Occupation and mesothelioma in Sweden: updated incidence in men and women in the 27 years after the asbestos ban

Our plain-English summary of Occupation and mesothelioma in Sweden: updated incidence in men and women in the 27 years after the asbestos ban, by N. Plato, J.I. Martinsen, P. Sparén, et al (Epidemiology and Health, 2016).

The study

• Authors: N. Plato, J.I. Martinsen, P. Sparén, G. Hillerdal, E. Weiderpass
• Journal: Epidemiology and Health
• Published: 2016;38:e2016039
• Cited by: 29 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: We updated the Swedish component of the Nordic Occupational Cancer (NOCCA) Study through 2009 in order to investigate the incidence of mesothelioma of the peritoneum and pleura in both genders, and explored occupational exposures that may be associated with mesothelioma.

Methods: The Swedish component of the NOCCA Study includes 6.78 million individuals. Data from this cohort were linked to the population-based Swedish Cancer Registry and Swedish Total Population Registry for three periods between 1961 and 2009, and then further linked to the Swedish NOCCA job-exposure matrix, which includes 25 carcinogenic substances and the corresponding exposure levels for 280 occupations. Multivariate analysis was used to calculate standardized incidence ratios (SIRs) for mesothelioma of the peritoneum and pleura by gender, occupational category, carcinogenic substance, and for multiple occupational exposures simultaneously.

Results: A total of 3,716 incident mesotheliomas were recorded (21.1% in women). We found a significantly increased risk of mesothelioma in 24 occupations, as well as clear differences between the genders. Among men, increased risks of mesothelioma of the pleura were observed in male-dominated occupations, with the greatest elevation of risk among plumbers (SIR, 4.99; 95% confidence interval, 4.20 to 5.90). Among women, increased risks were observed in sewing workers, canning workers, packers, cleaners, and postal workers. In multivariate analysis controlling for multiple occupational exposures, significant associations were only observed between asbestos exposure and mesothelioma.

Conclusions: Asbestos exposure was associated with mesothelioma incidence in our study. The asbestos ban of 1982 has yet to show any clear effect on the occurrence of mesothelioma in this cohort. Among women, the occupations of canning workers and cleaners showed increased risks of mesothelioma of the pleura without evidence of asbestos exposure.

In plain English

This Swedish registry-based cohort study followed 6.78 million census participants aged 30 to 64. The authors linked them to the Swedish Cancer Registry for 1961 to 2009 and estimated exposures from occupation using a job-exposure matrix. Observed cases were compared with those expected from national rates (standardized incidence ratios, SIRs). Of 3,716 mesotheliomas, 21.1% were in women. Among men, plumbers and pipe fitters had a pleural mesothelioma SIR of 4.99 (95% CI 4.20 to 5.90) and insulators 10.9 (6.81 to 16.50). Of 17 male occupations with chemical exposure and excess pleural risk, 12 were rated for asbestos; two occupations with no rated chemical exposure also had excess risk. Among women, sewing workers, canning workers and cleaners had raised pleural risks; sorting clerks and postal workers and packers had raised peritoneal risks. The authors could not explain several of these. The authors concluded that asbestos exposure was associated with mesothelioma. They noted post-ban follow-up was too short to show an effect and some results may be chance findings; smoking data were missing, though smoking is not expected to affect mesothelioma risk.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Registry-based cohort study (census cohort linked to the cancer registry and a job-exposure matrix), analysed with standardized incidence ratios against national rates
• Who was studied: 6.78 million men and women aged 30 to 64 who took part in the 1960, 1970, 1980 or 1990 Swedish censuses (Swedish part of the Nordic Occupational Cancer Study), followed for mesothelioma from 1961 to 2009
• Exposure: Occupation recorded in the censuses, linked to the Swedish NOCCA job-exposure matrix, which gives exposure levels for 25 carcinogenic substances, including asbestos (no fiber types specified), for 280 occupations. Of the 280 occupations, 96 were rated for exposure to carcinogenic substances.
• Main results:
  • 3,716 mesothelioma cases were recorded from 1961 to 2009, 785 (21.1%) of them in women.
  • Of the 3,334 pleural cases, 577 were in women. Of the 382 peritoneal cases, 208 (54.5%) were in women.
  • Men working as plumbers and pipe fitters had a pleural mesothelioma SIR of 4.99 (95% CI 4.20 to 5.90) and a peritoneal SIR of 3.56 (95% CI 1.31 to 7.76).
  • Male insulators had the highest pleural mesothelioma risk: SIR 10.9 (95% CI 6.81 to 16.50), based on 22 cases among 2,589 men.
  • Among men, 17 occupations rated for chemical exposure showed a significant excess risk of pleural mesothelioma. Twelve of these 17 were rated for asbestos exposure in the job-exposure matrix.
  • Two male occupations not rated for any chemical exposure in the matrix had excess pleural risk: ships' engineers (SIR 6.06; 95% CI 3.65 to 9.46) and divers and pipe layers (SIR 4.20; 95% CI 1.14 to 10.7).
  • Women in sewing work (an occupation rated for chemical exposure) had a pleural mesothelioma SIR of 2.14 (95% CI 1.27 to 3.39).
  • Women canning workers (SIR 4.90; 95% CI 1.33 to 12.50) and cleaners (SIR 1.59; 95% CI 1.05 to 2.31) had excess pleural risk. Neither occupation was rated for chemical exposure in the matrix.
  • For peritoneal mesothelioma in women, two occupations had significant excess risk: sorting clerks and postal workers (SIR 9.27; 95% CI 1.12 to 33.50) and packers (SIR 4.49; 95% CI 1.22 to 11.50).
  • Across the three follow-up periods (1961-1974, 1975-1989, 1990-2009), male sheet metal workers and electrical fitters and wiremen showed increased pleural risk in all three periods.
• The authors' conclusion: The authors concluded that asbestos exposure was associated with mesothelioma incidence, and that the 1982 asbestos ban had yet to show any clear effect in this cohort. They added that among women, canning workers and cleaners showed increased pleural mesothelioma risk without evidence of asbestos exposure.
• Limitations the authors state:
  • The authors presented the results in an exploratory manner and acknowledged that some SIRs may have been significant by chance.
  • The data lacked smoking information, although the authors state that smoking is not expected to affect mesothelioma risk.
  • The authors describe exposure assessment as a weakness in most epidemiological studies.
  • The job-exposure matrix may not be sensitive enough to rate low-prevalence asbestos exposure in some occupations.
  • The authors could not determine which time scale (age, period or birth cohort) drove the observed trends.
  • Peritoneal tumors may have been misclassified before 2000 because diagnostic procedures changed in 1999.
  • Follow-up after the asbestos ban was too short to show its effect.
  • The authors had no explanation for the excess risks among women canning workers, sorting clerks and postal workers, and packers. The authors state that these occupations are not exposed to asbestos.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Peritoneum, Pleura, Occupational Exposure, Cancer Registry, Carcinogenic, Multivariate Analysis, Standardized Incidence Ratio (SIR).

Related studies

• Pleural mesothelioma in Sweden: an analysis of the incidence according to the use of asbestos — B. Järvholm, A. Englund, et al. (1999)
• Mesothelioma incidence seems to have leveled off in Sweden — K. Hemminki, X. Li (2003)
• Incidence and familial risk of pleural mesothelioma in Sweden: a national cohort study — J. Ji, J. Sundquist, et al. (2016)
• Explaining differences in incidence rates of pleural mesothelioma between Sweden and the Netherlands — A. Burdorf, B. Järvholm, et al. (2005)
• Incidence, mortality and survival in malignant pleural mesothelioma before and after asbestos in Denmark, Finland, Norway and Sweden — K. Hemminki, A. Försti, et al. (2021)
• A Comparative Analysis of Lung Cancer Incidence and Tobacco Consumption in Canada, Norway and Sweden: A Population-Based Study — J. Chen (2023)

Browse return to medical research.