Older people with an apparent loss of skeletal muscle mass were at greater risk of developing dementia, the researchers found.

People with low temporalis muscle mass – a collection of jaw muscles linked to changes in skeletal muscle mass throughout the body – had a nearly 60% higher risk of developing dementia than people with low temporalis muscle mass. more significant (HR 1.59, 95% CI 1.09). -2.33, P.=0.016).

After more than 5 years of follow-up, about 3.5% of participants with low temporalis muscle mass showed signs of dementia, compared to 2.5% of those with larger temporalis muscles, reported researcher Kamyar Moradi, MD. postdoctoral fellow at the Johns Hopkins University School of Medicine in Baltimore, during Radiological Society of North America annual meeting in Chicago.

“Measuring temporalis muscle size as a potential indicator of generalized skeletal muscle status provides an opportunity for skeletal muscle quantification without additional cost or burden in older adults already undergoing brain MRI for neurological disease , such as mild dementia,” Moradi noted.

This is the first longitudinal study to suggest that skeletal muscle loss may be linked to future dementia, he added.

“As we age, we develop a loss of muscle mass, and interestingly, muscle mass is often seen in people with dementia,” Moradi said. “This observation made us wonder: could there be a direct link between muscle loss and the development of dementia?”

Age-related skeletal muscle loss, potentially modifiable, is often seen in older adults with dementia, the researchers noted. Previous studies have shown that the temporalis muscles can reflect overall muscle loss throughout the body.

“Thus, early detection of means of intervention targeting muscle loss, such as physical activity or nutritional support, could potentially prevent or slow down muscle loss and could also reduce the risk of developing dementia,” Moradi said. . “We believe this offers a new avenue for early intervention strategies in the fight against dementia.”

Commenting on the study, Max Wintermark, MD, chairman of neuroradiology at the University of Texas MD Anderson Cancer Center at Houston, said: Page Med today that these results should be considered with caution.

“I always view associations with a grain of salt, because many spurious associations exist,” Wintermark said. “In this particular case, it is unclear whether muscle loss is actually a risk factor for dementia or a consequence of the processes that lead to dementia.”

However, working to maintain muscle mass makes sense, Wintermark agreed. “In general, having a healthy lifestyle and getting proper exercise is beneficial in many ways, including maintaining muscle mass,” he said.

To determine the size of the temporalis muscle, Moradi and colleagues examined MRI scans of 621 participants aged 70 years or older (mean age 77 years) without dementia from baseline T1 brain MRI scans in the Alzheimer’s Disease Neuroimaging cohort. Initiative. The authors manually segmented the bilateral temporalis muscles and calculated the total cross-sectional area of ​​these muscles. Based on cross-sectional area, participants were classified into two distinct groups: 488 individuals with small cross-sectional area and 131 individuals with large cross-sectional area, based on a threshold of 1076.4 mm² to distinguish between two.

Over a median follow-up period of 5.8 years, the group monitored patients for the onset of dementia, changes in cognitive function and performance, and alterations in brain volume.

People with smaller temporalis muscle mass were more likely to develop dementia, after adjusting for other known risk factors such as age, sex, education and body mass index.

“They also showed greater decline in memory, functional activities and brain volume over time,” Moradi said.

The study showed that the low muscle mass group had a greater decrease in memory composite score, functional activity questionnaire score, and structural brain volumes, including whole brain, hippocampus, cortex entorhinal and fusiform gyri during the follow-up period (all P.<0.05).

One limitation of the study was the lack of repeated MRI measurements to determine changes in muscle mass during follow-up.