title: Genetic influence on thrombotic risk markers in the elderly--a Danish twin study.
abstract: OBJECTIVE
  Several hemostatic variables are identified as cardiovascular risk markers. In young and middle-aged individuals, plasma concentrations of these variables are partly determined by genetic factors. The genetic contribution to cardiovascular disease (CVD) decreases with increasing age, and it is therefore important to determine the heritability of hemostasis also in the elderly.
  
  
  METHODS
  The heritability of plasma levels of factor VII, fibrinogen, tissue factor, tissue factor pathway inhibitor, von Willebrand factor, thrombin activatable fibrinolysis inhibitor (TAFI), and D-dimer was determined in 130 monozygotic and 155 dizygotic same-sex twin pairs, aged 73-94 years, who participated in the Longitudinal Study of Aging of Danish Twins. Furthermore, we determined the influence of promoter polymorphisms in corresponding genes on the plasma level variation.
  
  
  RESULTS
  Genetic factors accounted for 33% (D-dimer) to 71% (TAFI) of the variation in plasma levels. Polymorphisms were associated with concentrations of FVII and TAFI in sib-pair based analyses, but in linkage analyses the polymorphisms did not explain a significant part of the genetic variation for any of the variables.
  
  
  CONCLUSIONS
  Concentrations of hemostatic variables have a substantial genetic variation in the elderly, but in this study the promoter polymorphisms only explained a minimal part of this variation.
authors.affiliation: Department for Thrombosis Research, University of Southern Denmark, Ribe County Hospital, Esbjerg, Denmark. emb@ribeamt.dk
authors.forename: E M
authors.initials: EM
authors.lastname: Bladbjerg
authors.forename: M P M
authors.initials: MP
authors.lastname: de Maat
authors.forename: K
authors.initials: K
authors.lastname: Christensen
authors.forename: L
authors.initials: L
authors.lastname: Bathum
authors.forename: J
authors.initials: J
authors.lastname: Jespersen
authors.forename: J
authors.initials: J
authors.lastname: Hjelmborg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000235:genetics*; D025901:Carboxypeptidase B2 / Q000097:blood / Q000235:genetics; D003718:Denmark; D004777:Environment; D005167:Factor VII / Q000032:analysis / Q000235:genetics; D005260:Female; D005340:Fibrinogen / Q000032:analysis / Q000235:genetics; D006487:Hemostasis / Q000235:genetics; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics; D012307:Risk Factors; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000235:genetics*; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*
chemical_list: D005167:Factor VII; D005340:Fibrinogen; D025901:Carboxypeptidase B2