Leisure-time physical activity from mid- to late life, body mass index, and risk of dementia.
BACKGROUND
Physical activity may be beneficial for cognition, but the effect may vary depending on personal characteristics.


METHODS
We investigated the associations between leisure-time physical activity (LTPA) from mid- to late life, the risk of dementia, and the role of body mass index, sex, and APOE in the CAIDE study during 28-year follow-up. Cognitive function of a random subsample was assessed at a mean age of 78.8 years (n = 1511), and dementia/Alzheimer's disease (AD) diagnoses were identified from national registers for the entire target population (n = 3559).


RESULTS
Moderate (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.08-1.99) and low levels of midlife LTPA (HR, 1.39; 95% CI, 0.99-1.95) were associated with higher risk of dementia in comparison with the most active category. The benefits were more pronounced among men, overweight individuals, and APOE ε4 noncarriers. Maintaining high LTPA (HR, 0.16; 95% CI, 0.06-0.41) or increasing LTPA (HR, 0.19; 95% CI, 0.09-0.40) after midlife was associated with lower dementia risk. Similar results were observed for AD.


CONCLUSIONS
The window of opportunity for preventive physical activity interventions may extend from midlife to older ages.
Department of Neurology, University of Eastern Finland, Kuopio, Finland. Electronic address: anna-maija.tolppanen@uef.fi.
Anna-Maija
AM
Tolppanen
Department of Neurology, University of Eastern Finland, Kuopio, Finland; Alzheimer Disease Research Center, Karolinska Institutet, Stockholm, Sweden; Aging Research Center (ARC), Karolinska Institutet and Stockholm University, Stockholm, Sweden.
Alina
A
Solomon
Gerontology Research Center, Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
Jenni
J
Kulmala
Aging Research Center (ARC), Karolinska Institutet and Stockholm University, Stockholm, Sweden; Institute for Gerontology, School of Health Sciences, Jönköping University, Jönköping, Sweden.
Ingemar
I
Kåreholt
Alzheimer Disease Research Center, Karolinska Institutet, Stockholm, Sweden; Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland.
Tiia
T
Ngandu
Department of Neurology, University of Eastern Finland, Kuopio, Finland.
Minna
M
Rusanen
Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland; Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Hospital District of North Karelia, Joensuu, Finland.
Tiina
T
Laatikainen
Department of Neurology, University of Eastern Finland, Kuopio, Finland; Department of Neurology, Kuopio University Hospital, Kuopio, Finland.
Hilkka
H
Soininen
Department of Neurology, University of Eastern Finland, Kuopio, Finland; Alzheimer Disease Research Center, Karolinska Institutet, Stockholm, Sweden; Aging Research Center (ARC), Karolinska Institutet and Stockholm University, Stockholm, Sweden; Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland.
Miia
M
Kivipelto
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D018672:Community Health Planning; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D018450:Disease Progression; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007899:Leisure Activities / Q000523:psychology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D059906:Neuroimaging; D009483:Neuropsychological Tests; D016016:Proportional Hazards Models; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors
Cohort study; Dementia; Exercise; Life course; Obesity; Physical activity