Early-life and concurrent predictors of the healthy adolescent microbiome in a cohort study

The microbiome of adolescents is poorly understood, as are factors influencing its composition. We aimed to describe the healthy adolescent microbiome and identify early-life and concurrent predictors of its composition.

We performed metagenomic sequencing of 247 fecal specimens from 167 adolescents aged 11-14 years participating in the Health Outcomes and Measures of the Environment (HOME) Study, a longitudinal pregnancy and birth cohort (Cincinnati, OH). We described common features of the adolescent gut microbiome and applied self-organizing maps (SOMs)-a machine-learning approach-to identify distinct microbial profiles (n = 4). Using prospectively collected data on sociodemographic characteristics, lifestyle, diet, and sexual maturation, we identified early-life and concurrent factors associated with microbial diversity and phylum relative abundance with linear regression models and composition with Kruskal-Wallis and Fisher's exact tests.

We found that household income and other sociodemographic factors were consistent predictors of the microbiome, with higher income associated with lower diversity and differential relative abundances of Firmicutes (increased) and Actinobacteria (decreased). Sexual maturation, distinct from chronological age, was related to higher diversity in females and differences in phylum relative abundances and compositional profiles in both males and females.

Our study suggests that adolescence is a unique window for gut microbial composition and that it may be shaped by both early-life and concurrent exposures, highlighting its potential in future epidemiologic research.