Impact of Malnutrition on Low Muscle Mass in Community-Dwelling Older People in Singapore: Findings from the SHIELD study

Malnutrition contributes to loss of muscle mass. There is limited information on the prevalence of low muscle mass in community-dwelling older people who are (not) at risk of malnutrition. Factors associated with muscle mass are also not well characterized. This cross-sectional study aimed to determine the prevalence of low appendicular skeletal muscle mass index (ASMI; ASM/height2) in older people with normal nutritional status (Malnutrition Universal Screening Tool, MUST risk category = low) and those at risk of malnutrition (MUST risk category = medium or high), and to determine factors associated with ASMI. Strengthening Health In ELDerly through nutrition (SHIELD) is a study involving 1211 (400 with normal nutritional status and 811 at risk of malnutrition) community-dwelling older people aged ≥65 years in Singapore. Low ASMI was determined by bioelectrical impedance analysis (Asian Working Group for Sarcopenia, 2014). One in five (20.6%) nourished participants had low ASMI vs. four in five (81.3%) participants at risk of malnutrition had low ASMI (P < 0.0001). Older people with low ASMI were more likely to be admitted to the hospital, had longer length of stay, 25-hydroxyvitamin D deficiency, and lower education level, compared to those with normal ASMI (all P ≤ 0.0472). In the multiple linear regression model, age (coefficient, b = –0.013 kg/m2; P < 0.001), gender (female: b = –0.963 kg/m2; P < 0.001), calf circumference (b = 0.042 kg/m2; P < 0.001), bone mass (b = 0.593 kg/m2; P < 0.001), BMI (b = 0.129 kg/m2; P < 0.001), and Physical Activity Scale for the Elderly (PASE) score (b = 0.001 kg/m2; P = 0.048) were associated with ASMI. Community-dwelling older people at risk of malnutrition had four-fold greater risk of having low ASMI as compared to nourished counterparts. Increasing age was associated with lower ASMI, whereas calf circumference, bone mass, BMI, PASE score, and being male were positively associated with ASMI. These findings highlight the importance of screening for low muscle mass and maintaining muscle health as part of the overall malnutrition management in this population group. The Economic Development Board of Singapore, Abbott Nutrition, and Changi General Hospital funded this study.