Green tea and death from pneumonia in Japan: the Ohsaki cohort study

Abstract

Background: Experimental and animal studies have shown the activities of catechins, the main constituents of green tea, against infectious agents. No data are available on the association between green tea consumption and the risk of pneumonia in humans.

Objective: We examined the association between green tea consumption and death from pneumonia in humans.

Design: We conducted a population-based cohort study, with follow-up from 1995 to 2006. The participants were National Health Insurance beneficiaries in Japan (19,079 men and 21,493 women aged 40-79 y). We excluded participants for whom data on green tea consumption frequency were missing or who had reported a history of cancer, myocardial infarction, stroke, and extreme daily energy intake at baseline. We used Cox proportional hazards regression analysis to calculate hazard ratios (HRs) and their 95% CIs for death from pneumonia according to green tea consumption.

Results: Over 12 y of follow-up, we documented 406 deaths from pneumonia. In women, the multivariate HRs of death from pneumonia that were associated with different frequencies of green tea consumption were 1.00 (reference) for <1 cup/d, 0.59 (95% CI: 0.36, 0.98) for 1-2 cups/d, 0.55 (95% CI: 0.33, 0.91) for 3-4 cups/d, and 0.53 (95% CI: 0.33, 0.83) for > or =5 cups/d, respectively (P for trend: 0.008). In men, no significant association was observed.

Conclusion: Green tea consumption was associated with a lower risk of death from pneumonia in Japanese women.