Air travel is not associated with an increase in risk of deep vein thrombosis
(DVT) according to Dutch researchers writing in the Lancet (2000;356:1492).
They report the results of a study of 788 patients with clinically suspected
DVT of the leg. Details of their medical history and travel in the previous
four weeks were obtained by questionnaire. DVT was confirmed in 186 patients
who formed the case group and the remaining patients formed the control group.
For air travel alone, the odds ratio was 1.0, indicating no increase in risk.
In addition, no association was found for other methods of transport or for
long journeys. The researchers conclude: “These results do not lend support
to the widely accepted assumption that long travelling time is a risk factor
for venous thrombosis. Even for journeys lasting more than five hours no association
was apparent.”