Antibiotics are commonly used to treat bacterial infections, and most of us have been prescribed several in our lifetime. But, it may be that the amount of antibiotics you take is linked to your risk for developing diabetes.

Danish researchers have discovered a strong possible link between using antibiotics and type 2 diabetes. Using Denmark’s health registries, they identified 170,504 people with type 2 diabetes and tracked their antibiotic prescriptions. Then they matched those people with 1.3 million people without diabetes of the same age and sex and compared data over 13 years.

According to the results published in The Journal of Clinical Endocrinology & Metabolism, those who filled two to four prescriptions had a 23 percent higher risk for diabetes, and those who filled five or more had a 53 percent higher risk compared to those who didn’t fill any. The risk was detected up to 15 years before a person was diagnosed with type 2 diabetes.

This connection could merely show that people who have diabetes or are at risk of developing the disease may take more antibiotics than other people due to increased vulnerability to infections, even years before a diagnosis can be confirmed. But many in the medical community thinks it’s more likely that antibiotics can raise the risk for diabetes.

Antibiotics disrupt our gut bacteria, dramatically reducing both bad and good bacteria in our body. Study authors believe this could affect the body’s sensitivity to insulin and glucose tolerance, which may lead to diabetes.

“In animal studies, antibiotic treatment has been shown to affect glucose and insulin metabolism,” said the lead author of the study, Dr. Kristian Hallundbaek Mikkelsen. “What we see in animals may be happening in people, and if so, then there are more good reasons to be strict about antibiotic prescription policy.”

The over-prescription of antibiotics is high; a Consumer Reports survey of 1,000 adults found that doctors often prescribe antibiotics when they aren’t necessary or useful, including for illnesses like the cold, flu, and sinus infections. We should trust our doctors but also be educated about what they are prescribing. Don’t be afraid to speak up when you have questions about your prescription, like one patient did in this Consumer Health Choices story.

While antibiotics do obvious good to heal our bodies of infections, they also may do serious harm if consumed in excess.

“[The study provides] evidence consistent with the idea that antibiotics have a cost—not just a monetary cost, but a biological cost in terms of potentially causing long-term effects,” Dr. Martin Blaser, professor of medicine and microbiology at New York University, told Time Magazine.

What do you think about this research?

To learn more about medication and diabetes:

The Gut — Your Ticket to Health
Antibiotic May Help Treat Diabetic Eye Disease
Eat Yogurt to Cut Diabetes Risk