Vitamin D Supplementation for Preventing Recurrent Benign Paroxysmal Positional Vertigo: A Randomized Clinical Study

Objective: To determine whether cholecalciferol supplementation reduces recurrence rates in patients with benign paroxysmal positional vertigo (BPPV) and concurrent vitamin D deficiency. Study design: Prospective, randomized, double-blind, placebo-controlled trial. Setting: Two tertiary otolaryngology centers in Baghdad, Iraq (Al-Kafaat Hospital ENT outpatient clinic and Al-Dora Hospital ENT outpatient clinic). Methods: One hundred sixty adults with confirmed idiopathic BPPV and serum 25-hydroxyvitamin D < 20 ng/mL were randomized 1:1 to receive cholecalciferol 10 000 IU weekly or matched placebo for 24 months. Primary outcome was BPPV recurrence (cumulative incidence, time-to-first recurrence) at 6, 12, 18, and 24 months. Secondary outcomes included vitamin D concentrations, DHI scores, per-participant recurrence frequency, and safety parameters. Full intention-to-treat analysis; missing data handled by multiple imputation. Results: Baseline characteristics were balanced between groups (mean age 36.8 ± 7.2 years). Cholecalciferol significantly elevated serum 25-hydroxyvitamin D concentrations at all timepoints (24 months: 24.8 ± 3.2 vs 9.8 ± 3.6 ng/mL, P < .001). BPPV recurrence was significantly reduced with cholecalciferol versus placebo at 6 months (15.0% vs 35.0%, P = .004), 12 months (22.5% vs 48.8%, P < .001), 18 months (25.0% vs 52.5%, P < .001), and 24 months (27.5% vs 55.0%, P < .001), representing a 50% relative risk reduction. Number needed to treat was 3.6. No hypercalcemic episodes occurred. Treatment adherence exceeded 94% in both groups. Conclusion: Cholecalciferol supplementation provides sustained, clinically meaningful reduction in BPPV recurrence among vitamin D-deficient patients over 24 months with excellent safety profile. Routine vitamin D assessment and targeted supplementation may be considered in vitamin D-deficient BPPV patients.