Green Tea Consumption and the Risk of Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study

Objective: Biologic studies have shown that certain components of green tea may have protective effects on neurocognition. However, because of the lack of human epidemiologic studies, the impact of green tea consumption on the incidence of dementia has never been confirmed. The objective of this cohort study was to clarify the association between green tea consumption and incident dementia. Methods: In this 5.7-year prospective cohort study, using a questionnaire, information on daily green tea consumption and other lifestyle factors was collected from elderly Japanese individuals aged 65 years or more. Data on incident dementia were retrieved from the public Long-term Care Insurance Database. Results: Among 13,645 participants, the 5.7-year rate of incident dementia was 8.7%. More frequent green tea consumption was associated with a lower risk of incident dementia (hazard ratio for >= 5 cups/day versus <1 cup/day: 0.73; 95% confidence interval: 0.61-0.87). The lower risk of incident dementia was consistent even after selecting participants who did not have subjective memory complaints at the baseline. Conclusion: Green tea consumption is significantly associated with a lower risk of incident dementia.