Healthy Living

Study Weighs Link Between Antibiotics and Obesity in Kids

Oct. 10, 2014

Health care providers have long warned about the consequences of over-prescribing antibiotics, and now, there’s another reason to be cautious.

mother getting medicine ready to give to toddlerA recent study in JAMA Pediatrics links broad-spectrum antibiotic use in children younger than 2 years old with risk for obesity. A broad-spectrum antibiotic is one that is effective against a wide range of bacteria.

The study’s findings are strong and should be taken seriously, according to UR Medicine childhood obesity expert Dr. Stephen Cook. Researchers controlled for a variety of factors such as ethnicity and measures of poverty, and increased antibiotic use still carried an association.

Analyzing records of 64,580 children over five years, researchers found that obesity risk was higher for children with several exposures to antibiotics. Though the study doesn’t offer a clinical explanation for the increase, previous studies in animals have shown that broad-spectrum antibiotics can alter the gut microbiome—the array of gut bacteria within the intestinal tract. Subsequently, the stomach ingests nutrients somewhat differently.

This suggests that for some, obesity is not a matter of personal choice.

It’s not a 1-year-old child’s decision to take antibiotics. So potentially, this is similar to an environmental factor completely out of the child’s control.

There are many factors that play a role in childhood obesity. Antibiotic use is potentially only a tiny piece of a very large puzzle.

But when possible, doctors and parents should try to limit broad-spectrum antibiotics to conditions where their use is clearly demonstrated to be the most effective treatment. In cases where broad-spectrum drugs aren’t proven to be the best option, alternatives should be considered. Narrow-spectrum antibiotics, for example, were not associated with obesity.


Stephen Cook, MD


Stephen Cook, M.D., M.P.H., is an associate professor of Pediatrics at the University of Rochester Medical Center and the Center for Community Health.  He sees patients as part of the general pediatric practice at UR Medicine’s Golisano Children’s Hospital.