Risk Factors of Mortality from All Asbestos-Related Diseases: A Competing Risk Analysis

Our plain-English summary of Risk Factors of Mortality from All Asbestos-Related Diseases: A Competing Risk Analysis, by R. Abós-Herràndiz, T. Rodriguez-Blanco, I. Garcia-Allas, et al (Canadian Respiratory Journal, 2017).

The study

• Authors: R. Abós-Herràndiz, T. Rodriguez-Blanco, I. Garcia-Allas, I.M. Rosell-Murphy, C. Albertí-Casas, J. Tarrés, I. Krier-Günther, X. Martinez-Artés, R. Orriols, I. Grimau-Malet, J. Canela-Soler
• Journal: Canadian Respiratory Journal
• Published: 2017;2017:9015914
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The mortality from all malignant and nonmalignant asbestos-related diseases remains unknown. The authors assessed the incidence and risk factors for all asbestos-related deaths.

Methods: The sample included 544 patients from an asbestos-exposed community in the area of Barcelona (Spain), between Jan 1, 1970, and Dec 31, 2006. Competing risk regression through a subdistribution hazard analysis was used to estimate risk factors for the outcomes.

Results: Asbestos-related deaths were observed in 167 (30.7%) patients and 57.5% of these deaths were caused by some type of mesothelioma. The incidence rate after diagnosis was 3,600 per 100,000 person-years. In 7.5% of patients death was non-asbestos-related, while pleural and peritoneal mesothelioma were identified in 87 (16.0%) and 18 (3.3%) patients, respectively.

Conclusions: Age, sex, household exposure, cumulative nonmalignant asbestos-related disease, and single malignant pathology were identified as risk factors for asbestos-related death. These findings suggest the need to develop a preventive approach to the community and to improve the clinical follow-up process of these patients.

In plain English

This community-based cohort study followed 544 patients diagnosed with an asbestos-related disease from 1970 to 2006 near Barcelona, Spain, where an asbestos cement plant operated from 1907 to 1997. Most (73.5%) were exposed at work, 15.3% environmentally and 11.2% by living with an asbestos worker. Over a median follow-up of 4.1 years, 167 (30.7%) died of an asbestos-related disease: 78 of pleural mesothelioma, 15 of peritoneal mesothelioma, 3 of both, 31 of lung cancers, 1 of bronchopulmonary cancer and 39 of benign disease. Another 41 (7.5%) died of other causes. The asbestos-related death rate after diagnosis was 3600 per 100,000 person-years (95% CI 3092 to 4191). The analysis took deaths from other causes into account. Compared with patients who had one benign disease, adjusted subdistribution hazard ratios for asbestos-related death were 10.28 (95% CI 3.36 to 31.43) for 4 or 5 benign diseases and 128.30 (61.82 to 266.25) for at least one malignant disease. Household exposure carried higher risk than environmental exposure. The authors concluded that age, sex, nonoccupational exposure, accumulated benign disease and malignant disease were risk factors. They noted that exposure intensity was not measured.

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: Community-based cohort study, with data collected retrospectively from 1970 to 2003 and prospectively after that, analysed with competing risk regression (subdistribution hazard analysis) that treated deaths from other causes as competing events
• Who was studied: All 544 patients with any asbestos-related disease (ARD) diagnosis identified between 1 January 1970 and 31 December 2006 in a catchment population of 485,578 people served by 14 Primary Care Centers in a low socioeconomic area of the region of Barcelona, Spain. 73.2% were male and the mean age was 63.7 years.
• Exposure: Asbestos from a cement processing plant that operated in the area for 90 years (1907 to 1997). The article prints its throughput as "14.446 MT" of asbestos per year: 80% white, 15% blue and 5% brown. Patients were classed by source of exposure: labor 400 (73.5%), environmental 83 (15.3%) and household 61 (11.2%). Median length of exposure was 21.0 years and median latency was 41.6 years.
• Main results:
  • During follow-up (median 4.1 years), ARD-related death occurred in 167 of 544 patients (30.7%); 142 (26.1%) of these were men.
  • Causes of the 167 ARD deaths: 78 (46.7%) pleural mesothelioma, 15 (9%) peritoneal mesothelioma, 3 (1.8%) both, 31 (18.5%) lung cancers, 1 (0.6%) bronchopulmonary cancer, and 39 (23.4%) at least one benign ARD.
  • 41 patients (7.5%) died of causes not related to asbestos.
  • The rate of ARD-related death after diagnosis was 3600 per 100,000 person-years (95% CI 3092 to 4191). The rate after the start of exposure was 620 per 100,000 person-years (men 760, women 304).
  • Median survival after diagnosis was 7.4 months for pleural mesothelioma and 8.4 months for peritoneal mesothelioma.
  • Compared with patients with 1 benign ARD, the adjusted subdistribution hazard ratio for ARD death was 1.94 (0.86 to 4.38) for 2 or 3 benign ARD, 10.28 (3.36 to 31.43) for 4 or 5 benign ARD, and 128.30 (61.82 to 266.25) for at least 1 malignant ARD.
  • Compared with environmental exposure, household exposure had a subdistribution hazard ratio of 1.98 (1.07 to 3.64) and labor exposure 1.22 (0.68 to 2.19); the overall p value for source of exposure was 0.074.
  • Former smokers had a lower risk of ARD death than nonsmokers: subdistribution hazard ratio 0.56 (0.35 to 0.87).
  • Length of exposure was not significantly associated with ARD death (p = 0.935).
  • Men had a significantly higher risk than women of dying from ARD after 40 years from the start of exposure. Women had a higher risk than men during the first 40 years, but this was not statistically significant.
  • Patients aged 60 to 69 had the highest risk of ARD death in the first 30 years of exposure, followed by those aged 70 to 79 (at 30 years, compared with under 50: 5.88 (2.39 to 14.47) and 4.64 (1.80 to 12.00)).
• The authors' conclusion: The authors concluded that age, sex, nonoccupational exposure, accumulated benign ARD and a single malignant disease were risk factors for death from ARD. They called for a clinical and preventive approach in the community.
• Limitations the authors state:
  • With no official exposure measurements available, duration of exposure was used as a stand-in for amount of exposure.
  • Intensity of exposure, which could vary between individuals and over time, was not considered, nor was recall bias about past exposures.
  • The effect of asbestos waste sites in the area was not quantified.
  • Diagnoses of ARD could be misclassified, for example because chest radiographs lack sensitivity for pleural plaques.
  • Labor confidentiality rules, refusal to participate, the healthy survivor effect and misclassification of cause of death could have caused selection bias that may underestimate the risk.
  • Smoking status was not fully collected, so a missing category was used.
  • Results can only be generalized to communities with similar competing risk rates.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Lung cancer, Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Incidence, Peritoneal Mesothelioma, Pathology.

Related studies

• Risk factors associated with asbestos-related diseases: a community-based case-control study — M.I. Rosell-Murphy, R. Abós-Herràndiz, et al. (2013)
• Malignant asbestos-related disease in a population exposed to asbestos — R. Orriols, J. Tarrés, et al. (2020)
• Estimating the contribution of individual risk factors to disease in a person with more than one risk factor — P. McElduff, J. Attia, et al. (2002)
• Anxious and depressive symptoms in the French Asbestos-Related Diseases Cohort: risk factors and self-perception of risk — I. Mounchetrou Njoya, C. Paris, et al. (2017)
• Occupational risk factors for mortality from stomach and lung cancer among rubber workers: an analysis using internal controls and refined exposure assessment — K. Straif, L. Chambless, et al. (1999)
• Mortality by cause of death and risk behaviors in farmers versus non-farmers: the importance of avoiding the healthy worker effect — G. Zhao, E. Ronda, et al. (2019)

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