Green tea and gastric cancer risk: meta-analysis of epidemiologic studies

Objective: To evaluate the association between green tea consumption and the risk of gastric cancer. Methods: Electronic search of the Cochrane Library, MEDLINE, EMBASE and Chinese Bio-medicine Database, which have articles published between (1966 and 2006), was conducted to select studies for this meta-analysis. Results: This meta-analysis included 14 epidemiologic studies, with a total number of 6123 gastric cancer cases and 134006 controls. The combined results based on all studies showed that green tea consumption was not associated with the risk of gastric cancer [odds ratio (OR) = 0.98, 95% confidence interval (CI) = 0.77-1.24]. The summary OR from all population-based case-control studies showed a minor inverse association between green tea consumption and risk of gastric cancer (OR = 0.68, 95% CI = 0.49-0.92), while no associations were noted from hospital-based case-control studies (OR = 1.12, 95% CI = 0.70-1.77) and cohort studies (OR = 1.56, 95% CI = 0.93-2.60). No associations were noted both in males (OR = 1.10, 95% CI = 0.76-1.60) and females (OR = 0.99, 95% CI = 0.64-1.51). The summary OR from seven studies suggest that the highest consumption level of green tea was more than 5 cups per day and no associations were noted (OR = 0.99, 95% CI = 0.78-1.27). Conclusions: The results of this meta-analysis indicated that there is no clear epidemiological evidence to support the suggestion that green tea plays a role in the prevention of gastric cancer.