Index-Based Dietary Patterns and the Risk of Prostate Cancer

Prostate cancer is the second leading cause for cancer incidence in male. Although this high incidence is due to prostate specific antigen screening, other risk-factors, such as diet, might also be involved. The results of previous studies on the association between prostate cancer risk and individual dietary components have been conflicting. Thus, evaluation by dietary pattern analysis rather than individual dietary factors is suggested. The purpose of this study was to review the association of prostate cancer with a priori dietary indices, which are less studied and reviewed to date compared to a posteriori indices. Studies reviewed in this research were published from January 1997 to March 2017. Seventeen studies with nine indices were selected. In Mediterranean Diet Score (MDS), all four studies were non-significant. In Dietary Inflammatory Index (DII), 3 out of 4 studies significantly increased risk by 1.33–2.39 times, suggesting that a higher pro-inflammatory diet may be a possible prostate cancer risk factor. In Oxidative Balance Score (OBS), 2 out of 5 studies had decreased risk by 0.28 and 0.34 times, whereas 1 study had increased risk by 1.17 times. Among other indices, Healthy Eating Index (HEI) and prostate cancer dietary index were associated with decreased risk, while the results from 2 studies of Low Carbohydrate, High Protein Diet (LCHP) score were conflicting. In conclusion, we observed that it is insufficient to support the association between a priori indices and prostate cancer risk, except for MDS and DII, which had relatively constant results among studies. Therefore, further studies are required to identify consistent criteria for each a priori index, and should be conducted actively in various populations.