A study published in the European Journal of Endocrinology has shown that patients who took two to five courses of pencillin in the year prior to their diagnosis had an 8% greater risk of developing type 2 diabetes.
This increased to a 23% greater risk if patients were exposed to more than five courses of penicillin treatment in this period.
Repeated use of cephalosporins, macrolides and quinolones was also linked to type 2 diabetes risk, with over five courses of the latter linked to the highest increased risk of 37%.
A single course of antibiotic treatment was not associated with an increased risk of developing the disease, but the results suggest that the risk increases with the number of antibiotic courses the patient is exposed to.
'Reduce unnecessary antibiotic treatments'
The researchers, from the University of Pennsylvania, looked at medical records of over 200,000 UK patients with diabetes to obtain the results. This data was compared to records for 800,000 matched control patients who did not have the disease.
Antibiotics alter the composition of the microbiota, which may affect metabolic pathways and contribute to development of the diabetes, the researchers suggested.
The researchers found no connection between antibiotics and type 1 diabetes risk, and there was no increase in risk associated with antivirals or antifungal treatments.
Lead author Dr Ben Boursi said: ‘Gut bacteria have been suggested to influence the mechanisms behind obesity, insulin resistance and diabetes in both animal and human models.
‘Our findings are important, not only for understanding how diabetes may develop, but as a warning to reduce unnecessary antibiotic treatments that might do more harm than good.’