Dietary Inflammatory Index and Pancreatic Cancer Risk-A Systematic Review and Dose-response Meta-analysis.

OBJECTIVE The meta-analysis was conducted to test the link between pancreatic cancer (PC) risk and dietary inflammatory index (DII®) score. DESIGN Systematic review and meta-analysis. SETTING We searched PubMed, Embase, Web of Science, and the Cochrane Library up to November 22, 2020, to identify the relevant studies. Studies that reported the risk estimates and the corresponding 95% confidence intervals (CIs) for the DII category and PC risk were included. The effect sizes were pooled using the random-effects model. Dose-response analysis was conducted where possible. PARTICIPANTS Two prospective cohort studies of 634 705 participants (3 152 incident cases), and four case-control studies of 2 737 cases and 4 861 controls. RESULTS Overall, the pooled risk ratio (RR) indicated that individuals in the highest category compared with the lowest category had an increased PC risk (RR=1.45; 95% CI 1.11, 1.90; P=0.006). Meanwhile, significant heterogeneity was also revealed. The dose-response meta-analysis indicated that a 1-unit increase in the DII score was associated with the PC risk (RR=1.08; 95% CI 1.002, 1.166; P=0.045; I2=94.1%, P<0.001). Nonlinear result showed an increased risk of moving from fewer to more inflammatory borders with increasing DII score (Pnonlinearity = 0.003; I2=76.5%, P<0.001). Subgroup analyses found that significant positive association between PC risk and DII score appeared to be in case-control studies (RR=1.70; 95% CI 1.16, 2.50; P=0.007) and studies with ≤31 DII components (RR=1.76; 95% CI 1.14, 2.72; P=0.011). CONCLUSION These findings suggested dietary habits with high inflammatory features (high DII score) might increase PC risk.