Are retinol, vitamin C, vitamin E, folate and carotenoids intake associated with bladder cancer risk? Results from the Netherlands Cohort Study

In the Netherlands Cohort Study among 120 852 subjects aged 55–69 years at baseline (1986), the association between vitamins and carotenoids intake, vitamin supplement use, and bladder cancer incidence was examined. Exposure status was measured with a food-frequency questionnaire. After 6.3 years of follow-up, data from 569 cases and 3123 subcohort members were available for case-cohort analyses. The age-, sex-, and smoking-adjusted relative risks (RRs) for retinol, vitamin E, folate, α-carotene, β-carotene, lutein and zeaxanthin, and lycopene were 1.04, 0.98, 1.03, 0.99, 1.16, 1.11, and 1.08, respectively, comparing highest to lowest quintile of intake. Only vitamin C (RR: 0.81, 95% CI: 0.61–1.07, P-trend = 0.08), and β-cryptoxanthin intake (RR: 0.74, 95% CI: 0.53–1.03, P-trend < 0.01) were inversely associated with bladder cancer risk. The association with vitamin C disappeared after adjustment for β-cryptoxanthin but not vice versa. The RRs for supplemental use of vitamin A, C or E compared to no use were around unity.