At least two of the bigger health issues facing people in developed countries these days may actually be related. Rising rates of type 2 diabetes and other metabolic diseases may actually be the result of the overuse of antibiotics, both those used to treat conditions for which they may not be appropriate, and those found in the feed of animals destined for the dinner table.

New research from the University of Pennsylvania shows that antibiotics, by altering the gut microbiome, the population of bacteria normally present in the intestine, pave the way for type 2 diabetes.

Patients who were prescribed at least two courses of antibiotics were at higher risk of being diagnosed with type 2 diabetes.

The findings make a strong case for scaling back antibiotic use.

“I think that connection between antibiotic use and the rise in metabolic disorders has been proposed previously by some people,” Yu-Xiao Yang, corresponding author on the study, told TheDoctor.

The researchers compared the number of antibiotic prescriptions given to over 200,000 people in the United Kingdom who developed type 2 diabetes a year or more later to the number of prescriptions given to 815,576 people who did not develop diabetes.

They found that patients who were prescribed at least two courses of antibiotics were at higher risk of being diagnosed with type 2 diabetes. The risk increased with the number of antibiotic courses prescribed.

“A lot of people get antibiotics for nonspecific symptoms and a lot of times doctors are pressured into prescribing it,” Yu-Xiao Yang, corresponding author on the study, told TheDoctor. Patients have a responsibility, too, when it comes to antibiotic use, he added. “[T]hey need to be aware of this association, and of the scientific evidence so far.”

The current study provides evidence that alterations in the gut microbiome by antibiotics can lead to obesity and metabolic disorders such as type 2 diabetes and insulin-resistance, but it falls short of establishing a cause-effect relationship. “[A]t the very least it does emphasize the importance of judicious use of antibiotics in clinical practice as well as in other areas,” Yang said.

Patients don’t need to do anything drastic, said Yang. They should just consider these potential metabolic effects before they ask their doctor for antibiotics when they are not clearly necessary.

Yang said the current study is based on existing work from other investigators, including that of Martin Blaser of New York University who has a book on the subject.

The investigators plan to look at how alterations to the microbiome affect metabolic disease next. “So we are shifting our attention to a more direct approach based on this indirect evidence,” said Yang.

The study was published online recently in the European Journal of Endocrinology.