Selenium is inversely associated with bladder cancer risk: A report from the Belgian case-control study on bladder cancer

Aim: Selenium is an essential trace element with suspected anticarcinogenic properties in humans. To date, eight epidemiological studies have examined the association between serum selenium concentration and bladder cancer risk. Methods: The authors carried out a population case-control study in 178 cases and 362 controls to assess the relationship between bladder cancer risk and selenium serum concentrations. Unconditional logistic regression was calculated to determine odds ratios (OR) for bladder cancer occurrence with corresponding 95% confidence intervals (95% CI). Effect modification by smoking status, low fruit and vegetable intake, retinol equivalent, vitamin C, vitamin E and total antioxidant status were also assessed. Results: Serum selenium level was negatively associated with bladder cancer risk. After adjustment for sex, age, smoking and occupational exposure, the OR was 0.48 (95% CI 0.29-0.79) comparing the second with the lowest tertile (serum selenium concentration > 82.40 mu g/L). The adjusted OR for the highest tertile (serum selenium concentration > 96.00 mu g/L), was 0.30 (95% CI 0.17-0.52) (P-trend < 0.001). An increase of 10 mu g/L in serum selenium concentration was associated with a significant decreased bladder cancer risk (OR: 0.76; 95% CI 0.67-0.85). Conclusion: This case-control study suggests an inverse association between serum selenium concentration and bladder cancer risk.