Association between systemic immune-inflammation index and sarcopenic obesity in middle-aged and elderly Chinese adults: a cross-sectional study and mediation analysis

Abstract

Abstract Background Despite the known association between chronic inflammation and reduced muscle mass, there is a gap in research regarding the association between the systemic immune-inflammation index (SII) and sarcopenic obesity (SO). This study aims to assess the relationship between SII and SO in middle-aged and elderly adults and the mediating role of triglyceride-glucose index (TyG). Methods This cross-sectional study involved 2,719 participants aged 45–90 years who underwent health check-ups. SO was evaluated by combining sarcopenia [assessed by handgrip strength and appendicular skeletal muscle index (ASMI)] with obesity (determined by body fat percentage). Association between SII and SO, sarcopenia, and obesity in middle-aged and elderly individuals was examined using multivariable logistic regression, restricted cubic spline analysis, and subgroup analysis. Bidirectional mediation analysis was conducted to determine the direct and indirect effects through SII and TyG. Results The study included 2,719 participants, of which 228 had SO (8.4%). SO prevalence increased as the SII quartiles rose (P for trend 0.05). Conclusions Elevated levels of SII were associated with an increased risk of SO in middle-aged and elderly adults, especially in the elderly population, and elevated TyG levels played a role in this relationship.

Keywords

• Systemic immune-inflammation index
• Sarcopenic obesity
• Sarcopenia
• Obesity
• Mediation analysis