We are interested in comparing the levels of harmful or potentially harmful constituents in Swedish and American smokeless tobacco products (STPs). We report here the concentrations of the IARC Group 2 A (probable human) carcinogen ethyl carbamate (EC) in seventy commercial STPs from the US and Sweden, representing 80–90% of the market share of the major STP categories in these countries. We also examine the effects of various additives, processing and storage conditions on EC concentrations in experimental snus samples.

There is considerable interest in the chemical composition of smokeless tobacco products (STPs), owing to health concerns associated with their use. Previous studies have documented levels of 210Po, 210Pb and uranium in STP samples. Here, the levels of 13 α-particle and 15 β-radiation emitting radionuclides have been measured in a broad and representative range of contemporary STPs commercially available in the United States and Sweden. For each radionuclide, the level of radioactivity and calculated mass per gram of STP are reported. The results indicate that, among 34 Swedish snus and 44 US STPs, a more complex radionuclide content exists than previously reported for these products. Of the 28 radionuclides examined, 13 were detected and quantified in one or more STPs. The most frequently identified radionuclides in these STPs were 40K, 14C, 210Po and 226Ra. Over half the STPs also contained 228Th, and an additional 8 radionuclides were identified in a small number of STPs. The presence of 14C, 3H and 230Th are reported in tobacco for the first time. The activity of β-emitters was much greater than those of α-emitters, and the β-emitter 40K was present in the STPs with both the greatest radioactivity and mass concentrations. Since the three radionuclides included in the FDA's HPHC list were either not detected (235U), identified in only three of 78 samples (238U), and/or had activity levels over fifty times lower than that of 40K (210Po, 238U), there may be a rationale for reconsidering the radionuclides currently included in the FDA HPHC list, particularly with respect to 40K. Using a model of the physical and biological compartments which must be considered to estimate the exposure of STP users to radionuclides, we conclude that exposure from α-emitters may be minimal to STP users, but 40K in particular may expose the oral cavities of STP users to β-radiation. Although a more comprehensive picture of the radioisotope content of STPs has emerged from this study, epidemiological evidence suggests that the levels of radionuclides measured in this study appear unlikely to present significant risks to STP users.

Dear Sir, We are writing to point out that the study of high blood pressure and hypertension amongst Swedish male snuff users by Hergens et al. [1] contains several apparent errors. In addition, the study omits prevalence estimates for the 37546 subjects who had an Inpatient Register diagnosis of hypertension prior to baseline, and it omits follow-up information on hypertension for 35464 subjects who were healthy at baseline but did not have repeated measurements. In Table 1 (‘baseline-cohort’ column) and Table 2 (all rows except ‘≥65’), the number of ever snuff users is larger than the sum of the numbers of former and current users (the largest discrepancy of 57 is in the ‘baseline cohort’ column in Table 1). Similarly, the number of all workers in the ‘repeated-measurements’ column of Table 1 (n = 42005) is larger than the sum of never- and ever-snuff users, and the percentages for the highest two dose categories, 5% and 3%, are incorrect. We also point out that the results in this manuscript differ from those in Table 10 of the original thesis of this work published by the Karolinska Institute [2]. There is an ambiguity in Tables 2 and 3, which report age-specific odds ratios (ORs) but contain footnotes describing age adjustment. It is highly unusual for age-adjustment to be carried out within 5-year age intervals, so the authors should either explain this logistic model or correct the footnote. Hergens et al. [1] present detailed information about the 5915 workers with high blood pressure at baseline, giving prevalence and OR estimates according to snuff use, age and consumption level (Tables 1–3). But the authors provide no corresponding estimates for the 37546 workers who had an Inpatient Register diagnosis of hypertension prior to baseline. As defined in this study, high blood pressure and hypertension are two separate case definitions for the same condition. Failure to provide the effect estimates for hypertension is incomprehensible, and the study must be considered incomplete until this important omission is corrected. Hergens et al. [1] emphasize in the Abstract, Introduction and Discussion, the longitudinal nature of their study. However, the person-time contributed by cohort members is not mentioned anywhere in the manuscript. In addition, longitudinal data are presented only in Table 4, which also omits critical outcome data. The table lists relative risks (RRs) for an Inpatient Register diagnosis of hypertension during follow-up amongst all workers who were healthy at baseline (n = 77469), and amongst a subset of workers who had repeated measurements (n = 42005), but there is no RR information for a second subset of 35464 workers who were healthy at baseline and did not have repeated measurements. The RRs for the repeated-measurement subset, regardless of snuff use (i.e. ever, former, current and all consumption levels) are higher than those for all workers, indicating that the former may have had other characteristics that contributed to these elevated risks. Hergens et al. [1] must provide RRs for hypertension amongst the 35464 workers who were healthy at baseline and did not have repeated measurements. Otherwise, the authors’ aim of assessing ‘...the risk of… hypertension amongst male long-term users of snuff, particularly based on longitudinal data’, is not achieved. Hergens et al. concluded that their ‘results are of potential public health importance as the prevalence of snuff use is high in Sweden and that hypertension is one of the major risk factors for cardiovascular disease’. The potential public health importance of this study is contingent upon the resolution of the errors and omissions that we have described. Our research is supported by unrestricted grants from smokeless tobacco manufacturers to the University of Louisville (US Smokeless Tobacco Company and Swedish Match AB) and to the University of Alberta (USSTC). The terms of the grants assure that the grantors are unaware of this letter, and thus had no scientific input or other influence with respect to its design, analysis, interpretation or preparation. Neither of us has any financial or other personal relationship with regard to the grantors.

Objectives: To compare smoking prevalence estimates from two nationally representative surveys in the USA.Study design: Smoking prevalence estimates derived from the National Health Interview Survey (NHIS) and the National Survey on Drug Use and Health (NSDUH) for the period 1998-2005. Methods: Comparisons according to age (18-34 or 35+ years) and according to smoking frequency (every day or some days).Results: In 1998, the prevalence of smoking in both surveys was nearly identical at 24%. From 1999 to 2005, a divergence occurred in smoking prevalence found by the NSDUH and the NHIS. By 2005, NHIS prevalence had declined to 20.9% [95% confidence interval (CI) 20.3-21.51, but the NSDUH estimate was 25.4% (95%CI 24.6-26.2), amounting to 9.1 million more smokers. In 1999, prevalence among 18-34 year olds in the NSDUH was only 18% (95%CI 13-22) higher than that in the NHIS, but that difference had doubled by 2005, when smoking prevalence among 18-34 year olds was 36% (95%CI 30-41) higher in the NSDUH than in the NHIS. NSDUH and NHIS prevalence among 35+ year olds were similar in 1999 and 2001, but the difference was 13% (95%CI 9-18) in 2005. Higher smoking prevalence estimates in the NSDUH were largely due to much higher estimates for some-day smoking in that survey, although everyday smoking prevalence among 18-34 year-olds was also higher in the NSDUH than in the NHIS.Conclusions: These results raise doubt about the recent decline in smoking prevalence described by the NHIS. Further investigation of the NSDUH/NHIS discrepancy may lead to better surveys and to a clearer picture of smoking trends in the USA. (C) 2009 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Objective: To study the prevalence of snus use and of smoking among Swedish schoolchildren from 1989 to 2003. Design: Surveys conducted by the Swedish Council for Information on Alcohol and Other Drugs. Setting: All of Sweden. Subjects: 84 472 boys and girls age 15–16 years. Main outcome measures: Subjects are classified as non-smokers, occasional smokers, and regular smokers, and into three similar categories for snus use. Tobacco use is reported as sex specific prevalence. Results: During the period 1989 to 2003, the prevalence of tobacco use declined both among boys and girls. For boys, regular smoking declined after 1992 from 10% to 4%. Their snus use was about 10% in the 1990s but increased to 13% by 2003. Regular smoking among girls was 20% in early years and declined to 15%. Smoking among girls was always double that among boys. Patterns of occasional tobacco use were similar to those of regular use. Conclusions: The high prevalence of snus use in Sweden not only reduces smoking rates among Swedish men, but suppresses smoking among boys as well.

Boffetta et al.1 presented relative risks (RR) for several forms of cancer among Norwegian men who were smokeless tobacco (SLT) users in the 1960s and they emphasized the RR of 1.67 for pancreas cancer. They employed unconventional SLT exposure groups, however, made no adjustment for alcohol consumption, and their unusual adjustment for smoking may have produced the implausible results that we describe below. A re-analysis of the data from this study is indicated. Boffetta et al.1 created a mixed referent group for the SLT analysis by combining never and occasional users. The designation of exposure groups, and especially of the referent group, greatly affects risk estimates in a study as small as this. For example, if occasional SLT users had a higher pancreas cancer rate than never users, their inclusion in the referent group would have resulted in an underestimation of pancreas cancer risks among SLT users. The authors should provide risk estimates using the 4 customary SLT exposure categories that they described in their Material and Methods section: never users (referent group), regular current, occasional current, and regular former users.1 In any case, it is unwise to place confidence in results based on up to 40-year-old information on a lifestyle risk factor as inconstant as snus use. In one study at least 25% of snus users quit in less than a decade.2 The authors acknowledge that “Residual confounding…by other potential risk factors for pancreatic cancer, such as heavy alcohol intake…cannot be ruled out.” In fact, alcohol consumption was reported as the strongest risk factor for pancreas cancer in the earlier report of this cohort, with odds ratios up to 10.8,3 and must be fully controlled in this update. The procedure that was used to control smoking has 3 major limitations. First, the information on smoking is as out-of-date as that of SLT use. Further, smokers at cohort inception are even more likely than SLT users to have quit over the 40-year follow-up period.2 Second, cigar and pipe smokers, who have very low risks for pancreas cancer, were combined with cigarette smokers, who have much higher risks. This is crucial because cigar and pipe smokers in this cohort were shown previously to be at low risk of pancreas cancer.3 Third, Boffetta et al.3 used daily cigarette smoking categories (1–9, 10–14, 15+ cigarettes) that seem inconsistent with the original survey's actual responses (1–9, 10–19, 20+).3 Failure to adjust fully for alcohol and for smoking may have contributed to the implausible results from this study, shown in our table. We compared the numbers of cancers observed among SLT users in the study with the number expected to occur if they had been never users. The expected numbers are derived directly from the smoking-adjusted RR in the article. For cancers of the oral cavity/pharynx, esophagus, stomach and pancreas the expected number is lower than that observed. For cancers of the lung, kidney and bladder, the expected number is actually higher than the observed number. The net result from the table shows that SLT use is associated with 12 fewer cases of cancer among ever users than would have occurred at never-user rates, a 4% difference that is not statistically significant. The 20% deficit of lung, kidney and bladder cancers combined is statistically significant (RR = 0.80, 95% CI = 0.68–0.93). This would seem to indicate that SLT use lowers the risk of these cancers beyond its protection against smoking because the RR were adjusted for smoking. Boffetta et al.1 may wish to provide an explanation for these reduced risks other than protection by SLT use. Any such explanation may require resolution of the fundamental analytic problems that we have described. Yours sincerely, Brad Rodu, Philip Cole.

For decades men in Sweden have smoked at far lower rates than those in comparable countries. Previous studies showed that snus use played a major role in low smoking rates among men in northern Sweden; daily smoking declined from 19% (95% CI 16—22%) in 1986 to 11% (CI 8.9—14%) in 1999. The prevalence of smoking among all men is now 9% (CI 7.0— 11%) and only 3% (CI 0.1—5.4%) among men age 25—34 years; the prevalence of exclusive snus use is 27% (CI 24—30%) and 34% (CI 27—42%) respectively. Combined smoking and snus use, an unstable and transient category, was under 5% in all surveys and was 2.2% (CI 1.4—3.4%) by 2004. For the first time snus use is also associated with a decrease in smoking prevalence among women. These patterns of tobacco use have implications for all smoking-dominated societies.

OBJECTIVE:To explore the effect of smoking and smokeless tobacco, 'snus', on the risk of type 2 diabetes.DESIGN:Population-based cross-sectional and prospective follow-up study in northern Sweden.SUBJECTS:A total of 3384 men, aged 25-74 years, who participated in the MONICA study in 1986, 1990, 1994 or 1999, 1170 of whom had an oral glucose tolerance test. In 1999, 1757 men from previous cohorts returned for re-examination. Main outcome measures. We compared the prevalence of type 2 diabetes or pathological glucose tolerance (PGT) amongst tobacco users to that of nonusers at entry into the study and at follow-up, using odds ratios.RESULTS:Compared with never users, the age-adjusted risk of prevalent clinically diagnosed diabetes for ever smokers was 1.88 (CI 1.17-3.0) and for smokers 1.74 (0.94-3.2). Corresponding odds ratios for snus users were 1.34 (0.65-2.7) and 1.18 (0.48-2.9). We found no increased risk of prevalent PGT in snus users or smokers. Former smokers and snus users had an insignificantly increased risk for PGT. Compared with nonusers, the age-adjusted risk of developing clinically diagnosed diabetes during follow-up was 4.63 (1.37-16) in consistent exclusive smokers, 3.20 (1.16-8.8) in ex-smokers and no cases in consistent snus users. The risk of PGT during follow-up was not increased in consistent tobacco users but evident, although not statistically significant, in those who quit snus during the follow-up period, 1.85 (0.60-5.7). Adjustment for physical activity and alcohol consumption did not change the major findings.CONCLUSIONS:The risk of diabetes for snus users was not significantly increased. Smoking was associated with prevalent and incident cases of diabetes. Ex-tobacco users tended towards more PGT.

This study evaluated the tobacco use status of 63 subjects seven years after enrollment in a single-intervention smoking cessation study employing smokeless tobacco (SLT) as a nicotine substitute. Information about tobacco use and cessation attempts was obtained in interviews. The duration of follow-up and of smoke-free periods were derived from the date of the subject's enrollment and were expressed as person-years (p-y). Because the study focused on the use of SLT for smoking cessation, subjects who used SLT to quit were invited to return for verification (less than 10 parts per million of carbon monoxide in expired air). Follow-up was completed on 62 of 63 original subjects, classified according to tobacco use status at the end of the initial study. Of the 16 subjects who had quit smoking using SLT at one year, 12 were smoke-free at seven years. For all 16 subjects there was 106 p-y of follow-up, 97 (92%) of which were smoke-free. Of six subjects who had quit smoking at one year by a means other than SLT, four were smoke-free at seven years. This entire group had 42 p-y of follow-up, 34 (81%) of which were smoke-free. Of the 41 subjects who were smoking at one year, 12 had quit smoking by the seven-year mark, three of these subjects by using SLT. Total follow-up for this group was 284 p-y, of which 26 (9%) were smoke-free. Although the study is small, the long-term success rate of this pilot trial compares favorably with other cessation studies.

Objective. To explore the effect of tobacco use (smoking and smokeless tobacco) and cessation on body weight.Desing. Cross-sectional and prospective follow-up study.Setting. Northern Sweden.Subjects. A total of 2993 men aged 25-64 years who participated in the northern Sweden MONICA study in 1986, 1990 or 1994, 1650 of whom were followed up in 1999.Main outcome measures. The prevalence of overweight [body mass index (BMI) greater than or equal to 27] amongst tobacco users was compared with nonusers at entry into the study. The average annual percentage weight gain amongst men was also determined according to tobacco use both at entry and at follow-up, and the development of overweight amongst tobacco-use groups was reported using standardized incidence ratios.Results. Smokers who quit tobacco during the follow-up period gained significantly more weight than smokers who switched to snus (annual gain 0.96% vs. 0.51%, P < 0.05). At entry, ex-smokers had higher prevalence of overweight than nonusers of tobacco [prevalence ratio (PR) = 1.24, 95% confidence interval (CI) = 1.10-1.40]. Snus users had slightly higher prevalence of overweight at entry (PR = 1.20, CI = 1.01-1.42). Snus users who quit gained more weight than nonusers (0.70% vs. 0.44%, P < 0.05) or those who continued to use snus (0.42%).Conclusions. Cessation of tobacco, either cigarettes or snus, leads to significantly increased weight gain. However, snus use may play a role in lowering the weight gain following smoking cessation.

Objective. To explore the effect of smoking and smokeless tobacco, ‘snus’, on the risk of type 2 diabetes. Design. Population-based cross-sectional and prospective follow-up study in northern Sweden. Subjects. A total of 3384 men, aged 25–74 years, who participated in the MONICA study in 1986, 1990, 1994 or 1999, 1170 of whom had an oral glucose tolerance test. In 1999, 1757 men from previous cohorts returned for re-examination. Main outcome measures. We compared the prevalence of type 2 diabetes or pathological glucose tolerance (PGT) amongst tobacco users to that of nonusers at entry into the study and at follow-up, using odds ratios. Results. Compared with never users, the age-adjusted risk of prevalent clinically diagnosed diabetes for ever smokers was 1.88 (CI 1.17–3.0) and for smokers 1.74 (0.94–3.2). Corresponding odds ratios for snus users were 1.34 (0.65–2.7) and 1.18 (0.48–2.9). We found no increased risk of prevalent PGT in snus users or smokers. Former smokers and snus users had an insignificantly increased risk for PGT. Compared with nonusers, the age-adjusted risk of developing clinically diagnosed diabetes during follow-up was 4.63 (1.37–16) in consistent exclusive smokers, 3.20 (1.16–8.8) in ex-smokers and no cases in consistent snus users. The risk of PGT during follow-up was not increased in consistent tobacco users but evident, although not statistically significant, in those who quit snus during the follow-up period, 1.85 (0.60–5.7). Adjustment for physical activity and alcohol consumption did not change the major findings. Conclusions. The risk of diabetes for snus users was not significantly increased. Smoking was associated with prevalent and incident cases of diabetes. Ex-tobacco users tended towards more PGT.

This study documented the perception among student health professionals of the relative health risks from cigarette smoking and from smokeless tobacco (SLT) use. Subjects consisted of dental students, internal medicine residents, and public health graduate students at UAB and dental students at UNMC. The subjects completed a questionnaire indicating their view of the relationship between cigarette smoking or SLT use and “general health,” “cancer,” and “oral cancer.” Response was on a 10-point scale ranging from zero (“not at all harmful”) to 10 (“deadly”). A comparison of responses was made between groups for each health category. Individual responses were categorized to indicate whether one product was perceived to be more harmful than (or equal to) the other. SLT use was perceived by 30% of respondents to be either equal to or more harmful than smoking in relation to general health. The corresponding results for cancer and oral cancer were 38% and 72%. However, when focusing on the responses of the third and fourth year dental students, these numbers dropped to 8%, 9%, and 35%, respectively. Students in the health professions overestimate health risks from SLT use. However, the dental school curriculum at these schools, including the core oral pathology courses, results in a more accurate perception of the lower risks from SLT than from smoking. This study documented the perception among student health professionals of the relative health risks from cigarette smoking and from smokeless tobacco (SLT) use. Subjects consisted of dental students, internal medicine residents, and public health graduate students at UAB and dental students at UNMC. The subjects completed a questionnaire indicating their view of the relationship between cigarette smoking or SLT use and “general health,” “cancer,” and “oral cancer.” Response was on a 10-point scale ranging from zero (“not at all harmful”) to 10 (“deadly”). A comparison of responses was made between groups for each health category. Individual responses were categorized to indicate whether one product was perceived to be more harmful than (or equal to) the other. SLT use was perceived by 30% of respondents to be either equal to or more harmful than smoking in relation to general health. The corresponding results for cancer and oral cancer were 38% and 72%. However, when focusing on the responses of the third and fourth year dental students, these numbers dropped to 8%, 9%, and 35%, respectively. Students in the health professions overestimate health risks from SLT use. However, the dental school curriculum at these schools, including the core oral pathology courses, results in a more accurate perception of the lower risks from SLT than from smoking.

Objective. To explore the effect of tobacco use (smoking and smokeless tobacco) and cessation on body weight. Design. Cross-sectional and prospective follow-up study. Setting. Northern Sweden. Subjects. A total of 2993 men aged 25–64 years who participated in the northern Sweden MONICA study in 1986, 1990 or 1994, 1650 of whom were followed up in 1999. Main outcome measures. The prevalence of overweight [body mass index (BMI) ≥ 27] amongst tobacco users was compared with nonusers at entry into the study. The average annual percentage weight gain amongst men was also determined according to tobacco use both at entry and at follow-up, and the development of overweight amongst tobacco-use groups was reported using standardized incidence ratios. Results. Smokers who quit tobacco during the follow-up period gained significantly more weight than smokers who switched to snus (annual gain 0.96% vs. 0.51%, P  < 0.05). At entry, ex-smokers had higher prevalence of overweight than nonusers of tobacco [prevalence ratio (PR) = 1.24, 95% confidence interval (CI) = 1.10–1.40]. Snus users had slightly higher prevalence of overweight at entry (PR = 1.20, CI = 1.01–1.42). Snus users who quit gained more weight than nonusers (0.70% vs. 0.44%, P  < 0.05) or those who continued to use snus (0.42%). Conclusions. Cessation of tobacco, either cigarettes or snus, leads to significantly increased weight gain. However, snus use may play a role in lowering the weight gain following smoking cessation.

Abstract. Rodu B, Stegmayr B, Nasic S, Cole P, Asplund K (University of Alabama at Birmingham, Birmingham, AL, USA; Umeå Hospital, Umeå, Sweden). Evolving patterns of tobacco use in northern Sweden. J Intern Med 2003; 253: 660–665. Background and objectives. Cross-sectional data from northern Sweden suggest that the increased use of Swedish moist snuff (snus) may have contributed to a decline in the prevalence of smoking, especially amongst men. This study describes the evolving patterns of tobacco use in this population over the period 1986–1999. Design. This is a prospective follow-up study of 1651 men and 1756 women, aged 25–64 years, who were enrolled in the northern Sweden MONICA project (entry in 1986, 1990, 1994) and who were followed-up in 1999. Information on tobacco use at entry and at follow-up was used to describe the stability of tobacco use over a period of 5–13 years ending in 1999. Results. Snus was the most stable form of tobacco use amongst men (75%); only 2% of users switched to cigarettes and 20% quit tobacco altogether. Smoking was less stable (54%); 27% of smokers were tobacco-free and 12% used snus at follow-up. Combined use (smoking and snus) was the least stable (39%), as 43% switched to snus and 6% switched to cigarettes. Former users of both products were much less stable than former users of either cigarettes or snus. The stability of smoking amongst women was 69%, which was higher than that amongst men ( P  < 0.05). Conclusions. The use of snus played a major role in the decline of smoking rates amongst men in northern Sweden. The evolution from smoking to snus use occurred in the absence of a specific public health policy encouraging such a transition and probably resulted from historical and societal influences.

BACKGROUNDThere has been concern that the use of alcohol-containing mouthwash may increase the risk of developing oropharyngeal cancer, or OPC. The authors examine the epidemiologic literature relating to this issue.TYPES OF STUDIES REVIEWEDThe authors identified all nine English-language epidemiologic studies of OPC that made reference to mouthwash. The findings and major strengths and limitations of each study are described. In addition, the authors reanalyzed data from one of the studies.RESULTSThe results of six of the studies reviewed are negative and provide no support for the hypothesis that use of alcohol-containing mouthwash increases the risk of OPC. One of the three studies with positive results was a case series and included a follow-up case-control study, the results of which were negative. The authors reanalyzed the study with the most positive results. This analysis found that the study results were just as positive for nonmucosal cancers developing in the mouth as they were for the usual type of OPC. The authors concluded that this study's positive finding resulted from recall bias.CLINICAL IMPLICATIONSIt is unlikely that the use of mouthwashes that contain alcohol increases the risk of developing OPC.

Background and objectives. Cross-sectional data from northern Sweden suggest that the increased use of Swedish moist snuff (snus) may have contributed to a decline in the prevalence of smoking, especially amongst men. This study describes the evolving patterns of tobacco use in this population over the period 1986-1999.Design. This is a prospective follow-up study of 1651 men and 1756 women, aged 25-64 years, who were enrolled in the northern Sweden MONICA project (entry in 1986, 1990, 1994) and who were followed-up in 1999. Information on tobacco use at entry and at follow-up was used to describe the stability of tobacco use over a period of 5-13 years ending in 1999.Results. Snus was the most stable form of tobacco use amongst men (75%); only 2% of users switched to cigarettes and 20% quit tobacco altogether. Smoking was less stable (54%); 27% of smokers were tobacco-free and 12% used snus at follow-up. Combined use (smoking and snus) was the least stable (39%), as 43% switched to snus and 6% switched to cigarettes. Former users of both products were much less stable than former users of either cigarettes or snus. The stability of smoking amongst women was 69%, which was higher than that amongst men (P < 0.05).Conclusions. The use of snus played a major role in the decline of smoking rates amongst men in northern Sweden. The evolution from smoking to snus use occurred in the absence of a specific public health policy encouraging such a transition and probably resulted from historical and societal influences.