By Sean Kinney
Health-conscious people are always looking for ways to live long and disease-free lives. There may be more to achieving that goal than just maintaining a healthy weight.
Older people may be able to live longer by concentrating on building muscle mass, according to new research.
In determining obesity, physicians found that a measure of overall body composition including muscle mass was a better predictor of premature death than the more widely used body mass index (BMI) calculation.
In this study, increased muscle mass appeared more closely associated with lower instances of premature death than less body fat.
Preethi Srikanthan, MD, assistant clinical professor in the endocrinology division at the University of California, Los Angeles’ David Geffen School of Medicine, led this study with co-author Arun Karlamangla, MD, PhD, an associate professor in the geriatrics division at the Geffen School.
This study suggested that greater muscle mass in older adults was associated with a lower rate of death from any cause.
“In other words, the greater your muscle mass, the lower your risk of death,” Dr. Karlamangla said. “Rather than worrying about weight or body mass index, we should be trying to maximize and maintain muscle mass.”
Drs. Srikanthan and Karlamangla analyzed data collected between 1988 and 1994 from a group of 3,659 individuals including men 55 years of age and older and women 65 years of age and older.
These researchers conducted a follow-up survey in 2004 to determine how many individuals from the baseline group had died from natural causes.
Instead of using the common body mass index (BMI) measurement, a height-based calculation of total body mass, this study used a muscle mass index.
To figure out muscle mass, the doctors used bioelectrical impedance. That process involves running an electric current through the body. Muscles allow the current to pass more easily than fat does due to water content.
Using the muscle mass figures for the study participants, researchers divided the group into four sub-groups based on index score.
Total mortality was “significantly lower” in the quarter of participants with the most muscle mass as compared to the quarter with the least muscle mass, according to the findings.
"As there is no gold-standard measure of body composition, several studies have addressed this question using different measurement techniques and have obtained different results," Dr. Srikanthan said.
"So many studies on the mortality impact of obesity focus on BMI. 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," Dr. Srikanthan said.
These findings were published online February 20 by The American Journal of Medicine.
This research was funded by the National Institutes of Health and National Institute on Aging.