Low appendicular skeletal muscle mass common among older adults in SG

Several older adults in Singapore have low appendicular skeletal muscle mass index (ASMI), particularly those who are at high risk for malnutrition, according to a recent study. Smoking, drinking, and low bone mass are other warning signs of low ASMI.

“Early identification of risk for low ASMI in older adults can guide appropriate interventions, which can in turn reduce associated health complications, lower healthcare costs, improve function and quality of life, thus supporting healthier, more independent and meaningful lives for as long as possible,” the researchers said.

A total of 1,211 community-dwelling older adults (aged ≥65 years, 707 women) were cross-sectionally evaluated to determine the prevalence of low ASMI, defined as <7.0 kg/m² in men and <5.7 kg/m² in women on bioimpedance analysis. Overall, 59.9 percent of participants were deemed to have low ASMI, though no significant sex effect was found (57.0 percent in men, 61.8 percent in women; p=0.1068). [Sci Rep 2021;11:23071]

On the other hand, low ASMI was significantly more prevalent among older adults who were at risk of malnutrition vs those with normal nutritional status (81.3 percent vs 20.6 percent; p<0.0001).

Compared with their normal-ASMI counterparts, participants with low ASMI were older, weighed less, had lower mid-upper arm and calf circumference, and had lower bone mass. The researchers also found a significant correlation between ASMI and vitamin D status (p=0.0472), such that vitamin D deficiency was significantly more common among those with low vs normal ASMI (13.02 percent vs 18.52 percent; p=0.0144).

The researchers then conducted multiple logistic regression modelling to identify factors associated with low ASMI. Their analysis revealed that participant lifestyle could significantly impact ASMI.

For instance, alcohol drinking emerged as an important predictor of low ASMI (p=0.0328), such that participants who drank at least once in the last 12 months were more than 2.5 times as likely to have low ASMI than nondrinkers (odds ratio [OR], 2.51, 95 percent confidence interval [CI], 1.34–4.67).

Smoking had a similar and stronger effect on ASMI (p=0.0134). Those who were daily or occasional smokers were nearly four times as likely to have low ASMI than nonsmokers (OR, 3.76, 95 percent CI, 1.55–9.16).

Other important correlates included age (OR, 1.06, 95 percent CI, 1.02–1.09; p=0.0011), calf circumference (OR, 0.72, 95 percent CI, 0.66–0.78; p<0.0001), bone mass (OR, 0.26, 95 percent CI, 0.15–0.47), and malnutrition risk as measured by the Malnutrition Universal Screening Test (high vs low risk: OR, 12.50, 95 percent CI, 7.02–22.25; p<0.0001).

“For community-dwelling older adults, early identification of low muscle mass offers opportunities to prevent or delay its worsening, and its associated adverse consequences,” the researchers said. “We advise identification of malnutrition risk as a targeted core strategy to screen for low muscle mass in older adults.”

“Furthermore, low ASMI was associated with modifiable risk factors such as smoking and drinking, which suggests that current targeted community health promotion programmes can improve muscle health, in addition to other established benefits,” they noted.