Bladder Cancer and Occupational Exposures: Results of a Multicentric Case-Control Study

Abstract

SAA1-O-04 The aim of this multicentric case-control study was to evaluate the frequency of occupational causes of bladder cancer and the distribution of exposure situations. Between 1998 and 2004, 316 male incident cases of bladder cancer and 316 male controls matched on age were recruited in 5 hospitals. Each subject had a face-to-face interview to collect information on tobacco consumption and on the complete job history occupational exposure to polycyclic aromatic hydrocarbon (PAH), aromatic amines (AA), and nitrosamines (NA) evaluated by 2 occupational experts, blindly according to the case/control status. For each subject, a cumulative exposure index (CEI) to PAH, AA, and NA was calculated, taking into account probability, frequency, and exposure level for all job periods during the working life. Logistic regression analyses were performed to calculate odds ratios (OR) with corresponding 95% confidence intervals (CI) for bladder cancer occurrence and PAH, AA, and NA exposures, adjusted for age and tobacco smoking. As expected, this study shows a dose-effect relationship between tobacco consumption levels and risk of bladder cancer (OR = 1.97; 95% CI, 1.14–3.41) for low tobacco consumption level (1–20 pack-years [PY], 5.36; 95% CI, 3.14–9.16) for high tobacco consumption level (21–40 PY and 11.66; 95% CI, 6.63–20.48) for very high tobacco consumption level (>40 PY). A dose-response relationship was observed between probability of exposure to PAH or cumulative exposure index to PAH and risk of bladder cancer after adjustment on age and tobacco consumption (OR = 2.31; 95% CI, 1.39–3.85) for definite exposure and OR = 1.93 (95% CI, 1.08–3.43) for higher CEI). By contrast, no relationship was identified between AA or NA and bladder cancer in this series. Excess bladder cancer risks were observed in various occupations, such as motor vehicle drivers (P < 0.0002), earthmoving plant or material handling drivers (P < 0.002), and sheet-metal workers (P < 0.0006) and in various industries, such as wood industry (P < 0.0002), ship building and repairing and manufacture of railroad equipment, motor vehicles and aircraft (P < 0.0005), freight transport by road (P < 0.006), and retail trade (P < 0.004). The lack of dose-response relationship between bladder cancer AA or NA exposures and bladder cancer could reflect a decrease of exposures to AA and NA in a few decades. By contrast, the relationship between PAH exposure and bladder cancer justifies going deeply into exposure situations identified of this study in order to propose specific prevention programs.