Dr. Kathleen Bainbridge, an epidemiologist with Social & Scientific Systems in Silver Spring, MD, observed the results of audiometric testing in 472 individuals with diagnosed or undiagnosed diabetes who were enrolled in the ongoing National Health and Nutrition Examination Survey (NHANES). She reported the findings at the annual meeting of the American Diabetes Association.
Hearing impairment affects more than two-thirds of adults with diabetes, yet little is known about the characteristics of individuals who develop this disability, Dr. Bainbridge observed.
For the analysis, pure-tone air conduction hearing thresholds in decibels were obtained for each ear at 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz.
Participants were considered hearing impaired if their pure-tone average in the worse ear exceeded 25 decibels over a given frequency range.
Results revealed that peripheral neuropathy and coronary heart disease each increased the odds of high-frequency hearing impairment by more than fivefold (odds ratios, 5.59 and 5.84, respectively).
Poor glycemic control, defined as a hemoglobin A1C >7%, more than doubled the likelihood of high-frequency impairment (OR 2.73).
Hearing impairment was not correlated with hypertension, high cholesterol, body mass index, smoking, and micro- or macroalbuminuria, duration of diabetes, medication type, or whether or not a person had been diagnosed.
Dr. Bainbridge noted that the very strong associations between hearing ability and neuropathy as well as hearing ability and coronary heart disease are consistent with neurological and vascular changes that have been observed within the inner ear.
We believe that hearing evaluations would benefit the majority of people with diabetes, she added. Hearing impairment is not just a problem for the elderly, especially among persons with diabetes.
Finally, she said, she hoped that longitudinal studies will determine the role of glycemic control, if any, in the prevention of hearing impairment.
