Motivation: Cardiovascular dysfunction and hypertension are some of the leading causes of morbidity and mortality in the African population. According to the World Health Organisation the increases in these diseases are escalating in developing countries. Apart from the contributory role of genetics towards the incidence of hypertension, evidence regarding lifestyle as a determinant or marker of cardiovascular diseases in this group is not well known. The interaction of psychological and physiological mechanisms can contribute towards a broader scope of behavioural physiology in the higher prevalence of hypertension in Africans. Objectives: The main objective of the research in this thesis was to compare specific coping mechanisms of Africans with regard to cardiovascular dysfunction. Methodology: Manuscripts presented in Chapters 3, 4, and 5 made use of the cross-sectional comparative epidemiological "Transition and Health during Urbanisation in South Africa" (THUSA) project. The subjects included apparently healthy African men and women, which were recruited as a convenience sample from the North West Province, South Africa. Anthropometric measurements were taken and demographic questionnaires completed. An adapted Setswana COPE questionnaire was used to classify men and women as predominantly active (AC) or passive (PC) in coping style. Subjects were further subdivided into rural and urban groups (Manuscript Two), as well as younger (≤ 40) and older (≥ 45) age groups (Manuscript Three). The General Health Questionnaire (GHQ) was used to measure subjective perception of health in all three manuscripts. Blood pressure was recorded continuously before and during application of the handgrip test using the Finapres apparatus. Subjects were classified as normotensive and hypertensive after blood pressure measurement by the Finapres and the Riva-Rocci/Korotkoff method. The emphasis in this study was on the cardiovascular reactivity values. Fasting, resting serum renin activity, cortisol, prolactin, testosterone, high density lipoprotein, triglycerides, glucose and plasma fibrinogen values were correlated with cardiovascular and psychological variables. Significant differences between variables were determined by means of variance analyses (Manuscript One and Two adjusted for age; Manuscripts One, Two and Three adjusted for resting cardiovascular data). A logistic regression analysis was performed to determine the most significant determinants of urbanisation. All THUSA subjects and parents of under-aged adolescents gave informed consent and the study - was approved by the Ethics Committee of the Potchefstroom University for Christian Higher Education. The reader is referred to the abstracts at the beginning of each separate manuscript in Chapters 3 - 5 for a description of the subjects, study design and analytical methods used in each paper. Results and conclusions of the individual manuscripts: Results from the THUSA study showed that PC men and women reported more symptoms typical of an abnormal psychological and physiological profile than AC men and women. The PC men, compared to AC men, exhibited a larger vascular reactivity response as well as larger plasma renin activity. In contrast, the AC women showed a larger non-significant vascular reactivity response than PC women. All subjects though reacted with increased vascular reactivity on the stressor. Men with a PC strategy showed enhanced vascular reactivity, a perception of poorer health and larger stressor plasma renin activity. PC women reported more depressive symptoms and younger PC women indicated a higher prevalence of hypertension than younger AC women. As a follow-up on the first manuscript, the aim was focused mainly on including the environmental effect, namely urbanisation, as possible explanatory factor for the atypical physiological AC women’s' coping style. The rural AC subjects indicated more typical active coping central cardiac responses than rural PC subjects whereas urbanised AC and PC subjects indicated greater peripheral responses and hypertension prevalence rates. In addition, the urbanised AC men and women and PC women as opposed to their rural counterparts indicated symptoms more of a distress situation with increased values of prolactin and decreased values of testosterone. This was also accompanied by a perception of poorer health in women. Results of the AC style suggests that the typical physiological AC stimulation pattern of urbanised subjects and especially the women is dissociated from the "normal" physiological AC reaction and is now exhibited as a typical PC physiological stimulation pattern. The greater vascular reactivity, hypertension prevalence, perception of poorer health and endocrine distressed profile are associated with a PC and dissociated physiological AC style in an urban context in African men and women. No differences with regard to resting blood pressure or endocrine values were obtained when the AC and PC urbanised groups were compared. Africans develop cardiovascular dysfunction/hypertension during chronic stress or urbanisation. This implies a dissociation/habituation of physiological systems of African men and women despite having an active coping strategy. Active coping is, therefore, not necessarily "successful". Results of the first two manuscripts direct further investigation concerning the effects of ageing and urbanisation on the development of cardiovascular dysfunction and metabolic syndrome indicators in gender groups. The second manuscript showed that all rural AC subjects exhibit a more typical active coping central cardiac response and that rural PC and all urbanised subjects (AC and PC) exhibit enhanced peripheral vascular responses on the - handgrip test. Where peripheral vascular responses were more expected from older individuals in Manuscript Three, the occurrence of this pattern is strengthened in the younger subjects. The greater fibrinogen values in all younger urbanised women (AC and PC) compared to rural women further strengthen the risk for the development of cardiovascular disease. Increased vascular reactivity, abdominal obesity and increased levels of triglycerides as well as perception of poorer health were apparent in the urbanised AC women, PC men and women in comparison to their rural counterparts. The typical physiological AC stimulation pattern of urbanised women is dissociated from the "normal" physiological AC responses and is now exhibited as a typical PC physiological stimulation pattern. A typical PC style in older urbanised subjects is implicated in the greater hypertension prevalence. To conclude, it seems as if young urbanised Africans, and especially women, exhibit an AC style behaviourally with a dissociated physiological AC reaction pattern. Physiologically these women resemble a typical PC physiological cardiovascular and endocrine profile. This typical PC cardiovascular stimulation pattern is strengthened by a distressed endocrine profile, significant metabolic syndrome indicators and a 'perception of poorer health. Older PC style subjects also presented a greater hypertension prevalence. In this study it seems that cardiovascular changes that appear at a younger age might be influenced by other factors including urbanisation as a lifestyle factor as well as specific coping styles. Finally, a careful suggestion is made that specific coping mechanisms could be seen as a possible risk marker in the development of the metabolic syndrome. / Thesis (Ph.D. (Physiology))--North-West University, Potchefstroom Campus, 2005.

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. / Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2009.

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. / Thesis (M.Sc. (Physiology))--North-West University, Potchefstroom Campus, 2009.

Thesis (M.S.)--Case Western Reserve University, 2008. / [School of Medicine] Department of Genetics. Includes bibliographical references.

Thesis (Ph. D.)--Massey University, Auckland, 2008. / Includes bibliographical references (leaves 287-317).

Thesis (Ph. D.)--Michigan State University. Dept. of English, 2008. / Title from PDF t.p. (viewed on July 23, 2009) Includes bibliographical references (p. 147-155). Also issued in print.

Originally presented as the author's Thesis (doctoral)--Université des Sciences sociales de Toulouse, 2004.

Thesis (Ph. D.)--University of Kentucky, 2004. / Title from document title page (viewed Jan. 7, 2005). Document formatted into pages; contains v, 253 p. Includes abstract and vita. Includes bibliographical references (p. 236-250).

Thesis (Ph.D.)--Ohio University, November, 2008. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until December 1, 2009. Includes bibliographical references (leaves 210-221)

Originally presented as the author's thesis (doctoral)--Université des Sciences sociales de Toulouse, 2004.