Objectives: We performed a meta-analysis to assess the association and possible dose-response relationship between dietary inflammation index (DII)™ and colorectal cancer (CRC).
Methods: A literature search was performed in PubMed, Web of Science and Chinese National Knowledge Infrastructure (CNKI) database for all relevant studies. The pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated by random effects model.
Results: A total of eight studies were included in this meta-analysis. The pooled RRs of CRC, colon and rectal cancer for the highest versus lowest DII categories were 1.43 (95% CI 1.25-1.63), 1.37 (95% CI 1.16-1.62) and 1.44 (95% CI 1.23-1.69), respectively. A significant positive association was observed both in cohort studies (RR = 1.26, 95% CI 1.14-1.38) and case-control studies (RR = 1.81, 95% CI 1.48-2.22). Nonlinear associations between DII scores and the risk of CRC, colon and rectal cancer were found in the dose-response analyses, the results showed that the risks of CRC, colon and rectal cancer increased slowly when the DII score was above 1.30, 2.21, and 1.30, respectively.
Conclusion: Higher DII scores might increase CRC risk. Thus, people should adopt more anti-inflammatory diets such as those high in vegetables, fruits, whole grains, herbs, and spices.