A SEASONAL-VARIATION IN THE INCIDENCE OF RUPTURED ABDOMINAL AORTIC-ANEURYSMS

Objective: To discover whether there is a seasonal variation in the in cidence of rupture of abdominal aortic aneurysms. Design: Deaths per m onth due to rupture of abdominal aortic aneurysm were analysed retrosp ectively using a cosinor regression model. Setting: England and Wales. Subjects: 19599 patients who died from rupture of abdominal aortic an eurysm between January 1991 and December 1995 according to death certi fication data. Interventions: None. Results: A seasonal variation in t he incidence of rupture of abdominal aortic aneurysm occurs, with a pe ak in winter (p = 0.003). The ratio of rupture of abdominal aortic ane urysm in males and females decreased from more than 12 to 1 below age 60 years to less than 5 to 1 over age 80 years. Conclusions: There is a seasonal variation in the incidence of recorded deaths from abdomina l aortic aneurysm in England and Wales, with a peak of deaths in the c old winter months. The underlying cause is unknown, but hypertension a nd tobacco smoking are predisposing factors to aortic aneurysm rupture . Exposure to tobacco smoke is known to be greater indoors in cold wea ther and there is a winter peak of blood pressure in hypertensive pati ents.