Urinary metabolomic profiling reveals distinct metabolic characteristics in children with overweight and obesity

Childhood obesity is a critical global public health problem. Untargeted metabolomics can identify metabolic alterations associated with childhood obesity, but pediatric evidence remains limited. This study characterized urinary metabolic profiles associated with overweight and obesity in children.

A total of 120 first-grade primary school children were selected. The population comprised 40 children with normal weight, 40 children with overweight, and 40 children with obesity, with equal sex distribution in each group. Urinary metabolic profiles were analyzed using liquid chromatography-mass spectrometry-based untargeted metabolomics, followed by multivariate analysis, differential feature analysis, pathway enrichment analysis, and ROC analysis.

Compared with children with normal weight, children with overweight showed 69 differential metabolic features (40 upregulated and 29 downregulated), whereas children with obesity showed 193 (161 upregulated and 32 downregulated). Three of 37 and 15 of 83 pathways, respectively, met the exploratory criteria of raw P < 0.05 and pathway impact > 0.01. After FDR correction, two and four pathways remained statistically significant, respectively. Phenylalanine metabolism (FDR=0.015 and 0.001, respectively) and phenylalanine, tyrosine and tryptophan biosynthesis (FDR=0.036 and 0.012, respectively) were significant in both comparisons with the normal-weight group. Thirteen metabolic features showed discriminatory potential between children with obesity and children with normal weight, with N-acetyl-D-glucosamine showing an AUC of 0.889 (95% CI: 0.821-0.958).

This study characterized urinary metabolic alterations and enriched pathways associated with overweight and obesity in children compared with normal weight. Several candidate metabolic features showed exploratory discriminatory potential but require targeted confirmation and independent validation.