title: Drinking green tea modestly reduces breast cancer risk.
abstract: Green tea is a commonly consumed beverage in China. Epidemiological and animal data suggest tea and tea polyphenols may be preventive against various cancers, including breast cancer. Catechol-O-methyltransferase (COMT) catalyzes catechol estrogens and tea polyphenols. The COMT rs4680 AA genotype leads to lower COMT activity, which may affect the relationship between green tea consumption and breast cancer risk. We evaluated whether regular green tea consumption was associated with breast cancer risk among 3454 incident cases and 3474 controls aged 20-74 y in a population-based case-control study conducted in Shanghai, China during 1996-2005. All participants were interviewed in person about green tea consumption habits, including age of initiation, duration of use, brew strength, and quantity of tea. Odds ratios (OR) and 95% CI were calculated for green tea consumption measures and adjusted for age and other confounding factors. Compared with nondrinkers, regular drinking of green tea was associated with a slightly decreased risk for breast cancer (OR, 0.88; 95% CI, 0.79-0.98). Among premenopausal women, reduced risk was observed for years of green tea drinking (P-trend = 0.02) and a dose-response relationship with the amount of tea consumed per month was also observed (P-trend = 0.046). COMT rs4680 genotypes did not have a modifying effect on the association of green tea intake with breast cancer risk. Drinking green tea may be weakly associated with a decreased risk of breast cancer.
authors.affiliation: Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt School of Medicine, Nashville, TN 37232, USA.
authors.forename: Martha J
authors.initials: MJ
authors.lastname: Shrubsole
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Xiao Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Qi
authors.initials: Q
authors.lastname: Dai
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Kai
authors.initials: K
authors.lastname: Gu
authors.forename: Zhi Xian
authors.initials: ZX
authors.lastname: Ruan
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000201:enzymology / Q000453:epidemiology / Q000517:prevention & control*; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics; D002681:China / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D012307:Risk Factors; D013662:Tea
chemical_list: D013662:Tea; D002394:Catechol O-Methyltransferase