Consumption of vegetables may reduce the risk of liver cancer: Results from a meta-analysis of case-control and cohort studies

SummaryPurposeWe conducted a meta-analysis of all published case-control and cohort studies to evaluate the relationship between vegetables intake and liver cancer risk.MethodsWe searched for cohort and case–control studies published before February 2014, using Pubmed and Cochrane Library Central database. Pooled relative risk (RR) estimates and corresponding 95% confidence interval (CI) were calculated using the inverse-variance method.ResultsEight case-control studies and one cohort study were included in this meta-analysis, involving a total of 136,425 subjects and 1349 liver cancer cases. Finally, we observed a statistically significant protective effect of vegetables consumption on liver cancer (RR = 0.78, 95% CI [0.62, 0.99]). In the present meta-analysis, no publication bias was observed among studies using Begg's P value (P = 0.532); Egger's (P = 0.180) test, which suggested there was no evidence of publication bias.ConclusionsOur results suggest that vegetables consumption may reduce the risk of liver cancer. More prospective cohort studies with larger sample size, well-controlled confounding factors are warranted to further evaluate the association.