Studies have demonstrated that HbA1c is a significant predictor of hearing impairment in type 1 diabetes. We identified additional factors associated with hearing impairment in participants with type 1 diabetes from the Diabetes Control and Complications Trial and its observational follow-up, Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study.
1,150 DCCT/EDIC participants were recruited for the Hearing Study. A medical history, physical measurements, and a self-administered hearing questionnaire were obtained. Audiometry was performed by study-certified personnel and assessed centrally. Logistic regression models assessed the association of risk factors and comorbidities with speech- and high-frequency hearing impairment.
Mean age was 55±7 years, duration of diabetes 34±5 years, and DCCT/EDIC HbA1c 7.9±0.9%. In multivariable models, higher odds of speech-frequency impairment were significantly associated with older age, higher HbA1c, history of noise exposure, male sex, and higher triglycerides. Higher odds of high-frequency impairment were associated with older age, male sex, history of noise exposure, higher skin intrinsic florescence (SIF) as a marker of tissue glycation, higher HbA1c, non-professional/non-technical occupations, sedentary activity, and lower LDL cholesterol. Among participants who previously completed computed tomography and carotid ultrasonography, coronary artery calcification (CAC)>0 and carotid intima-medial thickness were significantly associated with high- but not speech-frequency impairment.
Consistent with previous reports, male sex, age, several metabolic factors, and noise exposure are independently associated with hearing impairment. The association with SIF further emphasizes the importance of glycemia, as a modifiable risk factor, over time. In addition, the macrovascular contribution of CAC is novel and important.