An Umbrella Review of Diabetes Mellitus and Hearing Impairment

This study aims to synthesize current meta-analyses to propose a potentially existing association between diabetes and hearing impairment (HI), elevating their relationship to "high" level of evidence.

A systematic search was performed in 9 databases up to March 31, 2025. The pooled results were synthesized to elucidate the direction and magnitude of the effects. We used the AMSTAR-2 scale to assess study quality and the GRADE tool to assess the certainty of the evidence. Subgroup analysis was conducted according to age (PROSPERO-ID: CRD42024606416).

This umbrella review comprehensively encompassed over 22 million participants from more than 226 studies. After screening, 21 studies were finally included. Primary outcomes showed that individuals with HI were at a higher risk of developing diabetes, referring to [odds ratio (OR) = 1.88, 95% confidence interval (CI): (1.01, 3.50)] with moderate evidence certainty. Simultaneously, participants with diabetes exhibited a more prevalent occurrence of HI. Higher pure tone audiometric thresholds, lower distortion product otoacoustic emission amplitudes, and increased auditory brainstem-evoked response latency time collectively indicated an increased risk of HI associated with diabetes. Subgroup analysis results revealed that in the younger population, the association between HI and diabetes risk is also high.

Overall, the current body of evidence underscores a latent bidirectional association between diabetes and HI, coupled with mutually aggravating effects. Our findings suggest that HI may serve as an indicator of the risk of developing diabetes.