An estimate of cancers attributable to occupational exposures in France

Our plain-English summary of An estimate of cancers attributable to occupational exposures in France, by P. Boffetta, P. Autier, M. Boniol, et al (Journal of Occupational and Environmental Medicine, 2010).

The study

• Authors: P. Boffetta, P. Autier, M. Boniol, P. Boyle, C. Hill, A. Aurengo, R. Masse, G.D. Thé, A.J. Valleron, R. Monier, M. Tubiana
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2010;52(4):399-406
• Cited by: 57 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To perform a quantitative estimate of the proportion of cancers attributable to occupational exposures in France in 2000.

Methods: Exposure data for established carcinogens were obtained from a 1994 survey and other sources. Relative risks for 23 exposure-cancer combinations were derived from meta-analyses and pooled analyses.

Results: A total of 4335 cases of cancer among men (2.7% of all cancers) and 403 cases among women (0.3% of all cancers) were attributed to occupational exposures. Asbestos, polycyclic aromatic hydrocarbons, and chromium VI were the main occupational carcinogens in men, and asbestos and involuntary smoking were the main carcinogens in women. Corresponding proportions for cancer deaths were 4.0% and 0.6% in men and women, respectively. Lung cancer represented 75% of deaths attributable to occupational exposures.

Conclusion: Our estimates are comparable with those obtained for other countries in studies based on similar methodology.

In plain English

This study estimated how many cancers in France in 2000 were attributable to workplace exposures to established human carcinogens (International Agency for Research on Cancer group 1). The authors combined exposure estimates, mainly from a 1994 national survey of workers, with relative risks from published meta-analyses and pooled analyses or, where none existed, their own meta-analyses. For asbestos they used other sources, including the French National Mesothelioma Surveillance Program. Overall, 4335 cancer cases in men (2.7% of all cancers) and 403 cases in women (0.3%) were attributed to occupational exposures. For cancer deaths the figures were 4.0% in men and 0.6% in women. Asbestos was among the main occupational carcinogens in both men and women. The study attributed to asbestos 558 mesothelioma cases in men and 77 in women, and 1255 lung cancer cases in men and 151 in women. Lung cancer made up 75% of the deaths attributed to occupational exposures. The authors concluded that their estimates were comparable with those for other countries using similar methods. They also gave reasons why their figures could be too low or too high.

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: Quantitative estimate of attributable fractions (the proportion of cancers attributable to occupational exposures). It combined exposure prevalence data with relative risks from published meta-analyses and pooled analyses. Where such analyses were not available, the authors performed their own meta-analyses of published articles and reviews.
• Who was studied: Cancer cases and deaths in France in 2000, in the French population older than 15 years. Exposure data came mainly from the SUMER 1994 survey, in which 1205 occupational physicians each recorded the exposures of 50 randomly selected private-sector workers. Farmers, civil servants and self-employed workers were excluded from that survey.
• Exposure: Occupational agents classified by IARC as group 1 carcinogens, including asbestos (fiber types not specified), silica, cadmium, chromium VI, nickel, benzene, formaldehyde, 1,3-butadiene, aromatic amines, polycyclic aromatic hydrocarbons, untreated and mildly treated mineral oils, involuntary tobacco smoking, wood dust, leather dust and radon, plus work as painters and in the rubber industry. For asbestos and lung cancer, the authors used a relative risk of 1.63 with 15-year latency from a meta-analysis of 69 occupational cohort studies. For men's asbestos exposure prevalence, they used a French case-control study in which 9.1% of job periods in men had medium or high probability of asbestos exposure.
• Main results:
  • 4335 cancer cases among men (2.7% of the total) and 403 cases among women (0.3%) were attributed to occupational exposures in 2000
  • As a share of all cancer deaths, occupational exposures accounted for 4.0% in men and 0.6% in women
  • Asbestos, polycyclic aromatic hydrocarbons and chromium VI were the main occupational carcinogens in men. Asbestos and involuntary smoking were the main ones in women.
  • For mesothelioma, the attributable fraction for asbestos (taken from the French National Mesothelioma Surveillance Program) was 83.2% (95% CI, 76.8%–89.6%) in men and 38.4% (95% CI, 26.8%–50.0%) in women. This corresponded to 558 cases and 504 deaths in men, and 77 cases and 62 deaths in women.
  • Lung cancer attributed to asbestos had an attributable fraction of 5.4% in men (1255 cases, 1116 deaths) and 3.8% in women (151 cases, 140 deaths)
  • Lung cancer represented 75% of deaths attributable to occupational exposures
  • Among exposed workers (men), the attributable fraction ranged from 14% (leukemia in workers exposed to 1,3-butadiene) to 98% (mesothelioma in workers exposed to asbestos). For asbestos and lung cancer among exposed men it was 38.7%.
• The authors' conclusion: The authors concluded that their estimates are comparable with those obtained for other countries in studies using similar methodology
• Limitations the authors state:
  • The burden may have been underestimated for three reasons: past exposures may have been underestimated by using 1994 exposure data, some established carcinogens were excluded for lack of exposure data, and suspected carcinogens were not considered
  • For asbestos, the 1994 survey data were likely to grossly underestimate lifetime exposure prevalence, because asbestos was banned in France in 1996 and exposure had already declined. The alternative approaches used might not have completely solved the problem.
  • No reliable asbestos exposure data existed for women. Asbestos-related lung cancer deaths in women were therefore derived by applying the men's lung-cancer-to-mesothelioma ratio (2.2).
  • The figures may be too high, because cases attributed to different agents were added together, ignoring that the same workers may have been exposed to several carcinogens
  • Relative risks came from past studies with higher exposures, and these studies often failed to properly control for confounding by smoking and other factors
  • Information on prevalence of exposure in the survey was not validated
  • The exposure data were of limited quality, and the relative risks came mostly from studies in the United States and United Kingdom that referred mainly to men

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Relative Risk, Lung Cancer.

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