Inflammatory-endocrine state tied to muscle quality decline in elderly Asians
In elderly adults with mild cognitive impairment (MCI) or mild-to-moderate Alzheimer’s disease (AD), malnutrition appears to lead to progress muscle mass loss, reveals a new Singapore study, which also identifies a proinflammatory state combined with endocrine deficiency as a risk factor for declining muscle quality ending in sarcopoenia.
“While malnutrition is a precursor for progressive loss of muscle mass, being the common risk factor for presarcopoenia and sarcopoenia, a combined proinflammatory and endocrine-deficient state aggravates decline in muscle performance culminating in frank sarcopoenia,” researchers said.
Moreover, the current study “supports the clinical relevance of muscle quality beyond muscle mass as a determinant of functional performance in cognitively impaired older adults,” they added.
The research team recruited 129 elderly adults (mean age 76.6±6.5 years; 64.8 percent female) with baseline diagnoses of MCI or mild-to-moderate AD from the Tan Tock Seng Hospital in Singapore.
Muscle quality of the participants was measured using grip strength, knee extensor muscle strength, gait speed and dual-energy X-ray absorptiometry. The Chinese version of the mini-mental state examination (CMMSE) and the clinical dementia rating (CDR) were used to evaluate cognitive performance and dementia severity.
Based on the European working group on sarcopoenia in older people (EWGSOP) criteria, participants were divided into three groups: no sarcopoenia (n=41; mean age 76.2±5.5 years), presarcopoenia (n=14; mean age 72.4±7.5 years) and sarcopoenia (n=53; mean age 78.3±6.5 years). [Arch Gerontol Geriatr 2017;75:20-27s]
In multinomial logistic regression analysis adjusted for covariates such as age and gender, the risk of malnutrition was significantly higher in participants with presarcopoenia (relative risk ratio, 7.53; 95 percent CI, 1.20 to 47.51; p=0.032) and sarcopoenia (relative risk ratio, 11.91; 2.85 to 49.77; p=0.001) than in those without sarcopoenia.
While either did not pass as risk factors individually, the combined state of being proinflammatory and endocrine-deficient were significantly associated with elevated risks of sarcopoenia (relative risk ratio, 5.17; 1.31 to 20.37; p=0.019). The inflammatory-endocrine state was not associated with sarcopoenia in any way.
The findings of the current study confirm the importance of nutrition in maintaining muscle quantity and quality, as reported widely in the literature. However, because nutritional status could not completely account for rates of physical frailty, researchers hypothesized that there were other factors that drove muscle quality decline.
“While optimizing nutritional status will undoubtedly remain important to prevent progressive loss of muscle mass, more targeted interventions that simultaneously address immune and endocrine dysfunctions will be necessary to ensure maintenance of functional independence through preserving muscle quality,” they said.