title: The long-term effects of oophorectomy on cognitive and motor aging are age dependent.
abstract: BACKGROUND
  The evidence for a neuroprotective effect of estrogen in women remains controversial.
  
  
  OBJECTIVE
  We studied the long-term risk of parkinsonism and of cognitive impairment or dementia in women who underwent oophorectomy before menopause.
  
  
  METHODS
  We conducted a historical cohort study among all women residing in Olmsted County, Minn., USA, who underwent unilateral or bilateral oophorectomy before the onset of menopause for a noncancer indication from 1950 through 1987. Each member of the oophorectomy cohort was matched by age to a referent woman from the same population who had not undergone oophorectomy. In total, we studied 1,252 women with unilateral oophorectomy, 1,075 women with bilateral oophorectomy, and 2,368 referent women. Women were followed for a median of 25-30 years. Parkinsonism was assessed using screening and examination, through a medical records-linkage system, and through death certificates. Cognitive status was assessed using a structured questionnaire via a direct or proxy telephone interview.
  
  
  RESULTS
  The risk of parkinsonism and of cognitive impairment or dementia increased following oophorectomy. In particular, we observed significant linear trends of increasing risk for either outcome with younger age at oophorectomy.
  
  
  CONCLUSIONS
  Our findings, combined with previous laboratory and epidemiologic findings, suggest that estrogen may have an age-dependent neuroprotective effect.
authors.affiliation: Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic College of Medicine, 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: Demetrius M
authors.initials: DM
authors.lastname: Maraganore
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology / Q000523:psychology*; D003072:Cognition Disorders / Q000209:etiology / Q000378:metabolism / Q000523:psychology*; D015331:Cohort Studies; D003704:Dementia / Q000209:etiology / Q000378:metabolism / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology; D010052:Ovariectomy / Q000009:adverse effects / Q000639:trends*; D020734:Parkinsonian Disorders / Q000209:etiology / Q000378:metabolism / Q000523:psychology*; D013995:Time