Diabetes-Related Sensorineural Hearing Loss: The “Silent” Side Effect of Diabetes

Microangiopathy: How Diabetes Affects Hearing

Hearing loss from diabetes is usually the result of the microangiopathy in the cochlea vasculature. That is, the glucose in the blood builds up within the walls the cochlea (stria vascularis), thus damaging the capillaries and reducing blood. Because the stria vascularis can be 10 to 20 times thicker than usual in a PWD, hearing loss is likely to occur. These thicker vessel walls of the stria vascularis can lead to a sclerosis of the internal auditory artery. This reduction brings less oxygen to the inner ear hair cells, resulting in outer cell damage and subsequent loss in sound sensitivity (with or without tinnitus).

Hearing loss from diabetes does not appear as quickly as a diabetes-related visual impairment. But it is happening. DSNHL occurs in the cochlea and usually affects the high frequencies of speech. High-frequency losses affect the clarity of words. However, because the disease is systemic, hearing loss could occur in lower frequencies, too. Low frequencies provide the loudness of speech.

Researchers noted that there are 2 types of (micro)angiopathy in the cochlea: direct and indirect. Direct angiopathy interferes with the blood supply to the cochlea by reducing transport through the thickened capillary walls. Indirect angiopathy occurs by reducing the blood flow of a narrow vasculature or by causing secondary degeneration of the eighth cranial nerve. This could impact cognition if the auditory pathway to the brain is affected.

Why Does Diabetes-related Retinopathy Get More Attention Than Diabetes-Related Sensorineural Hearing Loss?

There is a simple reason why DSNHL is not prioritized: Diabetes-related retinopathy will affect mobility and increase fall risk, whereas hearing loss does not impede mobility.

If you ask a PWD, “Do you have any problems with your hearing?,” the answer will usually be, “No.” Why? With sensorineural hearing loss (regardless of the etiology), the person can still “hear.” But if you ask them, “How well do you understand words you are hearing?,” you will/could get an entirely different answer. Table 1 lists some causes of hearing loss according to the National Institute on Aging.

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Table 1

Causes of Hearing Loss

Age (presbycusis) History of occupational or recreational noise exposure Prescription or over-the-counter medication side effects Family history of hearing loss/genetics History of head trauma Ear infections Autoimmune inner ear disease (American Speech, Language, Hearing Association 2025) Other chronic illnesses (DiSogra and Beck 2025) Other neurological pathologies (ie, acoustic neuroma, etc) Cerumen (ear wax) buildup Ruptured ear drum

Symptoms of Hearing Loss

When asked, a person experiencing a mild degree of hearing loss will usually deny it: the first symptom of hearing loss. A person with hearing loss can still “hear,” but the quality/clarity of what they hear is the real problem. Table 2 lists the common symptoms of hearing loss.

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Table 2

Symptoms of Hearing Loss (Can Be Isolated or in Combination With the Other Symptoms)

Tinnitus Difficulty understanding speech, especially in noisy environments Difficulty hearing or understanding children’s or female voices Always asking others to repeat what they said Complaining that people mumble when they speak Television or radio volume louder than normal Difficulty hearing or understanding on the phone Loss of awareness of environmental sounds Withdrawal from social situations or not participating in conversations Balance issues

Hearing Loss Under 60 Years of Age and Over 60 Years of Age: The Diagnostic Dilemma

Hearing loss is twice as common in people who have diabetes as it is in people of the same age who do not. Even people with prediabetes (blood glucose levels higher than normal but not high enough yet to have type 2 diabetes) have a 30% higher rate of hearing loss than people with normal blood glucose levels.

Age-related hearing loss has been researched and documented over the decades. In clinical practice, audiologists are sometimes faced with a patient whose medical history does not fall in line with the audiometric data: high-frequency sensorineural hearing loss (HF SNHL) at an unexpected younger age (<60 years) than what would be expected with an older patient (>60 years). Sometimes, we cannot fully explain the etiology of the loss when the patient’s history is unremarkable.

For patients over the age of 60, it is more challenging because this age group almost assures us that there will be some age-related HF SNHL. Again, an unremarkable case history is an indicator that microangiopathy might have begun. Prediabetes needs to be ruled out.

Prescription and Over-the-Counter Medication Side Effects for Diabetes Management

There are over 80 prescription medications approved by the Food and Drug Administration (FDA) for type 1 and type 2 diabetes management.

Standards for pharmaceuticals are different from those of dietary supplements. FDA requirements for showing evidence of safety and efficacy is not required for vitamins, minerals, and other dietary supplements prior to appearance on the market. By law, dietary supplement packaging and advertising must state that the product is not intended to diagnose, treat, prevent, or cure any disease.

Dietary supplements are classified by the FDA as food, not as drugs. However, many dietary supplements contain ingredients that may conflict with a prescription medicine or other medical condition. Products containing hidden drugs are also sometimes falsely marketed as dietary supplements, putting consumers at even greater risk. For these reasons, it is important for patients to consult with a health care professional before using any dietary supplement.

The American Diabetes Association does not recommend the routine use of herbal supplements or micronutrients, only recommending supplements in the case of vitamin B₁₂ deficiency or multivitamin use in special populations, including pregnancy, older adults, vegetarians, and people following very low calorie or low carbohydrate diet.

For a comprehensive list of side effects of pharmaceuticals and dietary supplements used in diabetes management see DiSogra and Mcelhannon in the For Further Reading section.

Communication Strategies

Until a PWD with communication issues is evaluated by an audiologist, there are many communications strategies that can be used by a PWD and their family and friends. The reader can access these strategies on The Audiology Project website www.theaudiologyproject.com (click on “Educational Materials,” then click on “For Patients,” and then click on “Communication Strategies”).

Find an Audiologist Near You

Doctors of audiology (AuD) work in hospitals, medical centers, university speech and hearing centers, the Veterans Administration, or private practice. A simple Google search using “Find an audiologist near me” is all that has to be done.

To learn more about audiologists, visit www.audiology.org/consumers-and-patients/what-is-an-audiologist/.

Summary

Diabetes care and education specialists (DCESs) must be aware that a PWD experiencing diabetes-related retinopathy could also be experiencing DSNHL. Because diabetes-related retinopathy directly affects mobility (thus increasing the risk of a fall), a PWD will seek help for their vision loss sooner than help for a hearing loss from the same cause.

Hearing loss does not affect mobility. This is the reason DSNHL is the “silent” side effect” of diabetes.

Therefore, a DCES should include a referral for a comprehensive hearing examination by an audiologist with the same priority as a referral for a comprehensive eye examination to establish a baseline to monitor any reported changes in vision and/or hearing.

Audiologists are trained to evaluate, diagnose, and manage hearing loss in all age groups in addition to establishing a close working relationship with DCESs. ■