Causal relationship between allergic rhinitis and otitis media: A Mendelian randomization study

Otitis media and allergic rhinitis are prevalent conditions. Some data posit a significant association between the 2 ailments, proposing mechanisms such as allergic rhinitis-induced Eustachian tube dysfunction or concurrent allergic pathophysiology affecting both the nasal and aural cavities. Observational studies hint at an association between allergic rhinitis (AR) and nonsuppurative otitis media, yet definitive causality remains elusive. Thus, to elucidate the causal impact of AR on otitis media, a 2-sample Mendelian randomization study was undertaken. Data on AR, acute suppurative otitis media, chronic suppurative otitis media, and nonsuppurative otitis media were sourced from the Genome for Extensive Association Study, encompassing individuals of European ancestry. Single nucleotide polymorphisms linked with AR were utilized as instrumental variables. The inverse-variance weighting (IVW) method, alongside sensitivity analyses employing the weighted median and Mendelian randomization-Egger methods, was employed to assess causal effects. Our analysis revealed a significant causal effect of AR on nonsuppurative otitis media (IVW, odds ratio [OR] = 12.22, 95% confidence interval, 1.38-107.93, P = .024) and indicated an association with acute suppurative otitis media (IVW, OR = 6.95, 95% confidence interval, 0.80-60.35, P = .078). However, no causal effect of AR on chronic suppurative otitis media was discerned. Our findings delineate a measurable causal link between AR and nonsuppurative otitis media (OR = 12.22) and suggest an association with acute suppurative otitis media (OR = 6.95), though lacking evidence for a causal effect on chronic suppurative otitis media. These results underscore the propensity of AR to correlate with diverse forms of otitis media and furnish high-quality causal evidence pertinent to clinical management.