OC90 and Vertigo: Exploratory mediation analyses suggested that Otolin-1 and otoconin-90 statistically accounted for approximately 40 and 29% of the sleep-symptom association, respectively, with consistent findings across sensitivity and subgroup analyses.<h4>Conclusion</h4>These findings indicate that otolith-related inner-ear structural biomarkers are associated with both the presence and severity of BPPV and may partially explain the relationship between sleep quality and vertigo symptoms.