People with diabetes routinely have their eyes, kidneys and feet checked for signs of damage. Researchers from The University of Queensland say another important health check may need to be added to that list: hearing.
A major review has found that adults with diabetes are more than twice as likely to experience serious hearing loss as people without the condition. The researchers argue that simple hearing tests should become a regular part of diabetes care.
Diabetes is one of the world’s most common long-term diseases. It develops when the body cannot properly control the amount of glucose, or sugar, in the blood, and persistently high blood sugar can gradually damage blood vessels and nerves throughout the body.
This is why doctors already watch carefully for complications involving the eyes, kidneys and nerves. Damage to the retina can threaten vision, kidney damage can reduce the body’s ability to filter waste, and nerve damage can cause pain, numbness or loss of feeling.
Hearing problems have received much less attention. Dr. Mehwish Nisar from UQ’s School of Public Health said many patients are not even aware that diabetes and hearing loss may be connected.
Researchers reviewed 29 previous studies involving more than 17,000 people from around the world. Most of the participants had type 2 diabetes or prediabetes, a condition in which blood sugar is higher than normal but has not yet reached the level used to diagnose diabetes.
The review found that hearing impairment was a significant but often overlooked complication. According to the researchers, roughly one in four adults with diabetes may be living with serious hearing loss, representing about 130 million people worldwide.
Several biological processes could help explain the connection. The inner ear contains delicate sensory cells and tiny blood vessels that are essential for turning sound into signals the brain can understand.
Long-term high blood sugar may damage these small blood vessels and nerves, just as it can harm other parts of the body. Over time, this could interfere with the ear’s ability to detect sound and send clear information to the brain.
One concern is that hearing loss can develop gradually. A person may begin turning up the television, asking others to repeat themselves or having trouble following conversations in noisy places without immediately realizing that their hearing has changed.
The problem is not limited to very old adults. The researchers said diabetes-related hearing difficulties can affect people in their 40s and 50s, when communication remains especially important for work, family life and social relationships.
Untreated hearing loss can have effects beyond difficulty hearing words. It may make conversations exhausting, encourage people to withdraw socially and contribute to loneliness, and hearing impairment has also been associated in broader research with cognitive decline.
The review also suggested that hearing problems may appear earlier in the course of diabetes than many people assume. Even people who had lived with diabetes for less than 10 years showed more than twice the risk of significant hearing loss compared with people without diabetes.
This finding challenges the idea that hearing should only be checked after someone has had diabetes for decades or has already developed other complications. Waiting until hearing difficulties are obvious may mean missing an opportunity to identify problems earlier.
The researchers argue that basic hearing screening could provide that opportunity. Audiometric testing measures how well a person can hear sounds at different pitches and volumes and can detect hearing changes that may not yet be obvious in everyday life.
Early identification does not necessarily reverse hearing damage, but it can help people receive appropriate support sooner. Hearing aids and other communication strategies may improve conversations, social participation and quality of life.
Good diabetes management may also remain important for reducing further damage. Keeping blood sugar, blood pressure and other cardiovascular risks under appropriate control helps protect small blood vessels and nerves throughout the body.
The findings were published in Diabetes/Metabolism Research and Reviews. The research was led by Dr. Mehwish Nisar and colleagues from The University of Queensland’s School of Public Health.
The review has important strengths because it combined evidence from 29 studies and more than 17,000 participants. Bringing studies together can reveal a pattern that may be harder to see in smaller individual investigations.
However, the results do not prove that diabetes directly causes every case of hearing loss. Age, exposure to loud noise, cardiovascular disease, medicines, genetics and other health factors can also affect hearing, and the studies included in a review may differ in how they measured diabetes and hearing impairment.
More research is therefore needed to determine which people with diabetes face the greatest risk and how often hearing should be tested. Researchers also need to learn whether tighter diabetes control can directly slow the development of hearing loss.
Even with these uncertainties, the study raises a practical issue for diabetes care. Hearing is easy to overlook because changes can be slow, but identifying problems earlier could help millions of people maintain communication and independence.
Overall, the evidence supports taking hearing health more seriously in people with diabetes. Routine screening may eventually join eye, kidney and nerve checks as another way of detecting complications before they become harder to manage.
If you care about diabetes, please read studies about bananas and diabetes, and honey could help control blood sugar.
For more health information, please see recent studies about Vitamin D that may reduce dangerous complications in diabetes and plant-based protein foods may help reverse type 2 diabetes.
Source: The University of Queensland.
