title: Postmenopausal hormone use and cholecystectomy in a large prospective study.
abstract: OBJECTIVE
  To examine the association between postmenopausal hormone use and cholecystectomy.
  
  
  METHODS
  A prospective cohort study was performed, with follow-up every 2 years. Participants were 54,845 postmenopausal United States nurses, who reported both hormone use and cholecystectomy on mailed questionnaires.
  
  
  RESULTS
  Cholecystectomy was reported by 1750 women during 8 years of follow-up. After adjusting for confounding factors, women currently using postmenopausal hormones were at an increased risk of cholecystectomy (relative risk [RR] 2.1, 95% confidence interval [CI] 1.9-2.4) compared to never-users. For current users, the risk of cholecystectomy increased with increasing duration of hormone use (RR 2.6, 95% CI 2.2-3.1 for 10 years or more) and higher doses of estrogen (RR 2.4, 95% CI 2.0-2.9 for users of 1.25 mg or more). Although the risk for past hormone users decreased substantially in women who had discontinued use 1-2.9 years ago (RR 1.6, 95% CI 1.2-2.0), a small risk persisted for women who had stopped taking hormones 5 or more years previously (RR 1.3, 95% CI 1.1-1.6). However, after controlling for time since last use, duration of past use had little or no effect on the risk of cholecystectomy (RR 1.4 and RR 1.7 for past users of less than 2 years and 10 or more years' duration, respectively).
  
  
  CONCLUSIONS
  Women using postmenopausal hormones are at an increased risk of cholecystectomy. Women and their physicians should consider the spectrum of risks and benefits when deciding whether to take hormones.
authors.affiliation: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: F
authors.initials: F
authors.lastname: Grodstein
authors.forename: G A
authors.initials: GA
authors.lastname: Colditz
authors.forename: M J
authors.initials: MJ
authors.lastname: Stampfer
mesh_terms: D002763:Cholecystectomy / Q000706:statistics & numerical data*; D002769:Cholelithiasis / Q000209:etiology* / Q000601:surgery; D015331:Cohort Studies; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D011446:Prospective Studies; D012306:Risk