on March 14, 2002
Published online before print March 14, 2002, doi: 10.1161/01.ATV.0000015329.15481.E8
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Submitted on November 14, 2001
Accepted on March 4, 2002
Heritability of Subclinical Atherosclerosis in Latino Families Ascertained Through a Hypertensive Parent
Anny H. Xiang ;
From the Department of Preventive Medicine (A.H.X.,
S.P.A., S.T., H.N.H.), the Atherosclerosis Research
Unit (S.P.A., C.R.L., C.H.L., H.N.H.), and the Department of Medicine
(T.A.B., J.D., E.T., H.N.H.), University of Southern California Keck
School of Medicine, Los Angeles; the Division of Medical Genetics
(L.J.R., L.S.-C.C., J.I.R.), Departments of Medicine and Pediatrics,
Cedars-Sinai Medical Center, Los Angeles, Calif; and the Departments of
Medicine (M.Q., L.W.C., W.A.H., J.I.R.), Pediatrics (L.J.R., L.S.-C.C.,
J.I.R.), and Human Genetics (J.I.R.), University of California at Los
Angeles Medical School.
* To whom correspondence should be addressed. E-mail: watcher{at}usc.edu.
Abstract—Although clinical coronary heart disease and many cardiovascular risk factors are well known to aggregate within families, the heritability of carotid artery intima-media thickness (IMT) is less well documented. We report IMT heritability estimates in Mexican American, Salvadoran American, or Guatemalan American (all referred to as Latino) families ascertained through a hypertensive proband. IMT and cardiovascular risk factors (age, sex, blood pressure, body mass index, lipids, fasting glucose, and insulin sensitivity) were measured in 204 adult offspring of 69 hypertensive probands, along with 82 parents (54 probands and 28 spouses). In the offspring, variance component analysis revealed a heritability for IMT of 64% (P<0.0001) after adjustment for significant cardiovascular risk factors. Genetic factors accounted for 50% of the total variation in IMT, whereas significant cardiovascular risk factors explained 22% (14% were due to age). For offspring and parents combined, adjusted IMT heritability was less, 34% (P=0.0005), with genetic factors accounting for 18% of the total IMT variation, whereas significant cardiovascular risk factors explained 46% (38% were due to age). We conclude that variation in common carotid artery IMT is heritable in Latino families with a hypertensive proband. Heritability is particularly evident in younger family members, suggesting that acquired factors contribute progressively to IMT variability with aging.
Key words: intima-media thickness • coronary heart disease • heritability • genetic effects