A recent study* supported by the US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD) showed that hearing loss is about twice as common in adults with type 2 diabetes as it is in those without the disease.
According to a senior researcher with the NIDDKD "Hearing loss may be an under-recognised complication of diabetes. As diabetes becomes more common, the disease may become a more significant contributor to hearing loss. Our study found a strong and consistent link between hearing impairment and diabetes."
These results have been further supported by studies in Brazil and Australia which were published in 2009. In the Australian study, there was both an increase in the number of people with hearing loss and a faster progression of hearing loss in the diabetes group.
In fact, accelerated hearing loss progression over five years was more than doubled in persons with newly diagnosed diabetes.
The exact reason for this increased rate of hearing loss in people with diabetes is not yet known. It is likely that high blood sugar levels cause nerve damage in the ears, impairing the ability to transmit audio signals. This may particularly affect the ability to understand speech. It's also common for people with diabetes to lack a protein that forms a protective layer within the ear canal, leading to hearing problems.
These studies emphasise how important it is for people with type 2 diabetes to have regular hearing checks. While it may not be possible to stop hearing loss from progressing at all, regular checks and treatment will ensure people with diabetes are able to hear as well as possible.