The usual risk factors for DVT are listed below. However, these are based on the cases most likely to be observed and treated, the cases arising during or soon after hospitalization. DVT following hip surgery. for example, is likely enough to warrant prophylactic anticoagulants in every case.
However, the risk factors in a jetliner are very different from those in a hospital. The biggest risk factor in a jetliner, accounting for a large majority of victims, is athletic conditioning, particularly training for endurance-type sports like marathons.
Following are risk factors for economy class syndrome:
1. Athletic training, especially training for endurance-type sports like marathons.
2. Recent surgery or injury. If you have just run a marathon, you probably have at least minor bruising that can trigger clotting. Kick-boxing also produces such injuries. You must also avoid surgery for at least 30 days after air travel. If surgery is unavoidable, see the article by Patel referenced in the bibliography.
3. Personal or family history of DVT.
4. Cancer, heart disease, diabetes. Obesity is often cited as a risk factor, but probably ranks much lower than the preceding diseases.
5. Women who are pregnant or taking estrogen as birth control or hormone replacement.
6. Age over 40 is often cited as a risk factor; sometime age over 60 is cited. However, in our registry over 80% are under age 60, the majority are under 50.