Senior author Catherine Cowie of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Md., says the link between diabetes and hearing loss was evident across all frequencies, with a stronger association in the high frequency range.

Mild or greater hearing impairment of low- or mid-frequency sounds in the worse ear was about 21 percent in 399 adults with diabetes compared to about 9 percent in 4,741 adults without diabetes, Cowie says.

The study, published in the Annals of Internal Medicine, finds adults with pre-diabetes -- having blood glucose higher than normal but not high enough for a diagnosis of diabetes -- had a 30 percent higher rate of hearing loss compared to those with normal blood sugar tested after an overnight fast.

"Hearing loss may be an under-recognized complication of diabetes," Cowie said in a statement. "Our study found a strong and consistent link between hearing impairment and diabetes using a number of different outcomes."