title: Green tea consumption and gastric cancer in Japanese: a pooled analysis of six cohort studies.
abstract: BACKGROUND
  Previous experimental studies have suggested many possible anti-cancer mechanisms for green tea, but epidemiological evidence for the effect of green tea consumption on gastric cancer risk is conflicting.
  
  
  OBJECTIVE
  To examine the association between green tea consumption and gastric cancer.
  
  
  METHODS
  We analysed original data from six cohort studies that measured green tea consumption using validated questionnaires at baseline. Hazard ratios (HRs) in the individual studies were calculated, with adjustment for a common set of variables, and combined using a random-effects model.
  
  
  RESULTS
  During 2 285 968 person-years of follow-up for a total of 219 080 subjects, 3577 cases of gastric cancer were identified. Compared with those drinking <1 cup/day, no significant risk reduction for gastric cancer was observed with increased green tea consumption in men, even in stratified analyses by smoking status and subsite. In women, however, a significantly decreased risk was observed for those with consumption of > or =5 cups/day (multivariate-adjusted pooled HR = 0.79, 95% confidence interval (CI) = 0.65 to 0.96). This decrease was also significant for the distal subsite (HR = 0.70, 95% CI = 0.50 to 0.96). In contrast, a lack of association for proximal gastric cancer was consistently seen in both men and women.
  
  
  CONCLUSIONS
  Green tea may decrease the risk of distal gastric cancer in women.
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 Japan. mnminoue@ncc.go.jp
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: S
authors.initials: S
authors.lastname: Sasazuki
authors.forename: K
authors.initials: K
authors.lastname: Wakai
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Matsuo
authors.forename: T
authors.initials: T
authors.lastname: Shimazu
authors.forename: I
authors.initials: I
authors.lastname: Tsuji
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Mizoue
authors.forename: C
authors.initials: C
authors.lastname: Nagata
authors.forename: A
authors.initials: A
authors.lastname: Tamakoshi
authors.forename: N
authors.initials: N
authors.lastname: Sawada
authors.forename: S
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D011795:Surveys and Questionnaires; D013662:Tea / Q000737:chemistry
chemical_list: D013662:Tea