title: Intrafamilial correlations of carotid intima-media thickness and flow-mediated dilation in a Siberian population.
abstract: BACKGROUND
  Intima-media thickening and impaired endothelium-dependent vasodilation are complex phenotypes determined by genetic and environmental factors. Few studies assessed these phenotypes in the same subjects. The goal of our study was to assess the sex-specific intrafamilial aggregation of ultrasonographic carotid intima-media thickness (IMT) and brachial flow-mediated vasodilation (FMD) in a Siberian population.
  
  
  METHODS
  We randomly recruited 81 nuclear families of Caucasian ancestry (129 parents and 157 offspring, mean age 52.4 and 26.3 years) in Novosibirsk, Russia. Carotid artery IMT and brachial artery FMD were assessed by ultrasound. Intraclass correlation coefficients were calculated between first-degree relatives and between unrelated spouse pairs for IMT and FMD in age- adjusted, sex-adjusted, and multivariate-adjusted models.
  
  
  RESULTS
  Multivariate-adjusted correlation coefficients in sib-sib pairs were 0.27 (P = .042) for IMT and 0.29 (P = .049) for FMD with heritabilities (h(2)= 2r) of 0.54 and 0.58, respectively. For IMT, the mother-offspring (r = 0.17, P = .051) and mother-daughter correlations (r = 0.28, P = .025) were significant, whereas the father-offspring correlation did not differ from zero (r = 0.11, P = .33). For FMD the father-offspring (r = 0.24, P = .042) and father-son correlations (r = 0.40, P = .051) were significant, whereas the mother-offspring correlation was only -0.09 (P = .39). The P value for the difference in familial aggregation of FMD between father-offspring and mother-offspring pairs was .018.
  
  
  CONCLUSIONS
  Our findings confirm that a substantial proportion of the variability of carotid IMT and brachial FMD is attributable to genetic variation. They also suggest that offspring share more genetic or environmental determinants of FMD with fathers than their mothers.
authors.affiliation: Laboratory of Internal Medicine and Department of Non-invasive Diagnostics, Institute of Internal Medicine, Siberian Branch of the Russian Academy of Medical Science, Novosibirsk, Russia. andrew_ryabikov@mail.ru
authors.forename: Andrew
authors.initials: A
authors.lastname: Ryabikov
authors.forename: Sofia
authors.initials: S
authors.lastname: Malyutina
authors.forename: Maxim
authors.initials: M
authors.lastname: Ryabikov
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kuznetsova
authors.forename: Jan A
authors.initials: JA
authors.lastname: Staessen
authors.forename: Yuri
authors.initials: Y
authors.lastname: Nikitin
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D001783:Blood Flow Velocity; D001827:Body Height / Q000235:genetics; D001835:Body Weight / Q000235:genetics; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D009679:Nuclear Family; D010375:Pedigree; D010641:Phenotype; D012737:Sex Factors; D012800:Siberia; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology*; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography; D014664:Vasodilation / Q000235:genetics*