title: Risk factors for deep vein thrombosis and pulmonary embolism: a population-based case-control study.
abstract: BACKGROUND
  Reported risk factors for venous thromboembolism (VTE) vary widely, and the magnitude and independence of each are uncertain.
  
  
  OBJECTIVE
  To identify independent risk factors for deep vein thrombosis and pulmonary embolism and to estimate the magnitude of risk for each.
  
  
  METHODS
  We performed a population-based, nested, case-control study of 625 Olmsted County, Minnesota, patients with a first lifetime VTE diagnosed during the 15-year period from January 1, 1976, through December 31, 1990, and 625 Olmsted County patients without VTE. The 2 groups were matched on age, sex, calendar year, and medical record number.
  
  
  RESULTS
  Independent risk factors for VTE included surgery (odds ratio [OR], 21.7; 95% confidence interval [CI], 9.4-49.9), trauma (OR, 12.7; 95% CI, 4.1-39.7), hospital or nursing home confinement (OR, 8.0; 95% CI, 4.5-14.2), malignant neoplasm with (OR, 6.5; 95% CI, 2.1-20.2) or without (OR, 4.1; 95% CI, 1.9-8.5) chemotherapy, central venous catheter or pacemaker (OR, 5.6; 95% CI, 1.6-19.6), superficial vein thrombosis (OR, 4.3; 95% CI, 1.8-10.6), and neurological disease with extremity paresis (OR, 3.0; 95% CI, 1.3-7.4). The risk associated with varicose veins diminished with age (for age 45 years: OR, 4.2; 95% CI, 1.6-11.3; for age 60 years: OR, 1.9; 95% CI, 1.0-3.6; for age 75 years: OR, 0.9; 95% CI, 0.6-1.4), while patients with liver disease had a reduced risk (OR, 0.1; 95% CI, 0.0-0.7).
  
  
  CONCLUSIONS
  Hospital or nursing home confinement, surgery, trauma, malignant neoplasm, chemotherapy, neurologic disease with paresis, central venous catheter or pacemaker, varicose veins, and superficial vein thrombosis are independent and important risk factors for VTE.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic and Mayo Foundation, Rochester, Minn 55905, USA. heit.john@mayo.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Heit
authors.forename: M D
authors.initials: MD
authors.lastname: Silverstein
authors.forename: D N
authors.initials: DN
authors.lastname: Mohr
authors.forename: T M
authors.initials: TM
authors.lastname: Petterson
authors.forename: W M
authors.initials: WM
authors.lastname: O'Fallon
authors.forename: L J
authors.initials: LJ
authors.lastname: Melton
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D011655:Pulmonary Embolism / Q000453:epidemiology* / Q000209:etiology*; D012306:Risk; D012307:Risk Factors; D020246:Venous Thrombosis / Q000453:epidemiology* / Q000209:etiology*