Gender as a risk factor for pulmonary embolism after air travel

It was the objective of this study to confirm the hypothesis that women experience an increased risk of pulmonary embolism (PE) and/or thromboembolic events after long-distance air travel. We systematically reviewed the records of all patients with confirmed pulmonary embolism after arrival at Roissy-Charles-de-Gaulle (CDG) Airport (Paris, France) during a 13-year period. The incidence of PE was calculated as a function of distance travelled and gender using Bayesian conditional probabilities obtained in part from a control population of long-distance travellers arriving in French Polynesia (Tahiti). A total of 287.6 million passengers landed at CDG airport during the study period. The proportion of male to female long-distance travellers was estimated to be 50.5% to 49.5%. Overall, 116 patients experienced PE after landing [90 females (78%), 26 males (22%)]. The estimated incidence of PE was 0.61 (0.61-0.61) cases per million passengers in females and 0.2 (0.20-0.20) in males, and reached 7.24 (7.17-7.31) and 2.35 (2.33-2.38) cases, respectively, in passengers travelling over 10,000 km. Our study strongly suggests that there is a relationship between risk of PE after air travel and gender. This relationship needs to be confirmed in order to develop the best strategy for prophylaxis.