TEA CONSUMPTION AND LUNG-CANCER RISK - A CASE-CONTROL STUDY IN OKINAWA, JAPAN

To disclose the relationship between tea consumption and lung cancer r isk, we analyzed the data from a case-control study conducted in Okina wa, Japan from 1988 to 1991. The analysis, based on 333 cases and 666 age-, sex- and residence-matched controls, provided the following majo r findings. (a) The greater the intake of Okinawan tea (a partially fe rmented tea), the smaller the risk, particularly in women. For females , the odds ratios (and 95% confidence intervals) for those who consume d 1-4, 5-9, and 10 cups or more of Okinawan tea every day, relative to non-daily tea drinkers, were 0.77 (0.28-2.13), 0.77 (0.26-2.25) and 0 .38 (0.12-1.18), respectively (trend: P = 0.032). The corresponding od ds ratios for males were 0.85 (0.46-1.55), 0.85 (0.46-1.56) and 0.57 ( 0.31-1.06) (trend: P = 0.053). (b) The risk reduction by Okinawan tea consumption was detected mainly in squamous cell carcinoma. Daily tea consumption significantly decreased the risk of squamous cell carcinom a in males and females, the odds ratios being 0.50 (95% confidence int erval 0.27-0.93) and 0.08 (0.01-0.68), respectively. These findings su ggest a protective effect of tea consumption against lung cancer in hu mans.