title: Synergism between oral estrogen therapy and cytochrome P450 3A5*1 allele on the risk of venous thromboembolism among postmenopausal women.
abstract: BACKGROUND
  Hormone therapy increases the risk of venous thromboembolism (VTE) among postmenopausal women. This effect may be modulated by the expression of cytochromes P450 3A5 (CYP3A5) and 1A2 (CYP1A2) which are involved in the hepatic metabolism of estrogens.
  
  
  OBJECTIVE
  The objective was to investigate the impact of CYP3A5 and CYP1A2 genetic polymorphisms on the association of VTE with hormone therapy.
  
  
  METHODS
  We conducted a case-control study.
  
  
  METHODS
  This study was conducted in eight French hospital centers and in the general population.
  
  
  METHODS
  CYP3A5 and CYP1A2 genotypes were evaluated among 195 cases with a first documented episode of idiopathic VTE and 533 controls matched for center, age, and admission date.
  
  
  METHODS
  The outcome measure was hormone therapy by route of estrogen administration.
  
  
  RESULTS
  Overall, oral but not transdermal estrogen increased VTE risk [odds ratio (OR) = 4.5, 95% confidence interval (CI) = 2.6-7.6, and OR = 1.2, 95% CI = 0.8-1.8, respectively]. The allele frequency of CYP3A5*1 was 9 and 10% among cases and controls (OR = 1.0; 95% CI = 0.6-1.5) and that of CYP1A2*1F was 72 and 71% among cases and controls (OR = 1.5; 95% CI = 0.8-2.8). Compared with nonusers, OR for VTE in users of oral estrogen was 3.8 (95% CI = 2.1-6.7) among patients without CYP3A5*1 allele and 30.0 (95% CI = 4.4-202.9) among patients with this allele (test for interaction P = 0.04). By contrast, there was no significant interaction between CYP3A5*1 allele and transdermal estrogen on VTE risk. There is no interaction between CYP1A2 genetic polymorphism and hormone therapy on VTE risk.
  
  
  CONCLUSIONS
  Women with CYP3A5*1 allele using oral estrogen can define a subgroup at high VTE risk. Additional data are needed to assess the relevance of this genetic biomarker in the medical management of menopause.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM) Unit 780 (U780), Cardiovascular Epidemiology Section, 16 avenue Paul Vaillant Couturier, Villejuif Cedex, F- 94807 France. marianne.canonico@inserm.fr
authors.forename: Marianne
authors.initials: M
authors.lastname: Canonico
authors.forename: Elodie
authors.initials: E
authors.lastname: Bouaziz
authors.forename: Laure
authors.initials: L
authors.lastname: Carcaillon
authors.forename: Céline
authors.initials: C
authors.lastname: Verstuyft
authors.forename: Anne
authors.initials: A
authors.lastname: Guiochon-Mantel
authors.forename: Laurent
authors.initials: L
authors.lastname: Becquemont
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Scarabin
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics; D051544:Cytochrome P-450 CYP3A / Q000235:genetics*; D004967:Estrogens / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D017698:Postmenopause; D012306:Risk; D054556:Venous Thromboembolism / Q000209:etiology*
chemical_list: D004967:Estrogens; C504573:CYP1A2 protein, human; C510164:CYP3A5 protein, human; D019388:Cytochrome P-450 CYP1A2; D051544:Cytochrome P-450 CYP3A