"Hearing loss may be an under-recognized complication of diabetes. As diabetes becomes more common, the disease may become a more significant contributor to hearing loss," said senior author Catherine Cowie, Ph.D., of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), who suggested that people with diabetes should consider having their hearing tested.
The researchers discovered the higher rate of hearing loss in those with diabetes after analyzing the results of hearing tests given to a nationally representative sample of adults in the United States. The test measured participants' ability to hear low, middle, and high frequency sounds in both ears. The link between diabetes and hearing loss was evident across all frequencies, with a stronger association in the high frequency range.
Adults with pre-diabetes, whose blood glucose is higher than normal but not high enough for a diabetes diagnosis, had a 30 percent higher rate of hearing loss compared to those with normal blood sugar tested after an overnight fast.
Half of the 11,405 survey participants aged 20 to 69 were randomly assigned to have their hearing tested, and nearly 90 percent of them completed the hearing exam and the diabetes questionnaire. The hearing test, called pure tone audiometry, measures hearing sensitivity across a range of sound frequencies.
"Using the data from the hearing tests, we measured hearing impairment in eight different ways. Also, participants responded to questions about hearing loss in the questionnaire, which asked whether they had a little trouble hearing, a lot of trouble hearing, or were deaf without a hearing aid," said Cowie.
In addition, 2,259 of the participants who received hearing tests were randomly assigned to have their blood glucose tested after an overnight fast.
Diabetes may lead to hearing loss by damaging the nerves and blood vessels of the inner ear, the researchers suggest. Autopsy studies of diabetes patients have shown evidence of such damage.
MEDICA.de; Source: NIDCD