Blood cadmium may be associated with bladder carcinogenesis: The Belgian case-control study on bladder cancer

Background: The aim of this study was to assess the relationship between exposure to cadmium and bladder cancer risk. Methods: We conducted a case-control study in Belgium and measured the blood levels of cadmium in 172 bladder cases and 359 population controls. The data were analyzed as tertiles after logarithmic transformation. Cut-off points were based on the levels among the controls. Logistic regression was performed to calculate odds ratios (ORs) for bladder cancer occurrence with corresponding 95% confidence intervals (95% CI). Results: After adjustment for sex, age, and occupational exposure to PAHs or aromatic amines, the OR for cadmium was 8.3 (95% Cl 5.0-13.8) comparing the highest to the lowest tertile (p, for trend < 0.001). Additional adjustment for smoking (current cigarette smoking status, years of cigarette smoking and number of cigarettes smoked per day) decreased the OR, however it remained strongly significant (OR: 5.7; 95% Cl 3.3-9.9). Conclusion: Our study suggests that individuals with increased exposure to cadmium have an increased risk of bladder cancer. Future studies should expand on this investigation by studying a larger number of bladder cancer patients and by collecting extensive information on the lifetime occupational, residential, and environmental exposures to clarify the role of cadmium in bladder cancer. (c) 2007 International Society for Preventive Oncology. Published by Elsevier Ltd. All rights reserved.