Hormone Replacement Therapy and Prothrombotic Variants
Condition: Cardiovascular Diseases; Heart Diseases; Cerebrovascular Accident; Myocardial Infarction; Hypertension
MeSH terms: Stroke; Cardiovascular Diseases; Heart Diseases; Myocardial Infarction; Infarction
Study type: Observational

Summary: 
      To examine in postmenopausal women the potential interactions of hormone replacement therapy
      with other blood clotting factors on the risk of cardiovascular diseases such as heart attack
      or stroke.
    

Detailed description: 
      BACKGROUND:

      Estrogens are prothrombotic. Recently, the Heart and Estrogen/progestin Replacement Study
      (HERS), renewed interest in the adverse effects of hormone replacement therapy (HRT). In
      HERS, HRT was no better than placebo at preventing coronary events. In post hoc analyses,
      treatment was associated with early harm and late benefit. In an American Heart Association
      funded case-control study, a potential interaction was observed between HRT and the
      prothrombin G20210A variant on the risk of first myocardial infarction (MI) in
      post-menopausal women with hypertension.

      DESIGN NARRATIVE:

      The study has a case-control design. The Group Health Cooperative (GHC) computerized files
      will be used to identify postmenopausal women, aged 30 to 79 yrs, with incident myocardial
      infarction (MI) or stroke during 1/2000-12/2004. Population-based controls, sampled from the
      GHC enrollment files, will be frequency matched to cases by age, calendar year, and treated
      hypertension. Data collection will include medical-record review, telephone interview of
      consenting subjects, and venous-blood collection. Standard methods will be used to assay
      variant alleles. The GHC computerized pharmacy records will serve as the primary source of
      information about the use of HRT. Data analysis will involve restriction, stratification, and
      logistic regression. Case-control and case-only analyses are planned. There will be a total
      of 600 MI cases, 420 stroke cases and 1800 controls.

      The primary purpose is to examine the potential interactions of hormone replacement therapy
      with other procoagulant variants on the risk of cardiovascular events. The main variants of
      interest are: (la) factor XIIIA Val34Leu; (ib) platelet glycoprotein (PGP) Jib Ile843Ser;
      (ic) PGP IIIa Leu33Pro; and (id) PGP Ia C807T. The secondary aims include the assessment of
      other drug-gene, risk-factor-gene or gene-gene interactions on risk: (2a) the interaction
      between PGP IIb Ser843, PGP lila Leu33Pro and PGP Ia C807T and traditional cardiovascular
      risk factors such as smoking and obesity on the risk of MI and stroke; (2b) the interaction
      between three coagulation factor XIII polymorphisms and PAl-1 4G/5G on the risk of stroke in
      women; and (2c) the interaction between aspirin use and glycoprotein IIIa Leu33Pro on the
      risk of MI and stroke.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        General