(37%) of those who used smokeless tobacco on some days also smoked cigarettes every day. Among high school-aged boys, those who used smokeless tobacco were five times more likely to also smoke half a pack of cigarettes per day compared to high school boys who did not use smokeless tobacco. 90
increase in smokeless tobacco use suggests that smokeless tobacco is not being substituted for smoking but added to tobacco use. The concomitant use of smokeless tobacco and cigarettes is commonly referred to as “dual use.” Dual use is a developing public health concern. A study of males over the age of 25 found that more than one third
HEALTH RISKS OF SMOKELESS TOBACCO USE
active, the TSNA concentration continues to increase over the shelf-life of the product. However, this has no effect on the nicotine levels. 94 As described above, when considering the health risks associated with smokeless tobacco, it is important to remember that smokeless tobacco may be used in combination with smoking, smokeless tobacco-only users may progress to smoking, and smokers may attempt smoking cessation with substitution of smokeless tobacco. There is intense debate in the tobacco cessation community regarding the promotion of smokeless tobacco as a smoking cessation strategy. This concept is referred to as harm reduction. A recent prospective study involving 5,225 Air Force airmen reported harm escalation, rather than harm reduction, as a result of the dual use of smokeless tobacco and cigarettes. 95
There are 28 known carcinogens in smokeless tobacco manufactured in the United States. These include: ● Tobacco-specific N-nitrosamines (TSNAs). ● Polynuclear aromatic hydrocarbons. ● Benzopyrene. ● Heavy metals (lead, cadmium). ● Polonium-210. ● Uranium-235 and -238.91 The tobacco-specific N-nitrosamines (TSNAs) are the major contributors to carcinogenic activity of smokeless tobacco. 92 The amount of TSNAs in smokeless tobacco is expressed in milligrams of TSNAs per gram of tobacco, and this amount differs by an 18-fold range across brands. Brands with higher TSNA content carry greater carcinogenic potential. 93 Because the microbes in packaged moist snuff remain Smokeless tobacco-attributable diseases An increased risk for cancer of the oral cavity, kidney, pancreas, and digestive system has been attributed to the use of smokeless tobacco. Long-term smokeless tobacco Oral effects of smokeless tobacco use Strong epidemiologic evidence exists for adverse oral health effects of smokeless tobacco. 97 Between 60% and 78% of smokeless tobacco users have oral lesions associated with its use. 98 The prevalence of oral lesions increases with increased duration of use. This prevalence increased from 1.9% for users of less than one month to 38% among those who were users for more than two years. 99 The most common finding associated with smokeless tobacco use is mucosal hyperplasia (snuff dipper’s pouch) in the area adjacent to the site where it is usually placed.
use has also been associated with the risk of fatal myocardial infarction (MI) and fatal stroke. 96
Smokeless tobacco has also been linked to oral cancer. The risk is estimated to be about four to six times that of nonusers. 100 Periodontal disease and irreversible gingival recession have also been associated with smokeless tobacco use. 101 Recession is generally found at facial sites corresponding to the location in the mouth where the smokeless tobacco is placed. 100 Smokeless tobacco users commonly have abrasion and staining of teeth caused by their habit. Due to the presence of fermentable sugars in chewing tobacco, users had slightly higher mean numbers of decayed and filled coronal surfaces than persons using other forms of tobacco. 100
NICOTINE IN SMOKELESS TOBACCO
smokeless tobacco varies widely across brands and types. The nicotine available for absorption is dependent on the product pH, the size of the cuttings, and the type and amount of additives. A study by the CDC compared the available nicotine in 40 of the most widely used brands of moist snuff. The amount of nicotine per gram of tobacco ranged from 4.4 milligrams to 25.0 milligrams. 93 Examples of the variability in free nicotine levels (the amount of nicotine available for absorption) by selected brand are listed below: ● Skoal original fine cut mint 3.2 mg/g ● Hawken wintergreen 3.4 mg/g ● Skoal Bandits 10.1 mg/g ● Kodiak wintergreen 10.9 mg/g ● Copenhagen 12.0 mg/g ● Skoal long cut mint 14.5 mg/g 101
The nicotine delivered by smokeless tobacco is absorbed through the buccal mucosa. The time taken to reach peak plasma nicotine levels from smokeless tobacco is longer than that for smoking (30 minutes versus 12 seconds). The decline in plasma nicotine concentration is also more prolonged for smokeless tobacco compared to cigarettes. The plasma nicotine from smokeless tobacco at 1 hour is approximately 13 mcg/L compared to 7 mcg/L for a cigarette. 91 The plasma nicotine delivery curve for smokeless tobacco presents a unique challenge for clinicians determining the optimal level of nicotine replacement therapy for smokeless tobacco cessation. The standard American cigarette delivers a consistent level of nicotine, allowing for small variations in individual smoking patterns. In contrast, the nicotine delivered by
EMERGING SMOKELESS TOBACCO PRODUCTS
products, as well as the traditional smokeless tobacco forms, are not intended to reduce harm but to expand the tobacco market, circumvent smoke-free policies, decrease tobacco cessation efforts, and encourage the dual use of smokeless tobacco and cigarettes.
Although the term “smokeless tobacco” has been used interchangeably with the term “spit tobacco,” a more appropriate term at this point in time might be oral or noncombustible tobacco . Tobacco companies continue to develop and aggressively market new smokeless tobacco products such as snus and dissolvable products. 102 These
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