Background and aims: Childhood obesity is a growing public health concern increasingly linked to gut microbiota. We analysed associations between microbiota composition, functionality, and weight status in 1134 children aged 3-6 years from the CORALS cohort.
Methods: The baseline cross-sectional study stratified participants by weight status (underweight, normal weight, overweight, obesity) and performed shotgun metagenomic sequencing of stool samples. Analyses in R assessed alpha/beta diversity, taxonomic composition, enterotypes, and microbial pathways.
Results: Alpha diversity decreased with increasing BMI, particularly in obesity (Shannon adj.P = 0.00301; Simpson adj.P = 0.00158). Beta diversity revealed distinct microbial structures across groups (p = 0.001). Four enterotypes were identified: obesity was associated with Enterotype 3 (Segatella-dominated, p = 0.023), while Enterotype 1 (Alistipes, Akkermansia, Coprococcus) was enriched in underweight/normal weight. Species linked to obesity included higher Phocaeicola dorei (adj.P = 0.003) and Segatella hominis (adj.P = 0.001), and lower Longicatena caecimuris (adj.P = 0.03) and Blautia parvula (adj.P = 0.003). Functional analyses showed downregulation of vitamin and nucleotide biosynthesis pathways and reduced carbohydrate metabolism in overweight/obesity.
Conclusions: Gut microbiota composition and functionality are strongly associated with weight status in early childhood, suggesting microbial biomarkers and metabolic pathways relevant to understand early obesity development.
Clinicaltrials: gov ID NCT06317883.
Keywords: Childhood obesity; Childhood obesity risk assessment study - CORALS; Enterotypes; Gut microbiota; Metabolic pathways.
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