CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 4, July/August 2022 170 AFRICA appraisal of a stressor as either a threat or a challenge is followed by a secondary appraisal where coping options are evaluated to overcome the stressor.14,15 The three main coping strategies usually employed to deal with stress are active problem solving or defensive coping (DefS), seeking social support coping and avoidance coping.16 Effective management of stress and health promotion is usually associated with DefS and seeking social support coping.16 DefS involves the direct confrontation of the stressor in a highly action-orientated manner,14,16 whereas seeking social support coping usually involves approaching another individual or group for advice and comfort in the midst of stress.16,17 Avoidance coping on the other hand is more passive, directed at ignoring the stressful situation, facilitating negative health outcomes.14,16 Avoidance coping, but not DefS or seeking social support coping, has been associated with greater incidence of andmortality from various cardiovascular diseases, including ischaemic heart disease.18 On the other hand, chronic DefS utilisation and sympatho-adrenal dysregulation responses in Africans predicted the hypertension-related cTnT cut-off point, thus indicating possible ineffectiveness of this coping strategy.4 Similar findings were not evident in their Caucasian counterparts who applied effective DefS.4,6,13 DefS is said to be ineffective when an individual loses control over the stressor, resulting in exaggerated stress responses, with subsequent negative health outcomes.19 Coping or stress appraisal is partly determined by personality traits.19-23 The most widely accepted model used in personality trait research is the big five model of personality, which includes extraversion, neuroticism, conscientiousness, openness to experience and agreeableness.21,24,25 Viewing a stressor as a challenge and engaging in DefS have been ascribed to conscientiousness, extraversion and openness to experience,23 whereas threat appraisal of a stressor and engaging in avoidance coping have been related to higher scores in neuroticism.23 Both extraversion and agreeableness were also positively related with seeking social support coping.19,26 Furthermore, personality traits have been found to be prospectively linked to health outcomes, including cardiac health.27,28 Despite a controversy regarding the specific relationship between personality traits and cardiac health, neuroticism and conscientiousness have proven to be more consistent in outcome prediction.27 Neuroticism, characterised by affect instability, anxiety and depression,29 was found to be a risk factor for cardiac morbidity, especially in relation to depressed heart rate variability30 and ischaemic heart disease.31,32 By contrast, high conscientiousness is usually associated with better cardiovascular health31 because these individuals experience higher levels of control over life stressors by finding taxing situations less demanding.33 To the best of our knowledge, the effect of personality traits on stress coping responses and future cardiac health has not been investigated in a South African population. This investigation may also shed light on previous findings of DefS contributing to cardiac stress and ischaemia in Africans but not in Caucasians. As cTnT levels are indicative of cardiac morbidity risk in Africans and Caucasians from South Africa,4-6,13 studying this biomarker in relation to stress coping and personality traits may provide potential novel brain–heart link mechanisms. Therefore, in a bi-ethnic South African cohort, we aimed to (1) examine the relationships between personality traits and coping strategies, (2) assess associations between baseline personality traits and longitudinal changes in cTnT levels, and (3) examine hypertension-related cTnT cut-off points with regard to coping strategies. Methods The current study is nested in the SABPA prospective cohort study, of which a detailed protocol has been published elsewhere.34 Phase I of the SABPA study was conducted in 2008/2009 and the follow-up (phase II) data collection commenced three years later (2011/2012). The study complied with the guidelines of the Declaration of Helsinki on research in humans (2004). The SABPA study included urban-dwelling African and Caucasian teachers of both genders, between the ages of 20 and 65 years at baseline. The teachers were recruited from the Dr Kenneth Kaunda district in the North-West province of South Africa. Except for cultural diversity, socio-economic status and occupational environment were similar for both races. During phase I, there were 409 participants after excluding individuals who were pregnant, lactating, had tympanum temperatures ≥ 37.5°C and were vaccinated or had donated blood three months prior to the commencement of the study. Furthermore, individuals who abused or were dependent on psychotropic substances were excluded. All of the participants were invited three months prior to phase II and a high follow-up rate of 87.8% was achieved. For the current study, only participants who participated in both phases of the SABPA study (n = 359) were included. Additional exclusion criteria were β-blocker use, history of myocardial infarction or stroke and left ventricular hypertrophy (n = 11) at baseline. Participants with missing data (n = 8) and outliers for three-year percentage change (%∆) in cTnT level (n = 4) were also excluded. The final study sample included 336 participants. From Monday to Thursday between 07:00 and 08:00, four participants were fitted daily with 24-hour blood pressure (BP) and electrocardiogram (ECG) (Cardiotens CE120®, Meditech, Budapest, Hungary) as well as 24-hour physical activity (Actical® accelerometers, Montréal, Québec) apparatuses at the school. Thereafter participants continued with their normal daily activities. They had to report any irregularities on the issued 24-hour BP diary cards. Participants were transported to the Metabolic Unit Research Facility of North-West University that afternoon, where they were each allocated a private bedroom. They were requested to refrain from smoking, the intake of caffeine or alcohol, as well as exercise within 12 hours prior to data sampling. In addition, they were introduced to the experimental set-up, completed the general health and demographic questionnaires and received HIV/AIDS pre-counselling. The participants were served a standardised evening meal and completed the Coping Strategy Indicator (CSI), as well as the Basic Traits Inventory (BTI) questionnaire, all of which were done under the supervision of registered clinical psychologists. The participants were requested to go to bed at 22:00, fasting overnight. At 06:00 the next day, the 24-hour apparatuses were disconnected after the last BP recording. Anthropometric measurements were taken, and participants remained in a semirecumbent resting position for 30 minutes, with a 12-lead ECG
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