title: Can common carotid intima media thickness serve as an indicator of both cardiovascular phenotype and risk among black Africans?
abstract: BACKGROUND
  It is not known whether common carotid intima media thickness (CIMT) can serve as a surrogate marker of cardiovascular risk among black Africans. Therefore, we examined whether CIMT differed significantly among individuals with distinct cardiovascular phenotype and correlated significantly with traditional cardiovascular risk factors in a black African population.
  
  
  METHODS
  CIMT was measured in 456 subjects with three distinct cardiovascular phenotypes - 175 consecutive Nigerian African stroke patients, 161 hypertensive patients without stroke and 120 normotensive non-smoking adults. For each pair of cardiovascular phenotypes, c-statistics were obtained for CIMT and traditional vascular risk factors (including age, gender, weight, waist circumference, smoking, alcohol, systolic and diastolic blood pressures, fasting plasma glucose, fasting total cholesterol). Pearson's correlation coefficients were calculated to quantify bivariate relationships.
  
  
  RESULTS
  Bilaterally, CIMT was significantly different among the three cardiovascular phenotypes (right: p < 0.001, F = 33.8; left: p < 0.001, F = 48.6). CIMT had a higher c-statistic for differentiating stroke versus normotension (c = 0.78 right; 0.82 left, p < 0.001) and hypertension versus normotension (c = 0.65 right; 0.71 left, p < 0.001) than several traditional vascular risk factors. Bilaterally, combining all subjects, CIMT was the only factor that correlated significantly (right: 0.12 ≤ r ≤ 0.41, 0.018 ≤ p < 0.0001; left: 0.18 ≤ r ≤ 0.41, 0.005 ≤ p < 0.0001) to all the traditional cardiovascular risk factors assessed.
  
  
  CONCLUSIONS
  Our findings support CIMT as a significant indicator of both cardiovascular risk and phenotype among adult black Africans. However, specific thresholds need to be defined based on prospective studies.
authors.affiliation: Department of Medicine, University College Hospital, Ibadan, Nigeria College of Medicine, University of Ibadan, Nigeria mayowaowolabi@yahoo.com.
authors.forename: M O
authors.initials: MO
authors.lastname: Owolabi
authors.affiliation: College of Medicine, University of Ibadan, Nigeria Department of Radiology, University College Hospital, Ibadan, Nigeria.
authors.forename: A M
authors.initials: AM
authors.lastname: Agunloye
authors.affiliation: Department of Radiology, University College Hospital, Ibadan, Nigeria.
authors.forename: E O
authors.initials: EO
authors.lastname: Umeh
authors.affiliation: College of Medicine, University of Ibadan, Nigeria Department of Epidemiology and Medical Statistics, College of Medicine, University of Ibadan, Nigeria.
authors.forename: O M
authors.initials: OM
authors.lastname: Akpa
mesh_terms: D000328:Adult; D000368:Aged; D044383:Black People; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000208:ethnology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging*; D059168:Carotid Intima-Media Thickness; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D010641:Phenotype; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000000981:diagnostic imaging* / Q000208:ethnology
keywords: Carotid intima media thickness; cardiovascular risk marker; hypertension; stroke; surrogate marker