Industry and job-specific mortality after occupational exposure to silica dust

Abstract

Background: Occupational exposure to silica dust occurs in many workplaces and is well known to cause silicosis. However, the link between silica exposure, silicosis and other diseases is still disputed. Aims: To evaluate cause-specific mortality in a cohort of Italian silicotics. Methods: The cohort included 2034 male compensated for silicosis between 1943 and 1986, alive on 1 January 1987 and resident in the Latium region (Italy). Mortality follow-up was from 1987 to 2006. Vital status and death causes were ascertained from the regional mortality archive. Standardized mortality ratios (SMRs) were computed assuming a Poisson distribution of observed deaths. Results: Significant excess mortality was observed from all causes (SMR: 1.17, 95% CI: 1.11-1.24), cancer of trachea, bronchus and lung (SMR: 1.39, 95% CI: 1.17-1.64), cancer of larynx (SMR: 2.18, 95% CI: 1.32-3.60) and tuberculosis (SMR: 5.85, 95% CI: 3.03-11.30). Higher risks were observed for masons (lung cancer, SMR: 2.46, 95% CI: 1.65-3.66) and miners (larynx cancer, SMR: 5.31, 95% CI: 1.88-15.03). In a Poisson regression analysis, the relative risk of death from lung cancer and silicosis increased with silicosis severity and decreased in more recent compensation periods. Conclusions: The excess mortality from respiratory tract cancers and other diseases detected among Italian workers compensated for silicosis confirms previous epidemiological findings. © The Author 2011. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved.