The correlation between diabetes and hearing loss is well documented. According to the American Diabetes Association and the National Institute of Health, more than 30 million Americans have diabetes, with 90-95% experiencing Type 2 diabetes. Recent research would seem to show that diabetes mellitus does cause the increase in hearing loss which has long been correlated with Type 2; diabetics are twice as likely to have hearing loss than the rest of the population.
In a 2016 study of the connection between hearing loss and Type 2 diabetes, a hospital-based cross sectional study was carried out over a period of 1 year with 50 subjects aged 31–65 years who all presented with Type 2 diabetes and no sudden hearing loss. The study revealed that the percentage of sensorineural hearing loss was found to be 66%, being of gradual onset and progressive type as opposed to sudden or trauma induced hearing loss.
There was significant association between the duration of the diabetes mellitus (DM, which is Type 2) and sensorineural hearing loss (SNHL). For those with less than 5 year duration of DM, 35 % had SNHL. For those whose duration of of DM was more than 10 years, 85 % had SNHL. Older diabetic patients were found to have a higher incidence of and more severe grade hearing loss. Other potential connections include nerve damage, which is common among diabetics who have had uncontrolled symptoms for long periods of time.
Researchers also noted that when duration of DM increased over 6 years, the percentage of hearing deficit increased to an even greater extent. The researchers attributed this increase in hearing threshold to what is known as "microvascular angiopathy occurring in capillaries of stria vascularis." (Microvascular angiopathy is a thickening of the blood vessels, and the stria vascularis are vessels which carry blood to parts of auditory system.)
It is thought that controlling diabetes can possibly help to slow the progression of hearing loss. However, treating hearing loss may also help diabetics, as better hearing can lead to improved physical activity, more awareness about reminders to eat properly and take medication on time, and other factors which could help control diabetes.
Hearing aid use can provide a way for older diabetes to interact more easily with the world around them, and maintain a healthier lifestyle. A hearing aid specialist or audiologist can help by performing a hearing test and fitting hearing aids for optimal benefits.
Left untreated, mild to moderate hearing loss contributes to cognitive decline and may be an early indicator for Alzheimer’s disease – but treating hearing loss can reverse cognitive decline.