A new publication in JAMA Network Open describes faster decline in cognitive executive function in older adults with low muscle mass
Increasingly prevalent worldwide, dementia negatively affects the lives of millions of people and their families. By the time of diagnosis, the process appears to be irreversible. But researchers from the Research Institute of the McGill University Health Centre (RI-MUHC) and the School of Human Nutrition, McGill University have identified a modifiable factor that could potentially be used to decrease the risk of developing the condition, before it’s too late. Recently published in JAMA Network Open, their work highlights the importance of muscle mass as an independent factor linked with rapid cognitive decline.
“Low muscle strength has been recently associated with greater risk of dementia, but little is known about a possible link between muscle mass and cognition. With this study, we show for the first time that the presence of low muscle mass is significantly associated with faster cognitive decline and that this association is independent of muscle strength and physical activity level, among other factors,” says Stéphanie Chevalier, PhD, a scientist in the Metabolic Disorders and Complications Program (MeDiC) at the RI-MUHC, who led this study.
“These findings are important because muscle mass is a modifiable factor, meaning that we can do something about it. Exercise ─ particularly resistance exercise ─ and good nutrition with sufficient protein can help maintain muscle mass over the years,” adds Chevalier, who is also an Associate Professor at the School of Human Nutrition at McGill University.
The study was conducted using data from the ongoing Canadian Longitudinal Study on Aging (CLSA), which has a rich dataset on body composition and several cognitive tests conducted in person, over three-year intervals, in a cohort of 30,000 persons. The research team asked the question whether having low muscle predicts subsequent cognitive decline in three domains ─ memory, executive function and psychomotor speed ─ in adults aged 65 years and older.
“We found that having low muscle mass was associated with greater decline in executive cognitive functions over three years, compared to having normal muscle mass, but not with memory nor psychomotor function loss. Executive functions are important in our day-to-day activities and behaviours as they help us sustain attention, organize thoughts and make decisions,” explains first author Anne-Julie Tessier, RD, PhD, a doctoral student with Stéphanie Chevalier at the time of this study who is now a postdoctoral fellow at Harvard University.
Beyond their role in strength and physical functioning, muscles are the reservoir of proteins that serve several important bodily processes. Muscles also secrete molecules that can “talk” to the brain. It is also known that exercising and building muscle mass, by bringing more blood flow to the brain, can favour executive functioning.
“Our results show that measuring low muscle mass may help to identify people who have greater risk of cognitive decline. We should measure muscle more widely, in clinics, not only in research studies,” says Chevalier. “Further work should determine if maintaining or gaining muscle attenuates the cognitive decline with age, and if there is a causal link, what the mechanisms are.”
About the study
The study Association of Low Muscle Mass With Cognitive Function During a 3-Year Follow-up Among Adults Aged 65 to 86 Years in the Canadian Longitudinal Study on Aging was conducted by Anne-Julie Tessier, Simon S. Wing, Elham Rahme, José A. Morais and Stéphanie Chevalier.
Read the publication in JAMA Network Open
This research was made possible using data collected by the Canadian Longitudinal Study on Aging (CLSA).
Communications coordinator, Research, MUHC
Fabienne.landry [at] muhc.mcgill.ca