People with fatty muscles are more prone to Alzheimer’s disease, according to new research.
The condition, known medically as myosteatosis, can be symptomless – and lead to cognitive decline, say scientists.
It has opened the door to a screening program – and personalized treatments for vulnerable individuals.
Drug trials have failed to date. The reason is that they are prescribed too late after the disease has already taken hold.
Corresponding author Dr. Caterina Rosano, of Pittsburgh University, said: “Our data suggest muscle adiposity plays a unique role in cognitive decline, distinct from that of other types of fat or other muscle characteristics.”
Her team tracked 1,634 over-70 individuals for a decade. Increases in thigh muscle adiposity in the first six years were associated with faster cognitive decline.
The findings, published in the Journal of the American Geriatrics Society, applied to black and white men and women.
Dr. Rosano said: “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.”
With no cure in sight, there is an increasing focus on protective lifestyles. The number of dementia cases worldwide will triple to more than 150 million by 2050.
Results stood after taking into account other factors such as genetic susceptibility, diabetes, high blood pressure, and physical activity.
Dr. Rosano said: “Obesity and loss of muscle mass are emerging as risk factors for dementia, but the role of adiposity infiltrating skeletal muscles is less clear.”
Muscle fat increases with older age and especially among black women – a group at higher Alzheimer’s risk.
Dr. Rosano said: “Clinicians should be aware that regional adiposity accumulating in the skeletal muscle may be an important, novel risk factor for cognitive decline in black and white participants independent of changes to muscle strength, body composition and traditional dementia risk factors.”
Last month a study by Belgian scientists found individuals with myosteatosis were twice as likely to suffer a premature death than obese peers.
It is comparable to smoking or having type 2 diabetes – but the phenomenon has been largely overlooked, they said.
Dr. Rosano added: “Clinicians should be aware adiposity distribution is an important risk factor for cognitive decline, distinct from overall adiposity and muscle loss.”
Muscle adiposity is not yet routinely measured in surgeries. But it has started to be scanned as part of routine patient care.
“These CT (computed tomography) measurements have already been validated in many studies of older adults,” Dr. Rosano said. “So clinicians could have access to this novel information without additional cost, time or radiation exposure.
“As rapidly evolving methodologies are making this measure more feasible and broadly applicable in clinical settings, there are rich opportunities for collecting muscle adiposity and improve prediction models for dementia.
“Obtaining comprehensive measures of muscle in older age is very timely. Both diagnosis and treatment of frailty in older adults are finally transitioning from research settings to a routine part of patient care.
“Muscle adiposity may become a component of these routine assessments and provide useful and new information for dementia risk.”
It has also been linked to heart attacks and strokes. Since BMI is calculated using only height and weight, it is not an accurate reflection of body composition.
Patients with similar BMIs can have vastly different comorbidities and levels of health risk.
Myosteatosis is usually found in patients who are already sick and undergoing medical imaging for another illness. But little is known about its health risks in asymptomatic patients.
Produced in association with SWNS Talker
Edited by Kyana Jeanin Rubinfeld and Jessi Rexroad Shull
