People who lose muscle mass and strength as they age may face a significantly higher risk of developing dementia, according to a new analysis by researchers at Curtin University. The scientists reviewed more than 80 studies and found that people with sarcopenia, the age-related loss of muscle and decline in physical function, were 42 percent more likely to develop dementia than those without the condition.
The findings were published in the International Journal of Food Sciences and Nutrition.
Curtin University, based in Perth, Australia, is one of the country's largest research universities. Sarcopenia is a recognized medical condition marked by the gradual loss of muscle mass, strength and mobility. It most often develops with age and is linked to declining physical activity and poor nutrition. Dementia, meanwhile, is an umbrella term for a group of conditions that progressively impair memory, thinking and the ability to carry out everyday tasks.
Weight alone does not tell the full story
The research team set out to examine how body weight, fat tissue and muscle condition each affect the risk of dementia. They concluded that weight alone does not provide an accurate picture of brain health, and that the body's ability to preserve muscle strength may play a more important role.
That conclusion was reinforced by an unexpected pattern in how obesity relates to dementia risk depending on age. Among people under 65, excess weight was associated with a 9 percent increase in dementia risk. Among older people, the relationship reversed, with obesity linked to a 17 percent decrease in risk.
A complex link, not a green light for weight gain
The study's authors were careful to stress that the finding does not suggest carrying extra weight is beneficial in later life. Instead, they said it points to a complicated relationship between body composition and how the brain ages.
The researchers said maintaining muscle strength through regular exercise and adequate nutrition could be an important part of preventing age-related cognitive decline. They cautioned, however, that it remains unclear whether the loss of muscle actually causes dementia, or whether it is instead an early warning sign of underlying processes that raise a person's risk of the disease.
Warnings over rising dementia numbers
The Curtin University findings follow earlier warnings from scientists that the number of people living with dementia could rise sharply in the coming years, adding urgency to research into factors, such as muscle health, that might help identify or reduce risk before symptoms appear.
