Diabetes mellitus hypertension and related factors in black subjects residing in Qwaqwa and Bloemfontein

English: BACKGROUND The black population of South Africa underwent rapid urbanisation during the last century. This process was accompanied by major changes in lifestyle including less physical activity, the moving away from traditional low-fat diets to diets high in saturated fat, and the acquiring of unhealthy habits such as the smoking of cigarettes. Previously rare chronic diseases of lifestyle such as diabetes mellitus, hypertension, obesity, dyslipidaemia and atherosclerotic cardiovascular disease started to emerge during this period. AIMS The primary aims of the study were to determine the prevalence of diabetes mellitus, hypertension, obesity, and dyslipidaemia, in a partly rural and an urban black community. The secondary objectives were to investigate the hypotheses that the metabolic syndrome existed in the black population and that hypertension was associated with hyperinsulinaemia in the study populations. STUDY DESIGN A cross-sectional study SETTING: The study was conducted in the semi-rural area of Qwaqwa and in Mangaung, the main black residential area of Bloemfontein. METHODS A representative sample of 853 subjects 25 years and older (279 males and 574 females) was selected from Qwaqwa, a partly rural community in the Free State, and a similar sample of 758 subjects (290 males and 468 females) from Mangaung, the black residential area of Bloemfontein, as the urban sample for comparison. After informed consent, the prevalence of the following conditions was determined according to standardised procedures: diabetes mellitus, impaired glucose tolerance, impaired fasting glucose, hypertension, dyslipidaemia, and overweight and obesity. In addition, anthropornetrlcal measurements including the measurement of selected skinfold thickness and body circumferences were measured. A 12- lead resting electrocardiograph was obtained from each subject and blood specimens were collected for the measurement of insulin, proinsulin and C-peptide. A trained nurse administered a questionnaire to each respondent in his or her own language to obtain demographic and biosocial information. RESULTS The response rates were 68% in Qwaqwa and 62% in Mangaung. The age-standardised prevalence rates for the chronic diseases that were studied, are provided in the Table 51. Table A1 will be attached on the full document. The prevalence rates of the risk factors that were studied did not differ significantly between the Qwaqwa and Mangaung samples. Although the metabolic syndrome was present in 31% of subjects in both samples, no electrocardiographic evidence of an increased prevalence of coronary heart disease was found in subjects with the metabolic syndrome. Hyperinsulinaemia and thus insulin resistance was not associated with hypertension in any of these two black populations with a high prevalence of obesity and hypertension. It is unlikely that a population with such a clustering of cardiovascular risk factors can much longer escape the emergence of coronary artery disease as an important public health problem. CONCLUSION The black populations of Qwaqwa and Mangaung are well advanced on the raad of urbanisation and the nutrition transition. Chronic diseases of lifestyle are as prevalent in these communities as elsewhere in the Western world. Coronary artery disease is usually the last of the typical Western diseases to emerge in a population in transition and it is unlikely that these black populations will escape this disease much longer.