A time bomb of cardiovascular risk factors in South Africa: results from the Heart of Soweto Study "Heart Awareness Days"

Background: There is strong anecdotal evidence that many urban communities in Sub-Saharan Africa are in epidemiologic transition with the subsequent emergence of more affluent causes of heart disease. However, data to describe the risk factor profile of affected communities is limited. Methods: During 9 community screening days undertaken in the predominantly Black African community of Soweto, South Africa (population 1 to 1.5 million) in 2006-2007, we examined the cardiovascular risk factor profile of volunteers. Screening comprised a combination of self-reported history and a clinical assessment that included calculation of body mass index (BMI), blood pressure and random blood glucose and total cholesterol levels. Results: In total, we screened a total of 1691 subjects (representing almost 0.2% of the total population). The majority (99%) were Black African, there were more women (65%) than men and the mean age was 46 ± 14 years. Overall, 78% of subjects were found to have ≥ 1 major risk factor for heart disease. By far the most prevalent risk factor overall was obesity (43%) with significantly more obese women than men (23% versus 55%: OR 1.76 95% CI 1.62 to 1.91: p < 0.001). A further 33% of subjects had high blood pressures (systolic or diastolic) and 13% an elevated (non-fasting) total blood cholesterol level: no statistically significant differences between the sexes were found. There was a positive correlation between increasing BMI and other risk factors including elevated systolic (r² = 0.046, p < 0.001) and diastolic blood pressure (r² = 0.032, p < 0.001) with overweight subjects three times more likely to have concurrent hypercholesterolemia (OR 3.3, 95% CI 2.1 to 5.3: p < 0.01). Conclusions: These unique pilot data strongly suggest a high prevalence of related risk factors for heart disease in this urban black African population in epidemiologic transition. Further research is needed to confirm our findings and to determine their true causes and potential consequences.