Studying the effect of vitamin d on the intensity of torsional nystagmus in Benign paroxysmal positional vertigo (BPPV) in Rohani hospital of Babol

Background: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo and nystagmus in clinics. Vertigo has many causes and the recurrence of vertigo is unknown. Among a lot of factors, vitamin D deficiency is more important. This study was conducted to determine the effect of vitamin D supplementation on torsional nystagmus in BPPV patients. This study wants to show the deficiency of vitamin D leads to the recurrence of BPPV. Methods: This case-control study was conducted from April 2017 to May 2018. All eligible patients with BPPV were presented to the Audiology clinic of Babol Rouhani hospital consecutively. Diagnosis of BPPV and the presence of nystagmus were confirmed and serum vitamin D was assessed. Dix-halpike maneuver and videonystagmography (VNG) for assessing nystagmus were done and for serologic assessment, ELISA was performed for analyzing the level of hydroxy 25 vitamin D.Vitamin D sufficient patients (more than 20 ng/ml) with BPPV were considered as the control group and vitamin D deficient patients (less than 20 ng/ml) were as the test group.   In all the patients of two groups, torsional nystagmus (vertical, horizontal and oblique) were studied and compared. Results: Twenty-seven patients in each group have completed the study. The mean age of the control group and test group was 48.2+4.8, 47.8+5.7 and 47.2+4.9 years respectively (P=0.91). Two groups were comparable regarding nystagmus severity. All patients had at least two attacks During the last six months. The mean of serum 25 OHD was 33.81 in the control group and 11.41 in the test group that was statistically significant (P=0.001 for all) and the severity of torsional nystagmus in three axes of horizontal, vertical and oblique in the control group was 4.98, 9.06, 5.40 respectively and 3.32, 8.86, 6.93 in the test group that was statistically significant as compared with the control group (P=0.001). Conclusion: Findings of this study indicate a relationship between vitamin D deficiency and recurrence of nystagmus in BPPV patients