title: Increased risk of parkinsonism in women who underwent oophorectomy before menopause.
abstract: OBJECTIVE
  There is increasing laboratory evidence for a neuroprotective effect of estrogen on the nigrostriatal pathway; however, the epidemiologic evidence remains limited and conflicting. We studied the association of oophorectomy performed before the onset of menopause with the risk of subsequent parkinsonism.
  
  
  METHODS
  We included all women who underwent either unilateral or bilateral oophorectomy before the onset of menopause for a noncancer indication from 1950 through 1987 while residing in Olmsted County, MN. Each member of the oophorectomy cohort was matched by age to a referent woman in 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 through death or end of study using a combination of direct or proxy interviews, neurologic examinations, medical records in a records-linkage system, and death certificates.
  
  
  RESULTS
  Women who underwent either unilateral or bilateral oophorectomy before the onset of menopause had an increased risk of parkinsonism compared with referent women (HR 1.68; 95% CI 1.06 to 2.67; p = 0.03), and the risk increased with younger age at oophorectomy (test for linear trend; p = 0.01). The findings were similar regardless of the indication for the oophorectomy, and for unilateral or bilateral oophorectomy considered separately. The findings were also consistent for Parkinson disease alone, but did not reach significance.
  
  
  CONCLUSIONS
  Both unilateral and bilateral oophorectomy performed prior to menopause may be associated with an increased risk of parkinsonism and the effect may be age-dependent. However, our findings await independent replication.
authors.affiliation: Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA. rocca@mayo.edu
authors.forename: W A
authors.initials: WA
authors.lastname: Rocca
authors.forename: J H
authors.initials: JH
authors.lastname: Bower
authors.forename: D M
authors.initials: DM
authors.lastname: Maraganore
authors.forename: J E
authors.initials: JE
authors.lastname: Ahlskog
authors.forename: B R
authors.initials: BR
authors.lastname: Grossardt
authors.forename: M
authors.initials: M
authors.lastname: de Andrade
authors.forename: L J
authors.initials: LJ
authors.lastname: Melton
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D019610:Cytoprotection / Q000502:physiology; D004967:Estrogens / Q000378:metabolism; D005260:Female; D006801:Humans; D015994:Incidence; D008594:Menopause, Premature / Q000502:physiology*; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D017072:Neostriatum / Q000378:metabolism / Q000503:physiopathology; D009434:Neural Pathways / Q000378:metabolism / Q000503:physiopathology; D018696:Neuroprotective Agents / Q000378:metabolism; D010052:Ovariectomy / Q000009:adverse effects* / Q000706:statistics & numerical data; D010300:Parkinson Disease / Q000453:epidemiology* / Q000503:physiopathology; D012307:Risk Factors; D013378:Substantia Nigra / Q000378:metabolism / Q000503:physiopathology
chemical_list: D004967:Estrogens; D018696:Neuroprotective Agents