Type 2 diabetes may be associated with an increased risk of sudden sensorineural hearing loss, with a genetic analysis showing nearly 1.2 times the odds of the condition.
In a bidirectional and multivariable Mendelian randomization (MR) study, investigators examined whether type 1 and 2 diabetes, obesity, and hyperlipidemia may be causally associated with sudden sensorineural hearing loss (SSNHL). They used genome-wide association study data from patients of European ancestry and applied the inverse variance weighted method as the primary approach, with weighted median, MR-Egger, and MR-PRESSO used for sensitivity analyses.
The data sets included 202,046 participants for type 2 diabetes (17,268 cases), 189,302 for type 1 diabetes (6,729 cases), 209,714 for hyperlipidemia (4,535 cases), 218,735 for obesity (8,908 cases), and 196,592 for SSNHL (1,491 cases). Genetic variants associated with each exposure at genome-wide significance were selected as instrumental variables, with additional filtering to remove variants linked to confounders or hearing loss.
The investigators found that genetically predicted type 2 diabetes was associated with a higher risk of SSNHL, corresponding to 1.18 times the odds in a univariate MR analysis. This association persisted following adjustment for obesity and hyperlipidemia in multivariable analysis, demonstrating 1.17 times the odds of SSNHL. Sensitivity analyses showed consistent directional effects, and tests for heterogeneity and pleiotropy didn't identify bias.
No causal association was identified between SSNHL and type 1 diabetes, obesity, or hyperlipidemia. Reverse analyses also didn't support SSNHL as a causal factor for these metabolic conditions.
Limitations included the restriction to patients of European ancestry, thereby limiting generalizability, and the limited statistical power related to the number of SSNHL cases. The analysis also didn't allow for subtype-specific evaluation of SSNHL as a result of insufficiently detailed enome-wide association study data, and weaker instrument strength for hyperlipidemia may have affected the interpretation of those findings.
“[O]ur bidirectional MR and [multivariable] MR analyses demonstrate that [type 2 diabetes] may be a potential risk factor for the onset of SSNHL,” wrote lead study author Sufen Peng, MS, of the Department of Otorhinolaryngology at The People’s Hospital of Yubei District of Chongqing in China, and colleagues.
The study authors reported no conflicts of interest.
Source: Medicine