title: Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study.
abstract: BACKGROUND
  Green tea polyphenols have been extensively studied as cardiovascular disease and cancer chemopreventive agents in vitro and in animal studies. However, the effects of green tea consumption in humans remain unclear.
  
  
  OBJECTIVE
  To investigate the associations between green tea consumption and all-cause and cause-specific mortality.
  
  
  METHODS
  The Ohsaki National Health Insurance Cohort Study, a population-based, prospective cohort study initiated in 1994 among 40,530 Japanese adults aged 40 to 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (1995-2005) for all-cause mortality and for up to 7 years (1995-2001) for cause-specific mortality.
  
  
  METHODS
  Mortality due to cardiovascular disease, cancer, and all causes.
  
  
  RESULTS
  Over 11 years of follow-up (follow-up rate, 86.1%), 4209 participants died, and over 7 years of follow-up (follow-up rate, 89.6%), 892 participants died of cardiovascular disease and 1134 participants died of cancer. Green tea consumption was inversely associated with mortality due to all causes and due to cardiovascular disease. The inverse association with all-cause mortality was stronger in women (P = .03 for interaction with sex). In men, the multivariate hazard ratios of mortality due to all causes associated with different green tea consumption frequencies were 1.00 (reference) for less than 1 cup/d, 0.93 (95% confidence interval [CI], 0.83-1.05) for 1 to 2 cups/d, 0.95 (95% CI, 0.85-1.06) for 3 to 4 cups/d, and 0.88 (95% CI, 0.79-0.98) for 5 or more cups/d, respectively (P = .03 for trend). The corresponding data for women were 1.00, 0.98 (95% CI, 0.84-1.15), 0.82 (95% CI, 0.70-0.95), and 0.77 (95% CI, 0.67-0.89), respectively (P<.001 for trend). The inverse association with cardiovascular disease mortality was stronger than that with all-cause mortality. This inverse association was also stronger in women (P = .08 for interaction with sex). In women, the multivariate hazard ratios of cardiovascular disease mortality across increasing green tea consumption categories were 1.00, 0.84 (95% CI, 0.63-1.12), 0.69 (95% CI, 0.52-0.93), and 0.69 (95% CI, 0.53-0.90), respectively (P = .004 for trend). Among the types of cardiovascular disease mortality, the strongest inverse association was observed for stroke mortality. In contrast, the hazard ratios of cancer mortality were not significantly different from 1.00 in all green tea categories compared with the lowest-consumption category.
  
  
  CONCLUSIONS
  Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer.
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan. kuriyama-thk@umin.ac.jp
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kuriyama
authors.forename: Taichi
authors.initials: T
authors.lastname: Shimazu
authors.forename: Kaori
authors.initials: K
authors.lastname: Ohmori
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Kikuchi
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakaya
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nishino
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Tsubono
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsuji
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000401:mortality*; D004327:Drinking Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009026:Mortality; D009369:Neoplasms / Q000401:mortality*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013662:Tea
chemical_list: D013662:Tea