Antibiotic Overuse: Another Reason to Follow Doctor’s Orders
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Antibiotic orders both for just within the prior year and “cumulative orders,” meaning antibiotic prescriptions over multiple years, were associated with increased BMI, with the results the most pronounced in mid-teen years. Cumulative orders were associated with persistent increases in BMI, as opposed to the more reversible association noted among only prior-year antibiotic patients.

The models used in the study indicate that antibiotics could be tied to excess weight gains of 1.6 to 3.3 lbs at age 15. Specifically, the persistent association was stronger with increasing age, and among children with at least seven lifetime orders, antibiotics were associated with an average weight gain of approximately 3.1 lbs at age 15.

Antibiotic use early in life has been linked to weight gain, but until now there have been no large-scale, population-based, longitudinal studies of the full age range among healthy children. Because antibiotics are commonly prescribed for children, the findings are not good news, especially given that these children were healthy. The results also suggest that antibiotic use may influence weight gain throughout childhood and not just during the earliest years, as has been the primary focus of most prior studies.

The researchers hypothesize that antibiotics could affect metabolism and energy balance by changing the intestinal microbiota. The study further illustrates the need for patients and their parents to recognize the benefits and limitations of antibiotic use, to help avoid overuse.

The CDC survey referenced in August in Running & FitNews® found that, of almost 8,000 consumers, some 20% obtained antibiotics from a source other than their doctor or clinic, “most often grocery stores, friends and family, or leftovers from a previous illness.” The public should be reminded frequently that antibiotics are ineffective against viruses and colds. Colds are caused by viruses, and antibiotics only treat an infection that's brought on by bacteria. Antibiotics cannot fight viruses.

In addition to the weight gain they can promote in children, antibiotics can become less effective the more they are used, so it’s important to avoid taking them unless absolutely necessary.

 Int. J. Obesity, accepted article preview, October 2015,

MMWR, 2015, Vol. 64, No. 21, pp. 591-596,

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