Over the past 15 years, eight epidemiologic studies have examined the risk of cardiovascular diseases among ST users. Six of the studies found that ST users had no increased risk for heart attacks or strokes [47,90,97-100] . The other two reported modestly positive associations, with ST users having RRs of 1.2 and 1.4 [92,101] , which are lower than those of smokers. In 2003, Asplund completed a comprehensive review of the cardiovascular effects of ST use [102] . He concluded that, in distinct contrast to smokers, ST users do not exhibit any significant differences from nonusers of tobacco with regard to the following measures of cardiovascular health: heart rate, blood pressure, cardiac output and maximal working capacity, levels of hemoglobin and hematocrit, leukocytes, antioxidant vitamins, fibrinogen, components of the fibrinolytic system, C-reactive protein and thromboxane A2 production. In addition, ST users did not show important smoking-associated vascular changes, including increased thickness of blood vessels and atherosclerotic plaque development. In summary, most of the medical and epidemiologic evidence documents that ST users do not have elevated risks for cardiovascular diseases."