title: Evaluation of breast cancer risk associated with tea consumption by menopausal and estrogen receptor status among Chinese women in Hong Kong.
abstract: OBJECTIVE
  Experimental studies implicate tea and tea polyphenols may be preventive against breast cancer, but evidence from epidemiological studies has been inconsistent. We conducted a hospital-based case-control study to evaluate the role of tea especially green tea in breast cancer etiology.
  
  
  METHODS
  We consecutively recruited 756 incident breast cancer cases and 789 hospital controls who had completed information on tea consumption. We calculated odds ratios (ORs) for tea consumption using unconditional multivariable logistic regression. We further conducted stratified analyses to assess whether the effect of tea consumption varied by menopausal status and estrogen receptor (ER).
  
  
  RESULTS
  Overall, 439 (58.1%) breast cancer cases and 434 (55.0%) controls reported habits of regular tea drinking, showing an adjusted OR of 1.01 (95%CI: 0.78-1.31) and 1.20 (95%CI: 0.80-1.78) for any tea and green tea drinking, respectively. Regular tea drinking was significantly associated with a lower risk for breast cancer in pre-menopausal women (OR=0.62, 95%CI: 0.40-0.97) but an increased risk in post-menopausal women (OR=1.40, 95%CI: 1.00-1.96). The positive association among postmenopausal women was strongest among ER-negative green tea drinkers (OR=2.99, 95% CI: 1.26-7.11).
  
  
  CONCLUSIONS
  Tea or green tea drinking was not associated with overall breast cancer risk, which may be masked by the differential effect in pre- and post-menopausal women.
authors.affiliation: JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Mengjie
authors.initials: M
authors.lastname: Li
authors.affiliation: JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR, China. Electronic address: shelly@cuhk.edu.hk.
authors.forename: Lap Ah
authors.initials: LA
authors.lastname: Tse
authors.affiliation: Department of Surgery, North District Hospital, Hong Kong SAR, China.
authors.forename: Wing-Cheong
authors.initials: WC
authors.lastname: Chan
authors.affiliation: Department of Oncology, Princess Margaret Hospital, Hong Kong SAR, China.
authors.forename: Chi-hei
authors.initials: CH
authors.lastname: Kwok
authors.affiliation: Department of Surgery, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China.
authors.forename: Siu-lan
authors.initials: SL
authors.lastname: Leung
authors.affiliation: Department of Pathology, North District Hospital, Hong Kong SAR, China.
authors.forename: Cherry
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Medicine, Princess Margaret Hospital, Hong Kong SAR, China.
authors.forename: Wai-cho
authors.initials: WC
authors.lastname: Yu
authors.affiliation: JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Ignatius Tak-sun
authors.initials: IT
authors.lastname: Yu
authors.affiliation: Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Chloe Hui-Tung
authors.initials: CH
authors.lastname: Yu
authors.affiliation: JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, United States.
authors.forename: Hyuna
authors.initials: H
authors.lastname: Sung
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, United States.
authors.forename: Xiaohong R
authors.initials: XR
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000378:metabolism / Q000517:prevention & control; D016022:Case-Control Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism*; D012307:Risk Factors; D013662:Tea; D055815:Young Adult
chemical_list: D011960:Receptors, Estrogen; D013662:Tea
keywords: Breast cancer; Estrogen receptor status; Menopausal status; Tea consumption