Childhood BMI in relation to microbiota in infancy and lifetime antibiotic use.

Background Children with high body mass index (BMI) at preschool age are at risk of developing obesity. Early identification of factors that increase the risk of excessive weight gain could help direct preventive actions. The intestinal microbiota and antibiotic use have been identified as potential modulators of early metabolic programming and weight development. To test if the early microbiota composition is associated with later BMI, and if antibiotic use modifies this association, we analysed the faecal microbiota composition at 3 months and the BMI at 5–6 years in two cohorts of healthy children born vaginally at term in the Netherlands (N = 87) and Finland (N = 75). We obtained lifetime antibiotic use records and measured weight and height of all children.