Broad-Spectrum Antibiotics May Boost Childhood Obesity Risk

Broad-Spectrum Antibiotics May Boost Childhood Obesity Risk
Broad-Spectrum Antibiotics May Boost Childhood Obesity Risk
Childhood obesity may be related to broad-spectrum antibiotic use before age 2 years.

Repeated use of broad-spectrum antibiotics in children aged younger than 2 years may increase their risk for obesity during early childhood, new data published in JAMA Pediatrics suggest.

Of 64,580 children included in a study conducted by L. Charles Bailey, MD, PhD, of the Children’s Hospital of Philadelphia, and colleagues, 69% were exposed to antibiotics by age 24 months. Sixty-two percent were treated at least once with a narrow-spectrum antibiotic and 41% with a broad-spectrum antibiotic.

The average number of treatment episodes was 2.3 per child, according to the data.

When examining all antibiotics or broad-spectrum antibiotics only, the researchers found that the more exposure that a child had to antibiotics, the greater the risk was for obesity. Risk appeared highest for children who were treated at least 4 times (rate ratio [RR]=1.11; 95% CI, 1.02-1.21), they noted.

For broad-spectrum antibiotics, the relationship between treatment exposure and obesity risk was even stronger (RR=1.16; 95% CI, 1.06-1.29).

Results also revealed a connection between early exposure to broad-spectrum antibiotics and obesity at different ages. RRs were 1.11 (95% CI, 1.03-1.19) for ages 0 to 5 months and 1.09 (95% CI, 1.04-1.14) for ages 6 to 11 months, according to the researchers.

Narrow-spectrum antibiotics, however, were not associated with obesity, regardless of frequency or age.

The researchers’ analyses also highlighted other factors linked to childhood obesity, including steroid use, male sex, urban practice, public insurance, Hispanic ethnicity and diagnosed asthma or wheezing, but common infections and antireflux medications were not.

For their study, the researchers assessed electronic health records of children seen from 2001 to 2013 at a network of primary care clinics. Children had annual visits from ages 0 to 23 months and at least one visit at ages 24 to 59 months.

In the study cohort, prevalence of obesity was 10% at age 2 years, 14% at age 3 years and 15% at age 4 years, while prevalence of overweight/obesity was 23%, 30% and 33%, respectively.

“Because obesity is a multifactorial condition, reducing prevalence depends on identifying and managing multiple risk factors whose individual effects may be small but modifiable. Our results suggest that the use of broad-spectrum outpatient antibiotics before age 24 months may be one such factor,” the researchers wrote.

They also concluded that their findings indicate a need for treatment guidelines that may suggest limiting use of antibiotics or selecting narrow-spectrum antibiotics for common pediatric conditions in certain cases.


  1. Bailey LC, Forrest CB, Zhang P, Richards TM, Livshits A, DeRusso PA. Association of Antibiotics in Infancy With Early Childhood Obesity. JAMA Pediatr. 2014;168(11):1063-1069. doi:10.1001/jamapediatrics.2014.1539.