AJPH -- eLetters for Savitz et al., 96 (11) 1934-1939

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HEALTH POLICY AND ETHICS:
David A. Savitz, Roger E. Meyer, Jason M. Tanzer, Sidney S. Mirvish, and Freddi Lewin
Public Health Implications of Smokeless Tobacco Use as a Harm Reduction Strategy
Am J Public Health 2006; 96: 1934-1939 [Abstract] [Full text] [PDF]

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Errors and Omissions on Smokeless Tobacco: Scott L. Tomar, DMD, DrPH, Jon O. Ebbert, MD; Mayo Clinic College of Medicine (16 January 2007)

Errors and Omissions on Smokeless Tobacco 16 January 2007

Scott L. Tomar, DMD, DrPH,
Professor
University of Florida College of Dentistry,
Jon O. Ebbert, MD; Mayo Clinic College of Medicine
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Re: Errors and Omissions on Smokeless Tobacco

stomar{at}dental.ufl.edu Scott L. Tomar, DMD, DrPH, et al.

Savitz et al.[1] presented an interesting overview of smokeless tobacco use as a potential harm reduction strategy, but we note several errors and omissions.
The authors claim that Sweden has “achieved the lowest smoking prevalence rate in all of Europe.” That statement is true only if the definition of current smoking is limited to daily smoking, and only among men; the prevalence of current daily or occasional smoking is lower than Sweden in Finland, France, Iceland, Ireland, Italy, Malta, Portugal, Slovakia and the United Kingdom.[2] This distinction is important because non-daily smoking is quite prevalent in Sweden, and snus appears to serve as a complementary source of nicotine for many Swedish males who smoke.[3] Savitz et al. do not discuss the situation in Norway, the other European country where moist snuff use is legally available and widely used (moist snuff is banned in the European Union but a derogation was granted for Sweden and for the European Economic Area Member State Norway). The prevalence of snuff use by Norwegian males aged 16-24 years has increased nearly three-fold during the past 20 years, which unfortunately was accompanied by an increase in smoking during most of that time.[4] Because the conference at which this paper was presented, the tobacco company that sponsored it, and the journal that published it are all U.S.-based, it is relevant to note that the prevalence of current smoking is higher in Sweden than in 46 of the 50 U.S. states, and at least 18 states have achieved a lower prevalence of daily smoking among males than Sweden with almost no snuff use.
Savitz et al. refer to Swedish snus as “low nitrosamine” throughout the article. Although the levels of tobacco-specific nitrosamines (TSNAs) may be lower in moist snuff products sold in Sweden than in most U.S. brands, the levels are at least 100 times greater than the nitrosamine levels permitted by the USDA in any non-tobacco product on the U.S. market. Curiously, the moist snuff products produced by Swedish manufacturers for sale in the U.S. and elsewhere have higher nitrosamine levels than those sold domestically.[5]
Savitz et al. conclude that snus poses “minimal risk of oral or other cancers.” Only two of the five references cited to support that claim were original research reports, and those studies are misinterpreted. The case-control study conducted by Lewin et al.[6] in southern Sweden had few subjects who used snus and had no history of cigarette smoking, but found an elevated relative risk for head and neck cancer associated with ever using snus (RR=4.7; 95% CI: 1.6–13.8). The multivariable RR estimate for snus frequently cited as evidence that snus does not increase the risk for head and neck cancer is of questionable validity because 90% of men who used snus also had a history of smoking. That degree of multicollinearity may result in incorrect parameter estimates and incorrect conclusions. Similarly, Shildt et al.[7] found no increased risk for oral cancer in northern Sweden associated with snus use in multivariable modeling, but also found no increased risk for smoking or any type of alcohol consumption. The review paper cited by Savitz et al. that suggested that dry snuff increased the risk for oral cancer but moist snuff apparently did not[8] was skewed by relative risk estimates from those two Swedish studies and by the classification of an earlier case-control study by Winn et al.[9] as examining only dry snuff. In reality, Winn et al. did not distinguish between moist or dry snuff, and assays conducted around that time found no difference in TSNA levels for those two types of products, suggesting comparable carcinogenic potential.[10] None of the studies cited found that smokers who switched to snus had a lower risk for disease than did men who continued smoking, which is the true research question that should be asked in the harm reduction debate.
The discussion of cardiovascular diseases and smokeless tobacco omitted the large Swedish cohort study[11] that found that snus use was a significant predictor of cardiovascular mortality. Two large U.S. cohort studies had similar findings.[12]
The statement that “there is no evidence of an association of smokeless tobacco with recession of the gums independent of pre-existing gingivitis” is unsupported by a citation, although that may be based on one cross-sectional study of adolescents.[13] To the contrary, a number of U.S. and Swedish studies have reported a significant association between smokeless tobacco use and localized gingival recession.[14-20]
Finally, the authors have not fully disclosed their potential conflicts of interest. One co-author, Dr. Freddi Lewin, serves as medical spokesman for the North Europe Division of Swedish Match.[21]
References
1. Savitz DA, Meyer RE, Tanzer JM, Mirvish SS, Lewin F. Public health implications of smokeless tobacco use as a harm reduction strategy. Am J Public Health. 2006; 96:1934–1939.
2. European Commission, Health & Consumer Protection Directorate-General. Health status: indicators from the national Health Interview Surveys (HIS round 2004), Smokers by sex - all ages. [Data from Eurostat]. Available at http://ec.europa.eu/health/ph_information/dissemination/echi/echi_3_en.htm#23. Accessed 04 January 2007.
3. Gilljam H, Galanti MR. Role of snus (oral moist snuff ) in smoking cessation and smoking reduction in Sweden. Addiction. 2003; 98(9):1183–1189.
4. Directorate for Health and Social Affairs (Norway). Tall om Tobakk [number about tobacco]. 1973–2003. [Norwegian]. Oslo: Directorate for Health and Social Affairs, 2004.
5. Brunnemann KD, Qi J, Hoffmann D. Aging of oral moist snuff and the yields of tobacco-specific nitrosamines (TSNA). Boston: Massachusetts Department of Public Health, Massachusetts Tobacco Control Program; 2001.
6. Lewin F, Norell SE, Johansson H et al. Smoking tobacco, oral snuff, and alcohol in the etiology of squamous cell carcinoma of the head and neck: a population-based case-referent study in Sweden. Cancer. 1998; 82:1367–1375.
7. Schildt EB, Eriksson M, Hardell L, Magnuson A. Oral snuff, smoking habits and alcohol consumption in relation to oral cancer in a Swedish case-control study. Int J Cancer. 1998; 77:341–346.
8. Rodu B, Cole P. Smokeless tobacco use and cancer of the upper respiratory tract. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002; 93:511–515.
9. Winn DM, Blot WJ, Shy CM, Pickle LW, Toledo A, Fraumeni JF Jr. Snuff dipping and oral cancer among women in the southern United States. N Engl J Med. 1981; 304:745–749.
10. Hoffmann D, Adams JD, Lisk D, Fisenne I, Brunnemann KD. Toxic and carcinogenic agents in dry and moist snuff. J Natl Cancer Inst 1987;79:1281–1286.
11. Bolinder G, Alfredsson L, Englund A, de Faire U. Smokeless tobacco use and increased cardiovascular mortality among Swedish construction workers. Am J Public Health. 1994; 84:399–404.
12. Henley SJ, Thun MJ, Connell C, Calle EE. Two large prospective studies of mortality among men who use snuff or chewing tobacco (United States). Cancer Causes Control. 2005; 16:347–358.
13. Offenbacher S, Weathers DR. Effects of smokeless tobacco on the periodontal, mucosal and caries status of adolescent males. J Oral Pathol. 1985;14:169–181.
14. Ernster VL, Grady DG, Greene JC et al. Smokeless tobacco use and health effects among baseball players. JAMA. 1990; 264:218–224.
15. Robertson PB, Walsh M, Greene J, Ernster V, Grady D, Hauck W. Periodontal effects associated with the use of smokeless tobacco. J Periodontol. 1990; 61:438–443.
16. Robertson PB, Ernster V, Walsh M, Greene J, Grady D, Hauck W. Periodontal effects associated with the use of smokeless tobacco: results after 1 year. In: National Cancer Institute. Smokeless tobacco or health: an international perspective. Smoking and Tobacco Control Monograph 2. Rockville, MD: US Department of Health and Human Services, National Institutes of Health, National Cancer Institute; 1992: 78–86. NIH Publication No. 92-3461.
17. Wolfe MD, Carlos JP. Oral health effects of smokeless tobacco use in Navajo Indian adolescents. Community Dent Oral Epidemiol. 1987; 15:230–235.
18. Creath CJ, Cutter G, Bradley DH, Wright JT. Oral leukoplakia and adolescent smokeless tobacco use. Oral Surg Oral Med Oral Pathol. 1991;72:35–41.
19. Andersson G, Axell T. Clinical appearance of lesions associated with the use of loose and portion-bag packed Swedish moist snuff: a comparative study. J Oral Pathol Med. 1989;18:2–7.
20. Monten U, Wennstrom JL, Ramberg P. Periodontal conditions in male adolescents using smokeless tobacco (moist snuff). J Clin Periodontol. 2006;33:863–868.
21. Swedish Match. Two cancer specialists to contribute to new alternatives to smoking [news item]. 05 June 2006. Available at http://www.swedishmatch.com/News/Eng/Twocancerspecialiststocontributetonewalternativestosmoking.asp. Accessed 04 January 2007.