The terms hearing loss, hearing impairment and deafness refer to an inability to hear. The severity of a hearing disability can range from mild, through moderate or severe, to profound deafness. But can it be caused by diabetes? If so, what can be done about it?
Diabetes and hearing loss are two of the world’s most widespread health concerns.
Diabetes affects an estimated 10% of the adult population in the Western World. About 40% of these cases are undiagnosed.
About 16-17% of Americans and Europeans suffer from a partial or total inability to hear.
There is a strong relationship between age and hearing loss. For example, in America 8% of 18 to 44 years old, 19% of 45 to 64 years old, and 30% of 65 to 74 years old report trouble with their hearing.
What causes hearing loss?
Hearing loss develops when sound signals are unable to reach the brain. This may be due to one or both of the following causes:
 Sensorineural deafness
The inner part of the ear contains tiny hair cells (nerve endings) that change sounds into electric signals. The nerves then carry these signals to the brain.
Damage to the tiny hair cells, the nerve fibres in the inner ear, the auditory nerve that carries the sound signals to the brain (auditory nerve), or the brain itself can cause partial or full loss of hearing.
Known as sensorineural deafness, this kind of hearing loss is permanent.
 Conductive hearing impairment
Earwax, ear infections, a perforated ear drum or damage to the hearing bones can all prevent sounds from passing from your outer ear to your inner ear.
This conductive hearing impairment may be only a temporary problem.
Mixed hearing loss … it is possible for both of these problems to occur at the same time.
Hearing loss, of whatever sort, can be caused by a variety of factors. These include:
- Aging … getting progressively deaf as you grow older is a fact of life
- Prolonged exposure to loud noises … noise is the cause of roughly half of all cases of hearing loss and responsible for some degree of hearing problems in 5% of the global population
- Chemicals … certain chemicals (combined with loud noises) can increase a person’s hearing loss
- Genes … impaired hearing can be inherited
- Illness … measles, meningitis and mumps can all lead to some degree of hearing loss; so too can neurological disorders such as multiple sclerosis and stroke
- Medicines … such as antibiotics, anti-inflammatory drugs and diuretics can cause irreversible ear damage, which is one reason why their use is limited
- Physical trauma … people who sustain head injuries are especially vulnerable to hearing loss or tinnitus (ringing in the ears), either temporary or permanent
What are the signs of hearing loss?
Hearing loss can be so gradual that you may not notice it. In fact, your family or friends may notice a loss of hearing before you do.
You probably have impaired hearing if you:
- Find it hard to hear other people clearly or feel that their voices sound mumbled or slurred
- Have trouble following conversations that involve more than two people talking
- Have problems hearing in noisy places such as busy pubs or restaurants or other places where there is background noise
- Find it easier to understand men compared to women and children
- Need to turn up the volume excessively when listening to music or watching TV
- Find it difficult to hear your telephone, mobile, alarm clock or the door bell
- Find that some sounds seem too loud.
- Find it hard to tell high-pitched sounds (such as “s” or “th”) from one another.
- Have a feeling of being off-balance or dizzy
- Have a ringing or buzzing sound in your ears (tinnitus)
Does diabetes cause hearing loss?
The link between diabetes and hearing loss has been debated since the early 1960s.
Early attempts to establish an association between diabetes and hearing impairment either found a weak association or no association at all.
These studies however were based on small samples of older adults. Some of them were conducted in industrial or military settings and the possibility that the hearing loss suffered by diabetics was not due to occupational exposure to noise could not be ruled out.
In June 2008, a study by the US National Institutes of Health (NIH) published in the Annals of Internal Medicine, found a strong and consistent link between impaired hearing and diabetes.
The investigators found participants with diabetes or pre-diabetes were twice as likely to have at least mild hearing loss compared to people without diabetes … even after accounting for major factors known to affect hearing, such as age, race, ethnicity, exposure to noise, income level and the use of certain medications.
The link between diabetes and hearing loss was evident across all frequencies, with a stronger association in the high frequency range.
For high frequency sounds, mild or greater hearing impairment in the worst ear was 54% in diabetics compared to 32% in non-diabetics. Overall figures for low- or mid-frequency sounds in the worst ear were 21% and 9% respectively.
Adults with pre-diabetes had, overall, a 30% higher rate of hearing loss compared to persons who were not diabetic.
Furthermore, these conclusions held across a variety of socio-demographic characteristics such as age, gender, educational attainments and ethnicity.
The analyses also demonstrated a stronger link between diagnosed diabetes and hearing impairment in younger people compared to older people.
In addition, the greater occurrence of hearing loss among diabetics was not limited to those who might have been predisposed to the condition, such as smokers, those who had been exposed to excessive noise or persons taking medication that affected the ear.
The link between diabetes and hearing loss demonstrated by the NIH study has been reinforced by a later Japanese study.
In July 2011, scientists from the Tsukuba University Hospital Mito Medical Centre in Ibaraki, Japan, found that hearing loss is more than twice as common in people with diabetes than in non-diabetics.
The team amalgamated the findings of 13 studies involving nearly 8,800 people with deficient hearing and 23,839 people who could hear normally. They found that, compared to non-diabetics, persons with diabetes are 2.3 times more likely to suffer at least mild hearing loss.
How does diabetes cause hearing loss?
The differences in hearing loss between diabetics and non-diabetics diminish with increasing age. This suggests that diabetes may be aging the ear prematurely.
Perhaps, but right now we only know that there is a strong association between diabetes and loss of hearing. We don’t know whether or how diabetes actually causes hearing loss.
It is likely however that high blood glucose levels affect the supply of blood or oxygen to the tiny blood vessels and nerves of the inner ear which, over time, damages these blood vessels and nerves, causing hearing loss… similar to the way in which diabetes can damage the eyes, kidneys and feet.
Autopsies of deceased diabetics have shown evidence of such damage.
But more research needs to be done to discover why diabetics have a higher rate of hearing loss compared to non-diabetics.
Prospective studies (which watch for outcomes such as the development of a disease) need to be carried out to test whether hearing impairment begins earlier among diabetics than among persons without diabetes. If it turns out that diabetics begin to lose their hearing at an earlier stage, this would help decide whether diabetes contributes to loss of hearing.
In my opinion, the evidence so far and my own experience of hearing loss, diabetes is one of several causes of hearing impairment.
What can you do about diabetic hearing loss?
The answer to the question is … diet … the same diet that you use to control your diabetes and stay healthy.
To beat your diabetes and save what is left of your hearing you should eat natural, unprocessed foods, mainly plants, that are low in sugar, low in fat, low in salt, high in fibre and digested slowly. You also need to exclude dairy products and eggs from your diet and drink plenty of water.
While it probably will not reverse your deafness and enable you to hear clearly again it, this Beating-Diabetes diet can be expected to stop or slow down the degeneration in your hearing.
But for the diet to be successful, you also need to avoid things that can acerbate your hearing loss, such as loud noises and medicines that can affect your hearing.
As well as following a diet that should slow the rate of loss, there are several things you can do to improve your hearing.
Some modern assistive devices, such as telephone amplifiers and hearing aids, work remarkably well and can help restore your hearing enough for you to understand and participate in conversations with groups of people.
Persons with severe loss of hearing may find learning sign language and lip reading to be helpful.
Unfortunately surgery to place a cochlear implant (for persons with very severe hearing loss) does not restore normal hearing but only makes sounds seem louder.