title: The effect of midlife physical activity on cognitive function among older adults: AGES--Reykjavik Study.
abstract: BACKGROUND
  There are few studies on the long-term associations of physical activity (PA) to cognition. Here, we examine the association of midlife PA to late-life cognitive function and dementia.
  
  
  METHODS
  The sample consisted of a population-based cohort of men and women (born in 1907-1935) participating in the Age Gene/Environment Susceptibility-Reykjavik Study. The interval between the midlife ascertainment of PA and late-life cognitive function was 26 years. Composite scores of speed of processing, memory, and executive function were assessed with a battery of neuropsychological tests, and dementia was diagnosed according to international guidelines. There were 4,761 nondemented participants and 184 (3.7%) with a diagnosis of dementia, with complete data for the analysis.
  
  
  RESULTS
  Among the participants, no midlife PA was reported by 68.8%, ≤ 5 hours PA by 26.5%, and >5 hours PA by 4.5%. Excluding participants with dementia compared with the no PA group, both PA groups had significantly faster speed of processing (≤ 5 hours, β = .22; >5 hours, β = .32, p trend < .0001), better memory (≤ 5 hours, β = .15; >5 hours, β = .18, p trend < .0001), and executive function (≤ 5 hours, β = .09; >5 hours, β = .18, p trend< .0001), after controlling for demographic and cardiovascular factors. The ≤ 5 hours PA group was significantly less likely to have dementia in late life (odds ratio: 0.6, 95% confidence interval: 0.40-0.88) after adjusting for confounders.
  
  
  CONCLUSIONS
  Midlife PA may contribute to maintenance of cognitive function and may reduce or delay the risk of late-life dementia.
authors.affiliation: Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, National Institutes of Health, 7201 Wisconsin Avenue, Bethesda, MD 20892-9205, USA.
authors.forename: Milan
authors.initials: M
authors.lastname: Chang
authors.forename: Palmi V
authors.initials: PV
authors.lastname: Jonsson
authors.forename: Jon
authors.initials: J
authors.lastname: Snaedal
authors.forename: Sigurbjorn
authors.initials: S
authors.lastname: Bjornsson
authors.forename: Jane S
authors.initials: JS
authors.lastname: Saczynski
authors.forename: Thor
authors.initials: T
authors.lastname: Aspelund
authors.forename: Gudny
authors.initials: G
authors.lastname: Eiriksdottir
authors.forename: Maria K
authors.initials: MK
authors.lastname: Jonsdottir
authors.forename: Oscar L
authors.initials: OL
authors.lastname: Lopez
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Gudnason
authors.forename: Lenore J
authors.initials: LJ
authors.lastname: Launer
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D000483:Alleles; D001057:Apolipoproteins E / Q000235:genetics*; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D003704:Dementia / Q000517:prevention & control*; D056344:Executive Function / Q000502:physiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009483:Neuropsychological Tests; D040242:Risk Reduction Behavior; D013997:Time Factors
chemical_list: D001057:Apolipoproteins E
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