Uncontrollable stress associated with hyperglycaemic and vascular responses and a marker of left ventricular dysfunction: The SABPA Study

  • Prof Leoné Malan, Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North West University, South Africa
  • Prof Nicolaas Malan, Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North West University, South Africa
  • Prof Aletta Schutte, Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North West University, South Africa
  • Prof Johannes van Rooyen, Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North West University, South Africa
  • Prof Hugo Huisman, Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North West University, South Africa
  • Dr Johan Potgieter, School for Psychosocial Behavioral Sciences, North West University Pot, South Africa
  • Dr Mark Hamer, Department of Epidemiology and Public Health, University College of London, United Kingdom
  • Prof Yackoob Seedat, The Renal Hypertension Unit, Nelson Mandela School of Medicine, University of KZN, South Africa

Background: Utilising an active coping (AC) strategy is associated with control and central BP responses. It is well-known that emotional stress and hyperglycemia can precipitate left ventricular dysfunction usually caused by disturbed vascular function and myocardial ischemia.
Objective: We examined the association between left ventricular dysfunction and glucose-, vascular and ischaemic responses to mental stress and 24h AMBP and ECG.
Methods: Participants stratified into high AC groups (aged 44.9 ± 9.6 yrs), included urban Black (n=38) and Caucasian (n=46) men from the Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) Study. After an overnight fast the Stroop and Cold pressor mental tasks were completed and blood samples drawn during baseline and 10 minutes after each task for the assessment of NaF glucose. Finometer BP and NORAV ECG assessments were obtained during stress testing. A 24h ECG determined ischaemic events whilst the 12-lead ECG determined left ventricular hypertrophy (LVH; Cornell voltage for men >2.8 mV) and ST-segment deviation (ST).
Results: Multiple linear regression analysis showed that LVH during mental stress was explained (P < 0.05) by ischaemic events (ß = 0.94; SE = 0.21), ST (ß = 0.59; SE = 0.20), glucose (ß = 0.50; SE = 0.20) and vascular responses (ß = 0.60; SE = 0.26) in Black AC men only (adjusted for age, waist circumference, physical activity, estrogen, gamma gluthamyl transferase, C-reactive protein, basal levels of glucose and BP) [R2 = for model 0.63].
Conclusion: We conclude that increased glucose and vascular responses as well as ischaemic events were associated with LVH. A disengagement of an AC behavioral style from a physiological AC style indicates loss of control and an increased risk for LVH and stroke.