Impact of urbanisation on serum lipid profiles--the THUSA survey

To examine the impact of urbanisation on lipid profiles of black South Africans, stratified for HIV status.

Cross-sectional population-based survey.

North West province of South Africa.

A representative sample of 1,854 apparently healthy volunteers aged > or = 15 years, was recruited from 37 randomly selected sites throughout the province. Subjects were stratified into five urbanisation strata (S): S1 rural villages, S2 farms, S3 informal housing or 'squatter camps' S4 urban townships, and S5 surburban housing.

Demographic, physical activity and dietary intake information was collected using validated and culture-sensitive questionnaires. Anthropometric measurements and lipid analyses were determined using standardised methodology.

The results revealed significantly lower mean (95% confidence interval) total serum cholesterol (TC) levels in HIV-negative men in S1-S4 compared with S5 (S1 3.91 (3.77-4.05) v. S5 4.79 (4.54-5.04) mmol/l). In HIV-negative women, TC levels were significantly lower in S1-S3 than in S4 and S5 (S1 4.05 (3.94-4.17) v. S5 4.79 (4.59-5.00) mmol/l). The same trends were seen for serum low-density lipoprotein cholesterol (LDLC) and triglycerides and in HIV-positive subjects. Binary logistical analysis indicated that the main factor responsible for the increased TC levels seemed to be increased body mass index (BMI) due to decreased physical activity.

Serum lipid levels increased with urbanisation although they remained within levels recommended for other populations. This may, however, become an important health problem in future if preventive strategies are not implemented. Culturally sensitive physical activity programmes to decrease BMI, targeted at professional men and women, and women in urban townships, seem to constitute the most appropriate intervention.