Relationship between degree of central adiposity, inflammatory status and risk of sarcopenia in obese children

Childhood obesity is a most prevalent condition worldwide. The accumulation of adipose leads to its infiltration into various organs, including skeletal muscle, which called sarcopenia. Children with sarcopenic-obesity are at an increased risk of developing cardiovascular or metabolic diseases. This study aims to investigate the association between central adipose accumulation and the degree of chronic inflammation on muscle performance in obese children, a topic that has not been studied in Indonesia.

This study employed a crosssectional design with consecutive sampling involving obese primary school children aged 7-13 years from Semarang and its surrounding areas who met the inclusion and exclusion criteria. Data collection included anthropometric measurements (waist and hip circumferences, waist-to-hip ratio, muscle mass assessed by bioelectrical impedance analysis/BIA), handgrip strength, three-day dietary recall, and blood biomarkers (CRP and IL-6). Muscle mass was classified as low when skeletal muscle mass adjusted for age and sex (SMMa z-score) was less than -2 SD. Reduced muscle strength was defined as handgrip strength below the 15th percentile (age/sex-specific). Central adiposity was defined as waist-to-height ratio (WHtR) ≥ 0.50 or waist-to-hip ratio (WHR) above the 90th percentile for age and sex. Elevated inflammatory markers were defined as CRP ≥ 3 mg/L and IL-6 > 5 pg/mL. Associations between variables were analyzed using chi-square or Fisher's exact tests, and logistic regression models were applied with a significance level set at α=0.05.

Of the 86 children, 84.8% had low muscle mass, 38.4% had reduced muscle strength, and 69.8% demonstrated impaired physical performance. High waistto- height ratio (WHtR) was significantly associated with low muscle mass (p = 0.016) and reduced muscle strength (p = 0.007). High C-reactive protein (CRP) levels were also associated with low muscle mass (p = 0.013). In addition, protein intake was significantly related to muscle mass (p = 0.016). In logistic regression analysis, WHtR was an independent predictor of both reduced strength (OR = 5.324, p = 0.021, 95% CI: 1.280-22.148) and low muscle mass (OR = 0.163, p = 0.011, 95% CI: 0.037-0.714). Although interleukin- 6 (IL-6) was elevated in the majority of children, it did not show a significant association with sarcopenia outcomes.

Central adiposity, particularly as measured by WHtR, is a key predictor of sarcopenia in obese children, with significant associations observed with reduced muscle mass and strength. Elevated CRP levels further underscore the role of systemic inflammation in sarcopenia. These findings highlight the need for early identification and targeted interventions to mitigate the adverse effects of sarcopenic obesity in children.