Microbiome of the first stool and overweight at age 3 years: A prospective cohort study

Summary Background Several reports have revealed that the first‐pass meconium hosts a diverse microbiome, but its clinical significance is not known. Objective We designed a prospective population‐based cohort study to evaluate whether the meconium microbiome predicts subsequent growth in children. Methods The study comprised 212 consecutive newborns with a meconium sample and a follow‐up sample at 1 year of age. Trained nurses measured the children for weight and length using standardized techniques. We used next‐generation sequencing of bacterial 16S rRNA gene and machine‐learning approach for the analysis. Results The children with overweight at 3 years of age differed in their meconium microbiome from those with normal weight, having a higher proportion of Bacteroidetes phylum (29% vs 15%, P = .013). Using the machine‐learning approach, the gut microbiome at birth predicted subsequent overweight with area under the curve 0.70 (SD 0.04). A lower proportion of Staphylococcus at birth was associated with greater length/height at 1 year (ß = −.68, P = .029) and 2 years of age (β = −.74, P = .030). Conclusions The microbiome of the first‐pass meconium predicted subsequent overweight at the age of 3 years. The association between the gut microbiome and overweight appears to start already during pregnancy and at birth.