A new study says that oral contraceptives, sitting in a window seat, advanced age, and pregnancy increase risk of a deep vein thrombosis (DVT), or blood clot in long-distance travelers.
New evidence-based guidelines from the American College of Chest Physicians (ACCP) address the many risk factors for developing DVT as the result of long-distance travel.
The guidelines also suggest there is no definitive evidence to support that travelling in economy class can lead to the development of a DVT, therefore, dispelling the myth of the so-called "economy class syndrome."
"Traveling in economy class does not increase your risk for developing a blood clot, even during long-distance travel; however, remaining immobile for long periods of time will," said guideline co-author Mark Crowther, MD, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
"Long-distance travelers sitting in a window seat tend to have limited mobility, which increases their risk for DVT. This risk increases as other factors are present."
DVT is a serious condition that can lead to a potentially fatal blockage in the lung known as a pulmonary embolism (PE).
Although developing a DVT/PE as the result of long-distance travel is unlikely in most cases, the guidelines note that for long-distance flights, there are several factors that may increase your risk of developing a DVT/PE and related complications.
They include previous DVT/PE or known thrombophilic disorder, malignancy, recent surgery or trauma, immobility, advanced agestrogen use - including oral contraceptives, pregnancy, sitting in a window seat and obesity.
Conversely, the guidelines suggest there is no definitive evidence to support that dehydration, alcohol intake, or sitting in economy class (compared with sitting in business class) increases your risk for developing a DVT/PE resulting from long-distance flights.
"Symptomatic DVT/PE is rare in passengers who have returned from long flights; however the association between air travel and DVT/PE is strongest for flights longer than 8 to 10 hours," said Dr. Crowther.
"Most passengers who do develop a DVT/PE after long-distance travel have one or more risk factors," Dr. Crowther added.
The study has been published in the journal CHEST.