Cardiovascular function and psychological distress in urbanised black South Africans : the SABPA study
Motivation: Cardiovascular disease (CVD) is one of the leading causes of death worldwide, with the greatest mortality rates occurring in low and middle income countries. The increase in the prevalence of risk factors such as hypertension, obesity and diabetes in Sub-Saharan Africa has led in an increase of the prevalence of CVD. It remains largely unclear whether psychological distress and more specifically the perception of own health and / depression may contribute to this observed increase in the prevalence of CVD in this population group. To our knowledge investigations exploring these aspects have not been done in the African context, thus the association between depression as an outcome of psychological distress and cardiovascular dysfunction in Africans is a new frontier that requires further exploration in the population group. Objective: The aim of this study was to investigate the association between psychological distress and cardiovascular function in urbanized black South Africans which included a target population of 200 Africans, men (n=101) and women (n=99). The participants were stratified into a hypertensive (HT) and normotensive (NT) group. Methodology: The manuscript presented in chapter 2 made use of the data obtained from the SABPA (Sympathetic activity and Ambulatory Blood Pressure in Africans) project. A group of 200 black Africans from governmental institutions of the North West Province of South Africa were recruited. All procedures conducted were approved by the North-West University Ethics Committee and written informed consent was given by all the participants prior to the study. Anthropometric measurements were taken with the assistance of registered biokinetisists. Resting cardiovascular variables such as heart rate (HR), arterial compliance (Cw), total peripheral resistance (TPR) and the mean arterial pressure (MAP) were obtained with the use of a Finometer device. The 24 hours ambulatory blood pressure (BP) (AMBP) measurements were obtained with a Cardiotens apparatus. The resting ECG NORAV PL-1200 data determined left ventricular hypertrophy (L VH) by making use of the Cornell product (RaVL+ SV3) *QRS. Psychological distress questionnaire assessed the perception of health (General Health Questionnaire; GHQ-28) and depression severity (Patient Health Questionnaire; PHQ-9). Participants were stratified into hypertensive and normotensive groups based on the European Society of Hypertension (ESH) 2007 guidelines using the 24hr AMBP as a norm. Results were adjusted for confounders (age, body mass index, smoking, alcohol consumption and physical activity). One way Analysis of Covariance (ANCOVA) was done to determine significant differences between age, body mass index, lifestyle factors cardiovascular variables and psychological parameters. For more detailed description of the subjects, study design and analytical procedures used in this study the reader is referred to the Methods section in Chapter 2. Results and Conclusion: The hypertensive (HT) men and women were more obese (p<0.01) with a larger waist circumference (WC) (p=0.05) and a lower compliance (p</=0.05) compared to their normotensive (NT) counterparts. Only the HT men revealed a higher Cornell product value (p=0.06) compared to NT counterparts. In HT men, somatisation was positively associated with blood pressure (SBP & DBP), while in HT women it was associated with heart rate (HR). Major depression was associated with a left ventricular hypertrophy in HT men and MAP in HT women. Logistic regression analysis followed to predict the strongest contributor to HT in Africans. It was indicated that depressed women are 1.13 times more likely to develop hypertension than men. In conclusion, these results suggest a possible association between depression as an outcome of psychological distress and cardiovascular dysfunction in urbanised Africans. Depression has also been identified as a contributor to HT in African women.
- Health Sciences