Infection, rather than antibiotic use, in infancy is associated with increased risk of subsequent childhood obesity, according to a study published in The Lancet Diabetes & Endocrinology.1
Using the Kaiser Permanente Northern California (KPNC) member population, De-Kun Li, MD, PhD, senior research scientist at the Kaiser Foundation Research Institute, and colleagues, conducted a longitudinal birth cohort study comprising 260,556 individuals to determine whether it is antibiotic use in infancy or the underlying infection that is associated with the risk of childhood obesity. Using data from KPNC electronic medical records, the researchers grouped children into 3 categories according to infection diagnosis and antibiotic use in the first 12 months of life: those with either no infection nor antibiotic use (17%), those with untreated infection (30%), and antibiotic users (53%).
Using multiple sensitivity analyses, including a substudy among 547 same-sex twin sets who were discordant on exposure status, the researchers examined a large number of confounders, which included maternal factors.
After controlling for these potential confounders, the investigators observed no difference in obesity risk in antibiotic users vs those with untreated infection (odds ratio [OR] 1.01; 95% CI, 0.98-1.04). However, the group with untreated infection was found to be at increased risk for childhood obesity compared with those with no infection (OR 1.25; 95% CI, 1.20-1.29), with a “clear dose-response association between number of infection episodes and obesity risk (Ptrend <.0001).”
When examining the 3 most common types of infections (accounting for >90% of all infections) during infancy (respiratory infections, otitis media, and specific bacterial infections), the researchers noted a higher risk of childhood obesity when compared with other infections (OR 1.28; 95% CI, 1.24-1.33). Obesity risk increased slightly with antibiotic use in the first 6 months (OR 1.06; 95% CI, 1.01-1.10), but “further analysis with antibiotic use in the first 6 months did not show any dose-response relation.” There was no associated risk of obesity with antibiotic use between 6 and 12 months. Likewise, use of broad-spectrum vs narrow-spectrum antibiotics also showed no association with obesity risk.
While no information was available on the level of adherence to antibiotic intake, and the researchers were unable to determine if infections were caused by bacteria or viruses, one of key strengths of the study involved examining the effect of infection and antibiotic use separately. Similar to prior studies, Dr Li and colleagues reported that if they had simply compared antibiotic users with non-antibiotic users (including those with and without infections), there would have been a significant increase risk of childhood obesity (adjusted OR 1.20; 95% CI 1.17 – 1.22).
“Prevention of childhood obesity should focus on reducing infant infections. Not treating infant infections could lead to the increased risk of childhood obesity one intends to prevent,” said Dr Li, in an email interview with Infectious Disease Advisor.
Dr Li and colleagues concluded that these “novel findings need to be confirmed in other studies.” In a commentary, Christopher B. Forrest, MD, PhD, professor of pediatrics at the Children’s Hospital of Philadelphia in Pennsylvania, and colleagues echoed this sentiment, noting that “establishing the reproducibility of these findings is essential before the claim can be accepted that infections, rather than antibiotics, affect children’s growth.”2
- Li DK, Chen H, Ferber J, Odouli R. Infection and antibiotic use in infancy and risk of childhood obesity: a longitudinal birth cohort study. Lancet Diabetes Endocrinol. 2017;5:18-25. doi: 10.1016/S2213-8587(16)30281-9
- Forrest CB, Block JP, Bailey LC. Antibiotics, infections, and childhood obesity. Lancet Diabetes Endocrinol. 2017;5:2-3. doi: 10.1016/S2213-8587(16)30314-X