Purpose: Two prior cohort studies suggested that choline, but not betaine intake, is associated with an increased risk of advanced prostate cancer (PCa). Given that evidence remains limited, we evaluated whether intakes of choline and derivative betaine are associated with total and lethal PCa risk and PCa death in men with PCa. Methods: We included 6,528 men (24.4% African American) without a cancer diagnosis at baseline (1987–1989) followed through 2012. Dietary intake was assessed using a

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... d frequency questionnaire coupled with a nutrient database. We used Cox proportional hazards regression to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) of total and lethal PCa risk overall and by race. Results: Choline intake was not associated with total (n = 811) or lethal (n = 95) PCa risk overall or by race. Betaine intake was inversely associated with lethal (tertile 3 vs 1, HR 0.59, 95% CI 0.35–1.00, p trend = 0.04), but not total PCa risk; patterns for lethal PCa were similar by race. Neither nutrient was associated with PCa death in men with PCa. Conclusions: Choline intake was not associated with total or lethal PCa or with PCa death in men with PCa. Betaine intake was inversely associated with lethal, but not total PCa risk or with PCa death in men with PCa. Our results do not support the hypothesis that higher choline intake increases lethal PCa risk, but do suggest that higher betaine intake may be associated with lower lethal PCa risk. Further investigation with a larger number of lethal cases is needed.