Vegetable, Fruit Consumption and Risk of Biliary Cancer: Evidence from a Meta-Analysis

This meta-analysis was performed to assess the association between vegetable and fruit (VF) consumption and biliary cancer risk.

Relevant studies were identified by a search of MEDLINE and Embase databases. The summary relative risks (RRs) with 95% confidence intervals (CIs) for the highest vs. lowest consumption and dose-response analyses were assessed.

Fourteen studies were eligible. The summary RRs associated with the risk of biliary cancer for the highest vs. lowest were 0.48 (n = 10; 95% CI: 0.22-0.74; Q = 68.27, P_{heterogeneity} < 0.001, I = 86.8%) for vegetable consumption and 0.47 (n = 13; 95% CI: 0.32-0.61; Q = 32.68, P_{heterogeneity} = 0.001, I = 63.3%) for fruit consumption. Dose-response associations were analyzed for every 100 gram/day increment: for vegetable (n = 8; RR = 0.31, 95%CI: 0.20-0.47; P_{non-linearity} = 0.35) and for fruit (n = 8; RR = 0.89, 95%CI: 0.66-1.18; P_{non-linearity} = 0.20). There was no publication bias among studies (P_Begg = 0.53, P_Egger = 0.84 for vegetable; P_Begg = 0.95, P_Egger = 0.64 for fruit).

This meta-analysis indicated that VF consumption may significantly reduce the risk of biliary cancer. Further well-designed prospective studies are warranted to confirm our findings.