Vitamin K Status and markers of vascular function in older people with orthostatic hypotension

M. Lambert, J. J. F. Belch, F. Khan, C. Vermeer, G. Kennedy, A. Hill, M. D. Witham

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: Orthostatic hypotension in older people is common but difficult to treat. Vitamin K is required for the function of matrix gla protein (a powerful inhibitor of vascular calcification) so might exert beneficial effects on vascular health. We investigated differences in vitamin K status and vascular function in patients with orthostatic hypotension compared to those without.

Methods: Community dwelling men and women aged ≥65 years were recruited into a case control study. Exclusion criteria were taking warfarin, being unable to consent or stand unaided. Participants were allocated to orthostatic hypotension or control groups depending on the presence of symptomatic orthostatic hypotension (drop in systolic blood pressure ≥20mmHg or diastolic blood pressure ≥10mmHg). Vascular function was assessed by flow mediated dilatation, carotid compliance, carotid intima-media thickness, pulse wave velocity and augmentation index. Fasting blood was obtained to determine desphospho-uncarboxylated matrix gla protein (dp-ucMGP), vitamin K1 and vitamin D levels.

Results: 49 participants (24 with orthostatic hypotension, 25 control) were recruited. Mean age was 75.7 years and 29 (59%) were women. Mean (SD) dp-ucMGP levels were not significantly different between the orthostatic hypotension and control groups (816 (311.4) pmol/L, 815 (555.7) pmol/L respectively, p = 0.99). Mean vitamin K1 levels were non-significantly lower in the orthostatic hypotension group (122 v 261 pg/ml, p = 0.07). Flow mediated dilatation (6.8% v 5.5%, p = 0.40), pulse wave velocity (7.8 m/s v 8.0 m/s, p = 0.73), augmentation index (34.5% v 36.4%, p = 0.51), carotid intima-media thickness (0.79 mm v 0.75 mm, p = 0.39), carotid compliance (0.054 mm2/mmHg v 0.052 mm2/mmHg, p = 0.86) and vitamin D levels (50 nmol/L v 50 nmol/L, p = 0.97) were not significantly different between the orthostatic hypotension and control groups.

Conclusions: Vitamin K status, vitamin D levels, and markers of vascular function were no different in those with orthostatic hypotension compared to control participants
Original languageEnglish
Article number49
Pages (from-to)ii14
Number of pages1
JournalAge and Ageing
Volume44
Issue numberIssue suppl_2
DOIs
Publication statusPublished - 8 Sep 2015

Keywords

  • vitamin k
  • orthostatic hypotension
  • elderly

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