title: Induced abortion and breast cancer: results from a population-based case control study in China.
abstract: OBJECTIVE
  To determine whether induced abortion (IA) increases breast cancer (BC) risk.
  
  
  METHODS
  A population-based case-control study was performed from Dec, 2000 to November, 2004 in Shanghai, China, where IA could be verified through the family planning network and client medical records. Structured questionnaires were completed by 1,517 cases with primary invasive epithelial breast cancer and 1,573 controls frequency- matched to cases for age group. The information was supplemented and verified by the family planning records. Statistical analysis was conducted with SAS 9.0.
  
  
  RESULTS
  After adjusting for potential confounders, induced abortions were not found to be associated with breast cancer with OR=0.94 (95%CI= 0.79-1.11). Compared to parous women without induced abortion, parous women with 3 or more times induced abortion (OR=0.66, 95%CI=0.46 to 0.95) and women with 3 or more times induced abortion after the first live birth (OR=0.66, 95%CI =0.45 to 0.97) showed a lower risk of breast cancer, after adjustment for age, level of education, annual income per capita, age at menarche, menopause, parity times, spontaneous abortion, age at first live birth, breast-feeding, oral contraceptives, hormones drug, breast disease, BMI, drinking alcohol, drinking tea, taking vitamin/calcium tablet, physical activity, vocation, history of breast cancer, eating the bean.
  
  
  CONCLUSIONS
  The results suggest that a history of induced abortions may not increase the risk of breast cancer.
authors.affiliation: Department of Epidemiology and Social Science on RH, Shanghai Institute of Planned Parenthood Research/ WHO Collaborating Center on Human Research on Reproductive Health, Shanghai, China E-mail : wujq1688@163.com.
authors.forename: Jun-Qing
authors.initials: JQ
authors.lastname: Wu
authors.forename: Yu-Yan
authors.initials: YY
authors.lastname: Li
authors.forename: Jing-Chao
authors.initials: JC
authors.lastname: Ren
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.forename: Er-Sheng
authors.initials: ES
authors.lastname: Gao
mesh_terms: D000028:Abortion, Induced / Q000706:statistics & numerical data*; D000328:Adult; D000367:Age Factors; D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D055815:Young Adult