title: The effect of vitamin D replacement on markers of vascular health in stroke patients - a randomised controlled trial.
abstract: OBJECTIVE
  Low vitamin D levels are associated with increased incidence of future cardiovascular events and are common in stroke patients. We tested whether vitamin D supplementation could reduce blood pressure and improve markers of vascular health in patients who had previously suffered a stroke.
  
  
  RESULTS
  Randomised, placebo-controlled, double-blind trial. Community-dwelling patients with a history of stroke and baseline 25-hydroxyvitamin D levels <75 nmol/L received 100,000 units of oral vitamin D2 or placebo at baseline. Office and 24 h blood pressure, endothelial function measured by flow-mediated dilatation of the brachial artery, cholesterol, oxidised low density lipoprotein, B-type natriuretic peptide and heart rate turbulence were measured at baseline, 8 weeks and 16 weeks. 58 patients were randomised. Mean age was 67 years, mean baseline blood pressure 128/72 mmHg, mean baseline 25-hydroxyvitamin D level was 38 nmol/L. Serum 25-hydroxyvitamin D levels were higher in the intervention group at 8 weeks compared to placebo (54 vs 42 nmol/L, P = 0.002) and remained higher at 16 weeks. Office systolic and diastolic blood pressure showed no significant change between groups at 8 weeks (systolic 126.1 vs 131.3 mmHg; adjusted P = 0.97); (diastolic 73.1 vs 74.9 mmHg, adjusted P = 0.15). Flow mediated dilatation was significantly higher in the intervention group at 8 weeks (6.9% vs 3.7%, adjusted P = 0.007) but was not significantly different at 16 weeks.
  
  
  CONCLUSIONS
  High dose oral vitamin D supplementation did not improve blood pressure but produced short-term improvement in endothelial function in stroke patients with well-controlled baseline blood pressure.
  
  
  BACKGROUND
  ISRCTN28737567.
authors.affiliation: Ageing and Health, Centre for Cardiovascular and Lung Biology, Division of Medicine, University of Dundee, Dundee DD1 9SY, UK. m.witham@dundee.ac.uk
authors.forename: M D
authors.initials: MD
authors.lastname: Witham
authors.forename: F J
authors.initials: FJ
authors.lastname: Dove
authors.forename: J A
authors.initials: JA
authors.lastname: Sugden
authors.forename: A S
authors.initials: AS
authors.lastname: Doney
authors.forename: A D
authors.initials: AD
authors.lastname: Struthers
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects / Q000503:physiopathology; D019587:Dietary Supplements; D004311:Double-Blind Method; D004727:Endothelium / Q000378:metabolism; D005260:Female; D006339:Heart Rate; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D020521:Stroke / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood*; D014808:Vitamin D Deficiency / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D015415:Biomarkers; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D020097:Natriuretic Peptide, Brain; D014807:Vitamin D