'Economy class syndrome' still not proved after new study

As many as 10% of passengers on long-haul flights may have deep vein thrombosis (DVT) of the calf, claim the authors of a paper in 12 May Lancet. But the study design is criticised and the findings called into question by experts writing in the same issue.

Scurr et al studied 231 passengers over 50 years of age making long-haul flights of at least eight hours and returning within six weeks and who had no history of DVT. Half wore surgical compression stockings while half travelled normally. Within 48 hours of their return, all of the subjects were given ultrasound examinations. These revealed that 10% of the passengers who were not wearing the stockings had developed tiny symptomless DVT. In comparison, none of the passengers wearing stockings developed a clot.

In an accompanying Commentary, Jack Hirsh and Martin O'Donnell, from McMaster University, Ontario call into question the...