Type 1 diabetes and hearing loss: Audiometric assessment and measurement of circulating levels of soluble receptor for advanced glycation end products

Background: We examined the hearing function in adults with and without type 1 diabetes (T1D) to investigate whether an association exists between hearing loss and duration of diabetes, haemoglobin A1C level, diabetes complications and levels of select serum and urinary biomarkers. Methods: We measured pure tone audiometry (PTA) thresholds; serum levels of C-reactive protein (CRP), vascular endothelial growth factor (VEGF), soluble receptors for advanced glycation end-product (sRAGE); and urinary isoprostane in 30 adults with T1D (age 43.8 ± 11.4 years). We also measured PTA thresholds in 11 adults without diabetes (age 53 ± 5.5 years). Results: 63.3% of adults with T1D had high-frequency hearing loss. Among adults with T1D, those with hearing loss were older (48.2 vs 36.2 years old, P <.01), had a longer duration of diabetes (30.7 vs 21.2 years, P =.02), a greater prevalence of peripheral neuropathy (57.9 vs 9.1%, P =.02) and significantly lower median levels of sRAGE (1054.27 vs 1306.83 pg/mL, P =.03) compared to those with normal hearing. Adults with T1D between the ages of 40 and 60 years old, who had diabetes for ≥35 years, had significantly higher PTA thresholds at both 500and 8000 Hz than age-matched adults without diabetes. Conclusions: A significant proportion of adults with T1D have high-frequency hearing loss before age of 60 that is positively associated with age, duration of diabetes and presence of peripheral neuropathy. Our results are in support of previous studies suggesting a potential protective role of sRAGE against AGE toxicity and diabetes complications.