Sarcopenia prevalence and risk factors among residents in aged care : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand

Abstract

Sarcopenia is defined as an age-related decline in muscle mass and function and is associated with adverse health outcomes and loss of independence. The aim of this study was to evaluate the prevalence and risk factors of sarcopenia among older adults living in residential aged care (RAC). This cross-sectional study recruited 91 older adults (63% women, mean age 86.0 ± 8.3 years) across three RAC facilities within Auckland, New Zealand. Personal interviews were conducted, and physical measures were taken by trained researchers. Using the European Working Group on Sarcopenia in Older People criteria, sarcopenia was diagnosed from the assessment of; appendicular muscle mass/height², using an InBody S10-body composition analyser and a SECA portable stadiometer or ulna length to estimate standing height; grip strength using a JAMAR handheld dynamometer; and physical performance with a 2.4m gait speed test. Demographic and health data were collected. Malnutrition risk was assessed using the Mini Nutritional Assessment - Short Form (MNA-SF) and depression was evaluated using the Geriatric Depression Scale. Most (83%) of residents were malnourished or at risk of malnutrition, half (52%) had >5 comorbidities and 44% took >7 medications. Overall, 41% of the participants were found to be sarcopenic. Univariate logistic regression found increasing age, lower MNA-SF score, lower percentage body fat, higher depressive symptoms, and hospital versus rest home level of care were associated with sarcopenia. Multivariate regression analysis showed only lower body mass index (OR=1.4, 95% CI: 1.1, 1.7, P= .003) and lower MNA-SF score (OR=1.6, 95% CI: 1.0, 2.4, P= .047) were predictive of sarcopenia after controlling for age, level of care, depression and number of medications. The correlation between lower MNA-SF score and sarcopenia highlights the need for regular malnutrition screening in aged care to prevent the development and progression of sarcopenia. As decreasing BMI was also predictive of sarcopenia, low weight or unintentional weight loss should prompt screening and appropriate intervention.