Antibiotic use at <24 months of age was associated with a slightly higher body weight at age 5 years, a recent study found. Participant inclusion required same-day height and weight measurements at 1 to <12, 12 to <30, and 48 to <72 months of age. Researchers assessed the association between any antibiotic use at <24 months of age with BMI z score and overweight or obesity prevalence at 48 to <72 months (5 years) of age. They found:

• Among 1,792,849 children with a same-day height and weight measurement at <12 months of age, 362,550 were eligible for the cohort (52% boys, 27% African American, 18% Hispanic, and 58% received ≥1 antibiotic prescription at <24 months of age).
• At 5 years, the mean BMI z score was 0.40 (SD 1.19), and 28% of children had overweight or obesity.
• In adjusted models for children without a complex chronic condition at 5 years, there was an estimated higher mean BMI z score by 0.04 and higher odds of overweight and obesity (OR, 1.05) associated with obtaining any antibiotics at <24 months.