Food and Behaviour Research

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Early Exposure to Antibiotics Linked With Obesity

Brian Hoyle

Antibiotic exposure early in life is strongly linked with an increased risk of childhood obesity, according to results from a large, retrospective, longitudinal cohort study.

FAB RESEARCH COMMENT:

This study confirms previous reports linking increased risks of childhood obesity to antibiotic use in early life.

The researchers used data from a large-scale follow-up study of medical records, avoiding some of the limitations and confounds that applied to previous research showing similar results.

The precise mechanisms by which antibiotics could cause obesity have not been explicitly studied, but as the researcher noted, an obvious possibilty would be the changes to the gut microbiome that these drugs inevitably induce.

In farmed animals, feeding antibiotics (without good medical reason) has long been known to promote growth and weight gain - and therefore profitability (although this practice has been banned in the EU since 2006.)

It is therefore hardly surprising that antibiotic use might also promote weight gain in humans.

Reducing the overuse of antibiotics is already a public health priority, owing to the increasing problem of antiobiotic resistance.  These findings only add yet more weight (please forgive the pun) to the urgency of the case for doing this.
Antibiotics may provide a physician-modifiable risk factor for obesity prevention in early childhood,” stated lead investigator Elizabeth Dawson-Hahn.

Previous studies have demonstrated an association between early antibiotic exposure and obesity, but these findings were limited by recall bias, exposure ascertainment, and lack of inclusion of maternal factors.

Dr. Dawson-Hahn and colleagues evaluated the association between antibiotic exposure from birth to 47 months with weight status at 48 to 59 months of age, using electronic medical records between 2002 and 2010 from 4,938 subjects in the Group Health Cooperative database of Washington State. Of these subjects, 3,533 (72%) had been exposed to antibiotics.

“In this large, longitudinal cohort, antibiotic exposure at birth to 47 months was associated with being overweight at 48 to 59 months, with exposure during infancy associated with higher odds,” said Dr. Dawson-Hahn.

“Greater antibiotic exposure was associated with higher BMI z-score at 48 to 59 months. Antenatal maternal outpatient antibiotic exposure was also associated with obesity in the child,” she noted.

Lack of recall bias was a strength of this study, the authors suggested. Limitations included lack of generalisation of the data, as the majority of the mothers were white and from high-income households. There was also a lack of information on breastfeeding, and an inability to include information on intravenous antibiotic use.

Dr. Dawson-Hahn concluded that “Future studies should explore the mechanism of the relationship between early-life antibiotic exposure and obesity -- such as whether this association is due to changes in intestinal microbial composition.”