Muscle Mass May Mean Longer Lifespan

By Jane Farrell

Being stronger may equal a longer lifespan, according to new research.

The findings, by researchers from UCLA, indicate that the more muscle mass older Americans have, the less likely they are to die prematurely.

The study, published in the American Journal of Medicine, was led by Dr. Preethi Srikanthan, an assistant clinical professor in the endocrinology division at the David Geffen School of Medicine at UCLA. It seems to support a growing body of research that muscle mass may be a better predictor of all-cause mortality than the Body Mass Index (BMI).

"So many studies on the mortality impact of obesity focus on BMI,” Srikanthan said in a statement. “Our study indicates that clinicians need to be focusing on ways to improve body composition, rather than on BMI alone, when counseling older adults on preventative health behaviors."

For their study, the researchers analyzed data collected by the National Health and Nutrition Examination Survey (NHANES) III, conducted between 1988 and 1994. They focused on a group of 3,659 individuals that included men who were 55 or older and women who were 65 or older. The authors then determined how many people died from natural causes based on a follow-up survey in 2004.

They found that all-cause mortality was significantly lower in the among people with a higher muscle mass.

"In other words, the greater your muscle mass, the lower your risk of death," said Dr. Arun Karlamangla, an associate professor in the geriatrics division at the Geffen School and the study's co-author.

The researchers said that there is still no definitive cause and effect relationship that could be demonstrated by analyzing the study.

And the latest study does have some limitations. For instance, one cannot definitively establish a cause-and-effect relationship between muscle mass and survival using a cohort study such as NHANES III. "But we can say that muscle mass seems to be an important predictor of risk of death," Srikanthan said.