Cigarette smoking as a risk factor for high grade carotid artery stenoses

Background: We investigated the association of cigarette smoking with high- grade carotid artery stenosis in patients with ischemic stroke and transien t ischemic attacks. Methods: Prospectively collected data from 404 patients with focal brain ischemia were used for a cross-sectional study estimating the association between cigarette smoking and high-grade carotid artery st enosis (diagnosed by Doppler-ultrasound and defined as a luminal narrowing of greater than or equal to 70%). Cerebral ischemia patients with normal so nographic findings served as a comparison group. Multivariate logistic regr ession models were used for statistical tests to determine the association between smoking and high-grade carotid stenosis. Age, gender, hypertension, diabetes mellitus, hypercholesterolemia and coexisting heart disease (myoc ardial infarction, angina, heart failure) were considered potential confoun ders. Results: High-grade carotid stenoses were found in 25% (n=101) of the patients: 39% (n=156) were classified as smokers. Smoking (odds ratio 3.6, 95% confidence interval [CI] 2.2 to 5.8), hypercholesterolemia (odds ratio 1.8; CI 1.1 to 2.8) and preexisting heart disease (odds ratio 1.7: CI 1.1 to 2.7) were significantly associated with carotid stenosis greater than or equal to 70%. The impact of smoking augmented with increasing degree of st enosis (odds ratio for stenoses greater than or equal to 80%: 4.3, CI 2.3 t o 7.7), whereas the association with hypercholesterolemia, and co-existing heart disease decreased in strength for stenoses greater than 80%. Hyperten sion and diabetes mellitus were not found to be significantly with high-gra de carotid artery stenoses. Conclusion: Smelting is an independent determin ant of severe carotid artery stenosis in patients with focal cerebral ische mia.