The association between prenatal and early-life antibiotic use and obesity at 4-5 years in the Born in Bradford birth cohort.

BACKGROUND

The prevalence of childhood obesity has quadrupled globally over the last 30 years highlighting the urgency for robust research on modifiable risk factors. This study investigates the association between prenatal and early-life (0-24 months) antibiotic use and obesity at 4-5 years within the Born in Bradford (BiB) cohort, and whether this differs by ethnicity or by sex.

METHODS

BiB is a large, multi-ethnic birth cohort of 13 858 children in Bradford, UK. Data for children and their mothers were obtained from a baseline questionnaire, linked electronic health records (including maternity records and general practitioner prescriptions), and anthropometric measurements at school. Logistic regression models were employed to estimate the associations between antibiotic exposure in pregnancy and early-life and the outcome, having obesity at age 4-5 years, adjusting for several confounders.

RESULTS

In this population, nearly a tenth of children had obesity, just over a third were exposed to antibiotics in pregnancy, and nearly three quarters were exposed in the first two years of life. The adjusted analysis revealed no clear evidence of an association between prenatal antibiotic use and having obesity at 4-5 years (aOR 1.09; 95% CI 0.94, 1.27; p = 0.247). There was strong evidence of an association between early-life antibiotic use and having childhood obesity (aOR 1.36; 95% CI 1.14, 1.62; p = 0.001), and increasing numbers of prescriptions were associated with higher odds of obesity (aOR 1.058; 95% CI 1.030, 1.088; ptrend = 0.0001). No effect modification by ethnicity or sex was observed.

CONCLUSION

These findings support those found in previous experimental animal and epidemiological studies, highlighting the importance of further investigation into early-life antibiotic exposure, infection burden, and later obesity risk.