Obesity on the Rise: Related to Antibiotic Use?

Here is a nice NPR piece on the possible link between childhood obesity and antibiotics. This story is from back in August but I figured I'd bring it back up in case anyone missed it; I also alluded to this in an earlier post.

Obesity has become epidemic in the United States. According to the CDC, the prevalence of obesity has exploded over the past few decades: almost one in five children and adolescents (17%) is now obese, as well as over one-third of adults (36%). The obesity prevalence in children has nearly tripled since 1980.

Here is an instance where 'a picture is worth a thousand words.' The following maps illustrate obesity prevalence in US adults in 1990 versus 2010:

These maps are both compelling and disturbing; what has caused the explosion of obesity over the past twenty years?

An intriguing question is whether the increase in obesity prevalence is related to antibiotic use.

Antibiotics have long been used in animal husbandry to "fatten up" food animals. It is not exactly clear why this happens (e.g., why using low levels of antibiotics leads to fatter animals). An important question is whether antibiotic use also drives a similar process in humans.

A study by Cho and colleagues that was published in Nature in August found that the administration of antibiotics to mice was associated with changes in the composition of organisms in the gut that led to changes in fat metabolism and fatter animals. Although this was a mouse model, it does provide 'biologic plausibility' for how antibiotic administration could lead to obesity in humans.

Another article by Blustein and colleagues utilized a database from the UK with data from over 11,000 children born in 1991-1992. These authors found that antibiotic exposure within the first 6 months of life was subsequently associated with increased body mass from 10-38 months of age.

Although the above studies are intriguing, they do not provide definitive evidence that the current obesity epidemic is related to antibiotic exposure. Many things are likely contributing to this epidemic; one thing is clear, however: the prevalence of obesity has increased dramatically and this has had-and will have-enormous implications for our healthcare system and society.

Antibiotics have revolutionized modern medicine: they are critical for helping patients survive cancer therapy, for many complicated surgeries and are life-saving in the setting of many serious infections. However, studies such as those noted above illustrate that antibiotics may have effects beyond their intended purpose, and is further evidence that their use should be targeted and judicious. This is even more important given the widespread problem of antibiotic resistance and the paucity of new antibiotics that are being developed. More research into the link between obesity and antibiotic use is needed.