Researchers have found patients with type 2 diabetes used more antibiotics in the years prior to diagnosis compared to healthy individuals according to a new study published in the Journal of Clinical Endocrinology & Metabolism.

A population-based case-control study was conducted to track antibiotic prescriptions of 170,504 patients with type 2 diabetes and 1.3 million healthy people from three national health registries in Denmark. The researchers found that those with type 2 diabetes used significantly more antibiotics up to 15 years preceding their diagnosis. Those with type 2 diabetes filled on average 0.8 antibiotic prescriptions a year while the control subjects only filled 0.5 prescriptions a year. Many antibiotics were found to have a high correlation with diabetes but a stronger association was found with the use of narrow-spectrum antibiotics such as penicillin V.

Previous studies have suggested that alterations in gut microbiota may contribute to impaired sugar metabolism in diabetes. One study author, Kristian Hallundbaek Mikkelsen, MD, notes, “Although we cannot infer causality from this study, the findings raise the possibility that antibiotics could raise the risk of type 2 diabetes.”

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Data from a nested case-control study in the U.K. showed that the risk of developing type 2 diabetes increased when patients were treated with 2-5 antibiotic courses especially with penicillin, cephalosporins, quinolones, and macrolides. Over five courses of tetracyclines showed an elevated risk but no association was seen between diabetes risk and imidazole, antifungal, or antiviral exposure.

Researchers suggest that another possible explanation could be that those who develop type 2 diabetes may have a greater risk of infection during the years leading to diagnosis. They concluded that this correlation must be further investigated and recognizing patterns of antibiotic use could help prevent the development of type 2 diabetes or help diagnose it earlier.

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