Leisure-time physical activity at midlife and the risk of dementia and Alzheimer's disease.
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.
Rovio
Suvi
S
Aging Research Center, Division of Geriatric Epidemiology, Neurotec, Karolinska Institutet, Stockholm, Sweden.
Kåreholt
Ingemar
I
Helkala
Eeva-Liisa
EL
Viitanen
Matti
M
Winblad
Bengt
B
Tuomilehto
Jaakko
J
Soininen
Hilkka
H
Nissinen
Aulikki
A
Kivipelto
Miia
M
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
D053327:Apolipoprotein E4; D001057:Apolipoproteins E