title: Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome--a randomised controlled trial.
abstract: OBJECTIVE
  Low 25-hydroxyvitamin D levels are common in patients with chronic fatigue syndrome; such patients also manifest impaired vascular health. We tested whether high-dose intermittent oral vitamin D therapy improved markers of vascular health and fatigue in patients with chronic fatigue syndrome.
  
  
  RESULTS
  Parallel-group, double-blind, randomised placebo-controlled trial. Patients with chronic fatigue syndrome according to the Fukuda (1994) and Canadian (2003) criteria were randomised to receive 100,000 units oral vitamin D3 or matching placebo every 2 months for 6 months. The primary outcome was arterial stiffness measured using carotid-femoral pulse wave velocity at 6 months. Secondary outcomes included flow-mediated dilatation of the brachial artery, blood pressure, cholesterol, insulin resistance, markers of inflammation and oxidative stress, and the Piper Fatigue scale. As many as 50 participants were randomised; mean age 49 (SD 13) years, mean baseline pulse wave velocity 7.8 m/s (SD 2.3), mean baseline office blood pressure 128/78 (18/12) mmHg and mean baseline 25-hydroxyvitamin D level 46 (18) nmol/L. 25-hydroxyvitamin D levels increased by 22 nmol/L at 6 months in the treatment group relative to placebo. There was no effect of treatment on pulse wave velocity at 6 months (adjusted treatment effect 0.0 m/s; 95% CI -0.6 to 0.6; p = 0.93). No improvement was seen in other vascular and metabolic outcomes, or in the Piper Fatigue scale at 6 months (adjusted treatment effect 0.2 points; 95% CI -0.8 to 1.2; p = 0.73).
  
  
  CONCLUSIONS
  High-dose oral vitamin D3 did not improve markers of vascular health or fatigue in patients with chronic fatigue syndrome.
  
  
  BACKGROUND
  www.controlled-trials.com, ISRCTN59927814.
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK. Electronic address: m.witham@dundee.ac.uk.
authors.forename: M D
authors.initials: MD
authors.lastname: Witham
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK.
authors.forename: F
authors.initials: F
authors.lastname: Adams
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK.
authors.forename: S
authors.initials: S
authors.lastname: McSwiggan
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK.
authors.forename: G
authors.initials: G
authors.lastname: Kennedy
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK.
authors.forename: G
authors.initials: G
authors.lastname: Kabir
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK.
authors.forename: J J F
authors.initials: JJ
authors.lastname: Belch
authors.affiliation: Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK.
authors.forename: F
authors.initials: F
authors.lastname: Khan
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects / Q000378:metabolism; D002170:Canada; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood; D002784:Cholesterol / Q000097:blood; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015673:Fatigue Syndrome, Chronic / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000188:drug therapy; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D063177:Pulse Wave Analysis; D016896:Treatment Outcome; D059289:Vascular Stiffness; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications
chemical_list: D015415:Biomarkers; D002762:Cholecalciferol; D002784:Cholesterol
keywords: Arterial stiffness; Chronic fatigue; Randomised controlled trial; Vitamin D