title: Lifetime Risk of Venous Thromboembolism in Two Cohort Studies.
abstract: BACKGROUND
  Greater public awareness of venous thromboembolism may be an important next step for optimizing venous thromboembolism prevention and treatment. "Lifetime risk" is an easily interpretable way of presenting risk information. Therefore, we sought to calculate the lifetime risk of venous thromboembolism (deep vein thrombosis or pulmonary embolism) using data from 2 large, prospective cohort studies: the Cardiovascular Health Study (CHS) and the Atherosclerosis Risk in Communities (ARIC) study.
  
  
  METHODS
  We followed participants aged 45-64 years in ARIC (n = 14,185) and ≥65 in CHS (n = 5414) at baseline visits (1987-1989 in ARIC, 1989-1990 and 1992-1993 in CHS) for incident venous thromboembolism (n = 728 in ARIC through 2011 and n = 172 in CHS through 2001). We estimated lifetime risks and 95% confidence intervals of incident venous thromboembolism using a modified Kaplan-Meier method, accounting for the competing risk of death from other causes.
  
  
  RESULTS
  At age 45 years, the remaining lifetime risk of venous thromboembolism in ARIC was 8.1% (95% confidence interval, 7.1-8.7). High-risk groups were African Americans (11.5% lifetime risk), those with obesity (10.9%), heterozygous for the factor V Leiden (17.1%), or with sickle cell trait or disease (18.2%). Lifetime risk estimates differed by cohort; these differences were explained by differences in time period of venous thromboembolism ascertainment.
  
  
  CONCLUSIONS
  At least 1 in 12 middle-aged adults will develop venous thromboembolism in their remaining lifetime. This estimate of lifetime risk may be useful to promote awareness of venous thromboembolism and guide decisions at both clinical and policy levels.
authors.affiliation: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis. Electronic address: ebell@umn.edu.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Bell
authors.affiliation: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis.
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Lutsey
authors.affiliation: Division of Biostatistics, University of Minnesota, Minneapolis.
authors.forename: Saonli
authors.initials: S
authors.lastname: Basu
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, University of Vermont, Burlington.
authors.forename: Mary
authors.initials: M
authors.lastname: Cushman
authors.affiliation: Cardiovascular Health Research Unit and Department of Epidemiology, University of Washington, Seattle.
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Lloyd-Jones
authors.affiliation: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis.
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Folsom
mesh_terms: D000368:Aged; D000755:Anemia, Sickle Cell / Q000453:epidemiology; D044383:Black People / Q000706:statistics & numerical data; D015331:Cohort Studies; D005165:Factor V / Q000235:genetics; D005500:Follow-Up Studies; D006579:Heterozygote; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D012306:Risk; D012805:Sickle Cell Trait / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D054556:Venous Thromboembolism / Q000453:epidemiology*; D001741:Black or African American
chemical_list: C095381:factor V Leiden; D005165:Factor V
keywords: Embolism; Epidemiology; Risk factors; Thrombosis