However, a study revealed that smoking and hypertension may be more closely associated with IC atherosclerosis than EC atherosclerosis after adjusting for potential confounding by other risk factors [11]. It should be noted that the criterion for significant cranial atherosclerotic stenosis in the previous studies Imatinib Mesylate buy was defined as being greater than 50% as evaluated by magnetic

resonance angiography, and the definition of the IC anatomical border was not described clearly. Although smoking in Korea has decreased recently, the smoking rate in subjects aged over 20 years was about 26% (male versus female = 43.7% vs. 7.9%) in 2012 [12]. Young adults who are involved in gambling are more likely to report cigarette smoking [13]. In South Korea, a large number of young adolescents spend approximately 2 h per day in computer game rooms, which may increase their exposure to tobacco smoke [14]. This is because smoking among Korean men is still a

socially sanctioned behaviour in many indoor workplaces and commercial hospitality venues, including bars, nightclubs, restaurants and computer game rooms [14]. Few studies have examined the association between smoking and IC stenosis in young patients. IC stenosis was suggested to be more common in young patients, especially in those with a single, severe stenotic lesion [11, 15]. In addition, the IC artery is not clearly defined anatomically. Therefore, we are planning to elucidate the association between smoking and IC atherosclerosis based on an exact anatomical location defined angiographically. Furthermore, we aim to examine whether this association is confounded

by age, number of lesions and other atherosclerotic risk factors. MATERIALS AND METHODS Overall design Participants in this retrospective cohort study include patients with severe cerebral artery atherosclerotic stenosis or occlusion undergoing cerebral angiography because of stroke or transient ischaemic attack. The diagnosis of occlusion or the degree of stenosis is made using high-resolution, biplane digital subtraction angiography (DSA) (Siemens Axiom Artis Zee biplane angiography system, Siemens AG, Medical Solutions, Erlangen, Germany) of the internal GSK-3 carotid artery (ICA), common carotid artery (CCA), vertebral artery (VA) and/or proximal subclavian artery. All lesions are describe in terms of location (anterior (AC) vs. posterior (PC) circulation, IC vs. EC and intradural (ID) vs. extradural (ED)).[16] Risk factors for atherosclerosis or stroke include age, gender, smoking history, number of lesions (single or multiple), cardiac disease, diabetes mellitus (DM), hypertension (HTN), family history of stroke, hyperlipidaemia, previous stroke, alcohol intake, metabolic syndrome and body mass index (BMI).