Of the many effects of diabetes hearing loss remains a common but largely unrecognised feature of the disease, according to scientists.
A US-led research project has revealed that adults with diabetes are about twice as likely to have impaired hearing as people without the condition.
Team leader Dr Kathleen Bainbridge said: "We found that hearing loss was much more common in people with diabetes than people without the disease. The hearing loss we detected did not seem to be caused by other factors such as exposure to loud noises, certain medicines and smoking."
Almost two million people in the UK are diagnosed with type 2 diabetes, which is linked to obesity and lifestyle. More than 500,000 more Britons are thought to have the disease without knowing it. A further 250,000 have type 1, or insulin dependent, diabetes which is an auto-immune disease.
The new findings emerged after scientists analysed the results of a national hearing survey of more than 5,000 US adults. People were tested for their ability to hear low, middle and high frequency sound.
Results from 399 diabetes sufferers the prevalence of a mild or greater reduced ability to hear high frequencies was 54.1% among people with diabetes compared with 32% among adults without the disease.
Diabetes is known to damage small blood vessels and nerves in the body. In severe cases this can lead to blindness or lost limbs.
"It is possible that high blood sugar levels damage the small blood vessels and nerves of the inner ear, resulting in hearing impairment," said Dr Bainbridge. "People with diabetes might benefit from having their hearing checked."