Skeletal Muscle Loss Linked to Increased Dementia Risk

New research presented at the Radiological Society of North America's (RSNA) annual meeting reveals a significant connection between skeletal muscle loss and the development of dementia. The findings suggest that measuring skeletal muscle status through brain MRIs could provide a critical early warning for Alzheimer’s disease (AD) and other forms of dementia.

“Skeletal muscle loss may contribute to the development of dementia,” said Kamyar Moradi, MD, lead author and postdoctoral research fellow at Johns Hopkins University School of Medicine. “This is the first longitudinal study to demonstrate this connection, and it offers an opportunity for skeletal muscle quantification without additional cost or burden in older adults undergoing brain MRIs for neurological conditions.”

The multidisciplinary research, led by teams from the radiology and neurology departments at Johns Hopkins Medical Institutions, utilized data from the Alzheimer’s Disease Neuroimaging Initiative cohort. The study involved 621 participants without dementia at baseline with a mean age of 77. Researchers analyzed brain MRI scans to assess the size of the temporalis muscle, a head muscle connected to the lower jaw, which serves as an indicator of overall skeletal muscle loss.

The participants were divided into two groups based on their temporalis muscle cross-sectional area (CSA): a large CSA group (131 participants) and a small CSA group (488 participants). The researchers then tracked dementia incidence, cognitive and functional performance, and brain volume changes over a median follow-up of 5.8 years.

The study revealed that participants with smaller temporalis CSA were approximately 60 percent more likely to develop AD dementia, even after adjusting for other known risk factors. These individuals also experienced a greater decline in memory and functional activity scores, as well as structural brain volume, compared to those with larger CSA.

“Older adults with smaller skeletal muscles are at significantly higher risk for dementia,” said Marilyn Albert, PhD, co-senior author and professor of neurology at Johns Hopkins.

What makes this finding particularly promising is the accessibility of brain MRI scans for detecting skeletal muscle loss. “This muscle change can be opportunistically analyzed through any conventional brain MRI, even when conducted for other purposes, without incurring additional costs or burdens,” explained Shadpour Demehri, MD, co-senior author and professor of radiology.

Early detection of skeletal muscle loss through MRI could pave the way for timely interventions, such as physical activity, resistance training, and nutritional support, which may prevent or slow down both muscle and cognitive decline.

“These interventions may help reduce the risk of cognitive decline and dementia,” said Dr. Demehri.

For integrative practitioners, this study underscores the importance of addressing skeletal muscle health as part of a comprehensive approach to aging and dementia prevention. The research suggests that encouraging older patients to engage in resistance training, maintain a nutrient-rich diet, and undergo routine health screenings—including brain MRIs—could be pivotal in reducing their dementia risk.