title: Diabetes in midlife and cognitive change over 20 years: a cohort study.
abstract: BACKGROUND
  Type 2 diabetes is associated with dementia risk, but evidence is limited for possible associations of diabetes and prediabetes with cognitive decline.
  
  
  OBJECTIVE
  To determine whether diabetes in midlife is associated with 20-year cognitive decline and to characterize long-term cognitive decline across clinical categories of hemoglobin A1c (HbA1c) levels.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  The community-based ARIC (Atherosclerosis Risk in Communities) study.
  
  
  METHODS
  13,351 black and white adults aged 48 to 67 years at baseline (1990 to 1992).
  
  
  METHODS
  Diabetes was defined by self-reported physician diagnosis or medication use or HbA1c level of 6.5% or greater. Undiagnosed diabetes, prediabetes, and glucose control in persons with diagnosed diabetes were defined by clinical categories of HbA1c level. Delayed word recall, digit symbol substitution, and word fluency tests were used to assess cognitive performance and were summarized with a global Z score.
  
  
  RESULTS
  Diabetes in midlife was associated with a 19% greater cognitive decline over 20 years (adjusted global Z-score difference, -0.15 [;95% CI, -0.22 to -0.08];) compared with no diabetes. Cognitive decline was significantly greater among persons with prediabetes (HbA1c level of 5.7% to 6.4%) than among those with an HbA1c level less than 5.7%. Participants with poorly controlled diabetes (HbA1c level ≥ 7.0%) had greater decline than those whose diabetes was controlled (adjusted global Z-score difference, -0.16; P = 0.071). Longer-duration diabetes was also associated with greater late-life cognitive decline (P for trend < 0.001). Rates of decline did not differ significantly between white and black persons (P for interaction = 0.44).
  
  
  CONCLUSIONS
  Single HbA1c measurement at baseline, 1 test per cognitive domain, and potential geographic confounding of race comparisons.
  
  
  CONCLUSIONS
  Diabetes prevention and glucose control in midlife may protect against late-life cognitive decline.
  
  
  BACKGROUND
  National Institutes of Health.
authors.forename: Andreea M
authors.initials: AM
authors.lastname: Rawlings
authors.forename: A Richey
authors.initials: AR
authors.lastname: Sharrett
authors.forename: Andrea L C
authors.initials: AL
authors.lastname: Schneider
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.forename: Marilyn
authors.initials: M
authors.lastname: Albert
authors.forename: David
authors.initials: D
authors.lastname: Couper
authors.forename: Michael
authors.initials: M
authors.lastname: Griswold
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: Gottesman
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Wagenknecht
authors.forename: B Gwen
authors.initials: BG
authors.lastname: Windham
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Selvin
mesh_terms: D001741:Black or African American; D000368:Aged; D003072:Cognition Disorders / Q000097:blood / Q000150:complications* / Q000208:ethnology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000208:ethnology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D011446:Prospective Studies; D012307:Risk Factors; D044465:White People
chemical_list: D006442:Glycated Hemoglobin