Reduction in nicotine intake and oral mucosal changes among users of Swedish oral moist snuff after switching to a low-nicotine product

Oral lesions associated with daily use of snus, a moist smokeless tobacco product. A cross-sectional study among Norwegian adolescents

OBJECTIVE

Use of snus, a moist, smokeless tobacco product, may lead to local changes in the oral mucous membrane in the area where the snus is placed. It can also cause irreversible gingival retraction. This cross-sectional study aimed to investigate the relationship between use of snus, oral mucosal lesions (snus induced lesions) and gingival retractions among adolescents in Norway.

MATERIAL AND METHODS

All 18-20 years olds visiting public dental health clinics in the south-eastern region of Norway between October 2015 and December 2016 were invited to participate. All participants (n = 1363) filled in an electronic questionnaire before a clinical examination. Of these, 216 used snus daily.

RESULTS

Snus induced lesions were observed in 79.2% of daily snus using participants. In adjusted regression analyses, the odds of having a more severe lesion as opposed to a less severe lesion were 1.12 times greater for each additional box of snus used in a month (p < .01). Women were 46% less likely to have a severe lesion than men (p = .03). Gingival retractions were observed in 18.4% of the participants. The odds for dental retraction were significantly higher by 34% for each year of snus use.

CONCLUSIONS

Most of the adolescents using snus had snus induced lesions, whereas approximately one-fifth had gingival retractions. The severity of the lesion and gingival retraction increased with the amount of snus boxes used and the duration of the snus use, respectively.

The effect of a non‐tobacco‐based nicotine pouch on mucosal lesions caused by Swedish smokeless tobacco (snus)

Oral mucosal lesions are commonly found in Swedish smokeless tobacco (snus) users where the pouch is placed. These lesions are reversible, that is, clinical and histological tissue changes return to normal following cessation. However, the exact mechanisms behind these changes are unknown. The main aim of this study was to investigate how snus‐like non‐tobacco‐based nicotine pouches affect the oral mucosa and the severity of pre‐existing lesions. Sixty regular users of Swedish smokeless tobacco were encouraged to substitute their snus with non‐tobacco‐based nicotine pouch products during a 6‐week period. Meanwhile, oral mucosal lesions were assessed using a four‐degree scale. Over time, a reduction of pre‐existing mucosal lesions was observed between baseline and the final visit. In a second part, the effect of exposure to regular snus on the production of 48 different cytokines in peripheral blood mononuclear cells was compared in vitro with that resulting from exposure to the non‐tobacco‐based nicotine products. Results showed significantly increased production of proinflammatory cytokines in cells exposed to regular snus compared to untreated or cells exposed to the non‐tobacco‐based nicotine products. This may be related to the improved clinical appearance of the oral mucosa in the participants that used the non‐tobacco‐based nicotine test pouches.

Summary of the epidemiological evidence relating snus to health

Interest in snus (Swedish-type moist snuff) as a smoking alternative has increased. This wide-ranging review summarizes evidence relating snus to health and to initiation and cessation of smoking. Meta-analyses are included. After smoking adjustment, snus is unassociated with cancer of the oropharynx (meta-analysis RR 0.97, 95% CI 0.68-1.37), oesophagus (1.10, 0.92-1.33), stomach (0.98, 0.82-1.17), pancreas (1.20, 0.66-2.20), lung (0.71, 0.66-0.76) or other sites, or with heart disease (1.01, 0.91-1.12) or stroke (1.05, 0.95-1.15). No clear associations are evident in never smokers, any possible risk from snus being much less than from smoking. "Snuff-dipper's lesion" does not predict oral cancer. Snus users have increased weight, but diabetes and chronic hypertension seem unaffected. Notwithstanding unconfirmed reports of associations with reduced birthweight, and some other conditions, the evidence provides scant support for any major adverse health effect of snus. Although some claims that snus reduces initiation or encourages quitting are unsoundly based, snus seems not to increase initiation, as indicated by few smokers using snus before starting and current snus use being unassociated with smoking in adults (the association in children probably being due to uncontrolled confounding), and there are no reports that snus discourages quitting.

Health Risks of Smoking Compared to Swedish Snus

Interest in tobacco harm reduction strategies has raised the question of the comparative health risks of cigarette smoking and use of other tobacco products. Although there appears to be a general belief that a unique smokeless tobacco product called Swedish snus has fewer health risks than cigarettes, no one has systematically reviewed the literature and compared the data on health risks in a quantitative manner. We reviewed the literature to identify all analytic epidemiologic studies that provided quantitative risk estimates associated with Swedish snus and cigarette smoking in a single population, using a common reference group. Seven studies were identified that addressed eight health outcomes. Although few in number, these seven studies do provide quantitative evidence that, for certain health outcomes, the health risks associated with snus are lower than those associated with smoking. Specifically, this is true for lung cancer (based on one study), for oral cancer (based on one study), for gastric cancer (based on one study), for cardiovascular disease (based on three of four studies), and for all-cause mortality (based on one study). This review has likely omitted many of the adverse effects of cigarettes, but probably few of the potential health effects of snus. Continued investigation of the reduced health risks of Swedish snus compared to cigarette smoking is warranted.

Systematic review of the relation between smokeless tobacco and non-neoplastic oral diseases in Europe and the United States

Background

How smokeless tobacco contributes to non-neoplastic oral diseases is unclear. It certainly increases risk of oral mucosal lesions, but reviewers disagree as to other conditions. In some areas, especially South-East Asia, risk is difficult to quantify due to the many products, compositions (including non-tobacco ingredients), and usage practices involved. This review considers studies from Europe (in practice mainly Scandinavia) and from the USA.

Methods

Experimental and epidemiological studies published in 1963–2007 were identified that related risk of oral lesions to smokeless tobacco use. Data were assessed separately for oral mucosal lesions, periodontal and gingival diseases, dental caries and tooth loss, and oral pain.

Results

Oral mucosal lesions: Thirty-three epidemiological studies consistently show a strong dose-related effect of current snuff on oral mucosal lesion prevalence. In Scandinavia, users have a near 100% prevalence of a characteristic "snuff-induced lesion", but prevalence of the varied lesions reported in the USA is lower. Associations with chewing tobacco are weaker. The lack of clear association with former use suggests reversibility following cessation, consistent with experimental studies showing rapid lesion regression on quitting.

Periodontal and gingival diseases: Two of four studies report a significant association of snuff with attachment loss and four out of eight with gingival recession. Snuff is not clearly related to gingivitis or periodontal diseases. Limited evidence suggests chewing tobacco is unrelated to periodontal or gingival diseases.

Tooth loss: Swedish studies show no association with snuff, but one US study reported an association with snuff, and another with chewing tobacco.

Dental caries: Evidence from nine studies suggests a possible relationship with use of smokeless tobacco, particularly chewing tobacco, and the risk of dental caries.

Oral pain: Limited evidence precludes any clear conclusion.

Conclusion

This review confirms the strong association of current use of smokeless tobacco, particularly snuff, with prevalence of oral mucosal lesions. It provides suggestive evidence of an association of snuff use with gingival recession and attachment loss, and of chewing tobacco with dental caries. While smokeless tobacco clearly increases risk of oral mucosal lesions, interpretation for other endpoints is limited by study weaknesses, including poor confounding control.

Epidemiologic perspectives on smokeless tobacco marketing and population harm

Moist snuff is the most popular form of orally-used smokeless tobacco in North America and parts of Europe. Because moist snuff use conveys lower risks for morbidity or mortality than does cigarette smoking, its use has been proposed as a tobacco harm-reduction strategy. This article critically reviews new and published epidemiologic evidence on health effects of moist snuff and its patterns of use relative to smoking in the United States, Sweden, and Norway. The available evidence suggests that: (1) moist snuff is a human carcinogen and toxin, (2) increased promotion of moist snuff has led to increased sales in those countries, (3) the uptake of moist snuff in these three countries during the past several decades has occurred primarily among adolescent and young adult men, (4) increased prevalence of snuff use has not been associated consistently with a reduction in smoking initiation or prevalence, (5) moist snuff use apparently plays a very minor role in smoking cessation in the U.S. and an inconsistent role in Sweden, (6) U.S. states with the lowest smoking prevalence also tend to have the lowest prevalence of snuff use, (7) there are no data on the efficacy of snuff as a smoking-cessation method, (8) the prevalence of cigarette smoking is relatively high among people who use snuff, and (9) snuff use is more consistently associated with partial substitution for smoking than with complete substitution. The evidence base for promotion of snuff use as a public health strategy is weak and inconsistent.

The nicotine market: An attempt to estimate the nicotine intake from various sources and the total nicotine consumption in some countries

Tobacco--particularly smoked products--has been associated with great harm and growing public disapproval and can be expected to suffer in the marketplace. This situation has created opportunities for other less harmful nicotine-containing products such as smokeless tobacco and nicotine replacement products, which are gaining public support. Little is known about the level of nicotine intake in our society. Tobacco sales are known, but how much nicotine is extracted and actually absorbed by users is largely unknown. The present study is a first attempt to estimate uptake of nicotine from tobacco and nicotine replacement products and to map nicotine consumption in a few countries, with special emphasis on Sweden. Relevant pharmacokinetic studies for three types of nicotine-containing products (cigarettes, smokeless tobacco, and nicotine replacement products) were analyzed for bioavailable nicotine. Estimates of nicotine intake from each category were made. These were then multiplied by the amount consumed in the respective countries. Tobacco consumption statistics were usually from official records of taxed sales. In Sweden about 54% of all nicotine intake comes from smoked sources, 45% from nonsmoked tobacco, and 1.3% from nicotine replacement products. For men, 63% of the nicotine consumed comes from nonsmoked tobacco. Per-capita nicotine intake per year for adults aged 15 years or older is 3,321 mg for Austria, 3,043 mg for Sweden, 3,014 mg for Denmark, 2,955 mg for the United States, 2,244 mg for Norway, and 2,023 mg for Finland. Compared with cigarette smokers, snus users seem to have a somewhat higher daily intake (34 mg vs. 25 mg). The cleanest nicotine products, nicotine replacement products, represent a negligible part (about 1%) of the total nicotine consumption in most countries.