Higher tea consumption is associated with decreased risk of small vessel stroke

Background & aim Observational studies have reported that tea consumption is associated with risk of stroke. However, this observed association is inconsistent, and whether this observed association is due to confounding factors or reverse causation remains unclear. Thus, we applied a two-sample mendelian randomization (MR) approach to determine whether genetically predicted tea consumption is causally associated with risk of stroke, ischemic stroke (IS), and IS subtypes. Methods UK Biobank available data (349,376 samples of European ancestry) was used to identify single nucleotide polymorphisms associated with tea consumption (cups/day). The summary statistics for stroke, IS, and IS subtypes were obtained from the MEGASTROKE consortium with 40,585 stroke cases and 406,111 controls. Results We found that genetically predicted an extra daily cup of tea consumption was casually associated with a reduced risk of small vessel stroke (odds ratio (OR), 0.79; 95% confidence interval (CI), 0.69–0.91; P = 0.001), but not with cardioembolic stroke (OR, 0.97; 95% CI, 0.86–1.09; P = 0.582), large artery stroke (OR, 0.95; 95% CI, 0.82–1.10; P = 0.506), stroke (OR, 1.00; 95% CI, 0.95–1.06; P = 0.889) or IS (OR, 0.95; 95% CI, 0.89–1.01; P = 0.083). Conclusions Our study provided evidence that genetically predicted an extra daily cup of tea consumption is causally associated with a reduced risk of small vessel stroke.