title: Misrepresentation of the risk of ovarian cancer among women using menopausal hormones. Spurious findings in a meta-analysis.
abstract: BACKGROUND
  Based on a meta-analysis of 52 studies, and principally on a meta-analysis of 17 follow-up studies, it has been claimed that current-or-recent use (last use <5 years previously) of menopausal hormones causes ovarian cancer, even if the duration of use was <5 years, and that women aged about 50 years who use hormones for >5 years have about one extra case per 1000 users, and one extra fatal case per 1700 users.
  
  
  OBJECTIVE
  To evaluate the validity of the evidence.
  
  
  METHODS
  Generally accepted epidemiological principles of causation were applied to the evidence.
  
  
  RESULTS
  The study base included hysterectomised women, an unknown proportion of whom were oophorectomised, and not at risk for ovarian cancer. The findings did not satisfy the criteria of time order, bias, confounding, strength of association, dose-response, duration-response, consistency, and biological plausibility.
  
  
  CONCLUSIONS
  The meta-analysis did not establish that current-or-recent use of menopausal hormones causes ovarian cancer. The strong likelihood is that early symptoms of as yet undiagnosed ovarian cancer "caused" current-or-recent short-duration hormone use, not the reverse. The representation of the number of extra cases, and fatal cases, among hormone users was misleading and alarmist.
authors.affiliation: Epidemiology, Department of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. Electronic address: Samshap@mweb.co.za.
authors.forename: Samuel
authors.initials: S
authors.lastname: Shapiro
authors.affiliation: National Heart and Lung Institute, Imperial College London, Royal Brompton Hospital, London, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Stevenson
authors.affiliation: University Women's Hospital of Tuebingen, Tuebingen, Germany; Beijing OB/GYN Hospital, Capital Medical University, Beijing, China.
authors.forename: Alfred O
authors.initials: AO
authors.lastname: Mueck
authors.affiliation: Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Rod
authors.initials: R
authors.lastname: Baber
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy; D006801:Humans; D008593:Menopause; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000453:epidemiology*; D012306:Risk
keywords: Menopausal hormone therapy; Risk of ovarian cancer; Validity