A growing body of evidence suggests that hearing loss may be a significant yet under-recognized complication of type 2 diabetes. A new systematic review and meta-analysis published in Otolaryngology–Head & Neck Surgery found that people with type 2 diabetes are up to four times more likely to experience hearing loss than those without the condition, with prevalence ranging from 40.6% to 71.9% among individuals with diabetes.
The findings align with concerns raised by clinicians who warn that hearing difficulties may be an early sign of broader metabolic or microvascular changes. To mark American Diabetes Month, Dr. Sigurd Brandt, Medical Director at LISTEN TO THIS, emphasized the importance of understanding how diabetes may affect auditory health.
“All types of diabetes share a key characteristic: high blood sugar levels. When blood sugar becomes too elevated, it can disrupt normal body functions and impact a wide range of systems.
“One of the lesser-known effects of diabetes is hearing loss. While we still need more research to fully understand the link, current research suggests that high blood sugar levels can lead to nerve damage, including those involved in auditory function,” said Brandt.
Study Shows Elevated Risk and Earlier Onset of Hearing Loss
The meta-analysis reviewed 17 studies comprising 3,910 people with diabetes and 4,084 controls. Across pooled data, individuals with type 2 diabetes had a 4.19-times higher risk of hearing loss compared with those without diabetes.
Hearing thresholds were consistently higher in the diabetic group, with pure-tone audiometry revealing an average increase of 3.19 dB. High-frequency hearing (4,000–8,000 Hz) was more affected than low frequencies, supporting earlier research suggesting that early cochlear damage often occurs in the basal turn of the cochlea.
The study also found that hearing loss becomes more likely with longer disease duration. Individuals with diabetes for 10 or more years had more than double the risk of hearing loss than those with a shorter duration of illness. Higher HbA1c levels were associated with more severe hearing loss, suggesting that poorer glycemic control may accelerate auditory decline.
Expanding on the potential mechanisms, Dr. Brandt explained:
“The inner ear contains lots of tiny hair cells that detect sound waves and send signals to the brain. These cells rely on a steady supply of oxygenated blood to function. So when blood sugar is consistently high, it can have the potential to damage blood vessels that are vital for delivering oxygen to the inner ear. Over time, this damage may contribute to hearing loss.”
Clinical Impact: A Growing Public Health Concern
More than 38 million Americans live with diabetes, and the new analysis suggests that a substantial share may experience hearing loss—often without recognizing early symptoms. Because much of the hearing loss measured in the studies was mild, individuals may not immediately notice changes until communication difficulties appear.
“What is important here is the wider impact this growing research could have on the population,” commented Dr. Brandt.
“Diabetes already impacts over 38 million Americans, and what this research shows is that these individuals face significantly higher risk of developing hearing loss. That if left untreated could seriously affect their quality of life and place greater strain on health care systems. In fact, globally, unaddressed hearing loss costs the economy nearly US$1 trillion every year. That’s why it’s crucial for people with chronic conditions like diabetes to understand the early warning signs and seek timely intervention.”
The research underscores the need for routine hearing screenings, particularly for individuals with long-standing diabetes or elevated HbA1c levels. Unaddressed hearing loss has been associated with decreased social engagement, depression, and cognitive decline—areas already of concern in diabetes management.
Recognizing Early Symptoms: What Patients Should Watch For
To help individuals identify possible early signs of hearing changes, Dr. Brandt shared several indicators that warrant attention or further evaluation:
- Difficulty following conversations in noisy places
If you’re finding it harder to follow conversations in loud environments such as restaurants, coffee shops or bars, it could be an early sign of hearing loss. When your brain struggles to filter background noise, it must work harder to decode speech, which can reduce memory and focus and, over time, may contribute to cognitive decline. - Turning up the volume more frequently
If you find yourself consistently needing to increase the volume on the TV or your headphones, it could be an early sign of hearing loss. Prolonged exposure to loud volumes can worsen hearing, creating a cycle of damage. - Frequently asking others to repeat themselves
Regularly saying “what?” during conversations may mean you’re not processing speech sounds clearly. Beyond being inconvenient, this can knock your confidence and lead to social withdrawal, increasing the risk of loneliness, depression, and isolation. - Feeling drained after talking to people
If talking to people, especially in noisy environments, leaves you feeling mentally exhausted, it could be an early sign of hearing loss. Straining to hear forces your brain to fill in the blanks and, over time, that extra effort may affect how well your brain functions. - Voices sound muffled or unclear
If voices sound muffled on the phone or in person, it may be due to hearing loss. Sometimes, a blocked feeling comes from earwax or an infection, but if a professional rules that out and the problem continues, it could be a more serious sign. - Relying on facial cues or lip reading
If you find yourself watching people’s mouths to understand them, your ears may not be picking up speech accurately. Relying on facial cues can help in the short term, but it also adds cognitive load and may worsen both listening fatigue and brain function over time.
Experts say recognizing these early signs and seeking timely assessment can help people with diabetes protect both their hearing and overall health.
Implications for Care
Research suggests that hearing loss in diabetes may reflect microvascular changes, similar to retinopathy or neuropathy, and could serve as an early signal of broader metabolic stress. Damage to small blood vessels that supply the inner ear may reduce oxygen and nutrient delivery, contributing to degeneration of key cochlear structures involved in sound processing, according to the study authors.
While further prospective research is needed, experts recommend that clinicians incorporate hearing discussions into diabetes care, particularly for patients with long disease duration or elevated HbA1c levels. Regular audiologic monitoring, education about noise exposure, and timely referral for hearing evaluation may help limit the long-term impact of hearing changes in this high-risk group.
Citation
- Caballero-Borrego M, Andujar-Lara I. Type 2 Diabetes Mellitus and Hearing Loss: A PRISMA Systematic Review and Meta-Analysis. Otolaryngology–Head & Neck Surgery. 2025;173(5):1041–1053. doi:10.1002/ohn.1346.
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