title: Physical activity over the life course and its association with cognitive performance and impairment in old age.
abstract: OBJECTIVE
  To determine how physical activity at various ages over the life course is associated with cognitive impairment in late life.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Four U.S. sites.
  
  
  METHODS
  Nine thousand three hundred forty-four women aged 65 and older (mean 71.6) who self-reported teenage, age 30, age 50, and late-life physical activity.
  
  
  METHODS
  Logistic regression was used to determine the association between physical activity status at each age and likelihood of cognitive impairment (modified Mini-Mental State Examination (mMMSE) score >1.5 standard deviations below the mean, mMMSE score</=22). Models were adjusted for age, education, marital status, diabetes mellitus, hypertension, depressive symptoms, smoking, and body mass index.
  
  
  RESULTS
  Women who reported being physically active had a lower prevalence of cognitive impairment in late life than women who were inactive at each time (teenage: 8.5% vs 16.7%, adjusted odds ratio (AOR)=0.65, 95% confidence interval (CI)=0.53-0.80; age 30: 8.9% vs 12.0%, AOR=0.80, 95% CI=0.67-0.96); age 50: 8.5% vs 13.1%, AOR=0.71, 95% CI=0.59-0.85; old age: 8.2% vs 15.9%, AOR=0.74, 95% CI=0.61-0.91). When the four times were analyzed together, teenage physical activity was most strongly associated with lower odds of late-life cognitive impairment (OR=0.73, 95% CI=0.58-0.92). However, women who were physically inactive as teenagers and became active in later life had lower risk than those who remained inactive.
  
  
  CONCLUSIONS
  Women who reported being physically active at any point over the life course, especially as teenagers, had a lower likelihood of cognitive impairment in late life. Interventions should promote physical activity early in life and throughout the life course.
authors.affiliation: Heart and Stroke Foundation, Center for Stroke Recovery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada. Laura.middleton@sunnybrook.ca
authors.forename: Laura E
authors.initials: LE
authors.lastname: Middleton
authors.forename: Deborah E
authors.initials: DE
authors.lastname: Barnes
authors.forename: Li-Yung
authors.initials: LY
authors.lastname: Lui
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D003072:Cognition Disorders / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D015444:Exercise / Q000523:psychology; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008875:Middle Aged; D009043:Motor Activity; D015995:Prevalence; D014481:United States