Administration of three or more courses of antibiotics before a child reaches the age of two is linked to increased risk of early childhood obesity, says a new study.
"Antibiotics have been used to promote weight gain in livestock for several decades and our research confirms that antibiotics have the same effect in humans," said Frank Irving Scott from University of Pennsylvania, Philadelphia.
"Our results do not imply that antibiotics should not be used when necessary, but rather encourage both physicians and parents to think twice about antibiotic usage in infants in the absence of well-established indications," Scott added in the paper published in the journal Gastroenterology.
The researchers performed a large population-representative cohort study in the Britain to assess the association between antibiotic exposure before age 2 and obesity at the age of 4 years.
The findings showed that children with antibiotic exposure had a 1.2 per cent absolute and 25 per cent relative increase in the risk of early childhood obesity.
Risk was strongest when considering repeat exposures to antibiotics, particularly with three or more courses.
"Our work supports the theory that antibiotics may progressively alter the composition and function of the gut microbiome, thereby predisposing children to obesity as is seen in livestock and animal models," Scott explained.
Antibiotics are prescribed during an estimated 49 million pediatric outpatient visits per year in the US.
A large portion of these prescriptions (more than 10 million annually) are written for children without clear indication, despite increased awareness of the societal risks of antibiotic resistance, as well as other tangible risks, including dermatologic, allergic and infectious complications; inflammatory bowel disease; and autoimmune conditions.
Further research is required to assess whether these findings remain into adolescence and young adulthood, as well as to determine if early antibiotic usage leads to later-onset obesity.