Tehran University Medical Journal

Background and Aim: It seems that diabetes mellitus affects hearing system by several mechanisms including microangiopathy ,sorbitol deposition and glycosilation ,dealing to progressive bilateral sensorineural hearing loss which is related duration of diabetes.

Materials and Methods: This is a descriptive cross-sectional study performed on 300 patients with type 2 diabetes mellitus aged 30 to 50 years and a control group of 300 persons matched regarding age and gender .The cases were selected randomly and they were assessed by a quastionaire before performing audiogram. The exclusion criteria were conductive hearing loss sensorineural hearing loss with any other cause and other metabolic diseases .Audiometric test battery consisting of pure tone audiogram (PTA) and impedance were perfumed on both case and control groups.            

Reasults: In this study the hearing threshold in low and high frequencies in case group was higher than control group. In different age groups, the mean high and low frequencies hearing threshold in case group was higher than control groups. Based on duration of diabetes , the mean hearing threshold in the group with 8 to 18 years duration of diabetes was higher than the other two groups with 1 to 3 years and 4 to 7 years diabetes duration. The hearing level of hypertensive and normotensive diabetic patients were not significantly different. The mean hearing threshold was not significantly different between male and female diabetic patients.

Conclusion: In general, diabetic patients have a poorer hearing compared with normal population and there is a significant relationship between duration of diabetes and incidence of sensorineural learning loss.