Malan, LeonéHamer, MarkVon Känel, RolandLambert, Gavin W.Delport, RhenaSteyn, Hendrik S.Malan, Nicolaas T.2017-08-232017-11Malan, L., Hamer, M., Von Känel, R., Lambert, G.W., Delport, R., Steyn, H.S. & Malan, N.T. 2017, 'Chronic defensiveness and neuroendocrine dysfunction reflect a novel cardiac troponin T cut point : the SABPA study', Psychoneuroendocrinology, vol. 85, pp. 20-27.0306-4530 (print)1873-3360 (online)10.1016/j.psyneuen.2017.07.492http://hdl.handle.net/2263/61775BACKGROUND : Sympatho-adrenal responses are activated as an innate defense coping (DefS) mechanism during emotional stress. Whether these sympatho-adrenal responses drive cardiac troponin T (cTnT) increases are unknown. Therefore, associations between cTnT and sympatho-adrenal responses were assessed. METHODS : A prospective bi-ethnic cohort, excluding atrial fibrillation, myocardial infarction and stroke cases, was followed for 3 years (N = 342; 45.6 ± 9.0 years). We obtained serum high-sensitive cTnT and exposure measures [Coping-Strategy-Indicator, depression/Patient-Health-Questionnarie-9, 24 h BP, 24 h heart-rate-variability (HRV) and 24 h urinary catecholamines]. RESULTS : Blacks showed moderate depression (45% vs. 16%) and 24 h hypertension (67% vs. 42%) prevalence compared to Whites. A receiver-operating-characteristics cTnT cut-point 4.2 ng/L predicting hypertension in Blacks was used as binary outcome measure in relation to exposure measures [AUC 0.68 (95% CI 0.60-0.76); sensitivity/specificity 63/70%; P ≤ 0.001]. Bi-ethnic cTnT-incidence was similar (25-27%) with cTnT-recovery better in Blacks (9%) compared to Whites (5%), P = 0.001. In cross-sectional analyses, elevated cTnT was related to DefS [OR 1.08 (95% CI 0.99–1.16); P = 0.06]; 24 h BP [OR 1.03–1.04 (95% CI 1.01–1.08); P ≤ 0.02] and depressed HRV [OR 2.19 (95% CI 1.09–4.41); P = 0.03] in Blacks, but not in Whites. At 3 year follow-up, elevated cTnT was related to attenuated urine norepinephrine:creatinine ratio in Blacks [OR 1.46 (95% CI 1.01–2.10); P = 0.04]. In Whites, a cut point of 5.6 ng/L cTnT predicting hypertension was not associated with exposure measures. CONCLUSION : Central neural control systems exemplified a brain-heart stress pathway. Desensitization of sympatho-adrenal responses occurred with initial neural- (HRV) followed by neuroendocrine dysfunction (norepinephrine:creatinine) in relation to elevated cTnT. Chronic defensiveness may thus drive the desensitization or physiological depression, reflecting ischemic heart disease risk at a novel 4.2 ng/L cTnT cut-point in Blacks.en© 2017 Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Psychoneuroendocrinology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Psychoneuroendocrinology, vol. 85, pp. 20-27, 2017. doi : 10.1016/j.psyneuen.2017.07.492.DefenseDepressionHeart-rate-variabilityCatecholamineTroponin TSympatho-adrenal responsesCardiac troponin T (cTnT)Health sciences articles SDG-03SDG-03: Good health and well-beingHealth sciences articles SDG-17SDG-17: Partnerships for the goalsPostprint Article