Dr. Marla: Examining the link between antibiotics and childhood obesity
Published Tuesday, September 30, 2014 3:23AM EDT
Last Updated Tuesday, September 30, 2014 6:07AM EDT
Obesity is a major public health problem here in Canada and the United States. Over the last 30 years we have seen a threefold rise with 80% of obese and overweight children being the same as adults. In young children, obesity increases the risk for sleep apnea, type 2 diabetes, breathing issues, impact on ovulation and menstrual cycles as well as mental health effects with a greater risk of depression. Hypertension and other metabolic abnormalities put these children at risk for the metabolic syndrome and several diseases that extend into adulthood.
I was shocked to learn that by age 24 months, 10% of children are obese. We have learnt through research that there are several factors associated with childhood obesity such as maternal prepregnancy body mass index, nutritional intake, physical activity, sleep duration and screen time. All these have been identified by the Institute of Medicine.
A new and emerging risk factor is the role of intestinal microflora that may be associated with obesity. Our guts are populated or colonized if you will, by good bacteria. The kind of bacterial flora that lives in our guts is influenced by dietary and environmental factors. Different bacteria vary by their ability to extract energy and as a result these patterns of bacterial colonization can influence growth. This also can influence energy metabolism in our body. Previous studies have shown that intestinal microflora are associated with obesity in later life and that antibiotic exposure influences the microbial variability and composition. The question then remains whether there is an influence of antibiotic use on early childhood obesity?
The authors used electronic health records spanning from 2001 to 2013 from a network of primary care clinics. All children with annual visits at ages 0 to 23 months, as well as one or more visit at ages 24 to 59 months were enrolled. The final group included 64,580 children. Children were followed-up until they were 5 years old.
What did the study find?
The study found 69% of the children were exposed to antibiotics before the age of 24 months with an average exposure of 2.3 episodes per child. An increased risk of obesity was associated with greater antibiotic use, especially for children with four or more exposures, when all antibiotics or only broad-spectrum antibiotics were examined. No association was seen between obesity and narrow-spectrum antibiotics. For all children, the prevalence of obesity was 10 percent at age 2 years, 14 percent at 3 years and 15 percent at 4 years. The prevalence of being overweight/obese was 23 percent, 30 percent and 33 percent, respectively.
An antibiotic may be classified basically as "narrow-spectrum" or "broad-spectrum" depending on the range of bacterial types that it affects. Narrow-spectrum antibiotics are active against a selected group of bacterial types. Broad-spectrum antibiotics are active against a wider number of bacterial types and, thus, may be used to treat a variety of infectious diseases and is effective against a wide range of infectious microorganisms which includes both gram positive and gram negative bacteria .
Because obesity is a multifactorial condition, reducing prevalence depends on identifying and managing multiple risk factors whose individual effects may be small but modifiable. The results the authors state, suggest that the use of broad-spectrum outpatient antibiotics before age 24 months may be one such factor. Because the first 24 months of life comprise major shifts in diet, growth, and establishment of the intestinal microbiome, this interval may comprise a window of particular susceptibility to antibiotic effects. The repeated use of antibiotics may have an impact on intestinal flora that alters long-term energy homeostasis as one factor in a complex mixture of physiologic, environmental, socioeconomic, and medical factors affecting a particular child’s risk for obesity.
This provides additional support for the adoption of treatment guidelines for common pediatric conditions that emphasize limiting antibiotic use to cases where efficacy is well demonstrated and preferring narrow-spectrum drugs in the absence of specific indications for broader coverage.