Risk factors for abdominal aortic aneurysms in smokers

Objective: To investigate features of the smoking habit and other cardiovascular risk factors associated with the development of abdominal aortic aneurysm in smokers. Design and setting Case control study of smokers recruited between 1989 and 1992, in a London teaching hospital. Subjects: Consecutive smokers referred with abdominal aortic aneurysm (cases n=44) and 244 age and sex-matched smokers attending Dermatology, Orthopaedic and Urology clinics (controls). Main results: Hypertension was move common amongst the patients with aneurysm (30%) than the controls (19%). Measured systolic and diastolic blood pressures were significantly higher in the aneurysm patients. The relative risk of having an abdominal aortic aneurysm increased 3.4-fold (95% 1.06-20.89) for those with a distolic blood pressure of > 90mmHgg p = 0.035 and 4.1-fold (95% CI 1.27-13.16) for those with a mean arterial pressure greater than or equal to 100mmHg, p = 0.009. Plasma lipids, fibrinogen and cotinine were similar amongst patients with aneurysm and controls. The cumulative smoking exposure was similar in the patients with aneurysm and controls, median 49 and 44 pack-years respectively The relative risk of developing an aneurysm increased with tire number of cigarettes currently smoked, p = 0.008, and with increasing depth of inhalation, p = 0.025, but was not associated with the tar or nicotine yield of current cigarettes. Conclusions: In smokers, the risk of developing an abdominal aortic aneurysm increases with increasing mean arterial and diastolic blood pressure and two aspects of client smoking habit: the number of cigarettes currently smoked and the depth of inhalation.