Serum carotenoids and other antioxidative substances associated with urothelial cancer risk in a nested case-control study in Japanese men

Purpose: We assayed whether high serum carotenoids and antioxidative substances decrease the risk of urothelial cancer in a case-control study nested in a community based cohort in Japan, that is the Japan Collaborative Cohort Study. Materials and Methods: Information on subject life-styles and serum were collected in 1988 to 1990 and subjects were followed as late as 1999. Individuals who had or died of urothelial cancer and controls were matched for study area, sex and age. Serum was stored at -80C and analyzed in 2003. Of 14,097 male and 25,662 female subjects 40 to 79 years old there were 42 cases, which were matched to 124 controls. Results: The OR for the highest to lowest tertile of serum concentration was 0.28 (95% CI 0.07 to 1.15, trend p = 0.08) for β-carotene, 0.36 (95% CI 0.10 to 1.27, trend p = 0.10) for total carotenes and 0.31 (95% CI 0.09 to -1.09, trend p = 0.09) for total carotenoids after adjustment for smoking in addition to matching variables. High concentrations of tocopherols and xanthophylls slightly tended to decrease the risk of urothelial cancer. In contrast, serum retinol, oxidized low density lipoprotein and Cu/Zn-superoxide dismutase were not associated with urothelial cancer risk. Conclusions: Our results suggest that high serum carotenoids may decrease the risk of urothelial cancer with carotenes more effective than xanthophylls.