Antibiotics, C-Sections, and Childhood Obesity

Two more studies this week suggest that early life experiences — even before birth — may well shape a child’s risk for obesity. Antibiotics, C-sections, and childhood obesity appear to be linked.

In a study published by the International Journal of Obesity, researchers from Columbia University’s Mailman School of Public Health found that antibiotics in the second or third trimester of pregnancy, as well as Cesarean-section, were each linked independently to an increased risk of obesity for the child at the age of seven. In the case of antibiotics, the risk was increased by 84%. With C-section the risk was increased 46%.

The observation of increased obesity risk for children delivered by C-section is consistent with prior analyses. Increased risk with antibiotics during pregnancy is a new observation that needs further study. Both of these observations might be explained by disturbing the normal establishment of healthy microbiota in infants.

The second study was published this week in JAMA Pediatrics. Charles Bailey and colleagues found exposure to antibiotics in the first two years of life was linked to a 9-16% increase in the risk of childhood obesity by age five. The risk was reduced with narrow-spectrum antibiotics. Though the risk observed is relatively small in this context, there’s little dispute about the need to reduce unnecessary antibiotic for infants and to limit the use of broad-spectrum antibiotics. Antibiotic use in pregnancy and C-sections are being linked to a greater risk that deserves closer consideration.

Taken together, these data point to early-life experiences that have nothing to do with nutrition and physical activity, but potentially much to do with a child’s risk of obesity.

Click here for more on the study of C-sections and pre-natal antibiotics, and here for the study itself. Click here for more on the study of antibiotics in infants and here for the study.

Madagascar, photograph © Steve Evans / flickr

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