Association Between Drinking of Different Types of Tea and Risk of Stroke: A Systematic Review and Meta-analysis

Background and aims: Cerebrovascular accidents, commonly known as stroke, are among the leading causes of disability and death worldwide. As the second most consumed beverage globally, tea has attracted research interest regarding its potential role in stroke risk. Hence, this research sought to investigate the relationship between consumption of different types of tea and the risk of stroke. Methods: A comprehensive search was conducted in the Web of Science, Embase, ProQuest, Scopus, Cochrane, PubMed, Google Scholar databse, up to June 9, 2024. Data were analyzed using STATA 14, and statistical significance was set at P<0.05 for all tests. Results: Analysis of 29 studies showed that tea consumption was associated with a 13% decreased risk of stroke. Specifically, drinking oolong tea (OR: 0.46, 95% CI: 0.25, 0.85), green tea (OR: 0.76, 95% CI: 0.70, 0.82), and black tea (OR: 0.92, 95% CI: 0.86, 0.98) significantly lowered stroke risk. Tea consumption also lowered the risk of ischemic stroke by 19%, intracerebral hemorrhage by 17%, cerebral hemorrhage by 15%, cerebral infarction by 7%, and mortality risk by 20%. Additionally, tea consumption exerted a protective effect in in men, lowering stroke risk by 14%. Conclusion: Tea consumption was inversely associated with the risk of stroke. The likelihood of stroke decreased as the daily number of tea cups consumed increased. Among the different types, oolong tea had a greater effect against stroke compared to green and black teas.