ABSTRACT
RESEARCH BACKGROUND: Vitamin D insufficiency/deficiency is known to be related to occurrences and recurrences of benign paroxysmal positional vertigo (BPPV). However, the efficacy of vitamin D supplementation in reducing recurrences of BPPV remains to be established. We performed a meta-analysis to determine the therapeutic effects of vitamin D supplementation, with or without calcium, for preventing recurrences of BPPV. METHODS: We searched the PubMed, the Embase, the Web of Science and the reference lists of the articles. We included randomized or non-randomized trials that determined the efficacy of supplementing vitamin D or related compounds, alone or with calcium, in comparison to placebo or no intervention in preventing recurrences of BPPV. The primary outcome was the number of patients with BPPV recurrences. Data were collected and pooled using a weighted relative risk (RR) with corresponding 95% CIs, where possible, by adopting the fixed-effect or random-effect model according to the heterogeneity among the studies. The between-study heterogeneity was tested using the χ2 test and the I2 statistic, and funnel plots were used to evaluate any publication bias. RESULTS: We included five trials (four non-randomized trials and one randomized controlled trial) with a total of 1250 participants. The analyses showed a significant preventive effect on the recurrences of BPPV (RR = 0.37; 95% CI = 0.18-0.76; p = 0.007 with the random-effects model) with supplementation of vitamin D. Although a considerable heterogeneity was detected among the studies, the sensitivity analyses showed the reliability and stability of our results. CONCLUSIONS: Vitamin D supplementation provides a benefit for secondary prevention of BPPV. Supplementation of vitamin D should be considered in patients with frequent attacks of BPPV, especially when serum vitamin D is subnormal.