Older Americans who have low strength and poor physical function are at increased risk of being hospitalized, researchers report.

They advise that interventions to improve physical function, such as exercise, could help keep more vulnerable seniors out of the hospital, which would not only reduce further disability but could also save valuable health care dollars.

To find out which muscle-related factors are linked with older adults' risk for being hospitalized, Dr. Peggy M. Cawthon of California Pacific Medical Center in San Francisco, and her colleagues studied more than 3,000 adults between the ages of 70 and 80 years old.

All of them performed traditional tests of muscle power including grip strength, knee extension strength and walking speed. In addition, lean muscle mass and percentage body fat was measured, and all participants had CT scans of their thighs to calculate muscle area and muscle density.

Over roughly the next four and a half years, 56 percent of the participants were hospitalized at least once, the researchers report in the Journal of the American Geriatrics Society.

According to the report, weak strength, poor function in terms of walking and rising from chairs, and low muscle density, but not muscle size or lean mass, were all associated with a greater risk of being hospitalized.

Even in healthy, nondisabled older adults, poor physical function was associated with a greater risk of hospitalization, according to the researchers.

Being hospitalized puts elderly people at risk for increasing disability, Cawthon and colleagues note in their report.

They also point out, in the year 2000, direct health care costs due to age-related muscle loss in Americans was estimated at $18.5 billion.

SOURCE: Journal of the American Geriatric Society, 2009.

Aging