A prospective cohort study on intake of retinol, vitamins C and E, and carotenoids and prostate cancer risk (Netherlands)

Objectives: The roles of retinol, vitamins C and E, and carotenoids as risk factors for prostate carcinoma are still questionable. We evaluated these in the Netherlands Cohort Study. Methods: The cohort study consisted of 58,279 men ages 55-69 years at baseline in 1986. After 6.3 years of follow-up, 642 incident prostate carcinoma cases were available for analysis. Intakes of retinol, vitamins C and E, and several carotenoids were measured by means of a 150-item semi-quantitative food-frequency questionnaire. Results: In multivariate analyses a positive association with prostate cancer risk was observed for intake of beta-cryptoxanthin. Rate ratios (RRs) in increasing quintiles were 1.00 (ref), 0.94, 1.01, 1.16, 1.41; p-trend <0.01. For intake of retinol, vitamins C and E and other carotenoids (alpha-carotene, beta-carotene, lycopene, and lutein/zeaxanthin) no effect on overall prostate cancer risk was found. RRs for vitamin supplement use were decreased, but not significantly. Among nondrinkers, nonsignificant inverse associations were observed for intake of retinol, alpha-carotene, and beta-carotene (RRs, highest vs lowest quintile, were 0.23, 0.60, and 0.76, respectively). Among drinkers, beta-cryptoxanthin was positively associated (RR highest vs lowest quintile = 1.40). Conclusions: These data show a positive association between beta-cryptoxanthin and prostate cancer risk. Our study also shows inverse associations for retinol, alpha-carotene, and beta-carotene among nondrinkers; this suggests an interaction between vitamins and alcohol consumption, which needs confirmation. Lycopene was not associated with prostate cancer.