The impact of urbanization on physical, physiological and mental health of Africans in the North West Province of South Africa: The THUSA study: The THUSA study

We studied the impact of urbanization and the resultant demographic transition on the physical, physiological and mental health of Africans in the North West Province of South Africa in order to inform health policies and programmes. Thirty-seven randomly selected sites were investigated in rural and urban areas covering all the districts of the province. A cross-sectional comparison was made of a sample in terms of gender, age (15 years and older) and five levels of urbanization (deep rural tribal areas, farms, informal housing areas or squatter camps, established urban townships and 'upper' urban areas). A total of 1854 'apparently healthy' men, and non-pregnant and non-lactating African women without identified diseases and not taking chronic medication, were recruited. Demographic information, health history and behaviour, psychological profiles and dietary intakes were obtained during individual interviews in the language of the subject's choice, using culturally sensitive and validated questionnaires. Anthropometric and blood pressure measurements and a 2-hour glucose tolerance test with a 75-g glucose load were taken. Serum, citrated and EDTA plasma and blood cell samples were analysed for biochemical variables with enzymatic, colorimetric and immunological methods. Anonymous HIV testing was also done. The improved socioeconomic circumstances observed in the wealthiest urban areas were accompanied by superior nutritional status, lower mean blood pressure, better health behaviours (lower smoking, drinking and HIV infection rates), lower measures of all indices of psychological pathology and higher scores of psychological well-being. These subjects also had the highest fat intake and serum cholesterol levels. Farm workers were identified as the most vulnerable group, having inadequate diets, highest scores for psychological symptomatology and the lowest scores for psychological well-being. Subjects in the transitional groups had the highest blood pressures, greatest HIV infection rates, and smoked and drank more than other subjects. Obesity in women, hypertension and impaired glucose tolerance were observed in both rural and urban subjects. The data suggest that urbanization of Africans is associated with improved mental, physiological and physical health in the more affluent groups but that those in transition living in poverty on farms and in densely populated areas are experiencing a high risk of the double burden of diseases associated with undernutrition on the one hand and overnutrition on the other.