title: 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.
abstract: 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.
authors: Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa. Alta.Schutte@nwu.ac.za
authors: Aletta E
authors: AE
authors: Schutte
authors: Rudolph
authors: R
authors: Schutte
authors: Hugo W
authors: HW
authors: Huisman
authors: Johannes M
authors: JM
authors: van Rooyen
authors: Carla M T
authors: CM
authors: Fourie
authors: Nico T
authors: NT
authors: Malan
authors: Leoné
authors: L
authors: Malan
authors: Catharina M C
authors: CM
authors: Mels
authors: Wayne
authors: W
authors: Smith
authors: Sarah J
authors: SJ
authors: Moss
authors: G Wayne
authors: GW
authors: Towers
authors: H Salomé
authors: HS
authors: Kruger
authors: Edelweiss
authors: E
authors: Wentzel-Viljoen
authors: Hester H
authors: HH
authors: Vorster
authors: Annamarie
authors: A
authors: Kruger
mesh_terms: D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D044383:Black People; D001794:Blood Pressure / Q000502:physiology*; D002097:C-Reactive Protein / Q000378:metabolism; D016009:Chi-Square Distribution; D003404:Creatinine / Q000097:blood; D005260:Female; D015438:Health Behavior; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D016014:Linear Models; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D015415:Biomarkers; D008055:Lipids; D002097:C-Reactive Protein; D003404:Creatinine; D005723:gamma-Glutamyltransferase