title: Common carotid artery wall thickness and external diameter as predictors of prevalent and incident cardiac events in a large population study.
abstract: BACKGROUND
  Arterial diameters enlarge in response to wall thickening, plaques, and many atherosclerotic risk factors. We hypothesized that right common carotid artery (RCCA) diameter would be independently associated with cardiac disease and improve risk discrimination.
  
  
  METHODS
  In a middle-aged, biracial population (baseline n = 11225), we examined associations between 1 standard deviation increments of baseline RCCA diameter with prevalent myocardial infarction (MI) and incident cardiac events (MI or cardiac death) using logistic regression and Cox proportional hazards models, respectively. Areas under the receiver operator characteristic curve (AUC) were used to estimate model discrimination.
  
  
  RESULTS
  MI was present in 451 (4%) participants at baseline (1987-89), and incident cardiac events occurred among 646 (6%) others through 1999. Adjusting for IMT, RCCA diameter was associated with prevalent MI (female OR = 2.0, 95%CI = 1.61-2.49; male OR = 1.16, 95% CI = 1.04-1.30) and incident cardiac events (female HR = 1.75, 95% CI = 1.51-2.02; male HR = 1.27, 95% CI = 1.15-1.40). Associations were attenuated but persisted after adjustment for risk factors (not including IMT) (prevalent MI: female OR = 1.73, 95% CI = 1.40-2.14; male OR = 1.14, 95% CI = 1.02-1.28, and incident cardiac events: female HR = 1.26, 95% CI = 1.08-1.48; male HR = 1.19, 95% CI = 1.08-1.32). After additional adjustment for IMT, diameter was associated with incident cardiac events in women (HR = 1.18, 95% CI = 1.00-1.40) and men (HR = 1.17, 95% CI = 1.06-1.29), and with prevalent MI only in women (OR = 1.73; 95% CI = 1.37-2.17). In women, when adjustment was limited, diameter models had larger AUC than other models.
  
  
  CONCLUSIONS
  RCCA diameter is an important correlate of cardiac events, independent of IMT, but adds little to overall risk discrimination after risk factor adjustment.
authors.affiliation: Department of Epidemiology, Fay W, Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR, USA. eigenbrodtmarshal@uams.edu
authors.forename: Marsha L
authors.initials: ML
authors.lastname: Eigenbrodt
authors.forename: Rishi
authors.initials: R
authors.lastname: Sukhija
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Rose
authors.forename: Richard E
authors.initials: RE
authors.lastname: Tracy
authors.forename: David J
authors.initials: DJ
authors.lastname: Couper
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Evans
authors.forename: Zoran
authors.initials: Z
authors.lastname: Bursac
authors.forename: Jawahar L
authors.initials: JL
authors.lastname: Mehta
mesh_terms: D017677:Age Distribution; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006323:Heart Arrest / Q000453:epidemiology* / Q000473:pathology*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000473:pathology*; D009929:Organ Size; D011237:Predictive Value of Tests; D015995:Prevalence; D012372:ROC Curve; D044469:Racial Groups / Q000706:statistics & numerical data; D012307:Risk Factors; D017678:Sex Distribution; D016019:Survival Analysis; D014463:Ultrasonography; D014481:United States / Q000453:epidemiology