title: Vitamin D Levels in Takayasu's Arteritis and a Review of the Literature on Vasculitides.
abstract: OBJECTIVE
  Takayasu's arteritis (TAK) is a chronic, large-vessel vasculitis. Vitamin D, as a steroidal hormone, has recently been shown to have immunoregulatory and immunosuppressive effects. Low vitamin D levels are demonstrated in various autoimmune disorders. The aim of this study is to investigate vitamin D levels in patients with TAK. A comprehensive review of vitamin D levels in systemic vasculitides (SVs) is also performed.
  
  
  METHODS
  The study included 36 patients with TAK, 28 patients with Behçet's disease (BD) as disease control and 30 sex-matched healthy controls. Plasma 25-hydroxy vitamin D (25(OH) vit D) levels were measured with high-performance liquid chromatography. "Deficiency" was defined as 25(OH) vit D levels below 25 nmol/l and "insufficiency" as below 50 nmol/l.
  
  
  RESULTS
  Plasma 25(OH) vit D levels were significantly lower in TAK patients (16.93 ± 10.62 nmol/l) than healthy controls (64.63 ± 21.82 nmol/l). Vitamin D level in BD patients (38.8 ± 20.9 nmol/l) is lower than healthy controls but higher than TAK patients. The frequency of vitamin D deficiency was 83.3% in patients with TAK compared to 3.3% in healthy controls. Plasma 25(OH) vit D levels were same between clinically active and inactive patients. In literature review, very few studies were found to investigate vitamin D in SVs.
  
  
  CONCLUSIONS
  We observed a high prevalence of vitamin D deficiency in patients with TAK. As various immune effects of vitamin D on mononuclear cells and arterial endothelium is shown, vitamin D deficiency can be a predisposing factor for immune activation in SV. We therefore suggest monitorization and replacement of vitamin D status in all TAK and other SV patients.
authors.affiliation: Department of Rheumatology, School of Medicine, Marmara University, Istanbul, Turkey. falibaz@gmail.com.
authors.forename: Fatma
authors.initials: F
authors.lastname: Alibaz-Oner
authors.affiliation: Department of Internal Medicine, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Asmaz-Haliloglu
authors.affiliation: Department of Endocrinology, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: Dilek
authors.initials: D
authors.lastname: Gogas-Yavuz
authors.affiliation: Department of Rheumatology, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: Meryem
authors.initials: M
authors.lastname: Can
authors.affiliation: Department of Biochemistry, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: Goncagul
authors.initials: G
authors.lastname: Haklar
authors.affiliation: Department of Rheumatology, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: Haner
authors.initials: H
authors.lastname: Direskeneli
mesh_terms: D000328:Adult; D001528:Behcet Syndrome / Q000097:blood*; D016022:Case-Control Studies; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D016208:Databases, Factual / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013625:Takayasu Arteritis / Q000097:blood* / Q000378:metabolism; D014807:Vitamin D / Q000097:blood*
chemical_list: D014807:Vitamin D
keywords: Takayasu's arteritis; vasculitis; vitamin D deficiency