CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 4, July/August 2022 AFRICA 169 Cardiovascular Topics Associations of conscientiousness with cardiac troponin T and stress coping responses in a teacher cohort: the SABPA prospective cohort study Catharina Elizabeth Myburgh, Leoné Malan, Roland von Känel, Hendrik Stefanus Steyn, Nicolaas Theodor Malan Abstract Background: In a South African bi-ethnic cohort, defensive (DefS)/social support/avoidance coping strategies have been shown to influence cardiac troponin T (cTnT) levels through different stress signalling pathways. Personality traits (extraversion, neuroticism, conscientiousness, openness to experience, agreeableness) partially control stress coping responses and may affect prospective cardiac responses. Hence in this cohort, we aimed to examine relationships between personality traits and coping strategies, and to assess associations between cTnT changes over time, personality traits and coping strategies. Methods: A cohort of African and Caucasian male and female teachers (n = 359) participating in both phases of the Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study, was prospectively followed for three years. Personality traits (Basic Traits Inventory) and coping (Coping Strategy Indicator) scores were determined. Fasting serum samples for cTnT determination were collected. Established hypertension-related cTnT cut-off points of 4.2 pg/ml (Africans) and 5.6 pg/ml (Caucasians) were applied. Results: Higher neuroticism and lower conscientiousness scores were found in the Africans than in the Caucasians (p < 0.05). Both traits correlated with all three coping strategies in Caucasians, but only with DefS and avoidance coping in Africans. Over a period of three years, cTnT levels decreased in both races. Compared to Africans, Caucasians showed a greater recovery from the ethnic-specific cTnT cut-off point over time. In the Africans with high DefS scores, cTnT level changes were inversely associated with conscientiousness (adjusted R2 = 0.14; β = –0.26). In Caucasians scoring high in avoidance coping, conscientiousness (odds ratio 0.84) and neuroticism (odds ratio 0.90) showed a lower likelihood of predicting the cTnT cut-off point. Conclusion: In both races, conscientiousness may contribute to healthier stress coping responses and protect against cardiac ischaemia and risk of hypertension. Keywords: personality traits, coping, cardiac ischaemia, troponin T Submitted 18/1/21, accepted 6/11/21 Published online 9/12/21 Cardiovasc J Afr 2022; 33: 169–178 www.cvja.co.za DOI: 10.5830/CVJA-2021-058 Stress has an impact on many bodily systems through neuroendocrine changes [sympathetic adrenal–medullary (SAM) and the hypothalamic–pituitary–adrenal (HPA) axes] that accompany the stress response.1-6 The heart is especially vulnerable to the effects of the stress response, as the autonomic nervous system directly innervates and controls the heart.7,8 Peripheral vascular changes in response to SAM- and HPA-axis activity may also alter loading conditions of the heart.7,8 Associations between myocardial ischaemia and injury, left ventricular dysfunction, coronary perfusion deficits and mental stress have been reported.1,7-9 Cardiac troponin T (cTnT) is a cardiac-specific protein found in the contractile apparatus of the cardiomyocytes.10-12 Detection of this protein in blood samples has been ascribed to myocardial ischaemia with or without necrosis, left ventricular wall stress and a catecholamine overload following severe stress.10-12 In a South African cohort of Africans and Caucasians, a cTnT cut-off point of 4.2 pg/ml in the Africans and a higher cut-off point of 5.6 pg/ml in the Caucasians were predictive of 24-hour systolic hypertension.13 Moreover, in the African men, cTnT levels as low as 4.2 pg/ml were related to silent cardiac ischaemia and were proposed as a potential biomarker thereof.13 According to the transactional stress theory, the magnitude of the stress response and consequent health outcomes are greatly influenced by cognitive appraisal of a stressor.14,15 Primary Hypertension in Africa Research Team (HART), Faculty of Health Sciences, Centre of Excellence, North-West University, Potchefstroom, South Africa Catharina Elizabeth Myburgh, MHSc, BHSc Hons, BSc Leoné Malan, PhD, RN, leone.malan@nwu.ac.za Roland von Känel, MD, PhD Nicolaas Theodor Malan, DSc Department of Consultation-Liaison-Psychiatry and Psychosomatic Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland Roland von Känel, MD, PhD Statistical Consultation Services, North-West University, Potchefstroom, South Africa Hendrik Stefanus Steyn, PhD
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