title: Endogenous estrogen levels and Alzheimer's disease among postmenopausal women.
abstract: BACKGROUND
  Although several studies have suggested that hormone replacement therapy lowers the risk of AD among postmenopausal women, few studies have evaluated the relationship of endogenous estrogen levels and AD. The current study investigated whether serum estrone and estradiol levels were related to the presence of AD among postmenopausal women not currently taking hormone replacement therapy.
  
  
  METHODS
  Using a case-control design, we examined an ethnically diverse sample of postmenopausal women who met National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for AD (n = 50) and nondemented controls (n = 93). All women were participants in a study of aging and dementia and were seen consecutively between August 1997 and October 1998.
  
  
  RESULTS
  Patients with AD had lower estradiol (F[1,141] = 8.3, p = 0.005) levels than did normal controls. Patients also had lower estrone levels; however, this comparison did not quite meet significance criteria (F[1,141] = 3.6, p = 0.06). Compared to estradiol levels >20 pg/mL, women with AD were four to six times more likely to have levels <20 pg/mL after adjusting for age, years of education, presence of an APOE-epsilon4 allele, ethnicity, and body mass index. There were no significant differences in frequency of AD among women within different quartiles of estrone after adjusting for potential confounds.
  
  
  CONCLUSIONS
  The results of this preliminary case-control study suggest that estradiol levels may decline significantly in women in whom AD develops.
authors.affiliation: Department of Neurology, the Gertrude H. Sergievsky Center, Columbia University College of Physicians and Surgeons, New York, NY 10032-3702, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Manly
authors.forename: C A
authors.initials: CA
authors.lastname: Merchant
authors.forename: D M
authors.initials: DM
authors.lastname: Jacobs
authors.forename: S A
authors.initials: SA
authors.lastname: Small
authors.forename: K
authors.initials: K
authors.lastname: Bell
authors.forename: M
authors.initials: M
authors.lastname: Ferin
authors.forename: R
authors.initials: R
authors.lastname: Mayeux
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000097:blood*; D015331:Cohort Studies; D004958:Estradiol / Q000097:blood; D004967:Estrogens / Q000097:blood*; D005260:Female; D006801:Humans; D017698:Postmenopause / Q000097:blood*
chemical_list: D004967:Estrogens; D004958:Estradiol