Associations of cigarette smoking with intracranial atherosclerosis in the patients with acute ischemic stroke

Although cigarette smoking has been established as an important risk factor for stroke, the effect on the atherosclerotic stenosis, which are based on observational studies, have been controversial. We set out to examine the differences in the risk factors between smokers and nonsmokers and to investigate the association of cigarette smoking with cerebral arterial stenosis.A total of 989 consecutive patients with acute noncardioembolic ischemic stroke were prospectively enrolled from June 2004 to January 2010. The risk factor profiles were compared between smokers and nonsmokers. We analyzed the degree of stenosis in all MRA, and evaluated influencing factors in the patients with intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) who were randomly matched by age and sex.There were differences in the distribution of risk factors between the 467 (70.0%) nonsmokers and the 215 (30.0%) smokers. Nonsmokers were older (71.7±11.0 versus 61.7±12.0, p<0.001) and had a higher frequency of hypertension than smokers had (75.4% versus 64.0%, p=0.002). When smokers and nonsmokers were age- and sex-matched, smoking was more prevalent in patients with ICAS than with ECAS (32.9% versus 28.2%). Conditional regression analysis revealed that smoking and hypertension increased the odds of ICAS [smoking, odds ratio (OR): 1.83, p=0.026; hypertension, OR: 1.84, p=0.01], whereas hyperlipidemia increased the odds of ECAS (OR: 1.87, p=0.034).The distributions of the major risk factors for ischemic stroke were different between smokers and nonsmokers. Cigarette smoking may be more associated with ICAS than with ECAS after adjusting for potential risk factors.