To evaluate the prevalence and potential associations of hearing impairment in patients 30 to 50 years old with diabetes diagnosed before age 40 years-early-onset type 2 diabetes mellitus (T2DM).
The study cohorts consisted of 46 consecutive patients with early-onset T2DM and 47 age-matched control subjects with rheumatoid arthritis. All study subjects completed clinical, serologic, and auditory assessments.
The patients with T2DM had a mean age of 42 ± 6 years and a mean disease duration of 11 ± 6 years. Microalbuminuria was present in 26.1%, proliferative retinopathy in 26.1%, and symptomatic peripheral neuropathy in 23.9%. The prevalence of unilateral or bilateral hearing loss was significantly higher in the patients with T2DM than in the patients with rheumatoid arthritis (21.7% versus 6.4%, respectively; P = .01). Most cases of hearing loss were mild and involved high or acute tones. After multivariate analysis with adjustment for age, there was a significant association between hearing loss and hemoglobin A1c (odds ratio, 1.3; 95% confidence interval, 1.02 to 1.81; P = .035). In the patients with T2DM, the lengthening of the brainstem response was not significantly increased; however, the wave morphologic features were abnormal and the reproducibility was poor in both ears in 11 patients (24%).
Patients with early-onset T2DM and poor glycemic control have an increased prevalence of subclinical hearing loss and impaired auditory brainstem responses. Hearing impairment may be an underrecognized complication of diabetes.