title: Conventional and behavioral risk factors explain differences in sub-clinical vascular disease between black and Caucasian South Africans: the SABPA study.
abstract: OBJECTIVE
  There is an emerging burden of cardiovascular disease among urban black Africans in South Africa, which has been largely explained by the transition from traditional African lifestyles to more westernized behavior. We examined the role of health behaviors in explaining the excess burden of sub clinical vascular disease seen in black Africans compared to Caucasians.
  
  
  METHODS
  This was a cross-sectional study, comprising of urban African teachers (n=192 black, 206 Caucasian) working for one of the four Kenneth Kaunda Education districts in the North West Province, South Africa. Conventional cardiovascular risk factors, 24 h ambulatory blood pressure and objectively measured physical activity (Actical® accelerometers), smoking (confirmed by serum cotinine), and alcohol (serum gamma glutamyl transferase) were assessed. The main outcome was a marker of sub-clinical vascular disease, mean carotid intima media thickness (mCIMT), measured using high resolution ultrasound.
  
  
  RESULTS
  Compared with Caucasians, the black Africans demonstrated higher mCIMT (age and sex adjusted β=0.044, 95% CI, 0.024-0.064 mm). The blacks also had higher 24h systolic and diastolic blood pressure, triglycerides, adiposity, and C-reactive protein. In addition, blacks were less physically active (790.0 kcal/d vs 947.3 kcal/d, p<0.001), more likely to smoke (25% vs 16.3%, p=0.002), and demonstrated higher alcohol abuse (gamma glutamyl transferase, 66.6 μ/L vs 27.2 μ/L, p<0.001) compared with Caucasians. The difference in mCIMT between blacks and Caucasians was attenuated by 34% when conventional risk factors were added to the model and a further 18% when health behaviors were included.
  
  
  CONCLUSIONS
  There is an excess burden of sub clinical vascular disease seen in black Africans compared to Caucasians, which can be largely explained by health behaviors and conventional risk factors.
authors.affiliation: Department of Epidemiology and Public Health, University College London, 1-19 Torrington Place, London WC1E 6BT, UK. m.hamer@ucl.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Hamer
authors.forename: L
authors.initials: L
authors.lastname: Malan
authors.forename: A E
authors.initials: AE
authors.lastname: Schutte
authors.forename: H W
authors.initials: HW
authors.lastname: Huisman
authors.forename: J M
authors.initials: JM
authors.lastname: van Rooyen
authors.forename: R
authors.initials: R
authors.lastname: Schutte
authors.forename: C M T
authors.initials: CM
authors.lastname: Fourie
authors.forename: N T
authors.initials: NT
authors.lastname: Malan
authors.forename: Y K
authors.initials: YK
authors.lastname: Seedat
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000150:complications; D044383:Black People; D018660:Blood Pressure Monitoring, Ambulatory; D002097:C-Reactive Protein / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000209:etiology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013019:South Africa; D014280:Triglycerides / Q000097:blood; D017539:Tunica Intima / Q000000981:diagnostic imaging; D014463:Ultrasonography; D044465:White People
chemical_list: D014280:Triglycerides; D002097:C-Reactive Protein