Miller · Obesity reviews : an official journal of the International Association for the Study of Obesity 2018 · systematic review and meta-analysis · n=15 studies (17 articles)

The association between antibiotic use in infancy and childhood overweight or obesity: a systematic review and meta-analysis.

Cited 97 times in the scientific literature.

Level 3 - non-randomized controlled study

Systematic review and meta-analysis of observational studies

PubMed 30035851 · doi:10.1111/obr.12717 · record verified 2026-08-29

What was done

The authors searched CINAHL, Cochrane CENTRAL, Embase, and MEDLINE for studies examining the association between infant antibiotic exposure (<24 months of age) and subsequent childhood weight change, overweight, or obesity. Eligible studies comparing exposed to unexposed infants were synthesized narratively, and meta-analysis was performed where possible (specifically on datasets comparing the earliest age of exposure to any antibiotic with overweight or obesity at the latest outcome age).

What was found

From 17 articles representing 15 unique studies, meta-analysis of 12 sets of results found that infant antibiotic exposure was associated with a small increase in the odds of childhood overweight or obesity (pooled odds ratio 1.05, 95% CI 1.00-1.11). The strongest associations were reported in boys versus girls and in children exposed to multiple antibiotic courses or broad-spectrum agents.

Why it matters

This review quantifies the clinical evidence linking early-life antibiotic exposure to later childhood weight gain, demonstrating a statistically marginal overall association.

Limits

The review synthesized observational studies, leaving risk of residual confounding by indication, maternal BMI, socioeconomic status, or diet. The effect estimate is very small with the lower confidence interval bound touching 1.00. The abstract does not provide total participant numbers, specific numerical effect sizes for subgroups, or measures of between-study heterogeneity.

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