Ide 2007.

Study characteristics
Methods	Cohort study in Japan
Participants	Participants: 127,477 inhabitants of 45 areas of Japan, data retrieved from 20,550 men and 29,671 women Inclusion criteria: aged 40‐79 (≥ 18 years in 1949). Details reported in Ohno 2001. Parent cohort: Japan Collaborative Cohort Study of Evaluation of Cancer Risk (JACC Study) Recruitment: from 1988‐1990
Interventions	N/A
Outcomes	Number of cases Outcome assessment: 2001 Oral cancer: 37 (male/female: 20/17) cases, including cancers of the tongue (N = 22, male/female: 13/9) and other oral cavity (N = 15, male/female: 7/8)
Green tea in exposure categories	Exposure assessment: intake of green tea Lowest exposure: < 1 cup/d Intermediate exposure 1: 1‐2 cups/d Intermediate exposure 2: 3‐4 cups/d Highest exposure: ≥ 5 cups/d
Notes	Funding: Grants‐in‐Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan (Monbusho) (N. 61010076, 62010074, 63010074, 1010068, 2151065, 3151064, 4151063, 5151069, 6279102, 11181101 and 12218237) Statistical methods: Cox hazard proportional regression Variables controlled in analysis: sex, age, smoking status, alcohol consumption, consumption of coffee, consumption of green/yellow vegetables, salty foods and fruits Variables controlled by matching: ‐