title: Von Willebrand factor as marker of vascular function in South African women: the POWIRS Study.
abstract: BACKGROUND
  The increasing prevalence of hypertension and vascular-related morbidity and mortality among Africans emphasizes the need to identify markers for the early detection of vascular disease. Caucasian-based studies demonstrate that the von Willebrand factor (vWf) is a useful marker of vascular dysfunction. We investigated whether associations between this marker and markers of cardiovascular function in Caucasian women are comparable with African women.
  
  
  METHODS
  The study consisted of apparently healthy African (n = 99) and Caucasian (n = 114) women (mean age, 31.0 years), individually matched for age and body mass index. We measured blood pressure and arterial compliance noninvasively, and vWf in serum. We assessed univariate and multivariate-adjusted associations of blood pressure and arterial compliance with vWf.
  
  
  RESULTS
  Although no ethnic difference existed for mean vWf levels, Caucasian and African women showed opposite associations of blood pressure and arterial compliance with vWf after single, partial, and multiple regression analyses. In Caucasians, after full adjustment, systolic (beta = +0.179; P < 0.05) and diastolic (beta = +0.190; P < 0.05) blood pressure correlated positively and arterial compliance negatively (beta = -0.197; P < 0.01) with vWf. Conversely, in Africans, systolic blood pressure correlated weakly, but negatively (beta = -0.168; P = 0.059) with vWf. However, this opposite tendency seemed due to the confounding influence of the depot medroxyprogesterone acetate (DMPA) contraceptive injection and, although >99% power existed, significance disappeared after excluding these subjects (beta = -0.071; P = 0.46).
  
  
  CONCLUSIONS
  Associations of vWf with blood pressure and arterial compliance were not comparable between Caucasian and African women, suggesting that the vWf may not be a useful marker of vascular alterations in African women.
authors.affiliation: Subject Group Physiology, School for Physiology, Nutrition, and Consumer Sciences, North-West University (Potchefstroom Campus), Potchefstroom, South Africa. rudolph.schutte@nwu.ac.za
authors.forename: Rudolph
authors.initials: R
authors.lastname: Schutte
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Van Rooyen
authors.forename: Hugo W
authors.initials: HW
authors.lastname: Huisman
authors.forename: Iolanthé M
authors.initials: IM
authors.lastname: Palmer
authors.forename: Carla M
authors.initials: CM
authors.lastname: Fourie
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Péter
authors.forename: Leoné
authors.initials: L
authors.lastname: Malan
authors.forename: Nicolaas T
authors.initials: NT
authors.lastname: Malan
authors.forename: Manja
authors.initials: M
authors.lastname: Reimann
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D044383:Black People / Q000706:statistics & numerical data*; D001795:Blood Pressure Determination / Q000379:methods; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000208:ethnology*; D008875:Middle Aged; D015999:Multivariate Analysis; D012494:Sampling Studies; D013019:South Africa / Q000208:ethnology; D014655:Vascular Resistance; D044465:White People / Q000706:statistics & numerical data*; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D014841:von Willebrand Factor