title: Lower ankle-brachial index is related to worse cognitive performance in old age.
abstract: OBJECTIVE
  We aimed to study the associations between peripheral artery disease (PAD) and ankle-brachial index (ABI) and performance in a range of cognitive domains in nondemented elderly persons.
  
  
  METHODS
  Data were collected within the Lothian Birth Cohort 1921 and 1936 studies. These are two narrow-age cohorts at age 87 (n = 170) and 73 (n = 748) years. ABI was analyzed as a dichotomous (PAD vs. no PAD) and a continuous measure. PAD was defined as having an ABI less than 0.90. Measures of nonverbal reasoning, verbal declarative memory, verbal fluency, working memory, and processing speed were administered. Both samples were screened for dementia.
  
  
  RESULTS
  We observed no significant differences in cognitive performance between persons with or without PAD. However, higher ABI was associated with better general cognition (β = .23, p = .02, R2 change = .05) and processing speed (β = .29, p < .01, R2 change = .08) in the older cohort and better processing speed (β = .12, p < .01, R2 change = .01) in the younger cohort. This was after controlling for age, sex, and childhood mental ability and excluding persons with abnormally high ABI (>1.40) and a history of cardiovascular or cerebrovascular disease.
  
  
  CONCLUSIONS
  Lower ABI is associated with worse cognitive performance in old age, especially in the oldest old (>85 years), possibly because of long-term exposure to atherosclerotic disease. Interventions targeting PAD in persons free of manifest cardiovascular and cerebrovascular disease may reduce the incidence of cognitive impairment and dementia.
authors.affiliation: Aging Research Center, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet and Stockholm University.
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Laukka
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh.
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D055109:Ankle Brachial Index; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D058729:Peripheral Arterial Disease / Q000523:psychology*