Objective:
To investigate whether delivery mode (vaginal versus by caesarean section), maternal pre-pregnancy body mass index (BMI) and early exposure to antibiotics (<6 months of age) influence child's risk of overweight at age 7 years, hence supporting the hypotheses that environmental factors influencing the establishment and diversity of the gut microbiota are associated with later risk of overweight.
Design:
Longitudinal, prospective study with measure of exposures in infancy and follow-up at age 7 years.
Methods:
A total of 28¿354 mother–child dyads from the Danish National Birth Cohort, with information on maternal pre-pregnancy BMI, delivery mode and antibiotic administration in infancy, were assessed. Logistic regression analyses were performed with childhood height and weight at the 7-year follow-up as outcome measures.
Results:
Delivery mode was not significantly associated with childhood overweight (odds ratio (OR):1.18, 95% confidence interval (CI): 0.95–1.47). Antibiotics during the first 6 months of life led to increased risk of overweight among children of normal weight mothers (OR: 1.54, 95% CI: 1.09–2.17) and a decreased risk of overweight among children of overweight mothers (OR: 0.54, 95% CI: 0.30–0.98). The same tendency was observed among children of obese mothers (OR: 0.85, 95% CI: 0.41–1.76).
Conclusion:
The present cohort study revealed that a combination of early exposures, including delivery mode, maternal pre-pregnancy BMI and antibiotics in infancy, influences the risk of overweight in later childhood. This effect may potentially be explained by an impact on establishment and diversity of the microbiota.