title: Genetic basis of variation in carotid artery plaque in the San Antonio Family Heart Study.
abstract: OBJECTIVE
  In contrast to the commonly used quantitative marker of subclinical atherosclerosis, namely intima-media thickness, we investigated the extent to which the presence or absence of carotid artery plaque (CAP) was under genetic control.
  
  
  METHODS
  The study population consisted of 750 individuals distributed across 29 randomly ascertained extended Mexican American pedigrees who participated in the second examination cycle of the San Antonio Family Heart Study. Extracranial focal CAP was identified by B-mode ultrasound bilaterally in the internal carotid artery or the carotid bulb. Using a variance decomposition approach implemented in the SOLAR computer program, we performed genetic analysis on the discrete trait CAP (ie, liability to disease) using a threshold model. Covariates considered in the analysis included age, sex, diabetes, current smoking status, lipid levels, and markers of hypertension and obesity.
  
  
  RESULTS
  Fifty-one of 461 women and fifty-seven of 289 men with a mean age of 42.1 years had evidence of a plaque in the right and/or left carotid artery. The age- and sex-adjusted heritability (h(2)+/-SE) for CAP was significant (h(2)=0.28+/-0.15, P=0.01). Furthermore, after adjustment for additional covariates that contributed significantly to the model (P<0.05; diabetes, hypertension, body mass index, waist circumference, and smoking status), heritability remained significant (h(2)=0.23+/-0.15, P=0.03).
  
  
  CONCLUSIONS
  Our data indicate that after established cardiovascular risk factors are controlled for, the variation of the discrete trait CAP is under appreciable additive genetic influences.
authors.affiliation: Division of Clinical Epidemiology, Department of Medicine, University of Texas Health Science Center, San Antonio, Texas, USA. huntk@uthscsa.edu
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Hunt
authors.forename: Ravindranath
authors.initials: R
authors.lastname: Duggirala
authors.forename: Harald H H
authors.initials: HH
authors.lastname: Göring
authors.forename: Jeff T
authors.initials: JT
authors.lastname: Williams
authors.forename: Laura
authors.initials: L
authors.lastname: Almasy
authors.forename: John
authors.initials: J
authors.lastname: Blangero
authors.forename: Daniel H
authors.initials: DH
authors.lastname: O'Leary
authors.forename: Michael P
authors.initials: MP
authors.lastname: Stern
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001161:Arteriosclerosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D015992:Body Mass Index; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D015897:Comorbidity; D005190:Family / Q000208:ethnology; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D017058:Mexican Americans / Q000235:genetics; D008875:Middle Aged; D010375:Pedigree; D012307:Risk Factors; D017678:Sex Distribution; D013781:Texas / Q000453:epidemiology; D014463:Ultrasonography