Early-life antibiotic exposure has been proposed as a potential contributor to childhood type 1 diabetes mellitus (T1DM), possibly through alterations in gut microbiota and immune development. A meta-analysis published in Diabetes, Obesity and Metabolism evaluated the association between antibiotic exposure during prenatal and postnatal periods and the risk of childhood T1DM.

The analysis included studies identified through systematic searches of PubMed, MEDLINE, Scopus, and Web of Science up to June 2025. A total of 20 studies were included, comprising 11 cohort and nine case-control studies. These studies involved more than 1.5 million participants for prenatal exposure and over 4 million for postnatal exposure. Pooled effect sizes were calculated using random-effects models, with subgroup analyses based on antibiotic courses, class, and spectrum. Study quality was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS).

Prenatal antibiotic exposure showed no significant association with T1DM, with a pooled effect size of 1.05 (95% CI 0.98-1.11). For postnatal exposure, the pooled effect size was 1.07 (95% CI 1.01-1.14). Risk estimates increased with repeated antibiotic courses, reaching 1.11 (95% CI 1.02-1.20) for at least two courses and 1.14 (95% CI 1.00-1.30) for five or more courses.

Associations were stronger for broad-spectrum antibiotics (1.13, 95% CI 1.03-1.23) than for narrow-spectrum antibiotics (1.08, 95% CI 0.93-1.26), while no significant associations were observed across antibiotic classes. Evidence regarding the influence of obstetric delivery mode remained inconclusive. Although the observed associations were modest, the findings highlight the need for careful antibiotic use in early life and underscore the importance of further prospective studies to clarify potential causal relationships.