Association of benign paroxysmal positional vertigo with vitamin D deficiency: a systematic review and meta-analysis

Background and objective Benign paroxysmal positional vertigo (BPPV) is an idiopathic recurrent inner ear illness that is caused most often by an imbalance in the metabolism of calcium carbonate crystals (otoconia) inside the semicircular canals, in which the otoconia begin to circulate freely after being dislodged from the basic structure. The underlying etiology of this imbalance has not yet been well established; however, a few recent articles have revealed that vitamin D level abnormality in these patients might play a role. Therefore, we conducted the current systematic review analysis to explore potential associations of vitamin D level with the occurrence as well as the recurrence of BPPV disease. Methods A comprehensive literature search was conducted using different databases to retrieve all of the articles that have evaluated possible associations, irrespective of the study design. Then, we reported different vitamin D3 levels from BPPV groups and control groups to estimate the standardized mean difference (SMD) between the BPPV and control groups. We also calculated the effect size of each study under the random effects statistical model. Results Of the 703 studies that we identified, only 37 studies were found to be potential for our analysis, and of these, only seven met our predetermined criteria. Two meta-analyses were conducted with respect to the occurrence and the recurrence of BPPV. When the BPPV cases were compared to the controls (free of BPPV disease), there was an insignificant reduction in vitamin D level among the diseased groups (SMD = − 2.20; 95% CI − 6.66 to 2.26). In contrast, when the recurrent BPPV groups were compared with the non-recurrent BPPV groups, the statistical analysis showed significantly lower level of vitamin D among the recurrence BPPV groups (SMD = − 4.47; 95% CI − 7.55 to − 1.29). Conclusion Although a negative vitamin D imbalance has been reported among some BPPV patients, this review analysis failed to establish a relationship between the occurrence of BPPV and low vitamin D level. However, low vitamin D level was significantly evident among patients with recurrent episodes of BPPV.