title: Physical frailty is associated with incident mild cognitive impairment in community-based older persons.
abstract: OBJECTIVE
  To test the hypothesis that physical frailty is associated with risk of mild cognitive impairment (MCI).
  
  
  METHODS
  Prospective, observational cohort study.
  
  
  METHODS
  Approximately 40 retirement communities across the Chicago metropolitan area.
  
  
  METHODS
  More than 750 older persons without cognitive impairment at baseline.
  
  
  METHODS
  Physical frailty, based on four components (grip strength, timed walk, body composition, and fatigue), was assessed at baseline, and cognitive function was assessed annually. Proportional hazards models adjusted for age, sex, and education were used to examine the association between physical frailty and the risk of incident MCI, and mixed effect models were used to examine the association between frailty and the rate of change in cognition.
  
  
  RESULTS
  During up to 12 years of annual follow-up, 305 of 761 (40%) persons developed MCI. In a proportional hazards model adjusted for age, sex, and education, physical frailty was associated with a high risk of incident MCI, such that each one-unit increase in physical frailty was associated with a 63% increase in the risk of MCI (hazard ratio=1.63; 95% confidence interval=1.27-2.08). This association persisted in analyses that required MCI to persist for at least 1 year and after controlling for depressive symptoms, disability, vascular risk factors, and vascular diseases. Furthermore, a higher level of physical frailty was associated with a faster rate of decline in global cognition and five cognitive systems (episodic memory, semantic memory, working memory, perceptual speed, and visuospatial abilities).
  
  
  CONCLUSIONS
  Physical frailty is associated with risk of MCI and a rapid rate of cognitive decline in aging.
authors.affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center, Armour Academic Facility, Suite 1020B, 600 South Paulina Street, Chicago, IL 60612, USA. Patricia_Boyle@rush.edu
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Boyle
authors.forename: Aron S
authors.initials: AS
authors.lastname: Buchman
authors.forename: Robert S
authors.initials: RS
authors.lastname: Wilson
authors.forename: Sue E
authors.initials: SE
authors.lastname: Leurgans
authors.forename: David A
authors.initials: DA
authors.lastname: Bennett
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D002641:Chicago / Q000453:epidemiology; D003072:Cognition Disorders / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D016330:Frail Elderly; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012306:Risk