The effect of vitamin K On vascular health and physical function in older people with vascular disease

  • Roberta Fulton

    Student thesis: Master's ThesisMaster of Science

    Abstract

    “Population ageing” - the process by which older individuals make up a proportionally larger share of the total population over a period of time has thrown up new challenges such as the increasing demand and expense on health and social care. Cardiovascular disease, prevalent in older people, goes hand in hand with declining physical function and new ways of tackling the burden this places on older persons, their carers and health services are required.

    Recent work has suggested that vitamin K, a known cofactor for coagulation proteins, may be required for the function of several other key proteins. In particular, Matrix Gla protein may exert beneficial effects on vascular health. I hypothesised that supplementation of the diet with vitamin K would improve vascular health and physical function in older people with established vascular disease.

    In a double-blind randomised controlled clinical trial 80 participants aged ≥ 70years with established vascular disease were randomised to receive 100mcg vitamin K or placebo daily for 6 months. The primary outcome was a between group difference in endothelial function change between baseline and 6 months. The secondary outcomes were carotid-radial pulse wave velocity, carotid intima-media thickness, Short Physical Performance Battery and grip strength.

    Participant mean age was 77 years (SD 5), 44/80 (55%) were male. Only 3/80 (4%) participants failed to complete the study. Vitamin K levels rose in the intervention arm compared to placebo (+48pg/ml vs. -6pg/ml, p=0.03) at six months compared to baseline. There was no significant change in brachial artery flow mediated dilatation or indeed in any of the other markers of vascular health or physical function. This was despite excellent adherence to medication. There was however a modest 10% reduction in arterial stiffness by 6 months suggesting that changes to vascular calcification with vitamin K2 may be possible but may require longer to achieve.
    Date of Award2013
    Original languageEnglish
    SponsorsChest Heart and Stroke Scotland
    SupervisorMiles Witham (Supervisor) & Marion McMurdo (Supervisor)

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