Association between Dietary Inflammatory Index and the Risk of Prostate Cancer: A Meta-Analysis

Background: Diet is a known source of pro- and anti-inflammatory mediators, and inflammatory markers have been associated with mechanisms involved in prostate cancer initiation and progression. The Dietary Inflammatory Index (DII®) is a tool to assist researchers in determining the inflammatory potential of diet. The aim of this study was to conduct a meta-analysis to assess the association between DII and prostate cancer. Methods: EMBASE and MEDLINE were searched from inception to February 2018, for relevant observational studies. The random effects model was used to calculate the overall relative risks (RRs) with 95% confidence intervals (CIs). Results: Data from five case-control and one cohort study were eligible for inclusion. The adjusted pooled RR of prostate cancer for the highest (the most pro-inflammatory diet) versus lowest (the most anti-inflammatory diet) DII categories was 1.74 (95% CI: 1.24–2.43). The analysis in the DII score as a continuous variable was also performed and the results showed that the risk of prostate cancer was 9% higher for each one-point increase in the score. Conclusion: This meta-analysis suggests that promoting diets rich in anti-inflammatory food components (i.e., whole grains, fish, green vegetables, and fruits) should help in reducing preventing prostate cancer.