Gut Microbiome-Metabolome Interactions and Their Influence on Obesity-Associated Insulin Resistance in Adults in Lagos State

The gut microbiome modulates host metabolic phenotype through the production of metabolites including short-chain fatty acids, secondary bile acids, and trimethylamine N-oxide, which influence insulin signalling pathways and adipose tissue inflammation. This study investigates gut microbiome composition and its metabolomic correlates in obese adults with and without insulin resistance in Lagos State, South West Nigeria. A cross-sectional design was employed, recruiting 100 obese insulin-resistant adults (HOMA-IR greater than 2.5), 100 obese insulin-sensitive adults, and 80 lean normoglycaemic controls. Gut microbiome profiling was performed by 16S rRNA amplicon sequencing of faecal samples. Plasma and faecal metabolomes were characterised by untargeted UPLC-MS/MS. Short-chain fatty acid concentrations were quantified by gas chromatography-flame ionisation detection. Multi-omics data integration using sparse partial least squares canonical correlation analysis identified microbiome-metabolome interactions most strongly associated with insulin resistance status. Dietary glycaemic index, fibre intake, and physical activity were included as covariates. This research constitutes the first gut microbiome-metabolomics investigation in obese Nigerian adults and will develop an original theoretical framework linking gut dysbiosis to insulin resistance in a West African population. Keywords: gut microbiome, metabolomics, insulin resistance, short-chain fatty acids, Lagos State.