title: The effect of maintaining cognition on risk of disability and death.
abstract: OBJECTIVE
  To determine whether long-term maintenance of cognition is associated with health advantages such as lower mortality or incident disability in older adults.
  
  
  METHODS
  Longitudinal cohort study.
  
  
  METHODS
  Community clinics at two sites.
  
  
  METHODS
  Two thousand seven hundred thirty-three adults with a mean age of 74 at baseline and 80 at follow-up.
  
  
  METHODS
  Cognitive function was assessed using the Modified Mini-Mental State Examination (3MS), a test of global cognition, at least two times. Three cognitive groups were defined based on 4-year participant-specific slopes (maintainers, slopes of >or=0; minor decliners, slopes <0 but no more than 1 standard deviation (SD) below the mean; major decliners, slopes >1 SD below the mean). Whether the cognitive groups differed in mortality and incident disability during the subsequent 3 years was determined.
  
  
  RESULTS
  Nine hundred eighty-four (36%) participants were maintainers, 1,314 (48%) were minor decliners, and 435 (16%) were major decliners. Maintainers had lower mortality (7% vs 14%, hazard ratio (HR)=0.48, 95% confidence interval (CI)=0.36-0.63) and incident disability (22% vs 29%, HR=0.74, 95% CI=0.62-0.89) than minor decliners. After adjustment for age, race, sex, education, apolipoprotein E epsilon4, depression, body mass index, stroke, hypertension, and diabetes mellitus, these differences remained. As expected, major decliners had greater mortality (20%) and incident disability (40%) than minor decliners.
  
  
  CONCLUSIONS
  A substantial proportion of older adults maintain cognitive function in their eighth and ninth decades of life. These older adults demonstrate lower risk of death and functional decline than those with minor cognitive decline, supporting the concept of "successful" cognitive aging.
authors.affiliation: Department of Psychiatry, University of California at San Francisco, San Francisco, California 94121, USA. kristine.yaffe@ucsf.edu
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.forename: Karla
authors.initials: K
authors.lastname: Lindquist
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.forename: Deborah
authors.initials: D
authors.lastname: Barnes
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.forename: Anne
authors.initials: A
authors.lastname: Newman
authors.forename: Suzanne
authors.initials: S
authors.lastname: Satterfield
authors.forename: Caterina
authors.initials: C
authors.lastname: Rosano
authors.forename: Susan M
authors.initials: SM
authors.lastname: Rubin
authors.forename: Hilsa N
authors.initials: HN
authors.lastname: Ayonayon
authors.forename: Tamara
authors.initials: T
authors.lastname: Harris
mesh_terms: D000368:Aged; D003071:Cognition / Q000502:physiology*; D015928:Cognitive Behavioral Therapy; D015331:Cohort Studies; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009026:Mortality
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