Association between muscle-specific strength and inflammatory biomarkers in community-dwelling older women: a cross-sectional study

The Global Leadership Initiative on Sarcopenia (GLIS) has released recommendations on the use of muscle-specific strength (MSS) in the assessment of sarcopenia. MSS is considered the measurement of force per unit of muscle mass and has been recommended for comprehensive assessment of muscle tissue and assessment of sarcopenia in the older. While biomarkers have been associated with sarcopenia's pathophysiology and its diagnostic, the association between inflammatory markers and MSS in older people remains understudied. Therefore, this study aimed to evaluate the association between MSS and the concentrations of a panel of inflammatory biomarkers in community-dwelling older women. Seventy-one older women participated in this study, with Dual X-ray Absorptiometry used to assess lean muscle mass and the Jamar dynamometer employed to measure handgrip strength. The concentrations of IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, adiponectin, leptin, resistin, IFN, TNF, sTNFr-1, and sTNFr-2 were measured using flow cytometry and ELISA. Spearman correlation and linear regression analyses were conducted to evaluate the relationships between the variables, with a significance level set at 5%. The analyses revealed significant correlations between muscle-specific strength and the concentrations of IL-5 (ρ = -0.408), IL-6 (ρ = -0.258), IL-8 (ρ = -0.309) and sTNFr-2 (ρ = -0.390) in this sample. The association analysis showed the optimal model explaining variations in muscle-specific strength included IL-5 and sTNFr-2 (R: 0.47; R² 0.20; p = 0.02). These findings suggest a pro-inflammatory component contributing to the loss of muscle-specific strength in community-dwelling older women. Furthermore, they provide insights into the pathophysiology of sarcopenia and identify promising biomarkers that may be useful in screening strategies and early diagnosis of this condition in older adults.