New insights on occupational exposure and bladder cancer risk: a pooled analysis of two Italian case-control studies.

Purpose: The main risk factor for bladder cancer (BC) is cigarette smoking, but also occupational exposure to carcinogens is relevant, causing about 4-10% of BC. We aimed at investigating the association between BC risk, occupations held in the past and exposure to occupational carcinogens, also assessing whether these associations were influenced by tumor grade. Methods: We pooled data from two Italian case-control studies on male BC, analyzing 893 cases and 978 controls. Occupations were classified using the International Standard Classification of Occupations and exposure to carcinogens was assigned using a validated Job Exposure Matrix. Logistic regression approach was used as well as a semi- Bayesian model, based on a priori information on exposure. Results: A significantly increased BC risk was found for chemical engineering technicians, postmen, and lathe operators, but only for the latter the association remained significant after Bayesian control for type I error. Among carcinogens, cadmium and trichloroethylene were associated with BC. When analyzing data by grade, exposure to these carcinogens was associated with low-grade BC only. Conclusions: Our results suggest that monitoring workplaces to prevent exposure to carcinogenic agents is still an important task, which should be still given adequate importance in public health.