For men employed at least 1 a, an SMR of 129 for all causes and one of 285 for respiratory cancer were found in the chrysotile textile plant (A). The experience of respiratory cancer in this textile plant appears much worse in relation to fiber exposure levels than that observed in chrysotile mines and mills. Other findings in the three plants await clarification by analyses of exposure-response relationships. Among 2,341 deaths from the two chrysotile factories there has been one mesothelioma (0.4 per 1,000); among 1,429 deaths at factory C, which used mixed fibers, there have been 18 (12.6 per 1,000). This finding supports much other evidence that amphiboles are mainly responsible for mesothelioma, whereas chrysotile has little or no mesothelioma-producing potential.
Restricted cohort study designs. D. Oakes, J.C. McDonald. 1982;8 Suppl 1:30-3. PubMed

Abstract

Practical constraints may limit both cohort selection and the degree of follow-up in longitudinal studies of occupational mortality. For example, it may be possible to study only those men employed on a certain date or to trace (through pension fund records) only men employed at or close to normal retirement age or to follow men only for a very limited period after they have left employment. In an examination of the effects of such restrictions, advantage was taken of the availability of detailed work histories and the full follow-up of a large birth cohort of chrysotile asbestos workers. Age-matched case-referent analyses were performed under each type of restriction. All three analyses revealed the clear exposure-response relationship between cumulative dust exposure and lung cancer that was found in the full analysis. Most other findings were also not inconsistent with the earlier results. Such restricted cohort studies, with case-referent approaches to analysis can be justified in logic. The findings provide some empirical support for these methodological variants and suggest that they may be useful when complete follow-up of an entire birth cohort is not feasible.
Analysis of inorganic fiber concentrations in biological samples by scanning electron microscopy. B. Gylseth, R.H. Baunan, R. Bruun. 1981;7(2):101-8. PubMed · Publisher

Abstract

Analyzing fibers with electron microscopic techniques involves several preparation steps, especially during the analysis of fibers in human tissue. The influence of these steps on the analytical result was studied in detail. Fiber number was unaffected by the mild sonication of fiber suspensions analyzed with scanning electron microscopy. Significant fiber losses appeared during the filtration of fiber suspensions through 0.8-micrometer pore-size Nuclepore membranes. Shrinkage of the tissue during dry ashing broke lung fibers and consequently increased the fiber concentration and affected the fiber length distribution. Dry ashing, however, removed more of the organic debris than wet ashing; thus specimens prepared with dry ashing were more suitable for scanning electron microscopic analysis. A fairy good correlation was demonstrated for the analysis of fibers with scanning and transmission electron microscopy.
Inorganic fibers in lung tissue from patients with pleural plaques or malignant mesothelioma. B. Gylseth, G. Mowé, V. Skaug, et al. 1981;7(2):109-13. PubMed · Publisher

Abstract

The concentration of inorganic fibers in the lungs of patients with malignant mesothelioma and pleural plaques has been compared to that of patients without cancer or chronic respiratory diseases. The fiber concentrations have been determined by scanning electron microscopy and given as number of fibers per gram of dried tissue. A statistically significant difference in inorganic fiber content was found between the different groups.
Occurrence of cancer in a small cohort of asbestos-exposed workers. B. Hilt, J. Rosenberg, S. Langård. 1981;7(3):185-9. PubMed · Publisher

Abstract

During the construction period of a saltpeter plant from 1928 through 1929, 21 young men of equal age were heavily exposed to asbestos dust for 1 a. During an observation period from 1 January 1943 to 30 June 1980 three cases of lung cancer and two cases of mesothelioma were observed in the cohort. The number of lung cancers to be expected was 0.21. Radiographic changes associated with asbestos exposure were present in 17 of the 18 available chest radiographs.
Relation of soft-tissue sarcoma, malignant lymphoma and colon cancer to phenoxy acids, chlorophenols and other agents. L. Hardell. 1981;7(2):119-30. PubMed · Publisher

Abstract

An association between exposure to phenoxy acids or chlorophenols and soft-tissue sarcoma and malignant lymphoma has previously been reported. An association between exposure to organic solvents and malignant lymphoma has been demonstrated as well. In the present investigation the validity of the assessment of exposure to phenoxy acids and chlorophenols in the previous studies has been further analyzed, partly through a reconsideration of original data and partly through the utilization of another cancer type (colon cancer) for comparison. No observational bias was found which could distort the earlier findings. No significant association was found for these chemicals and colon cancer, whereas exposure to asbestos showed about a twofold increase in risk for colon cancer, an occurrence in agreement with previously reported findings.
Topographic and size distribution of asbestos bodies in exposed human lungs. B. Gylseth, R. Baunan. 1981;7(3):190-5. PubMed · Publisher

Abstract

The concentration and the length distribution of asbestos bodies in exposed human lungs have been determined in autopsy material by scanning electron microscopy after two different methods for preparing the tissue samples. The results demonstrate that the number of bodies vary between the right and left lung, as well as between the different lobes of a lung. The length distribution between the different lungs was, on the average, more or less the same; however small differences occurred between the different lobes. It was further shown that drying the tissue pieces before the analyses affected both the number and the length of the bodies. Examples of different types of asbestos bodies are presented, and their possible biological activity is discussed.
Statistical modeling of epidemiologic data. M. Nurminen, P. Mutanen. 1980;6(2):146-52. PubMed · Publisher

Abstract

The application of statistical modeling to epidemiology may help suggest a form for the mechanism of exposure action. But distinguishing between the entertained biological models is often difficult due to both inadequacies in epidemiologic studies and inaccuracies in the verbal specifications of the hypothesized interaction mechanisms. For example, the independent and interactive effects of asbestos and smoking on the production of lung cancer have not yet been fully established. In the present communication an analysis of illustrative data from a hypothetical case-compeer study was attempted with the estimation of rate ratios and the use of a log-linear model fitting technique. These analyses allow a parametric representation of the testable models. For adequate material they might provide tentative insight as to whether the data would conform more closely to an additive model than to a multiplicative one or to some other advocated pattern of action.

1970s

An exchange of membrane filter samples of airborne asbestos between one United Kingdom and three Scandinavian laboratories. S.T. Beckett, B. Gylseth, S. Krantz, et al. 1979;5(1):42-9. PubMed · Publisher

Abstract

An asbestos fiber counting trial based on the postal exchange of mounted and unmounted membrane filter samples was conducted between laboratories in Denmark, Norway, Sweden and the United Kingdom. The exchange was organized on the same basis as a previous international exchange involving nine countries (5); the United Kingdom laboratory had also participated in the previous exchange. Differences in counting techniques were distinguished from those due to the method used to make the filter transparent. Counting techniques gave rise to the biggest differences, giving a ratio of highest to lowest count of 2.75 for amphibole and 3.2 for chrysotile asbestos slides. A comparison was also made with the results of the previous international trial; it was made possible by the recounting of some of the slides from this exchange. Serious deterioration over two years was found in all slides except those mounted with the acetone/triacetin method.
Determination of inorganic fiber density in human lung tissue by scanning electron microscopy after low temperature ashing. B. Gylseth, E.M. Ophus, G. Mowé. 1979;5(2):151-7. PubMed · Publisher

Abstract

The concentration of asbestos fibers in lung tissue may give information about previous occupational asbestos exposure. A procedure for the preparation, quantification and identification of asbestos fibers in human tissue is presented in this report. The procedure is based on low-temperature plasma ashing of dry tissue, examination of the ash by scanning electron microscopy, and energy dispersive X-ray microanalysis. The advantages and disadvantages of this method are also discussed briefly.
Relation between radiological pleuropulmonary changes, clinical history and weight index of construction workers. A. Askergren, A. Szamosi. 1978;4(2):179-83. PubMed · Publisher

Abstract

Photofluorography was performed on 1,542 male construction workers in the Stockholm area. Postero-anterior, lateral and two anterior oblique views were obtained. The pleural and pulmonary changes found were classified into six groups. The results were correlated to the subjects' calculated weight index and to the occupational history of asbestos exposure and previous lung or pleural disease. There was a strong positive association between a high weight index and changes interpreted as increased amount of extrapleural fat. There was also a positive association between irregular thickenings and adhesions located mainly around the base of the lung and a clinical history of pleural or pulmonary disease. The importance of taking other etiological factors than exposure to asbestos dust into consideration is emphasized when pleural changes are detected in apparently healthy people.
Sputum cytology of asbestosis patients. M.S. Huuskonen, E. Taskinen, V. Vaaranen. 1978;4(4):284-94. PubMed · Publisher

Abstract

One hundred and fourteen patients with asbestosis, 59% of whom were chronic cigarette smokers, were subjected to a cytological sputum examination which showed: 36 workers (31.6%) with squamous metaplasia, 20 (17.5%) with benigh columnar cell atypia, 5 (4.4%) with benign dysplasia, 2 with suspicious cells for carcinoma, and 1 with anaplastic (microcellular) carcinoma. Clinically and histologically five lung cancers were verified, two of which were cytologically false negatives. All asbestosis patients with lung cancer were chronic smokers. Of the 114 asbestosis patients, 49 (43.0%) had ferruginous bodies in their sputum. The workers from an asbestos quarry more frequently had ferruginous bodies in their specimens than the other patients. Radiographically moderate and severe asbestosis cases showed squamous metaplasia more frequently than those with radiographically slight asbestosis. Most of the detected cellular atypias represented reversible alterations of the respiratory epithelium. It is, however, important to screen the sputum of older (greater than 40 years of age) smoking asbestos workers with benign and suspicious cellular atypias regularly because these alterations may represent the first step int he pathway to bronchogenic cancer. The results of this study did not answer the question of whether bronchial cancer of patients with asbestosis is curable if detected early with cytological methods.
Biochemical changes caused by asbestos dust in the lungs of rats. Q. Rahman, P.N. Viswanathan, S.H. Zaidi. 1975;1(1):50-3. PubMed · Publisher

Abstract

The contents of collagen, hexosamine, phospholipids, and cholesterol and the activities of acid and alkaline phosphatases, glutamic oxalo-acetate transaminase, glutamic pyruvate transminase, aldolase, hexokinase, and lactic dehydrogenase were determined in the lungs of rats 150 days after the intratracheal injection of amosite, anthophyllite, and chyrsotile. Anthophyllite did not cause any significant change, while amosite and chrysotile caused significant increases in the contents of collagen and mucopolysaccharides. Lactic dehydrogenase and acid phosphatase activities were increased by all the dusts, while the othe enzymes were not seriously affected. The biochemical significance of the findings in relation to abestosis was discussed.
Dissolution of silicic acid from amosite and quartz dusts under physiological conditions. Q. Rahman, M.U. Beg, P.N. Viswanathan. 1975;1(2):117-9. PubMed · Publisher

Abstract

The dissolution of silica from amosite dust in human serum and in Ringer buffer at 37 degrees C was found to be significantly higher than that from quartz. The significance of this finding in relation to their fibrogenic effects has been discussed.
The epidermiologic relationship between pleural mesothelioma and asbestos exposure. M. Nurminen. 1975;1(2):128-37. PubMed · Publisher

Abstract

This paper describes an investigation of 85 notifications of either probable or possible mesothelioma to the Finnish Cancer Registry from 1953 through 1969. The investigation covers characteristic epidemiologic features and the possibility of the mesothelioma being connected with occupational or other exposure to asbestos. The incidence rate of pleural mesothelioma was estimated at 1.1 per million per year. The male/female ratio was 1.3:1, which greatly differed fsrom that for malignant neoplasms of the bronchus or lung in Finland in 1960. The mean age at dealth from mesothelioma was over 7 years lower than that for bronchial carcinoma. The ratio of the crude incidence rates for the urban and rural populations was 4.2; the corresponding ratio for cases of carcinoma oopulations was 4.2; the corresponding ratio for cases of carcinoma of the bronchus or lung was 1.2 in Finland in 1960. THE LAST OCCUPATIONS OF THE 82 DECEASED PERSONS, OBTAINED FROM THE DEATH CERTIFICATES, WERE DIVIDIED INTO THREE CATEGORIES ACCORDING TO POSSIBLE ASBESTOS EXPOSURE. Exposure was present or probable in 9 (11.0) cases, 28 (34.2 %) had a possible exposure, and in 33 (40.2 %) cases exposure was absent or unlikely. The occupation of 12 (14.6) persons was unknown. Additional information of possible exposure history was obtained by interviewing the relatives of 10 mesothelioma patients. For half of the persons a definite, although in some cases trivial, exposure to asbestos could be ascertained. For the other five persons no exposure, either occupational, neighborhood or domestic, to asbestos could be traced. The residental distribution of the 85 persons with mesothelioma revealed no clustering of cases.

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