September may be the childhood obesity awareness month in the United States, but there is a growing epidemic around the world. According to the World Health Organization, childhood obesity is associated with an increased risk for serious health complications later in life, including diabetes and heart disease.
One factor influencing the initiation of obesity is an imbalance in the gut microbiota, the community of bacteria located in the intestines. A common cause of disruption in the normal colonization and development of infant gut microbiota is repeated antibiotic exposure—how this leads to weight gain in children is the missing piece in the puzzle.
“To our knowledge, no human study to date has evaluated the potential implication of the gut microbiota on the association between early antibiotic exposure and childhood obesity,” said Ling-Wei Chen, a Research Scientist at A*STAR’s Singapore Institute for Clinical Sciences (SICS). To address this gap, Chen and SICS colleague Jia Xu conducted a prospective study studying infant antibiotic exposure and childhood obesity risk, and the contribution of gut microbiota to this association. The study was led by senior authors Neerja Karnani and Yung Seng Lee, both principal investigators at SICS.
More than a thousand women were recruited into the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study, a collaboration between SICS, the National University of Singapore, KK Women’s and Children’s Hospital and the National University Hospital. This multi-ethnic, mother-offspring paired cohort resulted in 1,172 singleton births, which Chen and colleagues tracked over a five-year period.
From questionnaires answered by caregivers, combined with serial childhood weight and height measurements by trained staff, the research team found that 38 percent of infants in the study were exposed to antibiotics in their first year of life. This group had a higher risk of becoming obese until five years of age, particularly if they had been exposed to three or more courses of antibiotics.
At 24 months of age, the children’s stool samples were collected and sequenced to obtain their gut microbiota profile. Antibiotic use was associated with alterations to their gut microbiome, and these changes corresponded to a higher risk for adiposity within this group.
Interestingly, the researchers observed a stronger risk for obesity in boys exposed to antibiotics as compared to girls, but they still do not understand the mechanism behind this. The gender differences were only seen in infant fat storage and development, and not in the gut microbiota, Karnani noted.
Their results suggest the need for caution when administering antibiotics in children, and may assist doctors and caregivers in providing early intervention against obesity risk. “While in some instances antibiotics are necessary, our research calls for the careful consideration of the benefits versus risks in administering antibiotics, and the frequency of their use in children,” said Lee, who is also the Head of Pediatrics at the National University of Singapore’s Yong Loo Lin School of Medicine, and Head of the Khoo Teck Puat-National University Children’s Medical Institute.
The A*STAR-affiliated researchers contributing to this research are from the Singapore Institute for Clinical Sciences (SICS).