Clinical Trial: Vitamin K Status and Markers of Vascular Function in Patients With and Without Postural Hypotension

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Vitamin K Status and Markers of Vascular Function in Patients With and Without Postural Hypotension

Brief Summary:

Postural hypotension is common in older people, leading to falls, decline in function, and dependence. Available treatments have limited efficacy and tolerability; novel approaches to treatment are therefore needed. Decreased vascular health, stiffening of the arteries and consequent decreased vascular reactivity are thought to contribute to postural hypotension and are therefore therapeutic targets.

Recent trial evidence has suggested that vitamin K may exert beneficial effects on vascular health particularly in respect to inhibiting calcification. Calcification increases vascular stiffness, decreases compliance and thus decreases the ability of blood vessels to autoregulate blood pressure and flow - which could contribute to postural drops in blood pressure. Worsened vascular health could also impact adversely on baroceptor function, which is needed for blood pressure autoregulation and which is disrupted in patients with orthostatic hypotension.

Vitamin K intake is below recommended daily intake in 60% of adults in the UK. In animals, vitamin K supplementation may be able to reverse calcification of arteries, and in humans Vitamin K has been shown to arrest decline in carotid artery elasticity compared to placebo. High levels of circulating vitamin K were also associated with lower levels of CRP in the Framingham cohort, suggesting a possible role in the suppression of chronic inflammation that is known to accompany vascular disease. The recent ECKO study suggested that vitamin K may reduce falls and fractures; an intriguing question that follows on from this is whether this could be due to beneficial effects on vascular health and postural hypotension, leading to less dizziness and reduced falls.

This cross-sectional comparative study aims to find whether there is a dif

Detailed Summary:
Sponsor: University of Dundee

Current Primary Outcome: Serum non-phosphorylated, non-carboxylated Matrix Gla Protein [ Time Frame: Day 1 ]

Original Primary Outcome: Serum non-phosphorylated, non-carboxylated Matrix Gla Protein [ Time Frame: At recruitment ]

Current Secondary Outcome:

• Vitamin K1 Level [ Time Frame: Day 1 ]
• Vitamin D [ Time Frame: Day 1 ]
• Flow mediated dilatation [ Time Frame: Day 1 ]
  Measure of endothelial function
• Pulse wave velocity [ Time Frame: Day 1 ]
  Measure of arterial stiffness and reflectivity
• Carotid intima media thickness [ Time Frame: Day 1 ]
• Pulse wave augmentation index [ Time Frame: Day 1 ]
  Measure of arterial stiffness and refelctivity

Original Secondary Outcome:

• Vitamin K1 Level [ Time Frame: At recruitment ]
• Vitamin D [ Time Frame: At recruitment ]
• Flow mediated dilatation [ Time Frame: At recruitment ]
  Measure of endothelial function
• Pulse wave velocity and augmentation index [ Time Frame: At recruitment ]
  Measure of arterial stiffness and reflectivity
• Carotid intima media thickness [ Time Frame: At recruitment ]

Information By: University of Dundee

Dates:
Date Received: July 20, 2015
Date Started: April 2012
Date Completion:
Last Updated: July 23, 2015
Last Verified: July 2015