title: Hysterectomy, oophorectomy, estrogen, and the risk of dementia.
abstract: BACKGROUND
  The long-term cognitive effects of hysterectomy and oophorectomy remain controversial.
  
  
  OBJECTIVE
  To explore the association of hysterectomy and oophorectomy with the subsequent risk of cognitive impairment or dementia.
  
  
  METHODS
  We combined the results from two cohort studies graphically and conducted additional analyses.
  
  
  RESULTS
  Combined results from the Mayo Clinic Cohort Study of Oophorectomy and Aging and from a Danish nationwide cohort study suggest that the extent of gynecologic surgery may correlate with a stepwise increase in the risk of cognitive impairment or dementia. Compared with women with no gynecologic surgeries, the risk of cognitive impairment or dementia was increased in women who had hysterectomy alone, further increased in women who had hysterectomy with unilateral oophorectomy, and further increased in women who had hysterectomy with bilateral oophorectomy. The risk increased with younger age at the time of the surgery.
  
  
  CONCLUSIONS
  We hypothesize that both hysterectomy and oophorectomy may have harmful brain effects via direct endocrinological mechanisms or other more complex mechanisms. Estrogen deficiency appears to play a key role in these associations, and estrogen therapy may partly offset the negative effects of the surgeries.
authors.affiliation: Department of Neurology, College of Medicine, Mayo Clinic, Rochester, Minn 55905, USA. rocca@mayo.edu
authors.forename: Walter A
authors.initials: WA
authors.lastname: Rocca
authors.forename: Brandon R
authors.initials: BR
authors.lastname: Grossardt
authors.forename: Lynne T
authors.initials: LT
authors.lastname: Shuster
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stewart
mesh_terms: D000328:Adult; D000375:Aging; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology*; D015331:Cohort Studies; D003704:Dementia / Q000453:epidemiology / Q000209:etiology*; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007044:Hysterectomy / Q000009:adverse effects*; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D010052:Ovariectomy / Q000009:adverse effects*; D012307:Risk Factors; D055815:Young Adult
chemical_list: D004967:Estrogens