Link Between Muscle Loss and Increased Risk of Dementia Identified in New Study

A groundbreaking study presented at the annual meeting of the Radiological Society of North America (RSNA) has revealed a concerning link between the loss of skeletal muscle mass and a heightened risk of developing dementia in older adults. Skeletal muscles, which comprise about one-third of an individual's total body mass, are essential for movement and overall physical stability. As age advances, many individuals experience a reduction in muscle mass, which may have significant implications for cognitive health.

The study specifically examined the temporalis muscle, located in the head and used for jaw movement. Researchers sought to determine whether the reduction in size of this muscle could signify broader muscle loss in the body and correlate with increased chances of developing Alzheimer's disease (AD) dementia. The lead author, Dr. Kamyar Moradi from Johns Hopkins University School of Medicine, indicated that measuring the size of the temporalis muscle could provide valuable insights into an individual's skeletal muscle condition, potentially helping to identify those at risk of cognitive decline.

Utilizing data from the Alzheimer's Disease Neuroimaging Initiative, the researchers analyzed MRI scans of 621 participants with an average age of 77, all of whom were without any dementia diagnosis at the study's commencement. They assessed the size of the temporalis muscle using a method that involved segmenting the muscle on MRI images and calculating the cross-sectional area (CSA). The participants were categorized into two groups based on muscle size: those with larger CSAs and those with smaller CSAs. Throughout the study, the researchers tracked changes in cognitive function, the incidence of dementia, and alterations in brain volume across a median follow-up duration of 5.8 years.

The analysis revealed alarming patterns. Participants with smaller temporalis muscle CSAs exhibited a significantly higher risk of developing AD dementia, estimated at about 60% greater when controlling for other risk factors. Moreover, these individuals displayed more pronounced declines in memory performance, functional activity, and reductions in structural brain volume during the study period. These findings underscore the unique relationship between physical health and cognitive decline, suggesting that muscle loss may serve as a precursor to dementia onset.

The study's co-senior author, Dr. Marilyn Albert, emphasized the implications of these findings. The ability to assess skeletal muscle loss through routine brain MRIs adds a non-invasive approach for early detection, potentially allowing for timely interventions. Dr. Shadpour Demehri, another co-senior author, highlighted that simple lifestyle changes, such as increased physical activity and resistance training, could mitigate muscle loss and consequently reduce the risk of cognitive decline.

In conclusion, the research elucidates a crucial connection between skeletal muscle health and dementia risk, advocating for proactive monitoring and intervention in older populations. By recognizing and addressing muscle loss early, it may be possible to slow down its progression and improve overall cognitive outcomes. As the global population ages, these findings will play a vital role in shaping future health strategies aimed at preserving both physical and cognitive well-being.