People with low arm and leg muscle mass Alzheimer’s risk face a significantly higher likelihood of developing Alzheimer’s-type dementia compared to those with healthy muscle levels, a recent study has revealed. This strong association was particularly evident among younger individuals and those with fewer underlying chronic conditions.
Researchers led by Professor Jung Soo-jin from the Department of Neurology at Ilsan Paik Hospital announced on the 12th that they reached this conclusion after analyzing health check-up data from approximately 1.9 million adults aged 60 and older.
The research team utilized National Health Insurance Service data to track 1,897,197 adults aged 60 and older who underwent health screenings between 2009 and 2015, following their health outcomes through 2022. The average age of the participants was 66.1 years, comprising 875,094 men and 1,022,103 women.
How Low Muscle Mass Increases Dementia Risk
Using parameters such as height, weight, waist circumference, and blood test results, the team estimated the appendicular skeletal muscle mass of the participants. They then compared dementia occurrence rates between the lowest 25% muscle mass group and the remaining 75%.
The results showed that men in the low muscle mass group had a 34% higher risk of developing Alzheimer’s-type dementia compared to other men. Women in the low muscle group experienced a 27% higher risk. These figures were adjusted for potential confounding factors including age, chronic illnesses, smoking, alcohol consumption, and physical activity.
Actual incidence rates highlighted a stark contrast. Among men, the low muscle group saw 11.3 Alzheimer’s cases per 1,000 person-years, compared to 5.1 cases in the other group. For women, the rates were 16.2 and 7.0 cases respectively, showing more than a twofold difference.
Stepwise Increase in Risk and Future Prevention
The study also identified a stepwise escalation in dementia risk corresponding to diminishing muscle volume. Using the top 25% with the highest muscle mass as a baseline, the risk of Alzheimer’s-type dementia in the bottom 25% was 58% higher for men and 36% higher for women. Furthermore, vascular dementia risk linked to cerebrovascular damage was elevated by 28% in men and 23% in women with reduced muscle mass.
A particularly noteworthy finding was that the link between low muscle mass and dementia risk was stronger among younger individuals and those without severe chronic diseases. Researchers explained that while muscle loss in the elderly is often a byproduct of natural aging, having low muscle mass at a relatively young age may reflect underlying health issues or lifestyle factors.
Experts suggest that physical inactivity, chronic systemic inflammation, and insulin resistance connect muscle loss to cognitive decline. Changes in myokinesβsubstances secreted by muscles that regulate metabolism and inflammatory responsesβmay also play a role. However, because this was an observational study, it does not definitively prove a direct causal relationship, meaning building muscle does not automatically guarantee dementia prevention.
Professor Jung Soo-jin emphasized, “These findings demonstrate that maintaining adequate muscle mass is just as important as brain health for preventing dementia. It is especially vital to manage muscle health early in life through regular physical activity and a balanced diet.”
The findings of this research were published in the international academic journal Alzheimer’s Research & Therapy.
