Dietary Patterns and Prostate Cancer Risk in the Multiethnic Cohort Study.

[BACKGROUND] Healthy dietary patterns have been linked to reduced cancer risk, but evidence for prostate cancer remains inconsistent, especially across diverse populations.

[METHODS] In the Multiethnic Cohort study, we examined associations between 11 diet scores and prostate cancer risk among 79,930 men (White, African American, Japanese American, Latino, or Native Hawaiian). HRs and 95% confidence intervals (CI) per 1 SD increase in each score were estimated from Cox proportional hazards models for total prostate cancer and by grade, stage, and aggressiveness. Analyses were conducted overall and within racial/ethnic groups. A significance threshold of P < 0.003 was used to adjust for multiple testing.

[RESULTS] Over a mean follow-up of 18.8 years, 9,759 prostate cancer cases were identified. No significant associations were observed in the hypothesized direction between dietary scores and prostate cancer risk in the overall population. However, among African Americans, higher Dietary Approaches to Stop Hypertension scores were suggestively associated with a 14% lower risk of advanced prostate cancer (95% CI, 0.77-0.98; P = 0.02). Among Japanese Americans, higher Empirical Dietary Index for Insulin Resistance scores were linked to an increased risk of low-grade (HR = 1.09; 95% CI, 1.02-1.17; P = 0.01) and nonaggressive prostate cancer (HR = 1.10; 95% CI, 1.02-1.19; P = 0.02).

[CONCLUSIONS] Although no strong associations were found overall, specific dietary patterns may influence prostate cancer risk differently by race/ethnicity and tumor subtype, warranting further investigation in large and diverse populations.

[IMPACT] These findings highlight the need for future studies to explore disease-specific and culturally informed dietary patterns that may inform prostate cancer prevention across diverse populations.