title: Leisure-time physical activity at midlife and the risk of dementia and Alzheimer's disease.
abstract: BACKGROUND
  Physical activity may help maintain cognitive function and decrease dementia risk, but epidemiological findings remain controversial. The aim of our study was to investigate the association between leisure-time physical activity at midlife and the subsequent development of dementia and Alzheimer's disease (AD).
  
  
  METHODS
  Participants were randomly selected from the survivors of a population-based cohort previously surveyed in 1972, 1977, 1982, or 1987. 1449 persons (72.5%) age 65-79 years participated in the re-examination in 1998 (mean follow-up, 21 years). 117 persons had dementia and 76 had AD. Multiple logistic regression methods were used to analyse the association between leisure-time physical activity and dementia or AD.
  
  
  RESULTS
  Leisure-time physical activity at midlife at least twice a week was associated with a reduced risk of dementia and AD (odds ratio [OR] 0.48 [95% CI 0.25-0.91] and 0.38 [0.17-0.85], respectively), even after adjustments for age, sex, education, follow-up time, locomotor disorders, APOE genotype, vascular disorders, smoking, and alcohol drinking. The associations were more pronounced among the APOE epsilon4 carriers.
  
  
  CONCLUSIONS
  Leisure-time physical activity at midlife is associated with a decreased risk of dementia and AD later in life. Regular physical activity may reduce the risk or delay the onset of dementia and AD, especially among genetically susceptible individuals.
authors.affiliation: Aging Research Center, Division of Geriatric Epidemiology, Neurotec, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Suvi
authors.initials: S
authors.lastname: Rovio
authors.forename: Ingemar
authors.initials: I
authors.lastname: Kåreholt
authors.forename: Eeva-Liisa
authors.initials: EL
authors.lastname: Helkala
authors.forename: Matti
authors.initials: M
authors.lastname: Viitanen
authors.forename: Bengt
authors.initials: B
authors.lastname: Winblad
authors.forename: Jaakko
authors.initials: J
authors.lastname: Tuomilehto
authors.forename: Hilkka
authors.initials: H
authors.lastname: Soininen
authors.forename: Aulikki
authors.initials: A
authors.lastname: Nissinen
authors.forename: Miia
authors.initials: M
authors.lastname: Kivipelto
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000517:prevention & control; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics; D015331:Cohort Studies; D003625:Data Collection; D003704:Dementia / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D007899:Leisure Activities / Q000523:psychology*; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D016017:Odds Ratio; D012044:Regression Analysis; D011795:Surveys and Questionnaires
chemical_list: D053327:Apolipoprotein E4; D001057:Apolipoproteins E