Green tea consumption and the risk of stroke: A systematic review and meta-analysis of cohort studies

Objectives: Epidemiologic studies are inconsistent regarding the association between green tea consumption and the risk of stroke. We performed a meta-analysis to determine whether an association exists between them in cohort studies. Methods: We searched the PubMed and Embase databases for studies conducted from 1966 through September 2022. Prospective cohort studies that provided relative risk (RR) estimates with 95% confidence interval (CI)s for the association were included. Study-specific risk estimates were combined by using a randomeffects model. Results: A total of five studies, with 11 421 stroke cases among 645 393 participants, were included in the meta-analysis. The summary RR indicated a significant association between highest green tea consumption and reduced risk of stroke (summary RR: 0.74; 95% CI, 0.66-0.83). In the dose-response analysis, we observed a nonlinear association between green tea consumption and the risk of stroke (P for nonlinearity = 0.0000). Compared with non-consumers, the RRs (95% CI) of stroke across levels of green tea consumption were 0.91 (0.89-0.94) for 150 mL/d, 0.84 (0.80-0.89) for 300 mL/d, 0.79 (0.74-0.84) for 500 mL/d, 0.77 (0.72-0.82) for 900 mL/d, and 0.84 (0.77-0.91) for 1500 mL/d. Conclusions: This meta-analysis suggests that green tea consumption is inversely associated with the risk of stroke, especially among those with moderate consumption. Our results support recommendations for green tea consumption to the primary prevention of stroke.