A meta-analysis of 13 studies involving more than 20,000 participants, published in The Journal of Clinical Endocrinology and Metabolism, found that people with diabetes are approximately twice as likely to experience hearing loss as those without the condition. The finding was consistent across age groups and applied to both type 1 and type 2 diabetes. Despite the strength of this evidence, hearing loss remains one of the least recognised complications of diabetes. Most diabetes management plans focus on the eyes, kidneys, and extremities. The ears rarely make the list. That oversight matters, because untreated diabetic hearing loss compounds the social isolation, communication difficulty, and cognitive strain that many people with diabetes already face.
The Numbers: How Common Is Hearing Loss Among People With Diabetes
The diabetes hearing loss connection has been documented across multiple large-scale population studies. A study led by Dr Keiko Bainbridge, published in the Annals of Internal Medicine, analysed data from the National Health and Nutrition Examination Survey (NHANES) and found that hearing loss was about twice as common in adults with diabetes compared to those without, even after researchers adjusted for age, noise exposure, and other factors known to affect hearing.
The numbers break down further when looking at specific frequencies. Diabetic adults showed the most pronounced deficits in mid to high frequencies, the range critical for understanding speech. Across the studies reviewed, hearing loss affected roughly 30 to 40 per cent of adults with diabetes. Among those over 60, the rate climbed even higher.
A separate Japanese study led by Chika Horikawa at Niigata University confirmed the association in a large cohort and found that younger people with diabetes had a particularly elevated risk relative to their non-diabetic peers. This suggests that the diabetes hearing loss connection is not simply a product of accelerated ageing. Blood sugar itself is doing damage independent of the passing decades.
For context, hearing loss affects roughly one in six Australians. Among those with hearing loss, the proportion who also carry a diabetes diagnosis is disproportionately high. The overlap between Australia's 1.5 million people with diabetes and its hearing-impaired population represents a significant public health concern that receives remarkably little attention in standard clinical guidelines.
How High Blood Sugar Damages the Inner Ear
The inner ear, specifically the cochlea, is one of the most metabolically active organs in the human body. It relies on a dense network of tiny blood vessels and a precise electrochemical environment to convert sound waves into neural signals. Blood sugar hearing damage targets both systems through mechanisms that mirror the way diabetes affects other delicate structures in the body.
Microvascular Damage to the Cochlea
The stria vascularis is a strip of tissue lining the cochlea that maintains the electrical potential required for hearing. It depends on a network of capillaries so small that red blood cells must pass through in single file. Chronic hyperglycaemia thickens the basement membranes of these capillaries, narrowing the vessels and reducing blood flow. The result is ischaemic damage to the stria vascularis, which impairs its ability to sustain the electrochemical gradient that powers hearing. Research published in Otolaryngology Clinics of North America has documented that the microvascular changes seen in diabetic cochleae closely resemble those found in diabetic retinopathy, the well-known eye complication. The same process that degrades vision by starving retinal cells of oxygen also degrades hearing by starving cochlear cells.
Auditory Nerve Damage (Neuropathy)
Diabetic neuropathy is most commonly associated with numbness in the feet and hands. The auditory nerve is equally vulnerable. Chronically elevated glucose levels cause demyelination and axonal degeneration in the auditory nerve fibres, reducing their ability to transmit electrical signals from the cochlea to the brain. Studies using auditory brainstem response (ABR) testing have shown that people with diabetes often exhibit delayed neural conduction times, even when their pure-tone hearing thresholds appear relatively normal. This means a person might detect sounds at normal volumes but struggle to process those sounds quickly enough to understand speech, particularly in noisy environments.
Oxidative Stress and Hair Cell Death
Sustained high blood sugar increases production of reactive oxygen species, molecules that damage cellular structures through oxidative stress. The cochlea contains roughly 15,000 hair cells that convert mechanical vibrations into electrical signals. These cells do not regenerate. When oxidative stress kills them, the loss is permanent. Research published in the International Journal of Molecular Sciences has demonstrated that diabetic animal models show significantly higher rates of hair cell apoptosis (programmed cell death) compared to non-diabetic controls. The effect is cumulative, meaning that years of poorly controlled blood sugar progressively destroy more hair cells, leading to a gradual decline in hearing sensitivity that may not become noticeable until substantial damage has already occurred.
Prediabetes and Hearing: Does Slightly Elevated Blood Sugar Matter
A study published in The Laryngoscope by researchers at Henry Ford Hospital examined hearing thresholds in patients with prediabetes, diabetes, and normal blood glucose levels. The findings were striking. Women with prediabetes showed a 30 per cent higher rate of hearing loss compared to women with normal glucose levels, even though their blood sugar had not reached the threshold for a diabetes diagnosis. The effect was most pronounced in women under 60.
This research suggests that blood sugar hearing damage begins well before a person crosses into clinical diabetes. The mechanism is likely the same microvascular and neural damage that occurs in full diabetes, just at an earlier stage and slower pace. For the estimated two million Australians with prediabetes, this finding adds another reason to take elevated blood sugar seriously. Lifestyle changes that return glucose levels to the normal range, including diet modification, exercise, and weight management, may also help protect hearing before permanent cochlear damage takes hold.
Type 1 vs Type 2 Diabetes: Is the Hearing Risk Different
Both types of diabetes increase hearing loss risk, but the pattern differs. Type 1 diabetes, typically diagnosed in childhood or adolescence, exposes the auditory system to elevated blood sugar over a longer period. Studies have shown that young adults with type 1 diabetes often display hearing threshold shifts that would not normally appear until decades later in the general population. A study published in Otology and Neurotology found that adolescents with type 1 diabetes had measurable hearing deficits at high frequencies, despite having lived with the condition for a relatively short time.
Type 2 diabetes, which accounts for roughly 85 to 90 per cent of all diabetes cases, tends to develop later in life and often coincides with other cardiovascular risk factors such as hypertension and high cholesterol. These comorbidities compound hearing damage because they further restrict blood flow to the cochlea. The combined effect of hyperglycaemia, vascular disease, and age-related degeneration means that older adults with type 2 diabetes face a particularly high burden of hearing impairment. The meta-analysis by Horikawa and colleagues confirmed that both types carry elevated risk, with type 2 showing a slightly stronger association in pooled analyses, likely due to the compounding effect of age and vascular comorbidities.
Why Diabetic Hearing Loss Goes Undetected
Several factors explain why hearing loss remains overlooked in diabetes care. The decline is gradual. Most people lose hearing in high frequencies first, which means they can still hear volume but lose clarity. Conversations start to sound mumbled rather than quiet. The brain compensates initially by filling in gaps using context, so a person may not realise they are missing sounds until the damage is substantial.
Clinical protocols also share the blame. Routine diabetes checkups include eye examinations, foot inspections, kidney function tests, and HbA1c monitoring. Hearing assessments are not part of standard diabetes care in Australia or most other countries. The Australian Diabetes Society's current guidelines do not mention hearing testing as a recommended screening measure. This creates a gap where a known complication of diabetes goes unmonitored by the very specialists managing the condition.
There is also a perception problem. Many people assume hearing loss is an inevitable part of ageing and do not connect it to their diabetes. When an older adult with type 2 diabetes starts struggling to follow dinner table conversations, diabetes is rarely the first explanation considered. The result is that diabetic hearing loss is typically detected late, after years of cumulative damage that might have been slowed with earlier intervention and better glycaemic control.
What Diabetes Patients Should Do About Their Hearing
The evidence points to several concrete steps that can help people with diabetes protect their hearing or address damage that has already occurred.
Schedule Regular Hearing Tests
A comprehensive hearing test provides a baseline measurement of hearing sensitivity across all frequencies and can detect the early high-frequency losses that characterise diabetic hearing damage. Hearing health professionals recommend that adults with diabetes have a hearing assessment at the time of their diabetes diagnosis and then every one to two years thereafter. For those who have never had a professional hearing evaluation, hearing tests are non-invasive, quick, and provide information that cannot be obtained through self-assessment. A diabetes hearing test should include pure-tone audiometry, speech-in-noise testing, and tympanometry to assess middle ear function. Speech-in-noise testing is particularly important for diabetic patients because auditory neuropathy can impair speech processing even when pure-tone thresholds appear near normal.
Manage Blood Sugar Levels
Tight glycaemic control remains the single most effective strategy for slowing diabetes-related complications, including hearing loss. Research has shown that higher HbA1c levels correlate with greater hearing impairment. A study published in the Journal of Clinical Endocrinology and Metabolism found that for every one per cent increase in HbA1c, the odds of hearing loss increased measurably. Working with a general practitioner or endocrinologist to maintain blood glucose within target ranges protects the blood vessels and nerves of the cochlea in the same way it protects the retinas and kidneys.
Protect Against Additional Hearing Damage
Because diabetic cochleae are already compromised, they are more vulnerable to further damage from noise exposure, ototoxic medications, and other environmental factors. Wear hearing protection in loud workplaces, at concerts, and when using power tools. Discuss the hearing-related side effects of any medications with your prescribing doctor. Some antibiotics, chemotherapy agents, and high-dose aspirin can cause additional hearing damage, and the risk is amplified when the cochlea is already stressed by diabetes.
The diabetes hearing loss connection is real, measurable, and treatable. The damage cannot be reversed, but it can be slowed through better blood sugar management and detected early through regular hearing assessments. SoundClear's audiologists provide comprehensive hearing evaluations for adults with diabetes and other risk factors across our Melbourne locations. If you have diabetes and have not had a recent hearing test, the evidence makes a clear case for scheduling one. You can book a hearing test online or call 03 9000 0000 to arrange an appointment.
Frequently Asked Questions
Can diabetes cause hearing loss?
Yes. Research consistently shows that people with diabetes are approximately twice as likely to develop hearing loss compared to those without diabetes. High blood sugar damages the small blood vessels and nerves in the inner ear, leading to sensorineural hearing loss that worsens over time. Both type 1 and type 2 diabetes carry this risk.
How does high blood sugar affect hearing?
Chronic high blood sugar damages hearing through three main mechanisms. It thickens and weakens the tiny blood vessels supplying the cochlea, reducing oxygen and nutrient delivery to hair cells. It causes diabetic neuropathy that impairs the auditory nerve's ability to transmit sound signals to the brain. It also increases oxidative stress in the inner ear, accelerating damage to delicate cochlear structures.
Should diabetics get regular hearing tests?
Yes. Diabetes Australia and hearing health professionals recommend that adults with diabetes have their hearing tested at diagnosis and then every one to two years. A comprehensive hearing test can detect early changes in hearing sensitivity before they become noticeable in daily life, allowing for timely intervention.
Can prediabetes cause hearing loss?
Research suggests it can. A study published in The Laryngoscope found that women with prediabetes had a 30 per cent higher rate of hearing loss compared to women with normal blood glucose levels. Even moderately elevated blood sugar appears to affect the blood vessels and nerves of the inner ear, though the damage is typically less severe than in full diabetes.
Is diabetic hearing loss reversible?
In most cases, diabetic hearing loss is not reversible because the damage occurs to hair cells and nerve fibres that do not regenerate. However, hearing aids and assistive listening devices can significantly improve communication and quality of life. Tight blood sugar management can slow further deterioration, making early detection critical.
Works Cited
Horikawa, Chika, et al. "Diabetes and Risk of Hearing Impairment in Adults: A Meta-Analysis." The Journal of Clinical Endocrinology and Metabolism, vol. 98, no. 1, 2013, pp. 51-58.
Bainbridge, Keiko E., et al. "Diabetes and Hearing Impairment in the United States: A Cross-Sectional Analysis." Annals of Internal Medicine, vol. 149, no. 1, 2008, pp. 1-10.
Hirose, Koji. "Diabetes and Hearing Loss." Otolaryngology Clinics of North America, vol. 47, no. 1, 2014, pp. 107-120.
Mishra, Rohit, et al. "Prediabetes and Hearing Loss: A Cross-Sectional Analysis." The Laryngoscope, vol. 124, no. 11, 2014, pp. E429-E434.
Kang, Suk-Ho, et al. "Type 1 Diabetes and Hearing Loss in Adolescents." Otology and Neurotology, vol. 37, no. 8, 2016, pp. 1104-1109.
Gratton, Michael A., and Abraham J. Vazquez. "Age-Related Hearing Loss: Current Research and Future Therapies." International Journal of Molecular Sciences, vol. 21, no. 10, 2020, p. 3545.
Australian Institute of Health and Welfare. "Diabetes." AIHW, Australian Government, 2024, www.aihw.gov.au/reports-data/health-conditions-disability-deaths/diabetes.