Association between green tea ⁄coffee consumption and biliary tract cancer: A population-based cohort study in Japan Takeshi Makiuchi,1 Tomotaka Sobue,1 Tetsuhisa Kitamura,1 Junko Ishihara,2 Norie Sawada,3 Motoki Iwasaki,3 Shizuka Sasazuki,3 Taiki Yamaji,3 Taichi Shimazu3 and Shoichiro Tsugane3 1Department of Environmental Medicine and Population Sciences, Graduate School of Medicine, Osaka University, Suita; 2Graduate School of Nutrition Science, Sagami Women’s University, Sagamihara; 3Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan Key words Green tea and coffee consumption may decrease the risk of some types of can- Biliary tract cancer, coffee, cohort, green tea, prospective cers. However, their effects on biliary tract cancer (BTC) have been poorly under- study stood. In this population-based prospective cohort study in Japan, we Sencha, Bancha/ Correspondence investigated the association of green tea (total green tea, and Genmaicha Tomotaka Sobue, Department of Environmental Medicine ) and coffee consumption with the risk for BTC and its subtypes, gall- and Population Sciences, Graduate School of Medicine, bladder cancer, and extrahepatic bile duct cancer. The hazard ratios and 95% con- Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, fidence intervals were calculated using the Cox proportional hazard model. A Japan. total of 89 555 people aged 45–74 years were enrolled between 1995 and 1999 Tel: +81-6-6879-3920; Fax: +81-6-6879-3929; E-mail:
[email protected] and followed up for 1 138 623 person-years until 2010, during which 284 cases of BTC were identified.