title: Risk factors for breast cancer among Chinese women: a 10-year nationwide multicenter cross-sectional study.
abstract: BACKGROUND
  The characteristics of established risk factors for breast cancer may vary among countries. A better understanding of local characteristics of risk factors may help in devising effective prevention strategies for breast cancer.
  
  
  METHODS
  Information on exposures to risk factors was collected from the medical charts of 4211 women with breast cancer diagnosed during 1999-2008. The distributions of these exposures among regions, and by menopausal status and birth period, were compared with the χ(2) test. Crude associations between the selected factors and breast cancer were estimated using the cases in the present study and a representative control population, which was selected from qualified published studies.
  
  
  RESULTS
  As compared with cases from less developed regions, those from more developed regions were significantly more likely to be nulliparous, had fewer childbirths (P < 0.05), and were less likely to have breastfed (P = 0.08). As compared with premenopausal cases, postmenopausal cases were more likely to be overweight and to have breastfed and had more childbirths (P < 0.05). The number of live births and rate of breastfeeding decreased in relation to birth period (P for trends <0.001). Overweight, late menopause, and family history of breast cancer were significantly associated with breast cancer among Chinese women.
  
  
  CONCLUSIONS
  Breast cancer incidence was associated with nulliparity and history of breastfeeding. Population attributable risks should be assessed, especially for more developed areas and young women. The effects of body mass index, age at menopause, and family history of breast cancer should be given priority during assessment of breast cancer risk among Chinese women.
authors.affiliation: West China School of Public Health, Sichuan University.
authors.forename: Hui
authors.initials: H
authors.lastname: Lee
authors.forename: Jia-Yuan
authors.initials: JY
authors.lastname: Li
authors.forename: Jin-Hu
authors.initials: JH
authors.lastname: Fan
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.forename: Bao-Ning
authors.initials: BN
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Hong-Jian
authors.initials: HJ
authors.lastname: Yang
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Xie
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Tang
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: He
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Huang
authors.forename: You-Lin
authors.initials: YL
authors.lastname: Qiao
authors.forename: Yi
authors.initials: Y
authors.lastname: Pang
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D001942:Breast Feeding / Q000009:adverse effects; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000235:genetics; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008593:Menopause; D008875:Middle Aged; D010298:Parity; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors