Are behavioural risk factors to be blamed for the conversion from optimal blood pressure to hypertensive status in Black South Africans? A 5-year prospective study

Int J Epidemiol. 2012 Aug;41(4):1114-23. doi: 10.1093/ije/dys106. Epub 2012 Jul 23.


Background: Longitudinal cohort studies in sub-Saharan Africa are urgently needed to understand cardiovascular disease development. We, therefore, explored health behaviours and conventional risk factors of African individuals with optimal blood pressure (BP) (≤ 120/80 mm Hg), and their 5-year prediction for the development of hypertension.

Methods: The Prospective Urban Rural Epidemiology study in the North West Province, South Africa, started in 2005 and included African volunteers (n = 1994; aged > 30 years) from a sample of 6000 randomly selected households in rural and urban areas.

Results: At baseline, 48% of the participants were hypertensive (≥ 140/90 mmHg). Those with optimal BP (n = 478) were followed at a success rate of 70% for 5 years (213 normotensive, 68 hypertensive, 57 deceased). Africans that became hypertensive smoked more than the normotensive individuals (68.2% vs 49.8%), and they also had a greater waist circumference [ratio of geometric means of 0.94 cm (95% CI: 0.86-0.99)] and greater amount of γ-glutamyltransferase [0.74 U/l (95% CI: 0.62-0.88)] at baseline. The 5-year change in BP was independently explained by baseline γ-glutamyltransferase [R(2) = 0.23, β = 0.13 U/l (95% CI: 0.01-0.19)]. Alcohol intake also predicted central systolic BP and carotid cross-sectional wall area (CSWA) at follow-up. Waist circumference was another predictor of BP changes [β = 0.18 cm (95% CI: 0.05-0.24)] and CSWA. HIV infection was inversely associated with increased BP.

Conclusions: During the 5 years, 24% of Africans with optimal BP developed hypertension. The surge in hypertension in Africa is largely explained by modifiable risk factors. Public health strategies should focus aggressively on lifestyle to prevent a catastrophic burden on the national health system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthropometry
  • Biomarkers / blood
  • Black People*
  • Blood Pressure / physiology*
  • C-Reactive Protein / metabolism
  • Chi-Square Distribution
  • Creatinine / blood
  • Female
  • Health Behavior*
  • Humans
  • Hypertension / epidemiology*
  • Linear Models
  • Lipids / blood
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Risk Factors
  • South Africa / epidemiology
  • gamma-Glutamyltransferase / blood


  • Biomarkers
  • Lipids
  • C-Reactive Protein
  • Creatinine
  • gamma-Glutamyltransferase