Epidemiology of aneurysmal subarachnoid hemorrhage.

An estimated 1% to 5% of adults have a cerebral aneurysm. Each year, approximately 1 in 10,000 North Americans suffer an aneurysmal subarachnoid hemorrhage, with greater than 50% combined morbidity and mortality. Cerebral aneurysm formation and rupture is associated with a variety of factors, including increasing age, female gender, hypertension, alcohol, smoking, and genetic factors.