Public health impact of occupational carcinogens exposure and lung cancer

Background. Exposure to occupational carcinogens is an important preventable cause of lung cancer. Most previous studies were in highly exposed industrial cohorts. Our aim was to quantify lung cancer burden attributable to occupational carcinogens in a general population. Methods. We estimated lung cancer risk associated with occupational carcinogens using a new validated job-exposure matrix (JEM), in the Environment And Genetics in Lung cancer Etiology (EAGLE) study, a large (2100 cases and 2120 controls) population-based case-control study conducted in Lombardy, Italy, between 2002-2005. The JEM translated lifetime work-histories coded into standard job-titles into never, low, and high exposure levels for six known/suspected occupational lung carcinogens. We calculated odds ratios (OR) and 95% confidence intervals (CI) in men (1537 cases and 1617 controls), by multiple logistic regression, adjusted for potential confounders, e.g., tobacco smoking and co-exposure to JEM carcinogens. We estimated the Population Attributable Fraction (PAF) as impact measure. Results. Exposure to asbestos (OR=1.76, 95%CI=1.42 to 2.18), crystalline silica (OR=1.31, 95%CI=1.00 to 1.71), or nickel-chromium (OR=1.18, 95%CI=0.90 to 1.53) was associated with increased risk even at low exposures, with positive trends for intensity and duration. We found an excess risk for exposure to polycyclic aromatic hydrocarbons only among highly exposed workers (OR=1.64, 95%CI=0.99 to 2.70). The PAFs for any exposure to asbestos, crystalline silica and nickel-chromium were 18.1%, 5.7%, and 7.0%, respectively, corresponding to 300-800 lung cancer cases/year. Conclusion. These findings support the substantial role of selected occupational carcinogens on lung cancer burden, even in a low exposed general population. Health policy interventions are warranted.