title: Facilitated defensive coping, silent ischaemia and ECG left-ventricular hypertrophy:  the SABPA study.
abstract: BACKGROUND
  Defensive active coping responses (being-in-control, acceptance of the stressor as reality) have been associated with vascular hyper-responsiveness in urban Africans. However, the association between active coping responses, blood pressure (BP), and ECG-derived left-ventricular hypertrophy (LVH) responses is unknown.
  
  
  OBJECTIVE
  Associations between BP, silent ischaemia and ECG Cornell product LVH were assessed in 161 African and Caucasian men with active coping responses identified by the Amirkhan Coping Strategy Indicator. BP, ECG and silent ischaemia data were obtained from 24-h ambulatory monitoring. Beat-to-beat BP was continuously recorded during stress testing and fasting resting blood samples obtained for biochemical analyses.
  
  
  RESULTS
  Enhanced ß-adrenergic central cardiac responses were evident in active coping Caucasians as opposed to a predomination of α-adrenergic vascular responses in active coping Africans. Active coping African men displayed higher 24-h BP and prevalence of silent ischaemia events compared to the Caucasian men. Regression analyses revealed that α-adrenergic responses were associated with silent ischaemic events, adjusted R 0.21 [ß 1.07, 95% confidence interval (CI) 0.29-1.85] and that ischaemic events predicted LVH in active coping Africans (adjusted R 0.12, ß 0.35, 95% CI 0.11-0.59). Receiver-operated characteristic (ROC) analyses indicated a defensive pathway cut point of 16 in Africans as opposed to 32 in Caucasians predicting silent ischaemia with sensitivity/specificity 100/96%.
  
  
  CONCLUSIONS
  A defensive pathway revealed disturbed vascular function showing dissociation between behavioural and physiological ß-adrenergic active coping responses in Africans. Vascular responsiveness facilitated silent ischaemia events and structural LVH changes which potentially explain the increased risk for incident ischaemic stroke in black Africans.
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North West University, Potchefstroom, South Africa. leone.malan@nwu.ac.za
authors.forename: Leoné
authors.initials: L
authors.lastname: Malan
authors.forename: Mark
authors.initials: M
authors.lastname: Hamer
authors.forename: Markus P
authors.initials: MP
authors.lastname: Schlaich
authors.forename: Gavin W
authors.initials: GW
authors.lastname: Lambert
authors.forename: Brian H
authors.initials: BH
authors.lastname: Harvey
authors.forename: Manja
authors.initials: M
authors.lastname: Reimann
authors.forename: Tjalf
authors.initials: T
authors.lastname: Ziemssen
authors.forename: Eco J C N
authors.initials: EJ
authors.lastname: de Geus
authors.forename: Hugo W
authors.initials: HW
authors.lastname: Huisman
authors.forename: Johannes M
authors.initials: JM
authors.lastname: van Rooyen
authors.forename: Rudolph
authors.initials: R
authors.lastname: Schutte
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
authors.forename: Carla M T
authors.initials: CM
authors.lastname: Fourie
authors.forename: Yaackob K
authors.initials: YK
authors.lastname: Seedat
authors.forename: Nico T
authors.initials: NT
authors.lastname: Malan
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D044383:Black People; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000208:ethnology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000208:ethnology* / Q000378:metabolism; D009206:Myocardium / Q000473:pathology; D011941:Receptors, Adrenergic / Q000378:metabolism*; D013019:South Africa / Q000453:epidemiology; D013312:Stress, Physiological; D013315:Stress, Psychological / Q000208:ethnology* / Q000378:metabolism; D044465:White People
chemical_list: D011941:Receptors, Adrenergic