Association between ankylosing spondylitis and hearing loss: A Mendelian randomization study

Observational studies have suggested a potential link between ankylosing spondylitis (AS) and hearing loss. However, this association remains controversial due to potential drug-induced ototoxicity from treatments. Therefore, we employed a Mendelian randomization (MR) approach to evaluate the association between AS and hearing loss from a genetic perspective. This MR study utilized summary data from genome-wide association studies on AS and hearing loss, including sensorineural hearing loss (SNHL) and conductive hearing loss (CHL). The primary analysis was conducted using the inverse-variance weighted method. The primary analysis showed a causal effect of AS on both SNHL (odds ratio [OR] = 1.121, 95% confidence interval [CI]: 1.042-1.206, P = .002) and CHL (OR = 1.387, 95% CI: 1.123-1.712, P = .002). After excluding chromosome 6 variants, the association with CHL persisted (OR = 1.675, 95% CI: 1.212-2.315, P = .002), while the effect on SNHL was no longer significant (OR = 1.054, 95% CI: 0.942-1.181, P = .357). The primary inverse-variance weighted analysis showed no causal effect of SNHL on AS (OR = 0.984, 95% CI: 0.892-1.086, P = .747). Sensitivity analyses found no evidence of horizontal pleiotropy. This MR study suggests that AS is causally associated with higher risks of CHL and SNHL. The association with CHL appears independent of the chromosome 6 human leukocyte antigen region, whereas the risk for SNHL is largely driven by this region. These findings suggest that targeted audiometric evaluations should be considered for symptomatic patients with AS. Further studies are required to explore the specific mechanisms linking AS to different types of hearing loss.