The association between healthy and unhealthy dietary indices with prostate cancer risk: a case-control study

Introduction According to our knowledge, the relationship between dietary patterns such as pro-healthy, pro-vegetarian, and non-healthy dietary patterns and prostate cancer risk has not been clearly investigated in Iranian men. Therefore, we aimed to investigate the relationship between adherence to a pro-healthy (PHDI), pro-vegetarian (PDP), and non-healthy dietary indices (NHDI) and the risk of prostate cancer.Method In this matched case-control study, 125 participants (62 cases and 63 hospital-based controls) were enrolled from April to September 2015. Participants' dietary intakes were evaluated using a valid and reliable 160-item semi-quantitative food frequency questionnaire. Dietary indices calculated based on previous studies. The relationship between dietary indices (PHDI, NHDI and PDP) and prostate cancer risk was assessed using binary regression models.Results According to adjusted model, significant negative correlations were found between PHDI and PDP with prostate cancer (PHDI: OR = 0.31; 95% CI; 0.11-0.85; P = 0.023 - PDP: OR = 0.34; 95% CI; 0.15-0.75; P = 0.008). Also, a positive association was seen between NHDI and prostate cancer (OR = 3.01; 95% CI; 1.20-7.57; P = 0.019).Conclusion We found that adherence to healthy dietary indices which includes high amounts of fruits, vegetables, and whole grains reduces the risk of prostate cancer. While adherence to a dietary pattern high in red and processed meat, refined grains, and sweetened beverages increases the risk of prostate cancer.