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

We studied the impact of urbanization and the resultant demographic transit ion on the physical, physiological and mental health of Africans in the Nor th West Province of South Africa in order to inform health policies and pro grammes. Thirty-seven randomly selected sites were investigated in rural an d 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 olde r) and five levels of urbanization (deep rural tribal areas, farms, informa l housing areas or squatter camps, established urban townships and 'upper' urban areas). A total of 1854 'apparently healthy' men, and non-pregnant an d non-lactating African women without identified diseases and not taking ch ronic medication, were recruited. Demographic information, health history a nd behaviour, psychological profiles and dietary intakes were obtained duri ng individual interviews in the language of the subject's choice, using cul turally sensitive and validated questionnaires. Anthropometric and blood pr essure 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 we re analysed for biochemical variables with enzymatic, colorimetric and immu nological methods. Anonymous HIV testing was also done. The improved socioe conomic circumstances observed in the wealthiest urban areas were accompani ed by superior nutritional status, lower mean blood pressure, better health behaviours (lower smoking, drinking and HIV infection rates), lower measur es of all indices of psychological pathology and higher scores of psycholog ical well-being. These subjects also had the highest fat intake and serum c holesterol levels. Farm workers were identified as the most vulnerable grou p, having inadequate diets, highest scores for psychological symptomatology and the lowest scores for psychological well-being. Subjects in the transi tional groups had the highest blood pressures, greatest HIV infection rates , and smoked and drank more than other subjects. Obesity in women, hyperten sion and impaired glucose tolerance were observed in both rural and urban s ubjects. The data suggest that urbanization of Africans is associated with improved mental, physiological and physical health in the more affluent gro ups 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 diseas es associated with undernutrition on the one hand and overnutrition on the other.