title: The relationship between exercise and risk of venous thrombosis in elderly people.
abstract: OBJECTIVE
  To study whether exercise is associated with the risk of venous thrombosis in elderly people.
  
  
  METHODS
  Observational study with a median follow-up of 11.6 years.
  
  
  METHODS
  The Cardiovascular Health Study in four U.S. communities.
  
  
  METHODS
  People aged 65 and older without prior venous thrombosis (deep venous thrombosis or pulmonary embolism).
  
  
  METHODS
  Self-reported exercise was measured two or three times during follow-up and was defined as expending more than 500 kcal/wk on exercise, including walking for exercise. Venous thrombosis cases were verified using medical record review.
  
  
  RESULTS
  Of 5,534 participants, 171 developed a first venous thrombosis. Self-reported exercise at baseline was not related to the risk of venous thrombosis after adjustment for sex, age, race, self-reported health, and body mass index (adjusted hazard ratio (HR(adj))=1.16, 95% confidence interval (CI)=0.84-1.61), although with exercise modeled as a time-varying exposure, overall results were in the direction of greater risk of venous thrombosis (HR(adj)=1.38, 95% CI=0.99-1.91). For mild-intensity exercise, such as walking, there was a nonsignificant finding in the direction of benefit (HR(adj)=0.75, 95% CI=0.49-1.16), but strenuous exercise, such as jogging, was associated with greater risk of venous thrombosis (HR(adj)=1.75, 95% CI=1.08-2.83) than no exercise at all.
  
  
  CONCLUSIONS
  In elderly people, strenuous exercise was associated with a higher risk of venous thrombosis than no exercise at all. Future studies are needed to explain this unexpected higher risk.
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Karlijn J
authors.initials: KJ
authors.lastname: van Stralen
authors.forename: Carine J M
authors.initials: CJ
authors.lastname: Doggen
authors.forename: Thomas
authors.initials: T
authors.lastname: Lumley
authors.forename: Mary
authors.initials: M
authors.lastname: Cushman
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Folsom
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Psaty
authors.forename: David
authors.initials: D
authors.lastname: Siscovick
authors.forename: Frits R
authors.initials: FR
authors.lastname: Rosendaal
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D014481:United States; D020246:Venous Thrombosis / Q000453:epidemiology*