A new study published in the International Journal of Obesity links antibiotic use to childhood body mass index trajectory. The study was comprised of children aged 3-18 and the researchers used mixed effects linear regression to model associations of antibiotic orders with growth curve trajectories of annual body mass index (BMI) controlling for confounders. They were looking for three types of antibiotic associations including reversible, persistent, and progressive. They also looked to see whether these varied by age.

The results showed that of the 142,824 children a reversible association was observed and this short-term BMI gain was modified by age; effect size peaked in mid-teen years. The association became stronger with age. Among children with an antibiotic order in the prior year and, at least, seven lifetime orders, antibiotics were associated with an average weight gain of approximately 1.4 kg at age 15 years. When antibiotic classes were evaluated separately, the largest weight gain at 15 years was associated with macrolide use.

The researchers found evidence of reversible, persistent and progressive effects of antibiotic use on BMI trajectories, with different effects by age, among mainly healthy children. The results suggest that antibiotic use may influence weight gain throughout childhood and not just during the earliest years as has been the primary focus of most prior studies.

For more information read the full study.

http://www.nature.com/ijo/journal/vaop/ncurrent/full/ijo2015218a.html