Tea consumption and risk of gallbladder cancer: A meta-analysis of epidemiological studies

Previous epidemiological studies investigating the association between tea consumption and the risk of gallbladder cancer have yielded inconsistent results. Therefore, we aimed to assess this association by conducting a meta-analysis of all available studies. A search was conducted through Pubmed, Embase, Chinese Biomedical literature Database and China Knowledge Resource Integrated Database to identify relevant studies on tea consumption and the risk of gallbladder cancer. A random-effects model was used to calculate the overall combined risk estimates. Six studies (4 case-control and 2 cohort studies), involving a total of 753 patients and 115,349 controls, were included in this meta-analysis. The overall combined odds ratio (OR) for tea consumption and gallbladder cancer was 0.67 [95% confidence interval (CI): 0.40-1.12, P=0.13]. Similar results were obtained for the high or moderate tea consumption vs. the low/non-consumption groups. However, our meta-analysis identified a significant association between tea consumption and reduced gallbladder cancer risk in women (OR=0.46, 95% CI: 0.26-0.81, P=0.008), but not in men (OR=0.43, 95% CI: 0.12-1.59, P=0.21). Therefore, the results of the present meta-analysis suggest that, according to the currently available epidemiological studies, tea consumption may reduce the risk of gallbladder cancer in women, but not in men. Further epidemiological studies are required to determine the association between tea consumption and the risk of gallbladder cancer.