title: The impact of co-morbid conditions on family history of venous thromboembolism in Whites and Blacks.
abstract: BACKGROUND
  Our objectives were to compare the magnitude of family history as a risk factor for venous thromboembolism (VTE) risk between Blacks and Whites, and to assess the impact of co-morbid conditions on familial risk for VTE.
  
  
  METHODS
  We used data from the Genetic Attributes Thrombosis Epidemiology (GATE) study, a matched case-control study which enrolled Blacks and Whites aged 18-70years in Atlanta, Georgia. A total of 1,094 case patients with a deep vein thrombosis (DVT) or pulmonary embolism (PE) and 1,264 control patients were interviewed about their family history.
  
  
  RESULTS
  Family history of VTE was a statistically significant risk factor for VTE among Blacks (odds ratio (OR)=2.9, 95% confidence interval (CI) 2.0-4.1; P value<0.0001) and among Whites (OR=2.7, 95% CI 1.9-3.7; P value<0.0001); among Blacks and Whites who were obese or had hypertension; among Blacks who had diabetes mellitus or cancer; as well as among males and females, and across all age categories. Family history of VTE increased the risk of VTE among Blacks with cancer by about 6-fold, whereas among Blacks without cancer the increased risk due to a positive family history was about 3-fold; a 2-fold relative difference. In addition, family history was a risk factor for VTE among case patients with DVT only or with PE only. The effect of family history generally was stronger among those with recurrent episodes of VTE compared with a first episode of VTE. For example, family history of any VTE was a strong risk factor among Black females with recurrent VTE compared with Black females with first VTE (OR=3.9, 95% CI 2.0-7.5; P value<0.0001).
  
  
  CONCLUSIONS
  Our study indicated that the adjusted attributable fraction for VTE was 16.9% among Blacks vs. 18.3% among Whites, and certain co-morbid conditions could further increase the risk of VTE associated with a positive family history of VTE.
authors.affiliation: Clinical and Molecular Hemostasis Laboratory Branch, Division of Blood Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, 1600 Clifton Road, N.E., Mail Stop D-02, Atlanta, GA 30333, USA.
authors.forename: Fatima D
authors.initials: FD
authors.lastname: Mili
authors.forename: W Craig
authors.initials: WC
authors.lastname: Hooper
authors.forename: Cathy
authors.initials: C
authors.lastname: Lally
authors.forename: Harland
authors.initials: H
authors.lastname: Austin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044383:Black People / Q000235:genetics*; D016022:Case-Control Studies; D048909:Diabetes Complications / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D009765:Obesity / Q000150:complications; D011110:Polymorphism, Genetic; D011655:Pulmonary Embolism / Q000453:epidemiology; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000235:genetics; D020246:Venous Thrombosis / Q000453:epidemiology; D044465:White People / Q000235:genetics*; D055815:Young Adult