Zhao Jinying, Cheema Faiz A, Bremner J Douglas, Goldberg Jack, Su Shaoyong, Snieder Harold, Maisano Carisa, Jones Linda, Javed Farhan, Murrah Nancy, Le Ngoc-Anh, Vaccarino Viola
Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30306, United States.
Atherosclerosis. 2008 Apr;197(2):814-20. doi: 10.1016/j.atherosclerosis.2007.07.030. Epub 2007 Sep 6.
To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors.
We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ) and 40 dizygotic (DZ) pairs, from the Vietnam Era Twin Registry. All twins were free of overt cardiovascular disease. Carotid IMT was measured by ultrasound. Bivariate and multivariate analyses were used to determine the association between traditional cardiovascular risk factors and carotid IMT. Intraclass correlation coefficients and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in carotid IMT. In our sample, the mean of the maximum carotid IMT was 0.75+/-0.11. Age, systolic blood pressure and HDL were significantly associated with carotid IMT. The intraclass correlation coefficient for carotid IMT was larger in MZ (0.66; 95% confidence interval [CI], 0.62-0.69) than in DZ twins (0.37; 95% CI, 0.29-0.44), and the unadjusted heritability was 0.69 (95% CI, 0.54-0.79). After adjusting for traditional coronary risk factors, the heritability of carotid IMT was slightly reduced but still of considerable magnitude (0.59; 95% CI, 0.39-0.73).
Genetic factors have a substantial influence on the variation of carotid IMT. Most of this genetic effect occurs through pathways independent of traditional coronary risk factors.
评估颈动脉内膜中层厚度(IMT)的遗传度,颈动脉内膜中层厚度是动脉粥样硬化的替代标志物,独立于传统的冠心病危险因素。
我们利用越南战争时期双胞胎登记处的98对中年男性双胞胎(58对同卵双胞胎和40对异卵双胞胎)进行了一项关于颈动脉IMT的经典双胞胎研究。所有双胞胎均无明显心血管疾病。通过超声测量颈动脉IMT。采用双变量和多变量分析来确定传统心血管危险因素与颈动脉IMT之间的关联。使用组内相关系数和遗传建模技术来确定基因和环境对颈动脉IMT变异的相对贡献。在我们的样本中,最大颈动脉IMT的平均值为0.75±0.11。年龄、收缩压和高密度脂蛋白与颈动脉IMT显著相关。同卵双胞胎中颈动脉IMT的组内相关系数(0.66;95%置信区间[CI],0.62 - 0.69)大于异卵双胞胎(0.37;95% CI,0.29 - 0.44),未调整的遗传度为0.69(95% CI,0.54 - 0.79)。在调整传统冠心病危险因素后,颈动脉IMT的遗传度略有降低,但仍处于相当大的水平(0.59;95% CI,0.39 - 0.73)。
遗传因素对颈动脉IMT的变异有重大影响。这种遗传效应大多通过独立于传统冠心病危险因素的途径发生。