title: The effect of serum vitamin D normalization in preventing recurrences of benign paroxysmal positional vertigo: A case-control study.
abstract: BACKGROUND
  Benign paroxysmal positional vertigo (BPPV) is a condition with recurrent attacks in a significant proportion of patients. The present case- control study was conducted to assess the influence of serum vitamin D normalization on recurrent attacks of vitamin D deficient patients.
  
  
  METHODS
  Diagnosis of BPPV was made based on history and clinical examination and exclusion of other conditions. Serum 25-hydroxy vitamin D (25-OHD) was measured using ELISA method and a levels of < 20 ng/ml was considered a deficiency of vitamin D. Inclusion criteria were as follows: history of recurrent attacks and serum 25-OHD<20.ng/ml. While the patients with history of trauma, surgery and chronic systemic diseases were excluded. The patients were classified into two groups: treatment and control, intermittently. Both groups received Epley rehabilitation therapy one session per week for 4 weeks but the treatment group received an additional supplement of 50.000 IU of vitamin D (cholecalciferol) weekly for two months to achieve serum 25-OHD ≥ 30 ng/ml and the study patients were followed-up for 6 months.
  
  
  RESULTS
  Twenty-seven patients were allocated to each group. At baseline, serum 25-OHD was similar (10.7±2.3 vs 11.41±1.9, P=0.23). At month 2, serum 25-OHD in the treatment group increased significantly to ≥ 30 ng/ ml, whereas serum 25-OHD in the control group remained unchanged (34.2±3.3 vs 10.6 10.6±2.2 ng/ml, P=0.001). During the follow-up period, attacks of BPPV in the treatment group decreased significantly compared with the control group (14.8% vs 96.3% OR= 0.18, P=0.001).
  
  
  CONCLUSIONS
  The findings of this study indicate that the normalization of serum vitamin D significantly reduces BPPV recurrences.
authors.affiliation: 1.Department of Audiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Mahboobeh
authors.initials: M
authors.lastname: Sheikhzadeh
authors.affiliation: 1.Department of Audiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Yones
authors.initials: Y
authors.lastname: Lotfi
authors.affiliation: 2.Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Abdollah
authors.initials: A
authors.lastname: Mousavi
authors.affiliation: Mobility Impairment Research Center, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Heidari
authors.affiliation: Department of Statistics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Enyatollah
authors.initials: E
authors.lastname: Bakhshi
keywords: 25-hydroxy vitamin D; BPPV; Epley Therapy; Recurrent vertigo