title: Effect of Vitamin K on Vascular Health and Physical Function in Older People with Vascular Disease--A Randomised Controlled Trial.
abstract: OBJECTIVE
  Vitamin K insufficiency is common and linked to an increased risk of cardiovascular disease and osteoporotic fractures. The aim of this study was to examine whether daily supplementation with oral vitamin K could improve vascular health and physical function in older people with established vascular disease.
  
  
  RESULTS
  A double blind, randomised, placebo-controlled trial. Participants aged ≤ 70 years with a history of vascular disease were randomised to receive 6 months of daily oral 100mcg vitamin K2 (MK7 subtype) or matching placebo with outcomes measured at 0, 3 and 6 months. The primary outcome was between-group difference in endothelial function assessed using flow-mediated dilatation of the brachial artery at 6 months. Secondary outcomes included carotid-radial pulse wave velocity, augmentation index, blood pressure, carotid intima-media thickness, C-reactive protein, B-type natriuretic peptide, cholesterol and desphospho-uncarboxylated matrix Gla protein levels. Handgrip strength and the Short Physical Performance Battery assessed physical function, while postural sway was measured using a 3-dimensional force platform.
  
  
  RESULTS
  80 participants were randomised, mean age 77 (SD 5) years; 44/80 were male. Vitamin K levels rose in the intervention arm compared to placebo (+48 pg/ml vs -6 pg/ml, p=0.03) at 6 months. Desphospho-uncarboxylated Matrix Gla protein levels fell in the intervention group compared to placebo at 6 months (-130 [SD 117] pmol/L vs +13 [SD 180] pmol/L, p<0.001). No change was seen in endothelial function (between group difference -0.3% [95%CI -1.3 to 0.8], p=0.62). A modest, non-significant improvement in pulse wave velocity was seen in the vitamin K group (-0.8m/s [95%CI -1.8 to 0.3], p=0.15) while all other vascular and physical function outcomes unchanged.
  
  
  CONCLUSIONS
  Six months of vitamin K2 supplementation did not improve markers of vascular health or physical function in older patients with vascular disease.
authors.affiliation: RL Fulton, Ageing and Health, Mailbox 1, Medical Research Institute, Division of Diabetes and Cardiovascular Medicine, Ninewells Hospital and Medical School, Dundee DD1 9SY. Telephone 441382 383086, Fax 441382 383670, Email r.l.z.fulton@dundee.ac.uk.
authors.forename: R L
authors.initials: RL
authors.lastname: Fulton
authors.forename: M E T
authors.initials: ME
authors.lastname: McMurdo
authors.forename: A
authors.initials: A
authors.lastname: Hill
authors.forename: R J
authors.initials: RJ
authors.lastname: Abboud
authors.forename: G P
authors.initials: GP
authors.lastname: Arnold
authors.forename: A D
authors.initials: AD
authors.lastname: Struthers
authors.forename: F
authors.initials: F
authors.lastname: Khan
authors.forename: C
authors.initials: C
authors.lastname: Vermeer
authors.forename: M H J
authors.initials: MH
authors.lastname: Knapen
authors.forename: N E A
authors.initials: NE
authors.lastname: Drummen
authors.forename: M D
authors.initials: MD
authors.lastname: Witham
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects / Q000503:physiopathology; D002097:C-Reactive Protein / Q000032:analysis; D059168:Carotid Intima-Media Thickness; D002784:Cholesterol / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood; D063177:Pulse Wave Analysis; D017211:Treatment Failure; D014652:Vascular Diseases / Q000178:diet therapy* / Q000503:physiopathology*; D014812:Vitamin K / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain; D014812:Vitamin K; D002097:C-Reactive Protein; D002784:Cholesterol