Activity modestly improves cognition in seniors at risk of Alzheimer's disease

Last Updated: 2008-09-02 16:00:21 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Participation in a home-based physical activity program can modestly improve cognition in older adults with self-reported memory problems but who do not meet the criteria for dementia, new research shows.

Data from observational studies have suggested that physical activity can reduce the odds of cognitive decline in older adults, lead author Dr. Nicola T. Lautenschlager of the University of Melbourne in Victoria, Australia, and colleagues note, but confirmation from randomized trials has been lacking.

The current study, reported in the September 3rd issue of the Journal of the American Medical Association, involved 170 subjects, 50 years or older, who were randomized to a physical activity program or usual care for 6 months. The study was conducted between 2004 and 2007 within the metropolitan area of Perth, Western Australia.

Participants in the activity program were encouraged to perform moderate-intensity physical activity for at least 50 minutes three times a week. The main outcome measure was the change in Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) scores over 18 months. A total of 138 subjects completed the 18-month assessment.

On average, patients in the intervention group performed 142 minutes more physical activity per week than did controls. In the 6-month intention-to-treat analysis, the ADAS-Cog score increased by 0.26 in the intervention group, whereas it fell by 1.04 points in the control group. At 18 months, 0.73- and 0.04-point improvements were noted in the physical activity and control group, respectively.

Participation in the physical activity program was also tied to improvements in Clinical Dementia Rating sum of boxes and word list delayed recall. By contrast, the program seemed to have no effect on digit symbol coding, word list total immediate recall, verbal fluency, Beck depression score, and physical and mental components of the Medical Outcomes 36-Item Short-Form.

"To our knowledge, this trial is the first to demonstrate that exercise improves cognitive function in older adults with subjective and objective mild cognitive impairment," the authors conclude. Although the cognitive improvements were small, they are "potentially important when one considers the relatively modest amount of physical activity undertaken by participants in the study."

In a related editorial, Dr. Eric B. Larson, from the Group Health Center for Health Studies in Seattle, comments that "the findings point to the need to learn more about exercise as an intervention to prevent cognitive decline and Alzheimer's disease -- and especially how to promote adherence and widespread behavior change."

JAMA 2008;300:1027-1037,1077-1079.

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