Can Muscle Loss Lead To Dementia?

As per the Centers for Disease Control and Prevention (CDC), dementia is a common condition in the United States that affects millions of older adults. In 2022, 3.8% of men and 4.2% women in US were diagnosed with dementia. The percentage of people increase with age from 1.7% for those aged 65-74 to 13.1% for those aged 85 and older. Alzheimer's accounts for 60 to 80% of all dementia cases and it is most prevalent in California, Florida, and Texas, as these states have the highest number of people.

However, a new study which was presented at the Radiological Society of North America, titled Muscle loss could increase dementia risk by Moradi K et al., suggest that the reduced size of a specific muscle could indicate that someone has an increased risk of dementia. In simpler words, loss of muscle could be a sign of dementia.

The study analyzed data from 621 cognitively healthy people who participated in the Alzheimer's Disease Neuroimaging Initiative. The researchers then looked at the temporalis muscles, which are related to the jaw on MRI images. Participants were then grouped into several groups based on their muscle size and were tracked for almost 5.8 years. The researchers kept a record of if anyone was diagnosed with dementia or had any changes in their brain structure, cognition, and functioning.

The scientists found that those who had a smaller temporalis muscles had a 60% higher chance of developing Alzheimer's disease or dementia. A smaller temporalis muscle size was also linked with a drop in memory, functional abilities, and brain volumes.

Researchers in a statement said: "These results demonstrate that older adults with smaller skeletal muscles are at greater risk of cognitive decline."

A smaller temporalis muscle indicated sarcopenia, which means the age-related loss of muscle mass and strength. Experts suggests that systematic sarcopenia is also linked with frailty, reduced mobility, and metabolic dysfunction, all these factors are associated with cognitive decline.

In 2022, a study published in JAMA Network by Anne-Julie Tessier, et al., analyzed 8,279 older adults to find that low muscle mass was linked with a faster drop in cognitive functioning. In yet another 2022 research, published in The Journals of Gerontology Series A: Biological Sciences and Medical Sciences by Susanne Janette Oudbier, et al., also found that low skeletal muscle mass is linked with cognitive impairment and dementia risks in older adults.

Another recent study published in the medical journal of the American Academy of Neurology found that everyday activities like household chores, exercising, and socializing can help lower the risk of dementia. The study was conducted for 11 years, which involved 5 million people. The study found that the risk of dementia lowered in participants who were active. It was noted that people who exercised regularly had a 35% lower risk of dementia. This could also be because physical activities helps you build muscle mass.