Brains and Aging Comment on “Physical Activity and Cognition in Women With Vascular Conditions” and “Activity Energy Expenditure and Incident Cognitive Impairment in Older Adults”

Larson EB. — Mon, 25 Jul 2011 00:00:00 GMT

Two articles in this issue buttress growing evidence that habitual physical activity and fitness are associated with age-related changes in cognition and risk of dementia.

Activity Energy Expenditure and Incident Cognitive Impairment in Older Adults

Middleton LE, Manini TM, Simonsick EM, et al. — Mon, 25 Jul 2011 00:00:00 GMT

Background

Studies suggest that physically active people have reduced risk of incident cognitive impairment in late life. However, these studies are limited by reliance on self-reports of physical activity, which only moderately correlate with objective measures and often exclude activity not readily quantifiable by frequency and duration. The objective of this study was to investigate the relationship between activity energy expenditure (AEE), an objective measure of total activity, and incidence of cognitive impairment.

Methods

We calculated AEE as 90% of total energy expenditure (assessed during 2 weeks using doubly labeled water) minus resting metabolic rate (measured using indirect calorimetry) in 197 men and women (mean age, 74.8 years) who were free of mobility and cognitive impairments at study baseline (1998-1999). Cognitive function was assessed at baseline and 2 or 5 years later using the Modified Mini-Mental State Examination. Cognitive impairment was defined as a decline of at least 1.0 SD (9 points) between baseline and follow-up evaluations.

Results

After adjustment for baseline Modified Mini-Mental State Examination scores, demographics, fat-free mass, sleep duration, self-reported health, and diabetes mellitus, older adults in the highest sex-specific tertile of AEE had lower odds of incident cognitive impairment than those in the lowest tertile (odds ratio, 0.09; 95% confidence interval, 0.01-0.79). There was also a significant dose response between AEE and incidence of cognitive impairment (P = .05 for trend over tertiles).

Conclusions

These findings indicate that greater AEE may be protective against cognitive impairment in a dose-response manner. The significance of overall activity in contrast to vigorous or light activity should be determined.

JAMA Internal Medicine: Metabolism Topic Collection

Brains and Aging Comment on “Physical Activity and Cognition in Women With Vascular Conditions” and “Activity Energy Expenditure and Incident Cognitive Impairment in Older Adults”

Activity Energy Expenditure and Incident Cognitive Impairment in Older Adults