Abstract: Objective To investigate the association between sedentary time and the risk of sarcopenia among community-dwelling older adults, with the aim of providing targeted interventions for the prevention of sarcopenia in this population. Methods A cross-sectional study was conducted utilizing a multistage stratified quota sampling method to recruit 480 community-dwelling adults aged 60 years and older who had resided continuously for at least six months in cities such as Shanghai, Wuxi. The International Physical Activity Questionnaire-Short Form (IPAQ-S) was administered to assess sedentary time, and participants were evaluated for the prevalence of sarcopenia. A multivariate logistic regression model was employed to analyze the association between sedentary time and sarcopenia. Furthermore, a restricted cubic spline (RCS) model was used to explore the dose-response relationship between sedentary time and the risk of sarcopenia. Results A total of 496 valid questionnaires were returned, yielding a response rate of 97.25%. Sarcopenia was diagnosed in 91 participants, corresponding to a prevalence of 18.35%. Sedentary time ranged from 2 to 11 hours, with a mean of (6.41±2.37) hours. Multivariate logistic regression analysis indicated that sedentary time ≥8 h/d (OR=4.860) and 6-8 h/d (OR=2.943) were significant risk factors for sarcopenia in community-dwelling older adults (both P<0.01). The RCS analysis revealed a non-linear dose-response relationship between sedentary time and the risk of sarcopenia (P for non-linearity=0.044). Specifically, the risk of sarcopenia increased sharply with sedentary time exceeding 5 hours per day. In subgroup analyses stratified by age, sex, and physical activity level, a significant positive correlation was consistently observed between sedentary time and sarcopenia risk (P<0.05). The association was more pronounced in individuals aged 75-80 years (OR=1.396), females (OR=1.383), and those with no regular physical activity (OR=1.276). Conversely, the association was comparatively weaker in individuals aged 65-<75 years (OR=1.173), males (OR=1.171), and those who engaged in regular physical activity (OR=1.240). Conclusion The prevalence of sarcopenia is elevated among community-dwelling older adults, and prolonged sedentary time constitutes an independent risk factor for its development. The risk of sarcopenia increases significantly when daily sedentary time surpasses 5 hours.

Key words: Elderly population, Sedentary time, Sarcopenia, Dose-response relationship