Plasma tea catechins and risk of cardiovascular disease in middle-aged Japanese subjects: The JPHC study.

ABSTRACT

BACKGROUND AND AIMS: Although a potential benefit of drinking green tea has been suggested to reduce the development of cardiovascular disease, no study has investigated the relationship between plasma tea catechin and risk of cardiovascular disease. METHODS: A prospective, nested case-control study was conducted to examine the association between plasma tea catechin and risk of stroke and coronary heart disease (CHD) in a cohort of 29,876 men and women aged 40-69 years without history of heart disease, stroke or cancer. Participants completed a survey and donated blood samples between 1990 and 1994, and were followed-up through 2008. A total of 1132 stroke cases and 209 CHD cases, matched 11 to controls (n = 1132) for stroke and 12 to controls (n = 418) for CHD, were included in the analysis. RESULTS: We found no significant association between plasma tea catechin and the incidence of stroke or CHD in either men or women. However, we found that high plasma levels of epigallocatechin gallate (EGCG) were associated with reduced risk of stroke in non-smoking men; the adjusted odds ratio (95% CI) for the highest vs. non-detectable levels was 0.53 (0.29-0.98). The respective OR in male smokers was 1.23 (0.75-2.16). A significant interaction by smoking status was found for the highest vs. non-detected plasma EGCG in relation to stroke (p-for-interaction p = 0.09). CONCLUSIONS: Plasma tea catechin was not associated with reduced risks of either stroke or CHD, while a protective effect of certain tea catechin on stroke risk is suggested for male non-smokers.