Physical activity and risk of cognitive impairment and dementia in elderly persons.
BACKGROUND
Dementia is common, costly, and highly age related. Little attention has been paid to the identification of modifiable lifestyle habits for its prevention.


OBJECTIVE
To explore the association between physical activity and the risk of cognitive impairment and dementia.


METHODS
Data come from a community sample of 9008 randomly selected men and women 65 years or older, who were evaluated in the 1991-1992 Canadian Study of Health and Aging, a prospective cohort study of dementia. Of the 6434 eligible subjects who were cognitively normal at baseline, 4615 completed a 5-year follow-up. Screening and clinical evaluations were done at both waves of the study. In 1996-1997, 3894 remained without cognitive impairment, 436 were diagnosed as having cognitive impairment-no dementia, and 285 were diagnosed as having dementia.


METHODS
Incident cognitive impairment and dementia by levels of physical activity at baseline.


RESULTS
Compared with no exercise, physical activity was associated with lower risks of cognitive impairment, Alzheimer disease, and dementia of any type. Significant trends for increased protection with greater physical activity were observed. High levels of physical activity were associated with reduced risks of cognitive impairment (age-, sex-, and education-adjusted odds ratio, 0.58; 95% confidence interval, 0.41-0.83), Alzheimer disease (odds ratio, 0.50; 95% confidence interval, 0.28-0.90), and dementia of any type (odds ratio, 0.63; 95% confidence interval, 0.40-0.98).


CONCLUSIONS
Regular physical activity could represent an important and potent protective factor for cognitive decline and dementia in elderly persons.
Laurin
D
D
Laval University Geriatric Research Unit, Centre d'hébergement St-Augustin du Centre hospitalier affilié universitaire de Québec, 2135 Terrasse Cadieux, Beauport, Quebec, Canada G1C 1Z2.
Verreault
R
R
Lindsay
J
J
MacPherson
K
K
Rockwood
K
K
D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D003072:Cognition Disorders / Q000453:epidemiology* / Q000517:prevention & control; D003704:Dementia / Q000453:epidemiology* / Q000517:prevention & control; D015444:Exercise; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors