Dietary inflammatory index and cardiovascular risk and mortality: A meta-analysis of cohort studies

BACKGROUND: The role of dietary inflammatory index (DII) in cardiovascular disease (CVD) risk and mortality is still controversial. This systematic review and meta-analysis of cohort studies aimed to evaluate the effect of DII, indicating a pro-inflammatory diet, on the incidence and mortality of CVD. METHODS: A comprehensive literature search of articles published through August 2019 was performed in Medline, EMBASE, and Web of Science. The pooled relative risks (RRs) and 95% confidence intervals (CIs) for highest vs lowest DII in relation to CVD risk or mortality were estimated using a DerSimonian and Laird random effects model. The heterogeneity among studies was tested using Cochran's Q test and I(2) statistic. RESULTS: A total of 15 cohort studies were finally included in this meta-analysis. The highest DII score was significantly associated with a higher risk of CVD incidence (RR = 1.41, 95% CI 1.12–1.78) or mortality (RR = 1.31, 95% CI 1.19–1.44), compared with the lowest DII score. There was statistically significant heterogeneity among the studies on the association between DII and CVD mortality (P < .001; I(2) = 70.8%). No obvious heterogeneity was observed among the studies on the association between DII and CVD risk (P = .160; I(2) = 37.0%). In the sensitivity analysis, exclusion of any single study did not materially alter the pooled RRs. CONCLUSION: The present systematic review and meta-analysis indicates that a higher DII score is related to a higher risk of CVD. Further well-designed prospective cohort or trials are warranted to validate our preliminary findings.