Heavy smoking (>20 cigarettes/day) increases both the incidence [37-41] and mortality from stroke [40,41], Cigarette smoking is a major modifiable risk factor for subarachnoid hemorrhage [42-48], In contrast, evidence concerning the role of tobacco in the risk of intracerebral hemorrhage is still controversial, yet it appears that heavy, but not light-to-moderate cigarette smoking, increases the risk [9,38,49,50], Smoking is dose-dependantly associated with the risk of ischemic stroke [38,46], Cessation of smoking reduces stroke risk [37,39], with major reduction within 2-5 years after cessation [37,39,46], indicating that part of the effects of smoking is reversible. The risk of stroke seems to return to the level of never-smokers in light smokers, but heavy smokers seem to retain an increased risk even though also they benefit from cessation , There are several mechanisms by which smoking may cause stroke. Cigarette smoking causes an immediate, yet reversible increases in blood pressure [42,51-55] and cerebral blood flow , In epidemiologic studies, however, it has consistently been associated with reduced blood pressure in normotensive people [18,52,5760], although blood pressure has been elevated in diabetic  and hypertensive smokers , and cerebral blood flow has been decreased in chronic smokers  compared with respective nonsmokers. It is not plausible that smoking decreases blood pressure, but smokers may initially have lower blood pressure than those who remain nonsmokers , They may also have a reduced 'white coat effect', which would lead to artificially low measurements of blood pressure in clinics , There is no evidence that smoking causes hypertension, but in heavy smokers the rise in blood pressure may persist during waking hours because of frequent smoking factually causing a hypertensive state , Even though smoking may not be causally related to hypertension, it clearly modifies the effect of hypertension on stroke [40,51] and other cardiovascular risks  which are much higher in hypertensive than normotensive smokers. Cigarette smoking is associated with reduced levels of serum HDL cholesterol [18,20,51,57, 58,60,65,66] and increased levels of serum triglycerides [18,57,65-67], It increases platelet activity [51,53,68,69], plasma fibrinogen levels [27,51,57], hematocrit [57,65], and blood viscosity , It is also associated with endothelial dysfunction [57,70,71], Cigarette smoking increases the risks of carotid stenosis [72,73] and diabetes , which both are risk factors for ischemic stroke.
Tobacco smoke has over 4000 compounds, the effects of which are mostly unknown , Many of the effects of smoking are attributed to nicotine, which increases systolic and diastolic blood pressure and heart rate in a dose-response manner [74,75], Despite these hemodynamic effects, nicotine does not appear to enhance thrombosis [75,76], and the mechanism by which smoking is related to thrombogenesis is unclear. Besides nicotine, carbonmonoxide is a potential mediator of the effects of tobacco smoke on cardiovascular diseases [51,77], It may injure the vascular endothelium  and thus promote atherogenesis. The causal role of smoking in the development of atherosclerosis is plausible but so far unproven.
Was this article helpful?
Quit smoking for good! Stop your bad habits for good, learn to cope with the addiction of cigarettes and how to curb cravings and begin a new life. You will never again have to leave a meeting and find a place outside to smoke, losing valuable time. This is the key to your freedom from addiction, take the first step!