title: Hormone Use, Reproductive History, and Risk of Lung Cancer: The Women's Health Initiative Studies.
abstract: BACKGROUND
  Results from the Women's Health Initiative clinical trials demonstrated no increase in the risk of lung cancer in postmenopausal women treated with hormone therapy (HT). We conducted a joint analysis of the Women's Health Initiative observational study data and clinical trials data to further explore the association between estrogen and estrogen-related reproductive factors and lung cancer risk.
  
  
  METHODS
  Reproductive history, oral contraceptive use, and postmenopausal HT were evaluated in 160,855 women with known HT exposures. Follow-up for lung cancer was through September 17, 2012; 2467 incident lung cancer cases were ascertained, with median follow-up of 14 years.
  
  
  RESULTS
  For all lung cancers, women with previous use of estrogen plus progestin of less than 5 years (hazard ratio = 0.84; 95% confidence interval = 0.71-0.99) were at reduced risk. A limited number of reproductive factors demonstrated associations with risk. There was a trend toward decreased risk with increasing age at menopause (ptrend = 0.04) and a trend toward increased risk with increasing number of live births (ptrend = 0.03). Reduced risk of non-small-cell lung cancer was associated with age 20-29 years at first live birth. Risk estimates varied with smoking history, years of HT use and previous bilateral oophorectomy.
  
  
  CONCLUSIONS
  Indirect measures of estrogen exposure to lung tissue, as used in this study, provide only weak evidence for an association between reproductive history or HT use and risk of lung cancer. More detailed mechanistic studies and evaluation of risk factors in conjunction with estrogen receptor expression in the lung should continue as a role for estrogen cannot be ruled out and may hold potential for prevention and treatment strategies.
authors: *Karmanos Cancer Institute and Department of Oncology, Wayne State University, Detroit, Michigan; †Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle Washington; ‡C.S. Mott Center for Human Growth and Development and Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan; §St. Joseph Mercy Oakland Hospital, Pontiac, Michigan; ‖Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington; ¶Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California; #Department of Medicine, University of California, Irvine, California; **Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; ††Department of Obstetrics and Gynecology, University of Miami School of Medicine, Miami, Florida; ‡‡Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York; §§Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California; ‖‖Department of Epidemiology and Environmental Health, University of Buffalo School of Public Health and Health Professions, Buffalo, New York; and ¶¶Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford Cancer Institute, Stanford, California.
authors: Ann G
authors: AG
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authors: Roberta M
authors: RM
authors: Ray
authors: Michele L
authors: ML
authors: Cote
authors: Judith
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authors: Sokol
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authors: Chlebowski
authors: F Allan
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authors: Kooperberg
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authors: Manson
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authors: O'Sullivan
authors: Thomas
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authors: Rohan
authors: Marcia L
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authors: Stefanick
authors: Jean
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authors: Wactawski-Wende
authors: Heather
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authors: Simon
mesh_terms: D000368:Aged; D002986:Clinical Trials as Topic; D003278:Contraceptives, Oral, Hormonal / Q000008:administration & dosage*; D015914:Estrogen Replacement Therapy / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D064887:Observational Studies as Topic; D017584:Reproductive History; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D016387:Women's Health
chemical_list: D003278:Contraceptives, Oral, Hormonal