Inverse correlation of serum inflammatory markers with metabolic parameters in healthy, Black and White prepubertal youth

OBJECTIVE: To examine for the first time the associations between pro-inflammatory cytokines and obesity-related metabolic biomarkers in, exclusively prepubertal, otherwise healthy obese and non-obese Black and White children, 7-9 years of age. DESIGN AND METHODS: Body mass index (BMI), homeostasis model assessment-estimated insulin resistance, visceral adipose tissue and subcutaneous adipose tissue (SAT (magnetic resonance imaging)); total body fat (dual-energy X-ray absorptiometry), ectopic, intrahepatic lipid (IHL) and intramyocellular lipid (IMCL) fat (proton magnetic resonance spectroscopy) and serum levels of interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein-1 were measured in 40 obese and non-obese children. Relationships between inflammatory cytokines and obesity were assessed by analysis of variance and Spearman's rank correlation. RESULTS: Significant inverse correlations were found between BMI z-score, SAT, total BF, and IHL and levels of TNF-alpha (Spearman's rho = -0.36, -0.39, -0.43 and -0.39, respectively; P<0.05). Levels of IL-8 were significantly and inversely correlated with IMCL (-0.39; P = 0.03) and remained significant after adjusting for race. IMCL was inversely associated with TNF-alpha only after adjusting for race (-0.37; P = 0.04). CONCLUSIONS: Relationships between pro-inflammatory and metabolic markers commonly observed in adults are reversed in healthy, Black and White children before puberty. Prospective studies are warranted to determine how these inverse relationships modify chronic disease risk later in life.