[Overview of knowledge of health effects of smokeless tobacco. Increased risk of cardiovascular diseases and mortality because of snuff].

Oral snuff, used by 20% of all Swedish males in 1996, causes blood nicotine levels similar to those in smokers. In a report by the National Board of Health and Welfare in 1997, it is concluded that scientific evidence of oral snuff as a cause of oral cancer is weak. Epidemiological studies of more than 100,000 construction workers showed hypertension (blood pressure > 160/90) to be more common among oral snuff users than among non-users. Twelve-year follow-up showed the relative risk of death due to cardiovascular disease to be 2-fold greater among snuff users, but 3-fold greater among smokers, as compared to never-users of tobacco (p < 0.001). The risk of death due to cancer was similar among snuff users and among never-users. In a clinical study of 151 healthy middle-aged men, 24-hour monitoring showed daytime heart rates and blood pressure to be significantly higher in snuff users > or = 45 years of age than in age-matched non-users (p < 0.05). The estimated 10-year future risk of cardiovascular events was 13.2% for smokers (p < 0.001) and 4.6% for oral snuff users (p = 0.3) as compared with 3.4% for never-users. As compared with non-users, oral snuff users manifested neither significant signs of accelerated atherosclerosis nor significantly reduced maximum physical capacity. Oral snuff usage causes physiological nicotine dependence, and results in the release of sympatho-adrenergic stimuli associated with an increased risk of cardiovascular stress, which might in turn exacerbate the risk of fatal cardiovascular events. However, oral snuff usage does not seem to be associated with the same risk of accelerated atherosclerosis as is smoking.