Aim:
To find out the frequency of smoking in subgroups of ischemic stroke and to search for relation between smoking and asymptomatic ischemic lesions (AILs) in cranial magnetic resonance imaging (MRI), recurrence of ischemic stroke, hemorrhagic transformation, seizure, pneumonia, pulmonary embolism, myocardial infarction and deep vein thrombosis.

Methods:
The stroke database of the Neurology Clinic in Istanbul Faculty of Medicine were retrospectively screened and patients with ischemic stroke admitted between 1995-2014 were included in this study.

Results:
There were 3615 patients. The lowest frequency of smoking was found in patients with cardioembolism (348/1160, 30%) (p<0,001). But we found significantly more patients with AILs (p=0,022) and higher rate of pneumonia (p=0,016) in smokers compared with non-smokers in patients with cardioembolism. We looked for relation between AILs and other potential risk factors such as hypertension, alcohol consumption, diabetes mellitus and hyperlipidemia. Only hypertension was found to be related with AILs (p<0,001). Logistic regression analysis showed that both smoking (p=0,013, OR:0,61 %95 CI: [0,41-0,9]) and hypertension (p=0,01 OR: 0,39 %95 CI [0,23-0,66]) were independent risk factors for AILs. We also looked for relation between pneumonia and other potential risk factors such as hypertension, alcohol consumption, diabetes mellitus and higher modified Rankin Scale (mRS) score at admission. Only higher mRS score at admission was found to be related with pneumonia (4,54 vs. 4,37, p=0,027). Logistic regression analysis showed that both smoking (p=0,012 OR: 0,52 %95 CI [0,32-087], and higher mRS score at admission (p=0,017 OR:0,73 %95 CI [0,56-0,94]) were independent risk factors for pneumonia.

Conclusions:
The lowest frequency of smoking is found in patients with cardioembolic stroke but smoking in those patients is an independent risk factor for development of AILs and pneumonia.