Smoking and Aneurysmal Subarachnoid Haemorrhage: A Case-Control Study

Abstract

BACKGROUND: Despite recent advances in the management of subarachnoid haemorrhage, the mortality rate associated with the condition remains high. The identification of risk factors for subarachnoid haemorrhage may lead to the development of interventions aimed at its prevention. METHODS: We compared the prevalence of vascular risk factors using a case-control design in 141 consecutively admitted patients who had suffered a subarachnoid haemorrhage with that in age- and sex-matched subjects registered with a general practitioner in a western suburb of Lisbon. RESULTS: The prevalence of diabetes and hyperlipidaemia did not differ between the groups. Hypertension was 8.3 times more frequent among patients with subarachnoid haemorrhage (95% confidence interval 4.6-16.7) than in the control group, and smoking was four times more frequent (95% confidence interval 2.0-8.6). The association between smoking and subarachnoid haemorrhage persisted after controlling for the presence of hypertension (odds ratio for hypertensive participants = 10.5, 95% confidence interval 1.9-56.4; odds ratio for normotensive participants = 3.7, 95% confidence interval 1.6-10.1) and was independent of both age and sex. CONCLUSION: These results indicate that hypertension and smoking are both involved in the growth or rupture of cerebral aneurysms.