Type 2 Diabetes Linked to Worse Hearing Thresholds, and Medication Type May Matter

An Italian audiometry study finds adults with type 2 diabetes hear significantly worse than peers without diabetes, while some diabetes medications are associated with better hearing thresholds.

Hearing loss and type 2 diabetes are two of the most common chronic conditions of later life, and they often arrive together. Researchers have long suspected the connection is more than coincidence, since elevated blood sugar can damage the small blood vessels and nerves that the inner ear depends on.

A new study from the University of Palermo in Italy adds a fresh wrinkle to that story. Beyond confirming that adults with type 2 diabetes tend to hear worse than similar adults without it, the researchers found that hearing thresholds differed depending on which diabetes medications patients were taking.

Background: Why the Researchers Looked at This

Type 2 diabetes has increasingly been identified as a risk factor for sensorineural hearing loss, the permanent kind caused by damage to the inner ear or hearing nerve rather than to the eardrum or middle ear. The likely mechanisms include damage to the cochlea's tiny blood vessels and to the nerve pathways that carry sound to the brain, similar to the way diabetes affects the eyes, kidneys and feet.

What has remained poorly characterized is whether the choice of diabetes treatment makes any difference to hearing. Modern diabetes care spans several drug classes, including metformin, GLP-1 receptor agonists, and pioglitazone, and these medications differ in how they affect blood vessels, inflammation and metabolism. The Palermo team set out to compare hearing thresholds across these treatment groups.

How the Study Was Done

The researchers reviewed records of 240 patients with type 2 diabetes and 105 normoglycemic controls, all of whom underwent standardized pure-tone audiometry at the Audiology Section of the University of Palermo between February 2025 and January 2026. Pure-tone audiometry is the familiar hearing test in which listeners respond to beeps at different pitches and volumes.

Hearing was summarized as the pure tone average across 0.5, 1, 2 and 4 kHz, the frequencies most important for understanding speech. The analysis adjusted for age, sex, body mass index and smoking status, four factors that independently influence hearing, so that differences between groups would not simply reflect older or heavier smokers being concentrated in one group.

What the Researchers Found

Adults with type 2 diabetes had significantly worse hearing than controls. Their average speech-frequency threshold was 64.4 decibels, compared with 56.4 decibels in the normoglycemic group (p = 0.007). An 8 decibel gap is roughly the difference between straining at conversational speech and missing parts of it altogether.

The more novel finding concerned medications. Patients taking GLP-1 receptor agonists, metformin, or pioglitazone had lower, meaning better, hearing thresholds than patients on other regimens. When the researchers grouped drugs by pharmacological class, GLP-1 receptor agonists and biguanides, the class that includes metformin, stood out as associated with more favorable hearing.

The authors are careful to describe these as associations, not proof that any drug protects hearing. But the pattern was consistent enough after adjustment to suggest that antidiabetic therapy may have class-specific relationships with auditory function, a question they argue deserves prospective trials.

What It Means for People with Hearing Loss

For the millions of adults managing type 2 diabetes, this study is a reminder that hearing belongs on the list of things diabetes can affect, alongside vision, kidney function and circulation. Yet hearing checks are rarely part of routine diabetes care, and an 8 decibel disadvantage can creep in gradually enough to go unnoticed for years.

The practical takeaway is not to switch medications, which should only ever be discussed with the prescribing doctor, but to monitor hearing more deliberately. People with diabetes who notice themselves turning up the TV, asking for repeats, or struggling in group conversation have a concrete reason to get their hearing measured sooner rather than later.

Keeping Track of Hearing When You Manage Diabetes

Because this study adds hearing to the list of health measures worth watching in diabetes, easier access to hearing checks and hearing help matters. Newer FDA-OTC hearing aids are designed to lower that barrier for adults with mild to moderate hearing loss. Panda Air is one such device, an earbud-style, self-fitting OTC hearing aid whose optional app can run a frequency-specific hearing test through the aid itself and personalize gain and frequency response to the user's hearing profile, making it simpler to notice and respond to gradual change. The app and test are optional, and Air works out of the box without them.

Air uses 16-channel WDRC processing with multi-band adaptive noise reduction, streams calls, TV and music over Bluetooth, and its fast-charge case provides 60 hours of total use, with a 5-year warranty and a 45-day trial that starts when the device is received. Details are at pandahearing.com.

One caveat worth noting: OTC hearing aids are approved for mild to moderate hearing loss, and the average thresholds in this study's diabetes group were higher than that. People with severe or profound loss benefit most from clinical fittings with an audiologist.

Limitations of This Research

This was a retrospective, observational study at a single audiology center, so it can show associations but not cause and effect. Patients were not randomly assigned to medications, and those prescribed newer drugs such as GLP-1 receptor agonists may differ in ways the adjustment could not fully capture, such as overall health engagement, diabetes duration or blood sugar control. The participants were also drawn from an audiology clinic population, meaning most already had hearing concerns, which limits how far the findings generalize to all people with diabetes. No funding or conflict of interest concerns were highlighted in the available abstract.

What to Do With This

If you or someone you care for lives with type 2 diabetes, treat hearing the way you already treat eyes and feet: as something to check periodically, not only when a problem becomes obvious. Bring hearing up at the next diabetes review, get a baseline test, and act early if the numbers drift. The medication findings are a question for future research, but the case for paying attention to hearing in diabetes is already solid.

Martines F, Salvago P, Vaccaro F, Vaccaro D, Malta G, Plescia F, Cascioferro S, Lavanco G, Plescia F. Associations Between Antidiabetic Pharmacotherapy and Hearing Thresholds in Adult Hearing-Impaired Patients With Type 2 Diabetes. Pharmacology Research & Perspectives. 2026;14(5):e70316. Retrieved from PubMed. https://doi.org/10.1002/prp2.70316