Study on body composition characteristics and influencing factors of sarcopenia status among older adults in Shanghai: a cross-sectional study.

Objectives: Population aging results in substantial pressure on global healthcare systems. Sarcopenia is a recognized syndrome of old age. Sarcopenic obesity (SO) is a combination of sarcopenia and obesity that significantly affects the health of older adults. Therefore, this study aimed to evaluate the prevalence of sarcopenia and SO in older adults in Shanghai, evaluate the relationship of sarcopenia and SO with body composition and biochemical indicators, and identify possible factors associated with sarcopenia.

Methods: This cross-sectional survey included general demographic data, anthropometric parameters, laboratory examination, and body composition measurement results of older adults aged ≥ 60 years from a health examination center in Shanghai, China, from January to December 2021. The Asian Working Group for Sarcopenia 2019 diagnostic criteria divided the participants into sarcopenia and non-sarcopenic groups. Participants were classified into four groups based on the presence or absence of sarcopenia and obesity: sarcopenic obesity, sarcopenia without obesity, obesity without sarcopenia, and non-sarcopenia/non-obesity. Comparative analyses were performed across groups. Differences in body composition and biochemical indices were analyzed in patients with sarcopenia of different sexes. Logistic regression was used to identify independent factors associated with sarcopenia.

Results: A total of 700 participants were included in this study. Sarcopenia prevalence was 13.57%. The individuals with SO demonstrated significantly higher mean age (70.48 ± 6.74 years) than other groups with marked sex disparities. Multivariate regression identified female sex (OR = 0.07, 95%CI:0.02-0.28) as a protective factor, while age ≥ 79 years (OR = 11.30, 95%CI:2.63-48.48), increased VFA (per 1-cm²: OR = 1.14, 95%CI:1.11-1.17), and low ASMI (OR = 87.17, 95%CI:34.48-220.37) independently predicted sarcopenia risk.

Conclusion: This study is the first to report the prevalence of sarcopenia and SO in the elderly population (≥ 60 years old) in Shanghai and its associated risk factors, suggesting that attention should be paid to muscle health in the elderly population. In clinical practice, sarcopenia screening and intervention should be carried out as early as possible for elderly men to achieve timely and effective prevention. This study helps to raise awareness of sarcopenia and promote its identification and intervention in the Chinese population.