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 tumour 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.