Blood clot travel link disputed

New research claims blood clots are not a travel risk

The risk of developing dangerous blood clots during long journeys has been disputed, just days after a young woman died from the condition.

Dutch scientists claim that long-distance travel does not increase the likelihood of people suffering from deep vein thrombosis.

The link between long journeys, particularly by air, and formation of clots in the deep veins in the legs has been widely accepted.

But a study from the University of Amsterdam concludes that there is no association between travel and the potentially fatal condition.

The researchers assessed 788 patients who were suspected of having a DVT and asked them about their medical history.

They were also questioned about whether they had travelled by air, car, train or boat for more than three hours continuously in the previous four weeks.

These results do not lend support to the widely accepted dogma that long travelling time is a risk factor for venous thrombosis

Roderik Kraaijenhagen, University of Amsterdam

It is believed Emma Christoffersen, 28, from Newport, south Wales, died from the so-called "economy class syndrome" after flying 12,000 miles from Australia in a cramped seating position.

Tests showed Ms Christoffersen died from deep-veined thrombosis (DVT) which is suffered by dozens of airline passengers each year.

One quarter of the patients were found to have a DVT, but the researchers found no association between the development of their symptoms and any form of travel.

The research team, writing in the Lancet, also looked at age, sex and whether patients had suffered previous blood clots or undergone recent surgery and found no increase in risk.

Considering air travel along and even when the longest journeys of more than five hours were taken into account, the study found no evidence of any link.

'Not impressed'

Lead researcher Roderik Kraaijenhagen said: "These results do not lend support to the widely accepted dogma that long travelling time is a risk factor for venous thrombosis."

But Farrol Kahn, head of the Aviation Health Institute in the UK said he was "not impressed" by the research.

"There are a lot of variables which this research doesn't explain such as what kind of seats people were travelling in," he told BBC News Online.

"The Department of Health in the UK has said that 5% to 10% of cases of deep vein thrombosis are linked to immobility through long-haul travel.

"For these researchers to say it is a very small problem just shows the weakness of their study."

British Airways is supporting research into DVT at Newcastle University which also points to there being no direct link between flying and thrombosis.

"Prolonged periods of immobility have been recognised as a contributory factor in DVT for many years. This applies whether a person is seated in a train, a bus, a car or even in the theatre," a BA spokesman said.

Cabin crew draw the attention of passengers to health information in in-flight magazines when they welcome them on board, he said, including the need to walk around in the cabin and drink plenty of water.

"In the light of recent events it may well be that they reiterate this information more in future," he added.

The new research was criticised by a mother whose son collapsed and died two weeks after a 10,000 mile flight home from his honeymoon in Hawaii.

Ada Thomas is convinced her son John's death was linked to the cramped conditions on the 18-hour flight.

Mrs Thomas, of Cowbridge, South Wales, said: "It is ridiculous to talk about a myth. My son's death was caused by him sitting in that plane for so long."