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.
aDepartment of Radiology and Oncotherapy, Semmelweis University, Budapest, Hungary
bGenetic Epidemiology Unit, National Centre of Epidemiology, Istituto Superiore di Sanità, Rome
cVascular and Interventional Radiology Unit, Department of Radiological Sciences, La Sapienza University of Rome, Rome
dDepartment of Neurosciences, School of Medicine, University of Padua, Padua, Italy
eBajcsy Zsilinszky Hospital, III. Department of Internal Medicine, Budapest
fResearch Group for Inflammation Biology and Immunogenomics of Hungarian Academy of Sciences and Semmelweis University, Budapest
gDepartment of Cardiology, Military Hospital – State Health Center, Budapest
hNational Centre for Healthcare Audit and Inspection, Budapest
iInstitute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest
jSemmelweis University, Faculty of Medicine, Budapest
kSemmelweis University, Faculty of Pharmacy, Budapest
lCentral European University, Budapest, Hungary
mThe Methodist Hospital DeBakey Heart and Vascular Center, Houston, Texas, USA
nUnit of Internal Medicine, University of Perugia at Terni, ‘S. Maria’ Hospital, Terni, Italy
*Adam Domonkos Tarnoki and David Laszlo Tarnoki contributed equally to the writing of this article.
Correspondence to Adam Domonkos Tarnoki, MD, Contact information: Department of Radiology and Oncotherapy, Semmelweis University, 78/a Ulloi street, Budapest, H-1082, Hungary. Tel: +36 30 6401183; fax: +36 1 2780368; e-mail: email@example.com
Abbreviations: A, additive effect; AIx, augmentation index; BP, blood pressure; C, common environmental effect; CI, confidence interval; DZ, dizygotic; E, unique environmental effect; MZ, monozygotic; PP, pulse pressure; PWV, pulse wave velocity; rDZ, bivariate co-twin correlation in DZ; rMZ, bivariate co-twin correlation in MZ; SD, standard deviation
Received 22 December, 2011
Revised 17 March, 2012
Accepted 24 April, 2012
This article was presented during European Society of Hypertension's Annual conference in Milan, June 2011 (A.D.T., D.L.T., A.M.S., E.M., F.F., C.B., G.M., G.S., I.P., K.K., A.L., A.A.M., L.L., Z.G., V.B. Praise a fair day with twins: central blood pressure, pulse pressure and arterial stiffness. Journal of Hypertension, 29, e-Suppl A, June 2011, e469). The preliminary findings of arterial stiffness measurements based on fewer subjects were published in Journal for Vascular Ultrasound (Tarnoki AD et al. Twins lead to the prevention of atherosclerosis. Preliminary findings of International twin study 2009. Journal for Vascular Ultrasound 2011; 35(2):61–71.). A part of the results were presented at the European Society of Cardiology Annual Congress in Paris, August 2011 and at the Artery meeting in Paris, October 2011.