Dietary, Supplement, and Adipose Tissue Tocopherol Levels in Relation to Prostate Cancer Aggressiveness Among African and European Americans: The North Carolina-Louisiana Prostate Cancer Project (PCaP)

BACKGROUND. Controversies remain over the safety and efficacy of vitamin E (i.e., -tocopherol) supplementation use for the prevention of prostate cancer (CaP); however, associations of different tocopherol forms and CaP aggressiveness have yet to be examined. METHODS. This study examined whether food intake of tocopherols, vitamin E supplement use, and adipose tissue biomarkers of tocopherol were associated with CaP aggressiveness among African-American (AA, n=1,023) and European-American (EA, n=1,079) men diagnosed with incident CaP. Dietary tocopherols were estimated from a food frequency questionnaire, supplement use from questionnaire/inventory, and biomarkers from abdominal adipose samples measured using high-performance liquid chromatography. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were estimated from logistic regression comparing high-aggressive CaP to low/intermediate aggressive CaP, adjusting for covariates. RESULTS. Dietary intakes of -and -tocopherol were related inversely to CaP aggressiveness among EAs [OR (95%CI), highest versus lowest quartile: -tocopherol, 0.34 (0.17-0.69), P-trend=0.006; -tocopherol, 0.45 (0.21-0.95) P-trend=0.007]. Inverse associations between dietary and supplemental -tocopherol and CaP aggressiveness were observed among AAs, though these did not reach statistical significance [OR (95%CI), highest versus lowest quartile: dietary -tocopherol, 0.58 (0.28-1.19), P-trend=0.20; supplemental -tocopherol, 0.64 (0.31-1.21) P-trend=0.15]. No significant association was observed between adipose tocopherol levels and CaP aggressiveness [OR (95%CI), highest versus lowest quartiles of -tocopherol for EAs 1.43 (0.66-3.11) and AAs 0.66 (0.27-1.62)]. CONCLUSIONS. The inverse associations observed between dietary sources of tocopherols and CaP aggressiveness suggests a beneficial role of food sources of these tocopherols in CaP aggressiveness. (c) 2015 Wiley Periodicals, Inc.