Association between sarcopenia and components of metabolic syndrome among Chinese older adults: a population-based longitudinal study using CHARLS

Sarcopenia is an age-related loss of muscle mass and strength that affects quality of life in older adults and may also increase the risk of developing metabolic syndrome (MetS) and its components. This study aimed to explore the longitudinal association between sarcopenia and the components of MetS. Data for this study were derived from China Health and Retirement Longitudinal Survey (CHARLS). The sample included 3,758 participants aged ≥ 60 years who were included in the baseline survey of CHARLS (2011) and followed up until 2015. Sarcopenia status was defined according to the 2019 Asian Working Group for Sarcopenia (AWGS2019). The diagnostic components of MetS were assessed according to the clinical criteria outlined in the 2022 expert consensus on the management of MetS in older adults in China. Cox proportional hazards regression (HR) models were used to evaluate the effect of sarcopenia the risk factors of MetS. In this study, 1,252 individuals with sarcopenia and 2,506 individuals without sarcopenia were included. During follow-up, 489 MetS cases were observed among those without MetS at baseline. Participants with sarcopenia exhibited significantly lower body mass index (BMI), waist circumference, triglycerides (TG), and blood glucose levels (all p < 0.001) compared to those without sarcopenia. After adjusting for sex, age, education, marital status, smoking, alcohol consumption, and physical activity, hazard ratios (HR) in the sarcopenia group were significantly elevated for abdominal obesity (HR 8.24, 95% CI 6.56-10.27; p < 0.001), hypertriglyceridemia (HR 2.12, 95% CI 1.40-3.20; p < 0.05), and MetS (HR 5.33, 95% CI 4.01-7.08; p < 0.001). In the BMI subgroup, the risk of sarcopenia was found to increase in elderly individuals within the low BMI of 18.5-23.9 kg/m2 (HR 5.16, 95% CI: 4.91-5.36; p < 0.001) and < 18.5 kg/m2 (HR 6.06, 95% CI: 5.98-6.51; p < 0.001). Sarcopenia was significantly associated with specific components of MetS, particularly abdominal obesity and hypertriglyceridemia. In addition, low BMI emerged as a key factor related to sarcopenia development among older adults.