Antibiotic exposure in early life and childhood overweight and obesity: A systematic review and meta-analysis.

We conducted a systematic review and meta-analysis of observational studies investigating the association between antibiotic exposure in infancy and risk of childhood overweight and obesity. Thirteen studies, including a total of 527 504 children, were included in the systematic review and 8 were included in meta-analyses. Exposure to antibiotics in infancy was associated with an increased odds ratio (OR) of childhood overweight and obesity (OR 1.11, 95% confidence interval [CI] 1.02-1.20). Whereas exposure to 1 treatment only and exposure between 6 and 24 months were not associated with increased risk of childhood overweight and obesity, exposure to >1 treatment was associated with an OR of 1.24 (95% CI 1.09-1.43) and exposure within the first 6 months of life was associated with an OR of 1.20 (95% CI 1.04-1.37). In conclusion, antibiotic exposure in infancy was associated with a slightly increased risk of childhood overweight and obesity, mainly if children were exposed to repeated treatments or treatment within the first 6 months of life. It is unclear whether this association is mediated via direct effects of antibiotics on the gut microbiota.