CPMC Researchers Validate Non-invasive Lab Test as a Lower Cost and More Accurate Way to Assess Skeletal Muscle Mass Loss in Older Men

SAN FRANCISCO, June 20, 2018—Accurately measuring loss of skeletal muscle mass can help improve care for older men, who may be at risk of falls, mobility problems and other poor health outcomes due to age-related loss of strength. However, results from dual x-ray absorptiometry (DXA) testing — which is typically used to measure muscle mass) — often do not correlate well with physical performance, self-reported mobility, falls and other functional outcomes of skeletal muscle loss due to aging. The ability to carefully characterize muscle mass is central our understanding of sarcopenia – the age-related loss of muscle and its accompanying decline in physical performance.


In a prospective study of more than 1,000 older men, California Pacific Medical Center Research Institute (CPMCRI) scientists and collaborators throughout the U.S. found that a newer non-invasive urine test delivered muscle mass measures that were a more accurate predictor of the development of physical symptoms of sarcopenia than DXA. Furthermore, since the laboratory test is comparable in cost and is easier to administer than DXA, its use could improve access to early detection of loss of muscle in men.


In the study, 1,382 men with a mean age of 84.2 years agreed to have their skeletal muscle mass measured with the D3-creatine dilution method laboratory test. The non-invasive test involves swallowing a capsule of D3-creatine, a non-radioactive tracer isotope, and then measuring how much of the isotope is passed through to the urine. Through an algorithm, the amount of muscle mass is then calculated. The men also had a DXA lean mass test, completed a short series of physical performance tests and answered questions about their mobility limitations. The men, who were all part of the large cohort Osteoporotic Fractures in Men (MrOS) longitudinal research project, where then tracked over subsequent years for incidence of recurrent falls and new mobility problems.


The CPMCRI team found that even controlling for other factors that might impact health outcomes, such as their activity level and other health conditions, the D3-creatine method was a more accurate predictor of functional outcomes for the men than the DXA lean mass test.


“Demonstrating that this  non-invasive and relatively low cost test re is consistently related to  late-life functional outcomes opens up the possibility of improving care for older people, by identifying those at most risk of physical decline” Peggy Cawthon, Senior Scientist, CPMCRI. ”We hope that this test ultimately may be used to help identify novel treatment strategies for this population.”


The study is entitled “Strong Relation Between Muscle Mass Determined by D3-Creatine Dilution, Physical Performance and Incidence of Falls And Mobility Limitations in a Prospective Cohort of Older Men.” It appears in the June 12, 2018, issue of the peer-reviewed The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences. Read the abstract here.

About the Osteoporotic Fractures in Men (MrOS) Study


The MrOS study is a multi-center study of healthy aging in men that has been ongoing since 2000. It is funded by the National Institutes of Health and facilitated by the San Francisco Coordinating Center, a non-profit, academic research organization that is a collaborative enterprise among researchers from California Pacific Medical Center Research Institute and the UCSF School of Medicine, Department of Epidemiology and Biostatistics.



About California Pacific Medical Center (CPMC)—A Sutter Health Affiliate


At San Francisco’s California Pacific Medical Center, we believe in the power of medicine. We research the most up-to-date treatments, hire the most qualified individuals, and practice the most modern, innovative medicine available. We deliver the highest-quality expert care with kindness and compassion in acute, post-acute and outpatient services, as well as preventive and complementary medicine. As one of California’s largest private, community-based, not-for-profit, teaching medical centers, and a Sutter Health affiliate, we are able to reach deep into our community to provide education, screening and financial support in some of the city’s most underserved neighborhoods. Like us on Facebook, watch us on YouTube and follow us on Twitter. For more information visit our web site at cpmc.org.