Background and aims: We aimed to describe and characterize the gut microbiota composition and diversity in children with obesity according to their metabolic health status.
Methods: Anthropometry, Triglycerides, HDL cholesterol, HOMA-IR, and systolic and diastolic blood pressure (SBP, DBP) were evaluated (and z-score calculated) and faecal samples were collected from 191 children with obesity aged from 8 to 14. All children were classified depending on their cardiometabolic status in either a "metabolically healthy" (MHO; n = 106) or "metabolically unhealthy" (MUO; n = 85) group. Differences in gut microbiota taxonomies and diversity between groups (MUO vs MHO) were analysed. Alpha diversity index was calculated as Chao1 and Simpson's index, and β-diversity was calculated as Adonis Bray-Curtis index. Spearman's correlations and logistic regressions were performed to study the association between cardiometabolic health and the microbiota.
Results: Children in the MUO presented significantly lower alpha diversity and richness than those in the MHO group (Chao1 index p = 0.021, Simpson's index p = 0.045, respectively), whereas microbiota β-diversity did not differ by the cardiometabolic health status (Adonis Bray-Curtis, R2 = 0.006; p = 0.155). The MUO group was characterized by lower relative abundances of the genera Christensenellaceae R7 group (MHO:1.42% [0.21-2.94]; MUO:0.47% [0.02-1.60], p < 0.004), and Akkermansia (MHO:0.26% [0.01-2.19]; MUO:0.01% [0.00-0.36], p < 0.001) and higher relative abundances of Bacteroides (MHO:10.6% [4.64-18.5]; MUO:17.0% [7.18-27.4], p = 0.012) genus. After the adjustment by sex, age, and BMI, higher Akkermansia (OR: 0.86, CI: 0.75-0.97; p = 0.033), Christensenellaceae R7 group (OR: 0.86, 95% CI: 075-0.98; p = 0.031) and Chao1 index (OR: 0.86, CI: 0.96-1.00; p = 0.023) represented a lower risk of the presence of one or more altered cardiovascular risk factors.
Conclusion: Lower proportions of Christensenellaceae and Akkermansia and lower diversity and richness seem to be indicators of a metabolic unhealthy status in children with obesity.
Keywords: Childhood obesity; Metabolically unhealthy obesity; Microbiota.
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