The report is likely to prompt renewed calls for airlines to improve the seating on long-haul flights.

The airport clinic said it had identified 25 fatalities attributable to the syndrome, which is associated with a lack of leg-room and opportunities to exercise.

The study, Japan's first examination of the problem, found that between 100 and 150 long-haul passengers were treated for the syndrome upon arrival in Tokyo each year. The doctors said that about half the cases were serious.

Passengers who spend hours in the cramped conditions of economy cabins are believed to be at risk of developing deep-vein thrombosis - blood clots in the legs - which can be fatal if the clots travel up to the heart or lungs.

In October the syndrome was blamed for the death of the Australian Emma Christoffersen, 28, who collapsed at Heathrow airport minutes after disembarking from a 20-hour Qantas flight from Australia.

The postmortem showed that a blood clot had moved from her foot to her heart.

Experts are divided about the extent to which air travel heightens the danger of deep-vein thrombosis, but a parliamentary committee recently recommended that airlines should warn passengers of the health risks associated with long-distance flights.

According to the latest study, pilots and passengers in all classes are at risk.

"It's wrong to assume that it is limited to economy class passengers," said Dr Toshiro Makino, who heads the airport clinic. "The syndrome may have become well known only recently, but it has been around ever since people began flying."

He said overweight and elderly passengers were most at risk. The survey said the average age of those who died was 64.

Other at risk include sufferers of varicose veins or cancer, passengers with long legs, smokers, pregnant women and women taking birth-control pills.

The warning signs include pain and swelling in the legs, and difficulty breathing. Dr Makino said alcohol should be avoided on flights because - along with the dry air in plane cabins - it causes dehydration, a factor in blood-clotting.

A spokesman for Japan Airlines, the biggest user of Narita airport, told reporters that the company was aware of the syndrome and advised passengers to stretch their legs and drink water.

SOURCE: Jonathan Watts in Tokyo
DATE: Friday December 29, 2000
The Guardian