title: Green tea consumption and breast cancer risk in Japanese women: a case-control study.
abstract: Although many in vitro and animal studies have suggested a protective effect of green tea against breast cancer, only a few epidemiological studies have examined this association, and findings have been inconsistent. We examined the association between green tea consumption and breast cancer risk in consideration of the hormone receptor status of tumors and investigated whether the association was modified by dietary and genetic factors based on a hospital-based case-control study in Nagano, Japan. A total of 369 pairs completed a validated food frequency questionnaire and provided blood samples. Four single nucleotide polymorphisms (SNPs) were genotyped: CYP19A1 (rs10046), COMT (rs4680), MTHFR C677T (rs1801133), and MTHFR A1298C (rs1801131). We found no inverse association between green tea consumption and breast cancer risk. Compared with women who drank less than 120 ml of green tea per day, the adjusted odds ratio for women who drank more than 600 ml was 1.27 (95% confidence interval = 0.75-2.14; P for trend = 0.20). We also found no inverse association for either tumor subtype. No substantial effect modification was observed for menopausal status, 4 SNPs, or dietary intake of folate or isoflavone. This study provides additional evidence that green tea consumption is not associated with a decreased risk.
authors.affiliation: a Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening , National Cancer Center , Tokyo , Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Junki
authors.initials: J
authors.lastname: Mizusawa
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kasuga
authors.forename: Shiro
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onuma
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishimura
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kusama
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D001141:Aromatase / Q000235:genetics / Q000378:metabolism; D044466:Asian People; D001943:Breast Neoplasms / Q000235:genetics / Q000517:prevention & control*; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics / Q000378:metabolism; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D005838:Genotype; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage; D007564:Japan; D016015:Logistic Models; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013662:Tea
chemical_list: D007529:Isoflavones; D013662:Tea; D005492:Folic Acid; D001141:Aromatase; C561410:CYP19A1 protein, human; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2); C588010:COMT protein, human; D002394:Catechol O-Methyltransferase