Deafness Has Link to Type 2 Diabetes

The author of this article is almost too timid in what she/he writes. I disagree and feel that diabetes does play a role in hearing loss at all ages. Many studies to determine hearing loss are poorly done and the authors excuse their poor design as older people have hearing loss and the effect diabetes plays as negligible. Do understand that as people age, hearing loss can become a problem, with or without diabetes. Poorly managed diabetes can accelerate hearing loss. Well managed diabetes can prevent much of the hearing loss.

A review of studies of possible linkages between type 2 diabetes and hearing impairment concludes there is compelling evidence that diabetes can damage the auditory system, and that clinicians should include hearing testing in managing type 2 diabetes.

Elizabeth Helzner, PhD, assistant professor in the Department of Epidemiology and Biostatistics in the School of Public Health at SUNY Downstate Medical Center, said, “An association between diabetes and hearing impairment in human subjects has been shown in many, but not all, studies. Direct comparison of these studies is complicated due to a lack of consistency in defining hearing impairment and other factors.” The last statement is a key.

“However, the association between diabetes and hearing impairment tends to be stronger in studies that included younger participants, perhaps because in older samples, other causes of age-related hearing impairment may mask the contribution of diabetes to the impairment. This factor in itself lends weight to the notion that type 2 diabetes can damage hearing.”

Dr. Helzner and her co-author note in the article that the epidemiologic study of the relationship between diabetes and hearing impairment is relatively new. They add that well-designed longitudinal studies are necessary in order to explore whether patients with diabetes are at increased risk of early-onset hearing impairment, and whether the progression of hearing impairment varies based on diabetes status, as well as disease management factors, after taking other known contributors to hearing sensitivity into account.

Hearing impairment is one of the most pervasive disabling conditions, affecting 16.1 % of adults in the United States. Two thirds of adults have clinically significant hearing impairment by age 70. Hearing impairment has been associated with social isolation and depression, cognitive decline and incident dementia, a higher propensity for falls and hospitalizations, and increased mortality.

I have two blogs on the different types of hearing loss here and here.

Deafness – Part 2

Continued from the previous blog.

Noise-induced hearing loss. Hearing damage from noise exposure typically occurs in a very restricted frequency range, creating a gap in the sequence of frequencies that can be heard. The gap is usually in the high-frequency range, which can affect a person’s ability to understand speech. However, noise damage can sometimes affect such a narrow frequency range that the person may not even be aware that he has hearing loss.

Protecting your ears from loud sounds can reduce the potential for hearing loss caused by noise exposure. Many comfortable forms of hearing protection are available, including earplugs, which fit into the ear canal, and earmuffs, which secure over the ears with a band. Some people are reluctant to wear hearing protection in noisy environments because they are concerned they won’t be able to hear others talking to them. This is not something to be concerned about, however, because most people talk louder in noisy situations, so it is possible to hear conversations even with ear protection.

I have some noise hearing loss from the military, but the tests were so poorly done, that I was not able to contest the results. Over the years, I have become more acutely aware of some sounds and often have to leave some gatherings when music is too loud.

Age-related hearing loss. As we age, hearing loss occurs gradually, beginning with the high frequencies. In general, vowels, which account for the loudness of speech, are in the low-frequency range, while consonants, which provide the clarity of speech, are in the high-frequency range. Therefore, high-frequency hearing loss may not affect how loudly sounds are heard, but it can make speech less clear and, as a result, more difficult to understand. This is especially the case when watching television or listening to the radio, where speech is often fast and where visual cues, such as lip movements and body language, are not as readily available, as well as in noisy situations.

As far as age-related changes in hearing are concerned, it’s important to remember that the ear alone is not responsible for hearing. Sound is converted into electrical signals that travel from the cochlea through a series of nerve pathways to the brain for interpretation. In addition to problems associated with physical deterioration of the hair cells in the cochlea, there are age-related changes in the processing ability of the hearing-related nerves (the central processing disorders mentioned earlier) as well as cognitive changes that may slow a person’s ability to understand speech. These changes can have a profound effect on a person’s verbal communication abilities, regardless of whether hearing loss is present. For example, a common complaint of some older people is that people talk too fast. This is because as we age, the mental processes that are needed to understand speech can overload when information is presented too rapidly. In a study, conducted at the Veterans Affairs National Center for Rehabilitative Auditory Research (NCRAR) in Portland, Oregon, it was found that older people who have poorer performance on certain cognitive tests (those related to thinking, learning, and remembering) also perform poorly on speech recognition tests (tests that use lists of sentences speeded up by a computer).

Age-related hearing loss may not be immediately evident to the person whose hearing is damaged, and as a result, his hearing may be significantly diminished before he seeks help. Indeed, older people may not think they have hearing loss at all. They can still hear a lot of sounds loudly, so they simply think that other people are mumbling. In fact, this type of hearing loss is often noticed first by friends and family who find communication becoming increasingly difficult.

Age-related hearing loss progresses at different rates in different people. Some people still have very little loss even in their 80s, although that isn’t common. It is not clear what makes some people more susceptible to hearing loss than others, but as with any other age-related condition, good nutrition, physical activity, and good prevention practices (hearing protection, in this case) can contribute to lessening the effects or delaying the onset of hearing loss.

Infection or earwax can block ear canals and reduce hearing. Earwax can be safely removed in most cases, but earwax that has hardened requires some treatment to be safely removed.

The link between diabetes and hearing loss has been debated since the 1960s or before, and the results show that a relationship exists even when researchers account for the major factors known to affect hearing, such as age, race, ethnicity, income level, noise exposure, and the use of certain medications.

Diabetes may lead to hearing loss by damaging the nerves and blood vessels of the inner ear, the researchers suggest. Autopsy studies of diabetes patients have shown evidence of such damage.

Diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. Afflicting nearly 21 million people in the United States, it is a major cause of heart disease and stroke and the most common cause of blindness, kidney failure, and lower limb amputations in adults. Prediabetes, which causes no symptoms, affects about 54 million adults in the United States, many of whom will develop type 2 diabetes in the next 10 years. Prediabetes raises the risk of a heart attack or stroke even if diabetes does not develop. People with prediabetes can often prevent or delay diabetes if they lose a modest amount of weight by cutting calories and increasing physical activity.

For other information about diabetes and deafness or hearing loss please read this, this, and this article.

Deafness – Part 1

This is a topic that has many opinions and they are almost evenly divided into the opposing sides. There are those that do not believe diabetes causes hearing loss and those that can offer convincing evidence that it does cause hearing loss. They do agree that there are different types of hearing loss and can have different effects on how sounds are heard and understood. The different types of hearing loss tend to have different causes, and it appears that having diabetes can contribute to the development of certain types of hearing loss. Damage can occur anyplace along the hearing pathway. The location of the damage is the determining factor that determines the type of hearing loss.

The different types of hearing loss are:

Conductive hearing loss (outer and middle ear). Trauma to the structures of the ear that physically transmit sound, such as the eardrum and the bones in the middle ear, can result in conductive hearing loss, which reduces the ear’s ability to physically conduct sound vibrations. The eardrum can be damaged by chronic infection, trauma resulting from pressure changes in the ear (such as those that occur in deep-sea diving), or blunt force to the ear or head. The tiny bones in the middle ear also can be damaged by blunt force. A condition called otosclerosis, which involves abnormal growth of bone in the middle ear, can reduce the strength of the sound vibrations that are transmitted into the cochlea, thereby reducing the volume at which sounds are heard.

Conductive hearing loss causes a reduction in the overall volume of sounds, but if speech can be made loud enough, by means of a hearing aid or the speaker talking louder, for instance, it can most often be understood. In many cases, areas of the ear involved in conductive hearing loss may be treated with medicines or repaired with surgery.


Sensorineural hearing loss and central processing disorders (inner ear and central hearing pathway). Damage to the inner ear or to structures along the nerve pathway is called sensorineural hearing loss because it involves either the delicate sensory hair cells in the cochlea or the hearing nerve, and sometimes both. When the nerve pathway from the ear to the brain is damaged, this is usually referred to as a central processing disorder. Unlike people with conductive hearing loss, those with sensorineural hearing loss or processing disorders may have difficulty understanding speech even when it is amplified. In fact, too high a volume can result in distortion of the speech, causing an unpleasant sound and making it even more difficult to understand.

A person whose sensorineural hearing loss is caused by damage to the hair cells in the cochlea typically has difficulty hearing sounds at particular frequencies, or pitches. This is because each group of hair cells is sensitive only to one frequency, and when any damage occurs, some hair cells may be affected more than others. The hair cells nearest the entrance from the middle ear, which detect high-frequency sounds, seem to be more susceptible to damage related to aging and noise. This can lead to hearing loss in the high-frequency range, making it difficult to understand speech, which contains a mix of low- and high-frequency sounds.

Sudden sensorineural hearing loss. Sensorineural hearing loss that appears suddenly can have a number of causes, including a blow to the side of the head or a sudden loud sound like an explosion. This type of hearing loss can involve a wide range of frequencies, depending on the nature of the injury. Sudden sensorineural hearing loss that has no known explanation occurs only rarely, and in a large percentage of these incidents, the people recover their hearing spontaneously. (Many physicians think these cases are the result of viral infections, but this explanation has not been confirmed.)

There have been reports of sudden sensorineural hearing loss associated with diabetes, but this is extremely rare. However, there is evidence that high blood pressure may increase damage to the small blood vessels in the cochlea of people with diabetes, which could result in sudden sensorineural hearing loss. A recent study found that people with diabetes and sudden sensorineural hearing loss were more likely to have higher blood pressure, higher cholesterol, and a higher HbA1c (an indicator of blood glucose control over the previous 2–3 months) than people with diabetes but no sudden hearing loss.

If you experience sudden hearing loss, you should report it to a physician, preferably an otolaryngologist (ear, nose, and throat (ENT) specialist). It is important to get medical attention as soon as possible, because specific medicines can often recover some or most of the hearing if they are administered early.

Concluded in next blog.