Green tea consumption and the risk of liver cancer in Japan: The Ohsaki Cohort study

Objectives: To investigate the association between green tea consumption and liver cancer incidence. Methods: We prospectively followed 41,761 Japanese adults aged 40-79 years, without a history of cancer at the baseline or any missing data for green tea consumption frequency. Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI), adjusted for age, alcohol drinking, smoking, the consumption of coffee, vegetables, dairy products, fruit, fish, and soybean. Results: Over 9 years of follow-up, among 325,947 accrued person-years, the total incidence of liver cancer was 247 cases. We found that green tea consumption was inversely associated with the incidence of liver cancer. In men, the multivariate-adjusted HRs (95% CIs) for liver cancer incidence with different green tea consumption categories were 1.00 (reference) for <1 cup/day, 0.83 (0.53-1.30) for 1-2 cups/day, 1.11 (0.73-1.68) for 3-4 cups/day, and 0.63 (0.41-0.98) for ≥5 cups/day (p for trend = 0.11). The corresponding data among women were 1.00 (reference), 0.68 (0.35-1.31), 0.79 (0.44-1.44), 0.50 (0.27-0.90) (p for trend = 0.04). Conclusions: Green tea consumption is associated with a reduced risk of liver cancer incidence.