M.A. / Because of the high incidence of hypertension amongst South African blacks, many hypothesis have been forwarded to account for the relative higher index of hypertension amongst South African blacks when compared to whites. Because of the virtue lack of endemic proportions of hypertension in South African blacks at the beginning of this century, the often - quoted genetic hypothesis that hypertension is genetically determined would seem not to hold for South African situation. However, this was not yet tested as one of the risk factors or precursors to hypertension, namely the higher indices of cardiovascular reactivity had not been compared in the South African group between white and black subjects. This study investigated the hypothesis that the offspring of black hypertensive parents would show greater cardiovascular reactivity than those of black non-hypertensive parents, and also show greater cardiovascular reactivity than the children of white hypertensive parents as well as the children of white non-hypertensive parents. These hypotheses were partially supported. As expected the children of black hypertensives did show greater indices of cardiovascular reactivity when compared to both children of white hypertensives and the children of black non-hypertensives. An interesting finding however, was that the children of white hypertensives had shown greater indices of the psychological construct of state anxiety than the children of black hypertensive and black non-hypertensive subjects. Whereas this study supported the hypothesis that an inherited cardiovascular reactivity would and could account for the greater index of hypertension amongst South African blacks, it is also possible that the non-psychological expression of tension or cardiovascular reactivity in the form of state anxiety could partially account for the results herein obtained.

M.A. (Psychology) / Anger, hostility and aggression have long been regarded as important factors in the etiology of essential hypertension and coronary heart disease. Fast changing lifestyles and cultural differences are among a few of the factors that create stress, 'disease', stress in addition to the development of the self-generation of stress by means of the type A behavioral pattern. Anger and aggression are components that apparently account for the largest amount of variance in the type A behavior pattern. These emotions are again associated with elevated systolic blood pressure levels. The aim of this study was therefore to determine whether hypertension was indeed associated with anger and aggression amongst urban as well as rural Blacks in South Africa. Seftel (1980) found a very high prevalence of hypertension in Johannesburg Blacks and Seedat (1978) found a similarly high prevalence in Durban Zulu, possibly lending support to the hypothesis that urbanization was associated with the development of the type A behavioural pattern, and thus causal to the development of hypertension. Two groups, one consisting of hypertensives, and the other of people with other cardiovascular diseases were subjected to the Anger-Expression Scale and the Grant Urban-Rural Scale. The result of the study provided support for the thesis while the hypothesis that stated that hypertension would indicate a higher urbanization supported. In essence the results of the study indicated that there was a definite correlation between elevated blood pressure levels among urban Black South Africans and the chronic suppression of anger and aggression, as well as the inability to express these emotions.

The aim of this research project was to assess and compare cardiovascular disease (CVD) risk in black males and females from an urban, working population in the Makana (Grahamstown) region of the Eastern Cape, South Africa. Two-hundred and ninety one individuals (males: n = 143, females: n = 148) with a mean age of 42.6 (±8.1) years were voluntarily recruited from the greater urban Makana (Grahamstown) area. Eight Cardiovascular disease (CVD) risks were assessed: stature and mass were obtained in order to calculate body mass index (BMI) (mass/stature2). Obesity, defined as a morphological risk, was classified according to the World Health Organisation (WHO) BMI criteria (BMI>30kg.m-2), as well as according to measures of waist circumference (WC) and body composition. Hypertension, hypercholesterolemia and type II diabetes, were grouped as cardiovascular (CV) risks. Hypertension was defined as a blood pressure greater than 140/90mmHg (JNC-7); hypercholesterolemia, as total cholesterol greater than 6.2mmol.L-1 (NCEP); and type II diabetes, as total glucose greater than 12mmol.L-1 (WHO). Physical activity, diet, tobacco use, and alcohol consumption and dependence were grouped as lifestyle-related risks. These were assessed by means of self-reporting through the use of various validated questionnaires. Finally, self-reporting of obesity, hypertension, hypercholesterolemia and type II diabetes was assessed, in addition to perception questions on individuals’ perceived body shape and size (Ziebland figures). Self-reported and perceived responses were then compared to actual measures. Females were significantly (p<0.001) heavier than the males (92.7kg compared to 72.1kg) and had significantly (p<0.001) higher BMIs than their male counterparts (37.6kg.m-2 compared to 25.7 kg.-2). They also recorded significantly (p<0.001) higher waist circumference (WC) values and had significantly (p<0.001) higher percentage and total body fat. Significantly (p<0.001) more females were obese (81%) compared to males (17%). While a higher percentage of males (25 % compared to 22%) presented with stage I hypertension (≥140/90mmHg, <160/95mmHg), significantly (p<0.05) more females (14% compared to 8%) presented with stage II hypertension (>160/95mmHg). The prevalence of hypercholesterolemia at a high level of risk (>6.2mmol.L-1) was relatively low (2.1 % of males, 3.4% of females), but notably more participants (22% of males and 26% of females) presented with the condition at a moderate level of risk (>5mmol.L-1). Type II diabetes was the least prevalent CV risk factor, with no males and only 3% of females presenting with the condition. Males consumed significantly (p<0.05) more in terms of total energy intake (9024 vs. 7234 kJ) and were significantly (p<0.05) more active (3315 compared to 2660 MET-mins.week). A significantly (p<0.05) higher percentage of males smoked (51.1% compared to 3.4%), consumed alcohol (73.4% compared to 46.6%) and were alcohol dependent (40% compared to 33.5%). Both males and females tended to be ignorant of their health status, with both samples under-reporting obesity, hypertension and hypercholesterolemia, while over-reporting type II diabetes. Furthermore, obesity was significantly (p<0.05) underestimated, with both male and female individuals perceiving themselves to be notably smaller than they actually were. Physical activity and diet were important determinants of CVD risk in this black urban sample of individuals. Obesity, in particular central adiposity, was the most notable risk (particularly in females), followed by hypertension (particularly in males). Although some risks presented at a moderate level of risk, a clustering of risk factors was evident in both samples, with 12.6% and 41.2% of males and females presenting with two risk factors, and 2.8% and 8.1% of males and females respectively presenting with three risks.

The purpose of the study was to investigate the cardiovascular disease (CVD) risk profile of black African females in the Makana region, Eastern Cape, South Africa. Baseline measures from 40 participants, who met the criteria, were compared against the 2003 South African Demographic and Health Survey (SADHS) and the 2013 South African National Health and Nutritional Examination Survey (SANHANES-1). The risk factors measured were anthropometric (stature, body mass and body mass index (BMI)), morphological (waist circumference (WC), fat mass and lean mass), cardiovascular (heart rate and blood pressure (BP)), physical activity (step count and energy expenditure), biochemical (glycated haemoglobin and full blood lipid profile) and behavioural (alcohol and tobacco use). Results showed significantly higher (p≤0.05) values for overweight/obesity (BMI 37.60 kg.m⁻²; WC 1130.58 mm; fat mass 45.23%) and high BP (130/88 mmHg) compared to the previous national surveys, highlighting these CVD risk factors as problematic. The subsequent sub-study aimed to assess the efficacy of a pedometer-based walking intervention on high BP. The walking programme (n=25) was based on individual step goals to be completed at a moderate-intensity on five days.week⁻¹ for 12 weeks. The same measurements were taken at monthly intervals, Week 0, Week 4, Week 8 and Week 12, with the addition of dietary intake and fitness level, and the exclusion of the behavioural variables. There were no significant differences (p≤0.05) in systolic and diastolic BP with the exercise intervention, although there was a strong, negative relationship with time for diastolic BP (r²=0.9857). This trend suggests that the lack of significance may be a result of poor compliance and/or the small sample size. Individual results, however, showed no compliance-result relationship for the two risk factors of interest: overweight/obesity and high BP. Future recommendations include supervised or group-based exercise interventions to improve compliance, and the addition of resistance training to the aerobic programme.