Objective: Central blood pressure and aortic stiffness have been consistently reported as strong cardiovascular risk factors. Twin studies by comparing identical with nonidentical twins produce information on the relative contribution of genes and environment.
Methods: One hundred and fifty-four monozygotic (MZ) and 42 dizygotic (DZ) twin pairs (age 43 ± 17 years) from Hungary and the United States underwent brachial and central augmentation index (AIx), brachial and central pressure, and aortic pulse wave velocity (PWV) measurements with the invasively validated Arteriograph device. Bivariate Cholesky decomposition models were applied.
Results: Age-adjusted, sex-adjusted and country-adjusted heritability was 60.0% for central SBP [95% confidence interval (CI), 44.8-69.6%], 50.1% for aortic PWV (95%CI, 26.0-66.8%), 48.7% for aortic AIx (95%CI, 1.7-74.0%), 46.8% for brachial AIx (95%CI, 1.1-73.8%), 46.7% for central pulse pressure (PP) (95%CI, 12.4-61.4%), and 30.0% for brachial PP (95%CI, 0.0-53.4%). Central SBP and PP had strong bivariate correlations with brachial (r = 0.461 and 0.425) and central AIx (r = 0.457 and 0.419), as well as with aortic PWV (r = 0.341 and 0.292, all P < 0.001). Brachial PP had a weak correlation with brachial AIx (r = -0.118, P < 0.05), central AIx (r = -0.122, P < 0.05), and none with aortic PWV (r = 0.08, P = n.s.). Genetic factors explained a moderate phenotypic correlation between central PP, SBP, brachial SBP and aortic PWV.
Conclusions: Central systolic and PPs, brachial PP, AIx, aortic PWV are moderately heritable. A moderate genetic covariance among aortic PWV and central PP, central SBP and brachial SBP was found.