Cancer incidence in a cohort of asbestos-exposed workers undergoing health surveillance

Objectives. To compare a local cohort of 2,488 men occupationally exposed to asbestos and enrolled in a public health surveillance program with the 1995 – 2009 cancer incidence of the general population of Friuli Venezia Giulia (FVG) region, Northeast Italy, we conducted a historical cohort study. Methods. Standardized incidence ratios (SIRs), with 95% confidence interval (95%CI), for specific cancer sites were estimated in the cohort and in subgroups of workers employed in shipbuilding between 1974-1994. For internal comparisons, we estimated incidence rate ratios (IRRs) for all cancers, lung cancer and mesothelioma, by level of exposure to asbestos and sector of employment adjusted for smoking habits and age at start of follow-up. Results. Among cohort members the SIR was 8.82 (95%CI 5.95-12.61) for mesothelioma and 1.61 (95%CI 1.26-2.04) for lung cancer. In subgroup analyses, the SIR for lung cancer in subjects hired in shipbuilding between 1974-1984 was 2.09 (95%CI 1.32-3.13). In the overall cohort, a borderline increased incidence was also found for stomach cancer (SIR=1.53 95%CI 0.96-2.31). Internal comparisons within the cohort show that among men with high asbestos exposure level the relative risk was almost three-fold for lung cancer (IRR=2.94 95%CI 1.01-8.57). Conclusions. This cohort experienced an excess in the incidence of both mesothelioma and lung cancer, showing increasing incidence rates at higher level of asbestos exposure. For lung cancer, the relative incidence was highest among workers hired in shipbuilding between 1974-1984.