Not Much Fits

People who are overweight, very tall or short may run a risk up to 100 times higher of developing venous thrombosis after air travel, experts in Vienna said Friday. Experts at the 12th Congress of the European Hematology Association, shored up by a WHO study presented at the meeting, said certain risk factors would greatly increase the likelihood of developing thrombosis.

At the meeting, taking place from June 7 to 10, Frits R Rosendaal, hematologist at Leiden University in the Netherlands said that while the overall risk for travellers was still low the risk factors must not be neglected.

“The risk of developing thrombosis when travelling are higher for people with certain common abnormalities in the blood, for women who use birth control pills, or people who use sleeping pills on a flight, as well as people who are very tall, very short or overweight.”

In those cases a 50 to 100-fold increase in risk for people with combinations of those factors was possible, he added. Lack of movement and the cramped seating in economy class are regarded as the main factors for developing traveller’s thrombosis. Low cabin pressure may add to the risks, experts said.

The study surveyed 2,000 persons suffering from thrombosis in addition to 9,000 frequent flyers. One conclusion was that in the eight weeks after a flight of more than four hours, thrombosis risk increased two to threefold, with one in 4,500 travellers developing thrombosis.