Apolipoprotein AI is a protective factor for idiopathic sudden sensorineural hearing loss: a two-sample mendelian randomisation study

Observational studies have suggested an association between cardiometabolic factors and idiopathic sudden sensorineural hearing loss (ISSNHL), but the causal relationship remains unclear. We aimed to assess the causal effect of cardiometabolic factors on the risk of ISSNHL using a two-sample Mendelian randomisation (MR) approach. Two-sample MR study. We used summary-level data from genome-wide association studies (GWAS). Genetic instruments for cardiometabolic factors were obtained from GWAS. Summary statistics for ISSNHL were derived from a publicly available GWAS database. Genetically predicted higher ApoAI levels were significantly associated with an decreased risk of ISSNHL (IVW OR = 0.82, 95% CI: 0.68–0.98, P = 0.03). No evidence of directional pleiotropy was detected in MR-Egger regression (P = 0.30), and Cochran’s Q test indicated no significant heterogeneity (P = 0.94). MR-PRESSO detected no outliers. This study provides evidence supporting a potential causal relationship between higher ApoAI levels and decreased risk of ISSNHL. Further biological and clinical studies are warranted to elucidate the underlying mechanisms.