Differential associations of muscle and fat body composition profiles with inflammatory cytokines in preschool children: a cross-sectional study

Body composition in early childhood is closely linked to growth, metabolic function, and immune development, yet the specific relationships between muscle‑ and fat‑related body composition indicators and inflammatory cytokine profiles in preschool children remain inadequately characterized. In this cross‑sectional study, 171 preschool children aged 4 ~ 6 years in Guangzhou, China, were recruited by multistage cluster random sampling. Body composition parameters were assessed using a multifrequency bioelectrical impedance analyzer. Plasma levels of IL‑2, IL‑4, IL‑6, IL‑10, TNF‑α, and IFN‑γ were measured by flow cytometry. Sex differences in body composition were examined, and the associations between body composition indices and cytokine concentrations were analyzed using Spearman correlation and principal component analysis (PCA). Among the 171 children (57.9% boys), 15 of 24 body composition indicators were significantly higher in boys than in girls (P < 0.05). When cytokine levels were compared across BMI categories, no significant differences were observed for any of the six cytokines (all P > 0.05). Spearman analysis showed that 12 body composition indices were inversely correlated with IL‑10 (r = - 0.177 to - 0.235, all P < 0.05). PCA identified four composite factors with distinct cytokine associations: the basic body composition factor was inversely associated with IL-10 (r = - 0.167, P < 0.05), the body fat proportion factor was positively associated with IL-10 (r = 0.151, P < 0.05), the muscle mass factor was positively correlated with IL-6 (r = 0.165, P < 0.05), and the central obesity factor was positively correlated with IL-4 (r = 0.206, P < 0.05). In preschool children, distinct muscle‑ and fat‑related body composition profiles are differentially associated with circulating IL‑10, IL‑6, and IL‑4 levels, independent of BMI categories. These findings indicate correlations between early-life muscle and fat body composition profiles and low-grade inflammatory markers, providing potential evidence for the early prevention of metabolic disorders related to obesity.