title: Depression, Antidepressant Use, and Postmenopausal Breast Cancer Risk.
abstract: BACKGROUND
  Whether depression and antidepressant (AD) use might influence breast cancer risk is unclear, and these exposures have not been evaluated together in a single, prospective cohort study of breast cancer risk.
  
  
  METHODS
  Among 71,439 postmenopausal women in the Women's Health Initiative Observational Study (WHI-OS), we estimated multivariable-adjusted HRs for the independent and joint effects of depressive symptoms and AD use on breast cancer risk using Cox proportional hazards regression.
  
  
  RESULTS
  When analyzed separately, neither depressive symptoms nor AD use at baseline were associated with a significantly increased risk of total breast cancer (HR = 0.96, 95% CI, 0.85-1.08; HR = 1.04, 95% CI, 0.92-1.20, respectively) or invasive breast cancer (HR = 0.98, 95% CI, 0.86-1.12; HR = 1.00, 95% CI, 0.86-1.16, respectively). Current AD use was associated with a borderline-significant increase of in situ breast cancer (HR = 1.30, 95% CI, 0.99-1.75) after adjustment for depressive symptoms; however, this relationship was attenuated after adjustment for mammographic screening (HR = 1.08, 95% CI, 0.76-1.51). No significant variation in total breast cancer risk was observed when the separate and joint effects of depressive symptoms and AD use were explored (P for interaction = 0.14).
  
  
  CONCLUSIONS
  We found no evidence that either depression or AD use influences breast cancer risk. An elevated risk of in situ disease among AD users could not be ruled out, though is likely due to increased screening in this subgroup.
  
  
  CONCLUSIONS
  Given the high prevalence of these exposures, these results may provide reassurance to the millions of women who are depressed and/or use ADs each year.
authors.affiliation: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Brown
authors.affiliation: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
authors.affiliation: Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, Massachusetts.
authors.forename: Kathleen F
authors.initials: KF
authors.lastname: Arcaro
authors.affiliation: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts. kwreeves@schoolph.umass.edu.
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Reeves
mesh_terms: D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000139:chemically induced / Q000175:diagnosis* / Q000453:epidemiology; D016022:Case-Control Studies; D003863:Depression / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D016387:Women's Health; D055815:Young Adult
chemical_list: D000928:Antidepressive Agents