In a study shedding new light on the link between early-life behavior and childhood obesity, researchers have cast aside prevailing wisdom that antibiotic use in a child’s first year of life is predictive of later obesity.
Instead, they point to a related area – untreated infections – as a predominant link between behaviors in infancy and childhood obesity.
“Infection without antibiotic use in infancy was associated with an increased risk of childhood obesity compared with controls without infection,” write the study authors, led by De-Kun Li, Ph.D., a reproductive and perinatal epidemiologist with Kaiser Permanente, in The Lancet Diabetes & Endocrinology.
The research team analyzed the health data of more than 260,000 individuals born between 1997 and 2013, and they controlled for various factors, including the mother’s age during pregnancy, race, preterm delivery and birthweight and others.
Sifting through the data, they discovered a common thread – namely, that “infection, but not antibiotic use, during infancy is associated with risk of childhood obesity.”
The researchers found that children diagnosed with an infection during the first year of life who did not receive antibiotics were 25 percent more likely to become obese during their childhood years. What’s more, the researchers noted a cumulative effect – that is, the risk of obesity increased with more untreated infections.
More than one-third of children are overweight or obese, point out the researchers. They add that “energy imbalance (calories consumed versus energy expenditures) cannot account for the entire increase in obesity in childhood.”
That suggests alternatives are at play, “including chemicals in the environment, maternal gestational diabetes, and the metabolic programming of body weight during early childhood.”
Research shows that both infections and antibiotic use can influence microorganisms in the gut, which in turn can “affect metabolic processes, growth patterns and weight development.”
“Our study is one of the largest analyses of the interplay among infections, antibiotic use and childhood obesity, and adds important evidence to a small but growing body of research on how the microbiome, or gut bacteria, may be affecting children’s development,” explained Li.
Overturning previous evidence
“In previous studies, antibiotics used to treat infant infections have been associated with weight gain. However, we separated the two factors and found that antibiotics do not, themselves, appear to be associated with childhood obesity,” said Li.
In their research, Li and his team explored the impact of different antibiotic types to see if they would find a difference in health outcomes based on the type of drug involved. Specifically, they targeted two types of antibiotics, but their in-depth look also turned up empty. “Neither broad-spectrum nor narrow-spectrum antibiotics were associated with risk of childhood obesity,” they report.
However, other researchers urged caution. In a related editorial, a group of scientists notes that past medical literature has established a strong link between antibiotic use and weight, especially in animals. “Burgeoning empirical evidence suggests that antibiotics also affect human growth,” they write in the editorial.
These researchers urge additional study on the topic – something that Li and his team agree with. “This finding will need to be replicated in future studies,” write the Kaiser researchers.
Ultimately, Li and his team agree with the latest guidance on antibiotic use. “The use of antibiotics should always be judicious,” they add.