title: 25-Hydroxy vitamin D levels and endothelial vasodilator function in normotensive women.
abstract: BACKGROUND
  Vitamin D was shown to be related to endothelial function and blood pressure. Reactive hyperaemia index (RHI) measurement by pulse arterial tonometry is a new method to evaluate vasodilator function of endothelium. We aimed to evaluate the relationship between vitamin D levels and RHI in women.
  
  
  METHODS
  We enrolled 56 normotensive, nonsmoker, normolipidemic and normoglycemic women, (23 with 25-OH-vitamin D levels>20 µg/l, and 33 with values lower than 20 µg/l). The cardiologist who was blind for vitamin D results executed measurements by pulse arterial tonometry. The measurement was performed on the lying patient with pre- and post-occlusion measurements of RHI by digital sensors placed on each index finger, by 5 min intervals. Pulse amplitudes were recorded, pre-occlusion and post-occlusion ratio was compared by the software of device. Stepwise linear regression and multiple regression analyses were performed to evaluate predictors of endothelial function.
  
  
  RESULTS
  The low vitamin D group had a lower RHI value than the normal vitamin D group (p = 0.042). In regression analysis, positive predictors of RHI were serum 25-OHD (β = 0.401; 95% CI 0.010-0.042, p = 0.002), serum albumin (β = 0.315; 95% CI 0.286-2.350, p = 0.013), and, inversely, serum calcium (β = -0.247; 95% CI (-1.347)-(-0.010), p = 0.047).
  
  
  CONCLUSIONS
  Serum 25-hydroxy vitamin D was significantly related to endothelial functions measured as RHI, even in healthy non-smoker women.
authors.affiliation: Endocrinology and Metabolic Diseases Department, Ufuk University Medical Faculty, Dr. R. Ege Hospital, Ankara, Turkey.
authors.forename: Sibel
authors.initials: S
authors.lastname: Ertek
authors.forename: Ebru
authors.initials: E
authors.lastname: Akgül
authors.forename: Arrigo F
authors.initials: AF
authors.lastname: Cicero
authors.forename: Utku
authors.initials: U
authors.lastname: Kütük
authors.forename: Selda
authors.initials: S
authors.lastname: Demirtaş
authors.forename: Sengül
authors.initials: S
authors.lastname: Cehreli
authors.forename: Gürbüz
authors.initials: G
authors.lastname: Erdoğan