Plasma biomarkers for monitoring muscle function and physical performance decline in older adults: A 2-year longitudinal study.

BACKGROUND: Reliable biomarkers for diagnosing and monitoring sarcopenia remain limited, especially those reflecting longitudinal changes in muscle health. This study aimed to evaluate associations between plasma biomarkers and both cross-sectional and 2-year longitudinal changes in muscle mass, strength, and physical performance in older adults. METHODS: We analyzed plasma biomarkers in 93 participants (mean age: 74.3 years; 88% female) from a hospital-based longitudinal cohort. Biomarkers were quantified using ELISA, and multivariable regression analyses were conducted for sarcopenia components such as muscle mass, function, and performance, adjusting for age, sex, and body mass index (BMI). RESULTS: Leptin levels were negatively associated with both baseline and 2-year changes in appendicular lean mass indexed by ALM/height(2) and ALM/BMI after adjustments. DHEAS positively correlated with the baseline ALM/BMI, and IL-6 negatively correlated with a change in ALM/BMI. Regarding muscle function, higher baseline grip strength was associated with myostatin, DHEAS, and negatively with leptin and GDF-15. For physical performance, DHEAS and IGF-1 were positively associated with SPPB scores at the baseline, while IL-6 and GDF-15 were negatively associated with these. Notably, IL-6 was also positively associated with 2-year SPPB change. CONCLUSION: These findings highlight the potential of specific plasma biomarkers to identify individuals at risk of sarcopenia-related functional decline and to serve as practical tools for monitoring sarcopenia progression in older adults.