My father has chewed tobacco for years now.
From the CDC website
Smokeless tobacco products, especially moist snuff, contain potent carcinogens. Studies have consistently demonstrated a strong association between snuff use and oral cancer (7). Carcinogens in the five most popular U.S. snuff brands include polynuclaar aromatic hydrocarbons, radiation-emitting polonium, and a variety of tobacco-specific nitrosamines. Levels of nitrosamines in commercial snuff range from 9,800-289,000 parts/billion (ppb) (9), which are hundreds of times higher than the levels allowed in foods ind commercial products (1). Nitrosamines are strictly limited in these products. Bacon and bear, for example, are each limited to 5 ppb, and rubber nipples of baby bottles are limited to 10 ppb of nitrosamines.
Tissue changes have bien reported for school-age children who use smokeless tobacco. One study showed that in rural Colorado, 82.5% of teenagers who used smokeless tobacco had lesions described as alterations in texture, color, or contour of the mucosal lining; localized pariodontal degeneration; or a combination of the two (1O). In the recent Inspactor General’s survey (3), 39% of regular users of smokeless tobacco reported that they had a white, wrinkled patch (which characterizes leukoplakia, a precancerous condition), and 37% reported some other form of sore, ulcer, blister, or lesion of the gums, lips, or mouth. It has been estimated that from 1% to 18% of all leukoplakias transform to malignancies (7).
Smokeless tobacco use may also be associated with a number of other corditions including localized gingival recession, tooth loss, tooth abrasion, end stained teeth.
Exposure to nicotine from smokeless tobacco use is comparable with nicotine exposure from cigarette smoking; therefore, nicotine-related health coquences of smokeless tobacco use may be similar to those of smoking in addition to addiction, nicotine may contribute to coronary artery and peripheral vascular disease, hypertension, peptic ulcer disease, and fatal morbidity and mortality (11).
Hope that helps.
(Note to manny and Chronos: I could find no evidence that the above was copyrighted however, I also couldn’t find a “fair use” statement. Let me know if I have erred in posting this.)
Never mind. I just found this: