[Smoking and stroke].

Up to one quarter of all strokes are directly attributable to cigarette smoking, that percentage can get up to 50% for young adults admitted for an cryptogenic ischemic stroke. Cigarette smoking increases the relative risk of ischemic stroke about two-fold, three-fold for subarachnoid haemorrhage. Current smoking is not clearly identified as a risk factor for intra-cerebral haemorrhage. The risk is consistent for all subtypes of stroke according aetiology and is strongest for ischemic stroke caused by arterial atherothromboembolism. The risk is dependent upon the amount of cigarettes smoked and passive smoking is a substantial risk of stroke. The relative risk is maximal in middle age, declining with advancing years. The toxicity is higher among female smokers, especially when they have several risk factors such as oral contraceptiveS and migraine with aura. Whereas it is well known that the effectiveness of cigarette withdrawal reduces the risk of new vascular event, two thirds of young patients continue to smoke.