TY - JOUR
T1 - Cumulative flying time and risk of venous thromboembolism
AU - Maccallum, Peter K.
AU - Ashby, Deborah
AU - Hennessy, Enid M.
AU - Letley, Louise
AU - Martin, Jeannett
AU - Mt-Isa, Shahrul
AU - Vickers, Madge R.
AU - Whyte, Ken
PY - 2011/12
Y1 - 2011/12
N2 - The risk of venous thromboembolism (VTE) associated with cumulative flying time remains uncertain. In a case-control study in general practices throughout the UK, participants comprised 550 VTE cases identified from practice records and 1971 age- and gender-matched controls. Participants returned identical questionnaires asking for information including air travel details. Compared to not flying, cumulative flying time >12h within the previous 4weeks was associated with a threefold increase in the risk of VTE [odds ratio (OR) 2·75, 95% confidence interval (CI), 1·44-5·28]. Those who had flown >4h in a single leg in the previous 4weeks had twice the risk of VTE (OR 2·20, 95% CI, 1·29-3·73). These risks were no longer evident by 12weeks and were similar to those of day-case or minor surgery (OR 5·35, 95% CI, 2·15-13·33). Equivalent risks for moderate and high-risk surgery were over 30-fold (OR 36·57, 95% CI, 13·05-102·52) and 140-fold (OR 141·71, 95% CI, 19·38-1036·01) respectively. The temporary nature of the association of cumulative and long-haul air travel with VTE suggests a causal relationship. The risks of VTE in those with a higher baseline risk due to surgery, previous VTE or obesity are further increased by air travel.
AB - The risk of venous thromboembolism (VTE) associated with cumulative flying time remains uncertain. In a case-control study in general practices throughout the UK, participants comprised 550 VTE cases identified from practice records and 1971 age- and gender-matched controls. Participants returned identical questionnaires asking for information including air travel details. Compared to not flying, cumulative flying time >12h within the previous 4weeks was associated with a threefold increase in the risk of VTE [odds ratio (OR) 2·75, 95% confidence interval (CI), 1·44-5·28]. Those who had flown >4h in a single leg in the previous 4weeks had twice the risk of VTE (OR 2·20, 95% CI, 1·29-3·73). These risks were no longer evident by 12weeks and were similar to those of day-case or minor surgery (OR 5·35, 95% CI, 2·15-13·33). Equivalent risks for moderate and high-risk surgery were over 30-fold (OR 36·57, 95% CI, 13·05-102·52) and 140-fold (OR 141·71, 95% CI, 19·38-1036·01) respectively. The temporary nature of the association of cumulative and long-haul air travel with VTE suggests a causal relationship. The risks of VTE in those with a higher baseline risk due to surgery, previous VTE or obesity are further increased by air travel.
KW - Epidemiology
KW - Risk factors
KW - Venous thrombosis
UR - http://www.scopus.com/inward/record.url?scp=81155139542&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2141.2011.08899.x
DO - 10.1111/j.1365-2141.2011.08899.x
M3 - Article
C2 - 21981017
AN - SCOPUS:81155139542
VL - 155
SP - 613
EP - 619
JO - British Journal of Haematology
JF - British Journal of Haematology
SN - 0007-1048
IS - 5
ER -