People with fatty muscles are more vulnerable to declining brain health

PITTSBURGH — According to recent research, individuals with fatty muscles, a condition medically known as myosteatosis, have a higher susceptibility to cognitive decline — a warning sign for Alzheimer’s disease. This condition can exist without noticeable symptoms, scientists warn. The new findings provide a potential path to screening procedures and personalized treatments for those most at risk.

The lack of success in drug trials to date could be due to prescriptions being given too late, after the disease has already taken root.

“Our data suggest that muscle adiposity plays a unique role in cognitive decline, distinct from that of other types of fat or other muscle characteristics,” says corresponding author Caterina Rosano, MD, MPH, of the University of Pittsburgh’s School of Public Health.

Over a period of a decade, Rosano’s team studied 1,634 individuals over the age of 70. They discovered that an increase in thigh muscle adiposity during the first six years was linked with accelerated cognitive decline. These results were consistent across various races and genders and were published in the Journal of the American Geriatrics Society.

“If that is the case, then the next step is to understand how muscle fat and the brain ‘talk’ to each other, and whether reducing muscle adiposity can also reduce dementia risk,” Dr. Rosano elaborates in a media release.

Overweight woman hand pinching excessive belly fat
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With no cure for dementia currently available, emphasis is shifting toward preventative lifestyles. It is predicted that the number of dementia cases worldwide will triple by 2050, reaching over 150 million.

These results remain valid even after accounting for other factors such as genetic susceptibility, diabetes, high blood pressure, and physical activity levels.

Dr. Rosano adds that while obesity and muscle mass loss are emerging as dementia risk factors, the role of adiposity infiltrating skeletal muscles remains unclear. It’s important to note that muscle fat increases with age, particularly among Black women, who are at a higher risk of Alzheimer’s.

The study author continued that clinicians should be aware that regional adiposity accumulation in the skeletal muscle could be a significant, novel risk factor for cognitive decline in Black and White individuals. This holds true regardless of changes to muscle strength, body composition, and traditional dementia risk factors.

A study conducted last month by Belgian scientists found that individuals with myosteatosis were twice as likely to die prematurely compared to their obese counterparts. The risks associated with this condition are comparable to those of smoking or Type 2 diabetes, yet this phenomenon has largely been overlooked.

“Clinicians should recognize that the distribution of adiposity is an important risk factor for cognitive decline, distinct from overall adiposity and muscle loss,” Dr. Rosano stresses.

Cognitive or mental decline, brain disease
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Currently, muscle adiposity is not commonly measured in medical practices. However, scanning for this condition has recently become part of routine patient care. Dr. Rosano suggests that clinicians could benefit from using this information without any additional cost, time, or radiation exposure.

“As more advanced methodologies make these measurements more feasible and widely applicable in clinical settings, we have ample opportunities to collect muscle adiposity data and improve prediction models for dementia,” Rosano says.

“Diagnosis and treatment of frailty in older adults are transitioning from research settings to routine patient care. In this transition, muscle adiposity could become a component of these routine assessments, providing valuable insights into dementia risk.”

It’s also worth noting that muscle adiposity has been linked to heart attacks and strokes. Since Body Mass Index (BMI) only takes height and weight into account, it may not accurately reflect body composition. Therefore, patients with similar BMIs can have vastly different health risks and comorbidities.

Generally, myosteatosis is identified in patients who are already ill and undergoing medical imaging for another condition. However, the health risks associated with asymptomatic patients remain largely underexplored.

Mujer pisando la báscula (© Siam –

In addition to affecting cognition, myosteatosis has been linked to other severe health problems such as heart attacks and strokes. A more accurate understanding of body composition could be vital for preventative healthcare, given that two patients with identical Body Mass Index (BMI) could still have significantly different levels of health risk and comorbidities. BMI is calculated solely from height and weight, and as such, doesn’t provide a comprehensive view of an individual’s health status.

Usually, myosteatosis is discovered in patients who are already unwell and are undergoing medical imaging for a different health issue. The condition is typically overlooked until these advanced stages of illness. There is a lack of knowledge regarding the health risks associated with asymptomatic patients who have this condition. This gap in knowledge suggests that more research is needed to fully understand the implications of myosteatosis on general health, even when other symptoms are not present.

The implication is clear: there is a growing need for routine measures of muscle adiposity in medical practices. Dr. Rosano emphasizes that This measure could potentially provide useful and new information for dementia risk. As methods of measuring muscle adiposity continue to evolve and become more feasible in a clinical setting, there are likely to be more opportunities for clinicians to diagnose and treat dementia at its earliest stages, potentially improving outcomes for patients.

South West News Service writer Mark Waghorn contributed to this report.

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