“Protecting your muscles is a way to protect your memory”... Exercise is the answer to preventing dementia [Health Check]

[Financial News] Men aged 60 and older whose muscle mass in their arms and legs was in the bottom 25% had a 34% higher risk of Alzheimer’s disease than other men. The risk was also 27% higher among women.
A research team led by Professor Jung Su-jin of the Department of Neurology at Inje University Ilsan Paik Hospital used health-screening data from the National Health Insurance Service to analyze the relationship between muscle mass and dementia risk in adults aged 60 and older. The findings were published in the latest issue of the international journal Alzheimer’s Research & Therapy.
The study included 1,897,197 adults aged 60 and older who underwent health screenings between 2009 and 2015. Their average age was 66.1; 875,094 were men and 1,022,103 were women. The researchers estimated participants’ appendicular skeletal muscle mass and divided them into the bottom 25% and the remaining 75% by muscle mass, then tracked whether they developed dementia through 2022.
The incidence rates also differed markedly. The rate of Alzheimer’s disease among men with lower muscle mass was 11.3 cases per 1,000 person-years (a measure based on following 1,000 people for one year), more than twice the rate among other men (5.1). The rate was also higher among women with lower muscle mass, at 16.2 cases, compared with 7.0 among the rest.

The researchers also found that risk tended to rise in stages as muscle mass decreased. Compared with the group with the most muscle mass, men’s risk increased by 16%, 30% and 58% across successive lower-muscle-mass groups. For women, the increases were 4%, 13% and 36%, respectively. The trend was statistically significant for both men and women.
Similar results were found for vascular dementia. Men with lower muscle mass had a 28% higher risk, while the risk among women was 23% higher.

One notable finding was that the association between muscle mass and Alzheimer’s disease was more pronounced among people who were relatively young or had fewer chronic conditions. The researchers suggested that, compared with muscle loss that occurs naturally with age, low muscle mass at a relatively young age may reflect the effects of other health problems or lifestyle factors.
Possible reasons for the association between reduced muscle mass and Alzheimer’s disease risk included decreased physical activity, chronic inflammation, insulin resistance, mitochondrial dysfunction, and changes in myokines, substances secreted by muscles. However, because this was an observational study, it cannot be concluded that reduced muscle mass directly causes Alzheimer’s disease.
The research team noted the significance of analyzing the relationship between muscle mass and Alzheimer’s disease using large-scale nationwide data and long-term follow-up. The study also differs from previous research in that it separately examined the relationship between muscle mass itself and dementia risk, rather than sarcopenia as a whole, which includes factors such as muscle strength and walking ability.
Professor Jung said, “These findings show that, to prevent dementia, it is important to consider maintaining muscle mass as part of daily life, alongside brain health,” adding, “It is important to manage muscle health through regular physical activity and balanced nutrition, starting at a relatively young age.” 


[email protected] Jung Myung-jin, medical correspondent Reporter