Supplemental vitamin E intake and prostate cancer risk in a large cohort of men in the United States

A clinical trial of vitamin E and beta-carotene supplementation for lung ca ncer prevention among male smokers in Finland recently reported an unexpect ed, strong protective effect of vitamin E against prostate cancer incidence and mortality. Our objective was to prospectively examine supplemental vit amin E intake and prostate cancer risk in a distinct U.S. population, In 19 86, we identified 47,780 U.S. male health professionals, free from diagnose d cancer, who completed a dietary and lifestyle questionnaire; supplemental vitamin E and prostate cancer incidence were updated biennially through 19 96, We estimated relative risks (RRs) from multivariate pooled logistic reg ression models. There were 1896 total (non-stage A1), 522 extraprostatic, and 232 metastati c or fatal incident prostate cancer cases diagnosed between 1986-1996, Men consuming at least 100 IU of supplemental vitamin E daily had multivariate RRs of 1.07 (95% confidence interval [CI], 0.95-1.20) for total and 1.14 (9 5% CI, 0.82 -1.59) for metastatic or fatal prostate cancer compared with th ose consuming none, Current use, dosage, and total duration of use of speci fic vitamin E supplements or multivitamins were not associated with risk. H owever, among current smokers and recent quitters, those who consumed at le ast 100 IU of supplemental vitamin E per day had a RR of 0.44 (95% CI, 0.18 -1.07) for metastatic or fatal prostate cancer compared with nonusers. Thus, supplemental vitamin E was not associated with prostate cancer risk g enerally, but a suggestive inverse association between supplemental vitamin E and risk of metastatic or fatal prostate cancer among current smokers an d recent quitters was consistent with the Finnish trial among smokers and w arrants further investigation.