Infections during infancy — not antibiotic use — may lead to childhood obesity, a new study reports.
The study, published Nov. 1 in the peer-reviewed journal The Lancet Diabetes & Endocrinology, examined more than 260,000 infants over 16 years.
Children diagnosed with an infection during their first year of life who did not take antibiotics were about a quarter more likely to become obese, compared to those who didn’t have an infection. Those who had more untreated infections were at higher risk of obesity, the researchers from Kaiser Permanente found.
Meanwhile, children who took antibiotics during their first year didn’t have an increased risk of obesity.
Previous studies have associated infant use of antibiotics with later weight gain.
“However, we separated the two factors and found that antibiotics do not, themselves, appear to be associated with childhood obesity,” said De-Kun Li, the lead researcher and a reproductive and perinatal epidemiologist at the Kaiser Permanente Division of Research in Oakland.
More than a third of U.S. children are overweight or obese, according to the Centers for Disease Control and Prevention.
Researchers theorize that part of the increase in obesity could be due to changes in the gut bacteria. Infections and antibiotic use can influence the composition of intestinal microorganisms, which could in turn affect metabolism.
The study used data from births that occurred between January 1, 1997, and March 31, 2013, at Kaiser Permanente facilities in Northern California. Researchers used electronic health records to find data on infections and antibiotic use in infancy, and to capture heights and weights measured in these children for up to 18 years. All infant infections were included, with respiratory and ear infections being most common.
The scientists recommend that doctors try to reduce infections in infancy and carefully prescribe antibiotics.