- Although pediatric obesity and antibiotics exposure were associated in 1 study, when analyses were controlled for siblings and twins in a separate study the association vanished.
Why this matters
- Accompanying editorial: sibling/twin findings suggest confounding factors common among family members might explain the pediatric obesity-antibiotics association.
- In the first study, BMI z-scores increased significantly with increased dispensing of antibiotics to children.
- Children who received 9+ dispensings by age 4 years had increased odds for obesity vs those receiving no antibiotics: aOR, 2.41 (95% CI, 1.07-5.41).
- In the second study, each additional course of antibiotics prescribed to pregnant women was linked to increased odds for obesity in the child at age 4 years: aOR per added course, 1.02 (95% CI, 0.99-1.06).
- For each exposure for the child, obesity odds increased, but in fixed-effects analyses of siblings, including twins, the association disappeared:
- Maternal exposure: 0.95 (95% CI, 0.90-1.00).
- Singleton child exposure: 1.02 (95% CI, 0.99-1.04).
- Twin exposure: 0.91 (95% CI, 0.81-1.02).
- First study: prospective cohort, 5734 children whose weight and height were measured at age 54 months and tracked with dispensary data.
- Second study: cross-sectional, with initial 132,852 mothers and 151,359 children.
- Funding: New Zealand government.
- First study: no data on maternal BMI, gestational weight gain.
- Second study: retrospective, nonrandomized, antibiotic indication and adherence unknown.