title: Diabetes and cognitive decline in elderly African Americans: a 15-year follow-up study.
abstract: BACKGROUND
  Diabetes mellitus is associated with an increased risk for cognitive impairment and vascular factors seem to play a role in this relationship. In a sample involving elderly African Americans, we tested the hypothesis that diabetes accelerates cognitive decline and explored possible mediating mechanisms within a follow-up period of 15 years.
  
  
  METHODS
  A total of 1,702 subjects, of whom 441 had diabetes, were given the community screening interview for dementia to measure cognitive functioning at six different time points spread over a 15-year follow-up period. Mixed effects models with repeated measures were used to examine the association of diabetes and vascular risk factors with cognitive scores over time.
  
  
  RESULTS
  African American subjects with diabetes reported having a significant accelerated cognitive decline as compared with those without diabetes (P = .046), when controlling for basic demographics and baseline comorbid conditions (heart disease, hypertension, stroke, and depression). Adjusting for incident heart disease, and especially stroke, weakened this association (P = .098), thereby indicating a mediating effect of stroke on the association between diabetes and cognitive decline. However, when incident stroke was incorporated into the model, the effect for participants with diabetes increased greatly (P = .007).
  
  
  CONCLUSIONS
  Diabetes, mediated by cerebrovascular pathology, accelerates cognitive decline within a follow-up period of 15 years in a sample comprising African Americans.
authors.affiliation: Division of Clinical Pharmacology, Indiana University School of Medicine, Indianapolis, IN, USA. awessels@iupui.edu
authors.forename: Alette M
authors.initials: AM
authors.lastname: Wessels
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Lane
authors.forename: Sujuan
authors.initials: S
authors.lastname: Gao
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Hall
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Unverzagt
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Hendrie
mesh_terms: D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000453:epidemiology* / Q000208:ethnology*; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000208:ethnology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012111:Residence Characteristics; D012307:Risk Factors