When people think about complications of diabetes, they may think of poor eyesight, kidney disease or numbness in the feet.
A growing body of research suggests that hearing loss deserves a place on that list too.
Researchers at The University of Queensland say serious hearing loss affects about one in four adults with diabetes worldwide. Their review suggests that people with diabetes have more than double the risk of significant hearing problems compared with those without the disease.
That could mean roughly 130 million people are living with both diabetes and serious hearing loss. Yet hearing tests are not routinely included in diabetes checkups in the same way as examinations of the eyes, kidneys and nerves.
Diabetes affects hundreds of millions of people worldwide and is becoming increasingly common. Type 2 diabetes, the most common form, occurs when the body becomes resistant to insulin or cannot produce enough insulin to keep blood sugar under control.
High blood sugar does not only affect the bloodstream. Over many years, it can injure small blood vessels and nerves, which helps explain why diabetes can cause problems in organs that may seem unrelated.
The retina at the back of the eye contains tiny blood vessels that can be damaged by diabetes. The kidneys are also packed with small filtering vessels, while nerves throughout the body can become injured and produce numbness, pain or weakness.
The ear may be vulnerable for similar reasons. Deep inside the inner ear are extremely delicate structures that depend on a healthy blood supply and functioning nerves to detect sound and carry information to the brain.
If diabetes damages those small vessels or nerves, hearing may gradually become worse. Because the process can be slow, people may adjust to the change and fail to notice how much hearing they have lost.
To examine the evidence, researchers reviewed 29 studies involving more than 17,000 adults around the world. Most participants had type 2 diabetes or prediabetes.
The analysis identified hearing impairment as an important but underrecognized complication of diabetes. Dr. Mehwish Nisar from UQ’s School of Public Health said awareness of the connection remains surprisingly low.
The issue may be particularly important because hearing loss is not restricted to people in their 70s or 80s. The researchers highlighted serious hearing difficulties among working-age adults in their 40s and 50s.
At that stage of life, reduced hearing can affect meetings, telephone conversations, relationships and family responsibilities. A person who struggles to follow speech may also begin avoiding busy restaurants, social gatherings or other situations where hearing becomes difficult.
Over time, this can contribute to isolation. Hearing loss has also been linked in other research with a greater risk of cognitive decline, although that does not mean hearing loss automatically causes dementia.
Another important finding was that increased hearing risk appeared relatively early after diabetes developed. People who had diabetes for less than a decade were still more than twice as likely to have significant hearing loss as people without diabetes.
This suggests that hearing checks should not necessarily be saved for people with very long-standing or severe disease. By the time someone clearly notices a problem, some hearing loss may already be established.
The researchers are therefore calling for routine audiometric screening to become part of standard diabetes care. Audiometry is a straightforward test that checks the quietest sounds a person can hear across different sound frequencies.
Such testing can identify problems before they become severe enough to disrupt everyday communication. If hearing loss is detected, patients can be referred for a more complete assessment and offered hearing aids or other support when appropriate.
Better blood sugar management may also be useful for protecting general blood-vessel and nerve health. However, people should not assume that every hearing problem in someone with diabetes is caused by blood sugar, because many other conditions can damage hearing.
Age remains a major cause of hearing decline, while repeated exposure to loud noise can damage the inner ear. Certain infections, medications, cardiovascular conditions and inherited factors can also contribute.
The research was published in Diabetes/Metabolism Research and Reviews. It was conducted by Dr. Mehwish Nisar and colleagues from The University of Queensland.
Because the research reviewed previous studies rather than conducting one new clinical trial, its conclusions depend partly on the quality and methods of those studies. Differences between populations and hearing tests can make it difficult to calculate one exact level of risk for every person with diabetes.
The association also does not prove cause and effect. Researchers still need long-term studies that repeatedly test hearing and blood sugar control to understand when hearing changes begin and whether improved diabetes management can slow them.
Nevertheless, the review draws attention to a complication that is easy to miss and relatively easy to screen for. That combination makes hearing an important area for future diabetes guidelines to consider.
The study’s most useful message is not that everyone with diabetes will lose their hearing. Rather, people with diabetes appear to have enough additional risk that hearing changes should be taken seriously instead of dismissed as an unavoidable part of getting older.
Adding a simple hearing check to routine care could help doctors find problems sooner and help patients stay connected to work, family and friends. If future research confirms the benefits of regular screening, hearing care may become another standard part of protecting long-term health in diabetes.
If you care about hearing health, please read studies about antibiotic drug that can lead to hearing loss, and whether you should get an hearing aid or see a specialist.
For more health information, please read studies about how the Mediterranean diet could protect your brain health, and these antioxidants could help reduce dementia risk.
Source: The University of Queensland.
