Background and purpose: Few prospective studies have examined the impact of both green tea and coffee consumption on strokes. We investigated the association of the combination of those consumption with stroke incidence in a general population.
Methods: We studied 82 369 Japanese (aged 45-74 years; without cardiovascular disease [CVD] or cancer in 1995 and 1998 for Cohort I and II, respectively) who received 13 years of mean follow-up through the end of 2007. Green tea and coffee consumption was assessed by self-administered food frequency questionnaire at baseline.
Results: In the 1 066 718 person-years of follow-up, we documented the incidence of strokes (n=3425) and coronary heart disease (n=910). Compared with seldom drinking green tea, the multivariable-adjusted hazard ratios (95% confidence intervals) of all strokes were 0.86 (0.78-0.95) and 0.80 (0.73-0.89) in green tea 2 to 3 and ≥ 4 cups/d, respectively. Higher green tea consumption was associated with inverse risks of CVD and strokes subtypes. Compared with seldom drinking coffee, the multivariable-adjusted hazard ratios (95% confidence intervals) of all strokes were 0.89 (0.80-0.99), 0.80 (0.72-0.90), and 0.81 (0.72-0.91) for coffee 3 to 6 times/week and 1 and ≥ 2 times/day, respectively. Coffee consumption was associated with an inverse risk of CVD and cerebral infarction. Higher green tea or coffee consumption reduced the risks of CVD and stroke subtypes (especially in intracerebral hemorrhage, P for interaction between green tea and coffee=0.04). None of the significant association was observed in coronary heart disease.
Conclusions: Higher green tea and coffee consumption were inversely associated with risk of CVD and stroke in general population.