Blunted neuro-endocrine responses linking depressive symptoms and ECG left ventricular hypertrophy in black Africans: the SABPA study

Abstract

Objective: Chronic psychosocial stress as experienced in an urban environment plays an important role in the aetiology of depression-related cardiovascular risk. It is uncertain whether acute mental stress responses aggravate this risk. Therefore, we aimed to explore the associations between depressive symptoms, neuroendocrine acute mental stress responses and cardiovascular risk, that is ECG-left ventricular hypertrophy (ECG-LVH), in a black South African cohort. Materials and methods: The substudy sample consisted of 179 black African men and women from the Sympathetic Activity and Ambulatory Blood Pressure in Africans study. Depressive symptoms were evaluated using the nine-item Patient Health Questionnaire and the participants were stratified into black Africans with depressive symptoms and without. Cortisol and 3-methoxy-phenylglycol (MHPG) responses were analysed during rest and exposure to the Stroop mental stressor. Cortisol median split responses were determined and stratified sex groups accordingly into above (>1.5 ng/ml) and below (≤1.5 ng/ml) responders. Blood pressure and ECG-LVH data were obtained from 24-h ambulatory monitoring and 12-lead ECG. Results: The Africans with depressive symptoms demonstrated mean hypertensive status, blunted cortisol and MHPG acute mental stress responses (P≤0.05). In Africans with depressive symptoms and low cortisol stress responses, blunted MHPG acute mental stress responses were associated with ECG-LVH in Africans [adjusted R 2=0.20; β=0.92 (95% confidence interval 0.74, 1.10); P≤0.02]. Conclusion: Blunted neuroendocrine responses were linked to depressive symptoms and ECG-LVH in black Africans. When coupled to their hypertensive status, these vasoconstrictive agent responses may underpin the increased long-term depression and vascular disease risk in urban Africans.