Cigarette smoking and the development and rupture of cerebral aneurysms in a mixed race population: implications for population screening and smoking cessation

Background: Despite advances in the treatment of aneurysmal subarachnoid hemorhage (aSAH), major additional reductions in morbidity will require the identifications of unruptured aneurysms with a high propensity for bleeding. As screening the entire population is currently not cost-effective, risk factors for the presence of unruptured aneurysms must be identified, and if possible, these risk factors should be modified to reduce disease prevalence. Methods: To examine whether cigarette smoking independent of arterial hypertension is a risk factor for the development of cerebral aneurysms rather than just being associated with aSAH and to determine whether smoking cessation decreases this risk, we conducted a case-control study comparing the prevalence and degree of smoking in a consecutive series of patients undergoing surgery for ruptured or unruptured aneurysm with age-, sex-, race-, and geographically matched control subjects culled from the New York Healthy Heart Study. Results: Hypertension alone carries little additional risk for the development of ruptured or unruptured aneurysms. Smoking is a risk factor for not only aneurysmal subarachnoid hemorrhage (Relative Risk [RR]=2.83) but also aneurysm formation (RR=2.33). Coexistent hypertension increases the risk of smoking only minimally. Younger smokers are at threefold higher risk than middle-aged ones. Smoking cessation appears to reduce risk of aneurysmal rupture. The effect of smoking on aneurysm formation and rupture may be dose-dependent. Conclusions: Together these data suggest that smoking, independent of hypertension, plays a critical role in aneurysm development, especially in younger patients, but that physiological mechanisms exist for repair of the damage induced by this toxic insult if cessation is possible.