Determinants of gut microbiota in 7-year old children from INMA birth cohort: a pilot study

Abstract

Introduction: Gut microbiota plays an important role in humans. Its composition changes from birth to adulthood. Type of delivery, antibiotics use, diet, obesity, and host genetics, among others have been associated with gut bacterial composition. However, associations are not conclusive and not many studies have evaluated these factors in childhood. Objective: To evaluate the association of several factors with gut microbiota composition in 7-year children from the INfancia y Medio Ambiente (INMA) project. Methods: 154 stool samples were collected at the age of 7-years and gut composition assessed with the 16S rDNA method. The association between 14 factors and alpha and beta diversity was evaluated. We also performed a differential analysis for each taxon in respect to each factor. Multiple testing was controlled with the False Discovery Method (FDR). Results: Gut microbiota was heterogeneous among children, being Bacteroidetes and Firmicutes the more prevalent phyla. Higher number of siblings, consistent with lower maternal education, was robustly associated with higher alpha diversity. Mode of delivery was associated with overall gut diversity (Bray-Curtis dissimilarity). Overweight/obese had higher evenness and higher levels of Firmicutes. Fucosyltransferase 2 (FUT2) non-secretor children (rs601338 sese genotype) had higher evenness and higher levels of Rhodospirillales, Lachnospiraceae and Roseburia. Conclusions: As in adults, gut microbiota in 7-year children was heterogeneous and dominated by Bacteroidetes and Firmicutes. Determinants explained a small proportion of the gut bacterial composition.