title: Endogenous and exogenous hormone exposure and risk of cognitive impairment in Swedish twins: a preliminary study.
abstract: OBJECTIVE
  To analyze the risk of cognitive impairment among female Swedish Twins with regard to endogenous and exogenous hormone exposure.
  
  
  METHODS
  A cross-sectional analysis of data from the HARMONY Study, a population-based cohort study of cognitive impairment in the Swedish Twin Registry.
  
  
  METHODS
  Information regarding age at menarche and menopause, parity, and length and type of hormone therapy (HT) was collected via a telephone interview from 6604 women, aged 65-84. Cognitive impairment was assessed with the TELE, a brief telephone cognitive screen.
  
  
  RESULTS
  Length of reproductive period was inversely associated with risk of cognitive impairment (p<0.01). The OR was 1.15 (CI 95% 0.96-1.36) for women with reproductive periods <35 years and 0.82 (CI 95% 0.66-1.00) for women with reproductive periods >39 years. Age at menopause was inversely associated with risk of cognitive impairment. Use of HT was associated with average 40% decline in the risk of cognitive impairment, independent of type and timing of treatment.
  
  
  CONCLUSIONS
  Our results suggest that both increased length of reproductive period and HT are associated with reduced risk of cognitive impairment.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, 401 Quarry Road, Room 2360, Palo Alto, CA 94305-5723, USA. nrasgon@stanford.edu
authors.forename: Natalie L
authors.initials: NL
authors.lastname: Rasgon
authors.forename: Cecilia
authors.initials: C
authors.lastname: Magnusson
authors.forename: Anna L V
authors.initials: AL
authors.lastname: Johansson
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
authors.forename: Shana
authors.initials: S
authors.lastname: Elman
authors.forename: Margaret
authors.initials: M
authors.lastname: Gatz
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002979:Climacteric; D003072:Cognition Disorders / Q000453:epidemiology* / Q000517:prevention & control*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D015914:Estrogen Replacement Therapy / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D016555:Matched-Pair Analysis; D008572:Menarche; D016017:Odds Ratio; D010298:Parity; D011159:Population Surveillance; D012042:Registries; D012307:Risk Factors; D046468:Sexual Development; D013548:Sweden / Q000453:epidemiology; D016896:Treatment Outcome