Diabetes and Hearing Loss

Hearing loss is a major public health issue. It ranks third after arthritis and heart disease as one of the most common physical conditions. Nearly 36 million people in the United States have some degree of hearing loss.

According to the National Institutes of Health hearing loss is about twice as common in adults with diabetes compared to those who do not have the disease.

A recent study found a strong and consistent link between hearing impairment and diabetes. "Hearing loss may be an under-recognized complication of diabetes. As diabetes becomes more common, the disease may become a more significant contributor to hearing loss," said Catherine Cowie, Ph.D., of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), who suggested that people with diabetes should consider having their hearing tested.

After analyzing the results of hearing tests given to a representative sample of adults, researchers discovered higher rates of hearing loss in those with diabetes. The test measured participants’ ability to hear low, middle and high frequency sounds in both ears. The link between diabetes and hearing loss was evident across all frequencies. Hearing impairment of low or mid-frequency sounds was 21% for people with diabetes compared to 9% without diabetes. For high frequency sounds, the rates increased for both groups, measuring 54% among those with diabetes compared to 32% in those who did not have the disease.

Surprisingly, adults with pre-diabetes had a 30 percent higher rate of hearing loss compared to those with normal blood sugar.

According to co-author, Howard Hoffman, epidemiologist at National Institute of Deafness and other Communication Disorders (NIDCD), "this is the first study with a representative sample of working age adults, and we found an association between diabetes and hearing impairment evident as early as ages 30 to 40."

• Damage to the nerves and blood vessels of the inner ear cause the most common type of hearing loss, termed sensorineural hearing loss.  Although this type of hearing loss cannot usually be cured, most cases can be treated with hearing aids. Info on assistive devices and hearing aids.

• People with diabetes often have less keratin, a protein that lines the ear canal which can cause hearing loss.

• One branch of the eighth cranial nerve, which carries sound signals from the cochlea to the brainstem, may experience deterioration of the sheath that protects its nerve fibers (demyelination).

• The tissue in the ear canal can also degenerate, affecting hearing.
   
• The cochlea can experience a thickening of its walls or the loss of hair cells.
  
• Chemical changes may affect the nerves' ability to carry sound signals. The capillaries of the inner ear can also be thickened, affecting the ability of the ear to carry sound signals.
  
• Diabetics are also more prone to get external and middle ear infections. Repeated or chronic ear infections can also result in hearing loss.
  
• As diabetes is commonly an autoimmune disorder, autoimmune inner ear disease may also contribute to hearing loss. Autoimmune inner ear disease is progressive hearing loss and/or dizziness caused by antibodies or immune cells which are attacking the inner ear. A reduction in hearing is accompanied by tinnitus (ringing, hissing, roaring) which occurs over a few months, and abnormal blood tests for antibodies.
  
• Of course sometimes the problem is just an earwax build-up and the individual may simply have a doctor remove the wax.

Other Factors that may lead to hearing loss

Diabetes aside, there are many other factors that can also contribute to hearing loss:

• Aging. Exposure to sounds over the years can damage the cells of your inner ear.
• Heredity. Your genetic makeup may make you more susceptible to ear damage.
• Occupational noise. Jobs where loud noise is a regular part of the working environment, such as farming, construction or factory work, can lead to ear damage.
• Recreational noise. Exposure to snowmobiles, motorcycles or listening to loud music, especially through headphones. For example, if the person next to you can hear the lyrics of the song through your earbuds the volume is too high and you risk hearing loss. Explosive noises from firearms and fireworks, can cause immediate, permanent hearing loss.
• Some medications. Some drugs such as the antibiotic Gentamicin and certain chemotherapy drugs can damage the inner ear. Temporary ringing in the ear (tinnitus) or hearing loss can occur if you take very high doses of aspirin or non-steroidal anti-inflammatory drugs (NSAIDs), anti-malarial drugs or some diuretics.
• Some illnesses. Diseases or illnesses that result in high fever, such as meningitis, may damage the cochlea.

 How do you protect your hearing?

Noise-induced hearing loss is preventable. The key to avoiding hearing loss is to protect your ears and maintain good glucose control.

There are three things to consider about noise: How loud. How long. How close. Proximity, duration and loudness dictate how quickly you should seek protection for your ears.

• Be aware of damaging noise.
• Be prepared to protect your hearing. Carry earplugs or other protection.
• Understand how hearing works and how it can be damaged.

What should I do if I suspect a hearing loss?

Talk to your primary care physician. They may refer you to a hearing specialist like: an audiologist, a licensed hearing aid dispenser or a doctor who specializes in hearing problems. From a full hearing exam, you’ll learn more about your hearing loss. You will also be told what can be done to treat it.

Do you have a hearing problem? Take this quick test! 

NIH

National Institute on Deafness and Other Communication Disorders

Hearing Loss Association of America

Kathleen E. Bainbridge, PhD, MPH; Howard J. Hoffman, MA; and Catherine C. Cowie, PhD, MPH. "Diabetes and Hearing Impairment in the United States: Audiometric Evidence from the National Health and Nutrition Examination Survey, 1999 to 2004." Annals of Internal Medicine. Volume 149, Number 1, July 2008.

P. Mitchell, B. Gopinath, C.M. Mcmahon, E. Rochtchina, J.J. Wang, S. C. Boyages, S. R. Leeder. "Relationship of Type 2 diabetes to the prevalence, incidence and progression of age-related hearing loss." Diabetic Medicine. Volume 26, Number 5, May 2009.

Shargorodsky J, Curhan SG, Eavey R, Curhan GC. A prospective study of cardiovascular risk factors and incident hearing loss in men. Laryngoscope. 2010 Jul 7. [Epub ahead of print]