What Are Contributing Factors for DVT?

DVT can occur in anyone, but certain people may have more risk factors. The added number of factors an individual has, the greater the risk for developing blood clots. For example a woman taking estrogen who has an inherited condition for clotting has a greater likelihood of developing DVT than an otherwise healthy person who is taking estrogen.

The most common contributing factors and triggers for DVT are:²⁴

• Increasing age (especially age 75 and over)
• Immobility for long periods of time
• Stroke
• Paralysis
• History of prior blood clots
• Cancer and its treatment
• Major surgery, particularly operations on the abdomen, pelvis and lower extremities
• Respiratory failure
• Injury particularly a broken bone of the pelvis, hips or leg
• Obesity
• Varicose veins
• Congestive heart failure and myocardial infarction
• A tube inserted into the neck for treatment of other conditions
• Inflammatory bowel disease
• Use of oral contraceptives or postmenopausal hormone therapy
• Inherited clotting problems (hypercoagulability)
• Any medical condition that prompts admission to an Intensive Care Unit
• Recent air travel or long car trip*
• Smoking*

The National Alliance for Thrombosis and Thrombophilia includes smoking as a factor because smoking increases the tendency of the blood to clot.

*The affect of smoking and recent travel on the risk for DVT is controversial.²⁵

²⁴ American Public Health Association. (2003) “Deep-Vein Thrombosis: Advancing Awareness to Protect Patient Lives.” White Paper, Public Health Leadership Conference on Deep-Vein Thrombosis, Washington, D.C., Feb. 26, 2003. Available on the World Wide Web: www.apha.org/news/press/2003/DVT_whitepaper.pdf.

²⁵ Saman, M., et al. (2003) “Qualification of Risk Factors for Venous Thromboembolism: A Preliminary Study for the Development of a Risk Factor Tool.” Journal of Hematology 88(12):1410-1421. Available on the World Wide Web: www.haematologica.org/journal/2003/881410.pdf.