Relationships of dietary habits with prostate cancer risk: results from Mendelian randomization analyses and the National Health and Nutrition Examination Survey

Background: Prior investigations identified correlations between dietary habits and the risk of prostate cancer (PCa); however, the causative dynamics are unclear. Methods: Utilizing the Mendelian randomization (MR) framework, we investigated the causal links between dietary habits, daily nutrient intakes, and risk of PCa (79 148 cases and 61 106 controls). Exposure and outcome data were obtained from the UK Biobank and the Prostate Cancer Association Group to Investigate Cancer-Associated Alterations in the Genome (PRACTICAL) consortium, respectively. Univariable and multivariable MR analyses were employed. Sensitivity analyses were performed to detect outliers, evaluate heterogeneity, and discern potential pleiotropic effects. Utilizing data from the National Health and Nutrition Examination Survey (NHANES) database (2009-2010), we selected 1294 and 1778 men aged ≥40 years from a pool of 10 537 participants, ensuring no missing information. Regression analyses examined the associations between leafy/lettuce salad intake, daily nutrient intake, and the odds of PCa. Results: Univariable MR (UVMR) analysis reveals that the intake of pork and salad/raw vegetable correlated with an elevated PCa risk. Subsequent to confounder adjustment via multivariable MR (MVMR) analysis, a causal link was established between salad/raw vegetable intake and an increased risk of PCa (odds ratio [OR]: 1.658, 95% confidence interval [95% CI]: 1.037-2.644, P = 0.046). The analysis based on NHANES datasets demonstrated a link between leafy/lettuce salad intake and heightened odds of PCa (OR: 1.025, 95% CI: 1.003-1.049, P = 0.038). Increased daily intakes of β-carotene (original OR: 1.00006, 95% CI: 1.00001-1.00011, P = 0.024) and vitamin B1 (OR: 1.474, 95% CI: 1.104-1.967, P = 0.014) were associated with a higher likelihood of PCa. Conclusions: These MR analyses substantiate the causal nexus between salad/raw vegetable intake and PCa risk. Similarly, leafy/lettuce salad intake and the odds of PCa were significantly correlated in the cross-sectional observational study. Moreover, higher daily intakes of β-carotene and vitamin B1 were linked to an increased likelihood of PCa. These findings provide practical dietary recommendations for PCa prevention and enhance early identification and diagnosis.