Comparison of Skeletal Muscle Index and Relative Handgrip Strength, and Analysis of the Mediating Effect of Chronic Inflammation in Older Women with Abdominal Obesity

Abstract

Objectives: Older women experience a rapid increase in abdominal obesity post-menopause, leading to sarcopenic obesity accompanied by muscle weakness, which poses a significant threat to their health. Accordingly, this study aimed to investigate the effects of abdominal obesity on muscle mass and function in older women and to verify the mediating effect of chronic inflammation, providing foundational data for tailored health management strategies.Methods: Data from the 9th Korea National Health and Nutrition Examination Survey (KNHANES, 2022-2024) were utilized. A total of 1,990 older women aged 65 and older were included after excluding cases with missing values. Complex sample multiple linear regression and mediation analyses were performed. The independent variable was abdominal obesity (waist circumference), the dependent variables were skeletal muscle index (SMI) and relative handgrip strength, and the mediator was high-sensitivity C-reactive protein (Ln_CRP). Age and nutritional intake were controlled as covariates.Results: The results showed that while the abdominally obese group had a significantly higher SMI compared to the normal group, their relative handgrip strength was substantially lower. Furthermore, abdominal obesity was significantly associated with higher chronic inflammation levels, and a statistically significant partial mediation pattern through Ln_CRP was observed for relative handgrip strength. These findings suggest that chronic inflammation may partly account for the association between abdominal obesity and lower muscle function in older women, despite higher absolute muscle mass.Conclusions: These findings may provide a basis for considering integrated health-management strategies addressing systemic inflammation and nutritional status, in addition to weight management.