Blood Vitamin D Levels in Patients with Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo

The aim of the study was to evaluate whether patients with PSC BPPV have vitamin D levels lower than those considered normal in clinical practice, whether there is a correlation between BPPV recurrence and the degree of vitamin D deficiency, and whether vitamin D supplementation therapy after the first episode of BPPV represents an effective therapeutic tool to reduce the risk of recurrence. This retrospective observational study, was conducted on a clinical sample of 97 adult patients diagnosed with BPPV of the PSC. After resolution of BPPV through canalith repositioning maneuvers, each patient was asked to undergo serum vitamin D testing. Six months after the first visit, each participant completed a telephone questionnaire to obtain information on vitamin D levels after the first episode of PSC BPPV, on the presence of BPPV recurrences, and on any supplemental vitamin D therapy. The number of patients with blood vitamin D levels above 30 ng/mL recorded immediately after the first episode of BPPV was 41 (42%). Fifty-six patients (58%) had insufficient vitamin D levels. Similarly, using the same cut-off of 30 ng/mL, no statistically significant difference was observed between vitamin D levels in patients with and without recurrence in the six months following the first episode of BPPV. However, using a 40 ng/mL cut-off, it emerges that out of the 97 patients treated for a first episode of PSC BPPV, 88 patients (90%) had a vitamin D value below 40 ng/mL. Considering the cut-off at 40 ng/mL, similar significance was found among patients who reported a second episode within six months of the first: 21 out of 24, equal to 87.5%. The results of the study suggest an absence of a protective role of vitamin D both in the onset of otolithic pathology of the PSC and in the possibility of a second episode. However, if the reference value is raised to 40 ng/mL, vitamin D levels above 40 ng/mL appear to have a protective association in both pathological situations. This data should be taken into consideration to establish the appropriate dosage of vitamin D both in normal subjects and in patients requiring supplementation therapy after a first episode of BPPV.