title: Reproductive factors and risks of biliary tract cancers and stones: a population-based study in Shanghai, China.
abstract: BACKGROUND
  Parity has been linked to gallbladder cancer and gallstones, but the effects of other reproductive factors are less clear.
  
  
  METHODS
  We examined 361 incident biliary tract cancer cases, 647 biliary stone cases, and 586 healthy women in a population-based study in Shanghai.
  
  
  RESULTS
  The effects of parity (odds ratios, OR(> or =3 vs 1 child)=2.0, 95% confidence interval (CI) 0.7-5.1), younger age at first birth (OR(per 1-year decrease)=1.2, 95% CI 0.99-1.6), and older age at menarche (OR(per 1-year increase)=1.4, 95% CI 1.1-1.8) on gallbladder cancer risk were more pronounced among women with stones, but the interactions were not significant.
  
  
  CONCLUSIONS
  Our results provide support for high parity, younger age at first birth, and late age at menarche in the development of gallbladder cancer, particularly among women with biliary stones.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, DHHS, Bethesda, MD 20892, USA. andreotg@mail.nih.gov
authors.forename: G
authors.initials: G
authors.lastname: Andreotti
authors.forename: L
authors.initials: L
authors.lastname: Hou
authors.forename: Y-T
authors.initials: YT
authors.lastname: Gao
authors.forename: L A
authors.initials: LA
authors.lastname: Brinton
authors.forename: A
authors.initials: A
authors.lastname: Rashid
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: M-C
authors.initials: MC
authors.lastname: Shen
authors.forename: B-S
authors.initials: BS
authors.lastname: Wang
authors.forename: T-Q
authors.initials: TQ
authors.lastname: Han
authors.forename: B-H
authors.initials: BH
authors.lastname: Zhang
authors.forename: L C
authors.initials: LC
authors.lastname: Sakoda
authors.forename: J F
authors.initials: JF
authors.lastname: Fraumeni
authors.forename: A W
authors.initials: AW
authors.lastname: Hsing
mesh_terms: D001661:Biliary Tract Neoplasms / Q000453:epidemiology* / Q000209:etiology; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003710:Demography; D005260:Female; D005706:Gallbladder Neoplasms / Q000453:epidemiology / Q000209:etiology; D042882:Gallstones / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D012098:Reproduction; D012307:Risk Factors