Hearing Loss in Type 2 Diabetes in Association with Diabetic Neuropathy

Reports assessing hearing abnormalities in diabetes are debated. We aimed to evaluated auditory alterations and their possible associations with vascular and neurological dysfunction in 160 Type 2 diabetes mellitus individuals and 100 age and sex-matched healthy controls.

Participants underwent pure tone audiometry (PTA). Associations with demographic, metabolic and neuropathic variables were assessed.

Compared with healthy controls, diabetic patients had higher mean hearing thresholds at each frequency, with statistical significance at 2-8 kHz (p <0.05). Prevalence of hearing loss in diabetics was 67.5% (108/160), including high-frequency (72.22%, 78/108), and low/mid- and high-frequency (27.78%, 30/108). The mild hearing loss was predominant in diabetics with high-frequency impairment (52.56%), while the moderate/severe hearing loss was high in individuals with both low-and high-frequency hearing loss (80.00%). Multiple logistic regression analysis of PTA parameters showed that higher Semmes Weinstein Monofilament (OR 1.24, 95% CI 1.02-1.52), Michigan Neuropathy Screening Instrument score (OR 1.38, 95% CI 1.14-1.68), and vibration perception threshold (OR 1.19, 95% CI 1.05-1.34) were independent risk factors for hearing impairment in diabetics after adjusting for potential covariates.

These findings suggest that hearing loss is common in T2DM subjects, with predominantly high frequency involved. Diabetic neuropathic factors may explain the underlying mechanism of the association between diabetes and hearing loss.