title: Ethnic disparity in defensive coping endothelial responses: The SABPA study.
abstract: OBJECTIVE
  Defensive coping (DefS) in Blacks has been associated with greater cardiovascular risk than in their White counterparts. We examined associations between endothelial function mental stress responses and markers of vascular structure in a bi-ethnic cohort.
  
  
  METHODS
  We examined vascular function and structure in 368 Black (43.84±8.31years) and White Africans (44.78±10.90years). Fasting blood samples, 24h blood pressure, left carotid intima-media thickness of the far wall (L-CIMTf), and left carotid cross-sectional wall area (L-CSWA) values were obtained. von Willebrand factor (VWF), endothelin-1 (ET-1) and nitric oxide metabolite (NOx) responses to the Stroop mental stress test were calculated to assess endothelial function. DefS was assessed using the Coping Strategy Indicator questionnaire. Interaction between main effects was demonstrated for 283 participants with DefS scores above the mean of 26 for L-CIMTf.
  
  
  RESULTS
  Blunted stress responses for VWF (men 16.71% vs. 51.10%; women 0.85% vs. 42.09%, respectively) and NOx (men -64.52% vs. 74.89%; women -76.16% vs. 113.29%, respectively) were evident in the DefS Blacks compared to the DefS Whites (p<0.001). ET-1 increased more in Blacks (men 150% and women 227%, p<0.001) compared to the Whites (men 61.25% and women 35.49%, p<0.001). Ambulatory pulse pressure, but not endothelial function markers, contributed to L-CIMTf (ΔR(2)=0.11 p<0.001), and L-CSWA (ΔR(2)=0.08, p<0.001) in DefS African men but not in any other group.
  
  
  CONCLUSIONS
  Blunted stress-induced NOx and VWF responses and augmented ET-1 responses in DefS Blacks indicate endothelial dysfunction. DefS may facilitate disturbed endothelial responses and enforce vascular remodelling via compensatory increases in pulse pressure in Black men. These observations may indicate an increased risk of cardiovascular incidents via functional and structural changes of the vasculature in DefS Blacks.
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition, and Consumer Science, North-West University, Potchefstroom, South Africa.
authors.forename: Jacobus De Wet
authors.initials: Jde W
authors.lastname: Scheepers
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition, and Consumer Science, North-West University, Potchefstroom, South Africa; Medical Research Council: Research Unit for Hypertension and Cardiovascular Disease, North-West University; Potchefstroom, South Africa. Electronic address: leone.malan@nwu.ac.za.
authors.forename: Leoné
authors.initials: L
authors.lastname: Malan
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition, and Consumer Science, North-West University, Potchefstroom, South Africa.
authors.forename: Andrea
authors.initials: A
authors.lastname: De Kock
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition, and Consumer Science, North-West University, Potchefstroom, South Africa.
authors.forename: Nicolaas Theodor
authors.initials: NT
authors.lastname: Malan
authors.affiliation: Medicine Usage in South Africa (MUSA), North-West University, Potchefstroom, South Africa.
authors.forename: Marike
authors.initials: M
authors.lastname: Cockeran
authors.affiliation: Department of Psychosomatic Medicine, Clinic Barmelweid, Barmelweid, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: von Känel
mesh_terms: D000223:Adaptation, Psychological / Q000502:physiology*; D000328:Adult; D000367:Age Factors; D044383:Black People; D001794:Blood Pressure / Q000502:physiology*; D059168:Carotid Intima-Media Thickness; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D019332:Endothelin-1 / Q000378:metabolism*; D005006:Ethnicity / Q000523:psychology*; D005215:Fasting; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009569:Nitric Oxide / Q000378:metabolism*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D012307:Risk Factors; D044465:White People
chemical_list: D019332:Endothelin-1; D010980:Platelet Membrane Glycoproteins; C028254:von Willebrand factor receptor; D009569:Nitric Oxide
keywords: Coping; Endothelial dysfunction; Endothelin-1; Nitric oxide; von Willebrand factor vascular remodelling