A cross-sectional study on the characteristics of fat and skeletal muscle mass and the risk of sarcopenia in Chinese elderly people

Background Sarcopenia is a major health concern among the elderly over 60. Understanding the relationship between fat and skeletal muscle mass (SMM) and sarcopenia risk is crucial for its prevention and management.Methods This cross-sectional study involved the selection of 1523 participants from the baseline data of a health examination project for the elderly in Rugao and Dongtai City, Jiangsu Province, China, conducted between April and December 2024. The body composition parameters such as fat mass (FM) and SMM were measured by bioelectrical impedance analysis (BIA). Results Among the 1523 participants, the prevalence rates of sarcopenia among people aged 60 to 70, 71 to 80, and over 80 were 7.42%, 13.39%, and 46.15% respectively. The results of multivariate logistic regression showed that age, gender, body mass index (BMI), left calf circumference, FM and body fat percentage remained significantly associated with sarcopenia. Age was significantly positively correlated with the risk of sarcopenia (P < 0.001), BMI (P < 0.001) and FM (P < 0.001) were both significantly negatively correlated with the risk of sarcopenia. When age exceeded 79.90, age was significantly negatively correlated with BMI (P < 0.001). When age exceeded 73.43, it was significantly negatively correlated with FM (P < 0.001). In the age range above 80.00, age was significantly negatively correlated with body fat percentage (P = 0.025). In the age range below 82.00, age remained significantly negatively correlated with appendicular muscle mass (P < 0.001).Conclusions Among the elderly aged 60 and above, age, BMI, FM, body fat percentage and calf circumference were all independent influencing factors of sarcopenia. Detecting the body composition of the elderly is crucial for the early identification and intervention of sarcopenia.