Association of tea consumption and the risk of gastric cancer in Japanese adults : the Japan Collaborative Cohort Study

Objective To examine the possible relationship between tea consumption and risk of gastric cancer (GC) among Japanese men and women included in a large Japanese population-based study titled the Japan Collaborative Cohort (JACC) Study. Design Prospective cohort study. Setting A population-based cohort included subjects who were recruited from 24 areas of JACC Study, in which data regarding the incidence of cancer were available. Participants 63 848 participants (26 025 men and 37 823 women), aged 40-79, were included in the analyses and underwent follow-up (median 13.3 years) prospectively in research on cancer incidence. Primary and secondary outcome measures The primary outcome variable was the risk of GC according to the frequency intakes of total tea, green tea, black tea and oolong tea. The adjusted HRs for the risk of GC associated with tea consumption were calculated using the Cox proportional hazards model. Results 1494 cases of GC were detected (960 men and 534 women) during the follow-up period. The multivariable-adjusted HRs for the risk of GC in the highest versus lowest quintiles of total tea intake were 1.05 (0.83-1.33); p trend=0.50 in men, and 0.82 (0.60-1.12); p trend=0.45 in women. There was no association found between the consumption of green tea, black tea or oolong tea with the risk for GC in either gender. Conclusions In this large community-based prospective cohort study, tea consumption was not associated with the risk of GC in either gender.