The estimated causal effect of frailty index on vestibular disorders may be still significant after adjustment for BMI (OR = 1.006, 95% CI 1.000–1.012, FDR-corrected p = 0.035), CRP (OR = 1.008, 95% CI 1.003–1.012, FDR-corrected p = 0.0007), IBD (OR = 1.006, 95% CI 1.000–1.012, FDR-corrected p = 0.035) and smoking (OR = 1.008, 95% CI 1.004–1.012, FDR-corrected p = 0.0007) (shown in Supplementary Tables 5, 6). Here, CRP is linked to inflammatory bowel disease.