To date, several factors have been identified as influencing the decline of overall health. A new study shows a surprising finding: your muscle mass may be linked to the speed of your cognitive decline!

A recent Quebec study conducted by researchers from the Research Institute of the McGill University Health Centre (RI-MUHC) and the School of Human Nutrition of McGill University reveals a link between low muscle mass and cognitive decline. The Canadian Longitudinal Study on Aging, conducted on adults aged 65 to 86 years over a 3-year period, shows an association between low muscle mass and cognitive function.

"A weak muscle strength has recently been associated with a higher risk of dementia, but little is known about a possible link between muscle mass and cognition. In this study, we show for the first time that the presence of low muscle mass is significantly associated with faster cognitive decline and that this association is independent of muscle strength and physical activity level, among other factors," says Stéphanie Chevalier, PhD, a scientist with the Metabolic Disorders and Complications Research Program (MDCP) at the RI-MUHC, who led the study.

Elements measured in the study

Appendicular soft tissue lean mass (MMA) was assessed by dual-energy X-ray absorptiometry (DEXA). Low MMA was identified using the Canadian gender-specific determinants. Memory was assessed using the Rey Auditory Verbal Learning Test (RAVLT). Executive function was assessed using the Mental Alternation Test, the High Interference Stroop (word/dot) Test, the Animal Fluency Test, and the Oral Controlled Word Association Test. Psychomotor speed was assessed using reaction time to a computer-administered choice. Composite scores by domain were created. Of the 8279 participants, 4003 (48%) were female and the mean age was 72.9 (5.6) years. A total of 1605 participants (19.4%) had low MMA at baseline. 

Results

This study found longitudinal associations between low MMA and age-related cognition. Identifying older adults with low muscle mass, the targeted modifiable factor, may help identify individuals at risk for accelerated executive function decline.

Participants with low MMA were older, had lower body mass index, and lower physical activity levels. According to the multiple linear regression method, the presence of low MMA at baseline was associated with faster cognitive decline at 3 years in executive functions and psychomotor speed. After adjusting for variables such as age, education level, percent body fat, and grip strength, low MMA was only independently associated with a decline in executive function. Low MMA, however, was not associated with memory.

Muscle mass - a modifiable factor

Executive functions are important in our daily activities and behaviors because they help us stay focused, organize our thoughts and make decisions. Low muscle mass - compared to normal range for age - was associated with a greater decline in - The fact that muscle mass has been identified as a modifiable factor that could be used to reduce the risk of dementia opens up several opportunities for preventive treatments.

Muscles not only play a role in physical strength and capacity, but are also the place where many proteins are stored and secreted to bind to the brain. Exercise - especially resistance exercise - and building muscle tissue can increase blood flow to the brain and help with concentration and decision making. Combining exercise with a good diet - including enough protein - helps maintain muscle mass for many years.

Compared to normal muscle mass optimal for age, low muscle mass was associated with greater decline in executive function over three years, but not with loss of memory or psychomotor function. Executive functions are important in our daily activities and behaviors because they help us stay focused, organize our thoughts and make decisions.

Millions of people and their families are affected by dementia every day. Once a person is diagnosed with dementia, it appears that the process of cognitive decline is permanent. However, new developments in research may lead to potential treatments and even cures. 

Source: https://cusm.ca/nouvelles-et-histoires/nouvelles/une-etude-de-lir-cusm-demontre-lexistence-dun-lien-entre-faible