Swedish snus use is associated with mortality: a pooled analysis of eight prospective studies

Use of oral moist tobacco (snus) in puberty and its association with asthma in the population-based RHINESSA study

OBJECTIVES

To investigate the association of early snus use initiation (≤15 years of age) with asthma and asthma symptoms.

DESIGN

Cross-sectional analysis of a population-based cohort.

SETTING

Study centres in Norway, Sweden, Iceland, Denmark and Estonia, from 2016 to 2019.

PARTICIPANTS

9002 male and female participants above 15 years of age of the Respiratory Health in Northern Europe, Spain and Australia study.

MAIN OUTCOME MEASURES

Current asthma and asthma symptoms.

RESULTS

The median age of study participants was 28 years (range 15-53) and 58% were women. 20% had used snus, 29% men and 14% women. Overall, 26% of males and 14% of females using snus started ≤15 years of age. Early snus use initiation was associated with having three or more asthma symptoms (OR 2.70; 95% CI 1.46 to 5.00) and a higher asthma symptom score (β-coefficient (β) 0.35; 95% CI 0.07 to 0.63) in women. These associations were weak in men (OR 1.23; 95% CI 0.78 to 1.94; β 0.16; 95% CI -0.06 to 0.38, respectively). There was evidence for an association of early snus initiation with current asthma (OR 1.72; 95% CI 0.88 to 3.37 in women; OR 1.31; 95% CI 0.84 to 2.06 in men). A sensitivity analysis among participants without smoking history showed stronger estimates for all three outcomes, in both men and women, statistically significant for three or more asthma symptoms in women (OR 3.28; 95% CI 1.18 to 9.10). Finally, no consistent associations with asthma outcomes were found for starting snus after age 15 years.

CONCLUSIONS

Snus initiation in puberty was associated with higher likelihood of asthma and asthma symptoms, with the highest estimates in females and those without smoking history. These results raise concerns about the health adversities of early snus initiation and emphasise the need for public health initiatives to protect young people from this tobacco product.

A systematic review of cancer risk among users of smokeless tobacco (Swedish snus) exclusively, compared with no use of tobacco

The main objective of this systematic review was to assess cancer risk, and mortality after cancer diagnosis, for exclusive users of Swedish snus, compared with non-users of tobacco. We followed international standards for systematic reviews and graded our confidence in the risk estimates using the GRADE approach. Our search gave 2450 articles, of which 67 were assessed in full text against our inclusion criteria. Of these, 14 cohort-studies and one case-control study were included in the review. The studies investigated risk of cancer in the oral cavity or oropharynx (3 studies), esophagus (1 study), stomach (1 study), pancreas (2 studies), colorectum (2 studies), anus (1 study) and lung (1 study), as well as malignant lymphoma (1 study), leukemia and multiple myeloma (1 study), melanoma (1 study), any cancer (1 study) and mortality after cancer diagnosis (4 studies). Cancer risk could only be evaluated in men as there was a general lack of data for women. All included studies were evaluated to have a moderate risk of bias, mostly related to validity of exposure information. An increased risk of cancer of the esophagus, pancreas, stomach and rectum as well as an association between use of snus and increased mortality after a cancer diagnosis was reported. Our confidence in the various risk estimates varied from moderate through low to very low.

Dietary habits among snus users: a population-based cross-sectional study

Background

The dietary habits among snus users are largely unknown and have not been accounted for in observational studies on the health effects of snus use.

Aim

To examine whether snus users eat unhealthier than never tobacco users.

Methods

A total of 3,397 male participants, examined between 1994 and 2014 in the Northern Sweden Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) study, were included. Snus use and dietary habits were self-reported using questionnaires, from which intakes of different food groups, macronutrients, and a healthy diet score (HDS) were calculated (the latter as a proxy for overall diet quality). The association between snus use and dietary habits was examined by quantile regression models.

Results

In the multivariable-adjusted model, current snus users had a lower HDS (median difference: -0.86 [95% confidence interval: -1.32, -0.40]) than never tobacco users. Snus users also consumed fewer weekly servings of fruits and berries (median difference: -1.03 [-1.65, -0.40]), and their estimated percentage of energy intake consisted of less carbohydrates (median difference: -1.43 [-2.12, -0.74]) and of more total fat (median difference: 0.99 [0.30, 1.67]), saturated fat (median difference: 0.67 [0.29, 1.05]), monounsaturated fat (median difference: 0.44 [0.20, 0.68]), trans fat (median difference: 0.03 [0.01, 0.06]), and alcohol (median difference: 0.21 [0.02, 0.40]).

Conclusion

We observed that snus users had an unhealthier diet than never tobacco users. Future studies on the association between snus use and health outcomes should, therefore, consider diet as a potential confounder.

Tobacco impact on quality of life, a cross-sectional study of smokers, snuff-users and non-users of tobacco

BACKGROUND

Tobacco smoking is a major public health issue, and also affects health-related quality of life. There has been considerable debate as to whether oral moist snuff, a form of tobacco placed in the oral cavity between the upper lip and gum as in sublabial administration, can be considered a safe alternative to smoking. The aim of this study was to investigate the association between health-related quality of life and smoking, snuff use, gender and age.

METHOD

This cross-sectional study included 674 women and 605 men aged 18 to 65 recruited through a Swedish population database. Subjects completed a questionnaire about tobacco use and the 36-item Short Form Health Survey (SF-36). Multivariable logistic regression analyses were performed for the association between health-related quality of life and tobacco use, gender and age. The median perceived health-related quality of life (SF-36) for an age-matched Swedish population was used as the cutoff: above the cutoff indicated better-than-average health coded as 1, or otherwise coded as 0. The independent variables were smoking (pack-decades), snuff-use (box-decades), gender and age in decades. The outcome was presented as the Odds Ratio (OR) with a 95% confidence interval (CI) for each independent variable.

RESULTS

The experience of cigarette smoking is associated with decreased physical functioning (PF), general health (GH), vitality (VT), social functioning (SF) and mental health (MH) as well as both lower physical component summary (PCS) and mental component summary (MCS). Further, the experience of snuff use is associated with bodily pain (BP), lower VT, and lower PCS. In the study population older age is associated with lower PF,GH, VT, MH, PCS and MCS. Female gender is associated with lower PF and VT.

CONCLUSION

This study shows that smoking is associated with lower health-related quality of life. The results also illuminate the detrimental health effects of using snuff, implying that snuff too is a health hazard. As studies on the bodily effects of snuff are relatively scarce, it is imperative that we continue to address and investigate the impact on the population using snuff on a regular basis.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT05409963 05251022 08/06/22.

Association between snus use and lipid status in Swedish men

Snus is a common tobacco product in Sweden, but the cardiovascular risk profile for snus users is less known than for cigarette smokers. We examined the association of snus use with lipid status, particularly in comparison to non-tobacco use and cigarette smoking, using data from 5930 men in the Northern Sweden MONICA study. Tobacco use was self-reported in 1986 to 2014 (24.4% used snus) and blood samples were collected at the same time. Harmonized analyses on non-high-density lipoprotein (non-HDL) cholesterol, HDL cholesterol, and triglycerides were conducted in 2016 to 2018. Three hundred eighty-one snus users had also been examined more than once, allowing us to study the effect of discontinued use (achieved by 21.0%). In multivariable linear regression models, snus use was associated with higher HDL cholesterol and triglyceride concentrations compared to non-tobacco use (p values ≤ 0.04), and it was associated with higher HDL cholesterol concentrations and lower triglyceride concentrations compared to cigarette smoking (p values ≤ 0.02). Snus use was not associated with non-HDL cholesterol concentrations, irrespective of the comparison group (p values ≥ 0.07). There was no indication that higher intensity of snus use led to a worse lipid profile, given that high-consumers had higher HDL cholesterol concentrations than low-consumers (p value = 0.02), or that discontinuation of snus use led to a better lipid profile, given that continued users had lower triglyceride concentrations than discontinued users (p value = 0.03). Further studies are needed to confirm or refute our findings.

The association between dental caries and physical activity, physical fitness, and background factors among Finnish male conscripts

Studies on measured physical fitness and oral health are sparse. The aim of this study was to investigate the associations between self-reported physical activity and measured physical fitness and oral health of young men. The study population consisted of 13,564 Finnish male conscripts who had mandatory clinical oral examinations and physical fitness tests at the beginning of military service in 2011. Finally, around 10,800 conscripts had physical fitness test outcomes available and a total of 8552 conscripts answered a computer-based questionnaire on background factors. Decayed Tooth (DT) and Decayed, Missing, or Filled Tooth (DMFT) indices, outcomes of surveys and fitness tests were used in analyses by cross-tabulation and multivariable logistic regression model (odds ratios [OR] with 95% confidence interval [CI]) were calculated. Regularly exercising conscripts had a reduced need for dental restorative treatment than those reporting no physical activity (p < 0.0001). The proportion of participants with sound dentition (DT = 0) increased steadily with increasing physical activity (39.0-59.4%). Good measured physical fitness was a protective factor against increased dental restorative treatment need. A low prevalence of smoking and low use of alcohol and energy drinks were associated with frequent exercise, whereas consumption of sport drinks and snuff use were common among those who exercised frequently. Good measured physical fitness and self-reported physical activity are associated with reduced caries burden. There is a need for information about the harms of tobacco products and the benefits of a healthy diet, even for the increased energy needs of the physically active.

Swedish snuff (snus) dipping, cigarette smoking, and risk of peripheral artery disease: a prospective cohort study

Tobacco smoking is an important risk factor for peripheral artery disease (PAD), but it remains unknown whether smokeless tobacco, such as Swedish snuff (snus), is also associated with this disease. We used data from the Cohort of Swedish Men including 24,085 men. Individuals were grouped into never, past, and current snus dippers as well as never, past quitting ≥ 10 years, past, quitting < 10 years, and current smokers. Incident PAD cases were defined by linkage of the cohort with the Swedish National Patient Register. Cox proportional hazards regression was used to analyze the data. Over a mean follow-up period of 9.1 years (from July 1, 2009 to December 31, 2019), 655 incident PAD cases were ascertained. Cigarette smoking but not Swedish snus dipping was associated with an increased risk of PAD. Compared with never snus dippers, the hazard ratio of PAD was 0.95 (95% confidence interval [CI] 0.73–1.24) for past snus dippers and 0.88 (95% CI 0.66–1.17) for current snus dippers. Compared to never smokers, the hazard ratio of PAD was 1.38 (95% CI 1.14–1.68) for past smoker who stopped smoking for ≥ 10 years, 2.61 (95% CI 1.89–3.61) for past smoker who stopped smoking for < 10 years, and 4.01 (95% CI 3.17, 5.08) for current smoker. In conclusion, cigarette smoking but not Swedish snus dipping increases the risk of PAD.

Tobacco use disorder and cardiovascular health

This narrative review examines the impact of cigarette smoking and the use of other tobacco and nicotine products on cardiovascular disease. Smoking increases the incidence of both acute and chronic cardiovascular diseases, and the harmful effects are substantially and relatively quickly reversible after quitting. Recommended cessation treatment includes offering pharmacotherapy, counseling which should emphasize the rapid risk reduction that occurs after quitting and adequate follow-up contacts. Although most research on cardiovascular disease in relation to tobacco use has focused upon cigarette smoking, we also review available data related to other combustible tobacco products, smokeless tobacco, electronic nicotine delivery systems and second-hand smoke. We discuss the implications of smoking on clinical management of patients with heart disease and newer developments with potential relevance to treatment of such patients.

Socioeconomic Differences in Cigarette Smoking and Alternative Tobacco Product Use Among Adolescents in a School-Based Smoking Preventive Intervention: Findings From the Second Year of the X:IT II Study

Background

Health interventions may differently impact adolescents from diverse backgrounds. This study examined whether a smoking preventive intervention was equally effective in preventing cigarette smoking and use of alternative tobacco products (ATPs, i.e., snus, e-cigarettes, and waterpipe) among students from different socioeconomic backgrounds, i.e., occupational social classes (OSC).

Methods

Data was from the school-based intervention X:IT II targeting 13- to 15-year-olds Danes. The intervention focused on three main components: smoke-free school time, smoke-free curriculum, and parental involvement. In total, 46 schools were included at baseline (N = 2,307, response rate = 86.3%). Using a difference-in-differences approach, changes in current smoking and ever use of ATPs were estimated among students in high versus low OSC at second follow-up. Analyses were based on available cases (N = 826) and multiple imputations of missing data at the second follow-up (N = 1,965).

Results

At baseline (age 13), 1.0% of students from high OSC and 4.8% from low OSC currently smoked cigarettes, while this was the case among 24.5 and 25.6%, respectively, at the second follow-up (age 15). Estimates indicated that social inequalities in current smoking diminished over time (p < 0.001). Regarding ATPs, 10.0% of high OSC students and 13.9% of low OSC students had ever used ATPs at baseline, while at second follow-up, 46.8 and 60.8%, respectively, had ever used ATPs. Estimates indicated that social inequalities in ever use of ATPs widened over time (p < 0.001).

Conclusions

The X:IT II intervention seemed to diminish socioeconomic disparities in smoking over the study period. Meanwhile, social inequalities in ever use of ATPs increased. Therefore, besides focusing on narrowing the social disparities in cigarette smoking, future efforts may, to a larger extent, focus on adolescents' use of ATPs.

Smokeless Tobacco and Its Ill-Effects: Recent Literature Update

According to the Global Adult Tobacco Survey part 2 (GATS-2), approximately 200 million adult Indians consume smokeless tobacco (SLT). Circumvention of SLT product ban has been observed. We conducted a review of the literature to summarize the ill effects of tobacco for the articles published from 2019 to 2020. A systematic search of the databases PubMed (2019 onward) and Web of Science (2019 onward), through February 2021 was done. Search yielded 1,061 articles and after excluding articles based on the inclusion criteria, 37 articles were taken in to consideration. The review shows that differential SLT product has specific odds of oral carcinogenesis. Review also indicates the emerging data of cardiovascular risk due to higher use of SLT products along with its known cause of oral cancer. It also cautions about the adverse consequences of pregnancy associated with SLT use.

Prevalence, duration of exposure and predicting factors for snus use among young Finnish men: a cross-sectional study

OBJECTIVE

The health hazards of tobacco products depend on the level of exposure, but little is known about the characteristics of snus use. The aim of this study was to investigate the duration of daily exposure to snus among occasional and daily users and its associated predictive factors among young Finnish men.

DESIGN

Cross-sectional questionnaire study.

SETTING

Three out of 16 Finnish Defence Forces units.

PARTICIPANTS

1280 young Finnish male conscripts starting their military service in 2016 chosen by simple random sampling.

PRIMARY AND SECONDARY MEASURES

The prevalence, duration of use and the amount of daily usage of snus and cigarettes were investigated. The attitudes towards perceived harmfulness of snus and the predictive factors affecting the total time of snus consumption were examined.

RESULTS

Almost a fifth (19.5%) of the conscripts reported daily snus use, and a further 16% reported occasional use. Daily snus use was associated with an earlier starting age, longer duration of use and higher daily exposure time compared with occasional use. On average, daily snus users consumed 10 portions and occasional users three portions per day (p<0.001). The daily total exposure time for daily users was 372 min (95% CI 344 to 401) and for occasional users 139 min (95% CI 106 to 171). Respondents with an upper secondary education had significantly less daily total exposure than those with basic comprehensive education (p=0.036). Perceptions of snus as a harmful substance resulted in a significantly lower duration of exposure.

CONCLUSION

Snus use was very common among young Finnish men. High snus exposure duration was associated with an earlier starting age, a longer history of use and a careless attitude to its health hazards. A higher education level was a protective factor for total exposure time. Studies of the long-term health effects and dependency profile of snus use are needed.

Incidence trends in bladder and lung cancers between Denmark, Finland and Sweden may implicate oral tobacco (snuff/snus) as a possible risk factor

Background

The dominant risk factor for urinary bladder cancer has been cigarette smoking, but, as smoking prevalence is decreasing in many populations, other risk factors may become uncovered. Such new risk factors could be responsible for halting the declining incidence of bladder cancer. We hypothesize that snuff use by Swedish men may increase the rate for bladder cancer, as snuff contains carcinogenic nitrosamines.

Methods

We carried out an ecological study by comparing incidence trends in lung and bladder cancers between Danish, Finnish and Swedish men in order to test if the Swedish bladder cancer rate deviates from the Danish and Finnish ones. We used the NORDCAN database for cancer data from 1960 through 2016 to test the hypothesis.

Results

In the three countries, the incidence of lung cancer started to decrease after a peak incidence, and this was later followed by declining incidence in bladder cancer in Denmark from 1990 to 2016 by 14.3%, in Finland by 8.3% but not in Sweden (the decline of 1.4% was not significant). The difference in trends can be partly explained by the increasing incidence in Swedish men aged 70 or more years. Sweden differs from the two other countries by low male smoking prevalence but increasing use of snuff recorded by various surveys.

Conclusion

The stable bladder cancer trend for Swedish men was opposite to the declining trends in Denmark, Finland and globally. We suggest that this unusual finding may be related to the increasing use of snuff by Swedish men. Average users of snuff are exposed to at least 3 times higher levels of carcinogenic tobacco-specific nitrosamines than a smoker of one daily pack of cigarettes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08371-w.

Heterogeneity and other problems in a pooled analysis of snus use and mortality

A recent analysis of Swedish snus use and mortality combined eight Swedish datasets and found that exclusive Swedish male snus users have statistically significant increased mortality from all causes, cardiovascular diseases and other causes. These findings, from the Swedish Collaboration on Health Effects of Snus Use, are in sharp contrast with previous pooled results from the same group. The discrepant results may be indicative of unresolved statistical problems that haven’t been addressed by the collaboration authors in any of their studies. The most important problem is unresolved heterogeneity among the eight cohorts, which we describe in detail, and we show how the use of the random effects method by the authors was not sufficient. We explain why the tables in the article are uninformative, and we demonstrate why the exclusion of smokers in the analysis was not validated and eliminated important information. Finally, we strongly recommend some straightforward and easily implemented corrective measures.

Impact of tobacco control policies implementation on future lung cancer incidence in Europe: An international, population-based modeling study

BACKGROUND

Despite recent trends in declining smoking rates, tobacco smoking remains the most preventable cause of cancer in Europe. We aimed to estimate numbers and proportions of future lung cancer cases that could be potentially prevented over a 20-year period if countries in Europe were to achieve a comprehensive implementation of tobacco control policies.

METHODS

Historical data from population-based cancer incidence (or mortality) was used to predict sex-specific lung cancer incidence for 30 European countries up to 2037. Hypothetical country-specific smoking prevalence that would be expected if countries would have achieved the highest-level implementation of tobacco control policies (defined by the maximum total score of the Tobacco Control Scale, TCS) was estimated by combining national prevalence data on current smoking and data on the status of implementation of key tobacco control policies. Resulting numbers and proportions of potentially preventable lung cancer cases were estimated taking into account latency periods between changes in smoking prevalence and excess cancer risks.

FINDINGS

In Europe, an estimated 1·65 million lung cancer cases (21·2%, 19·8% in men and 23·2% in women) could be prevented over a 20-year period with the highest-level implementation of tobacco control policies. Large variation was seen in European regions and countries reflecting the current level of tobacco control, with the largest potential for prevention in Western Europe (24·5%), Southern Europe (23·1%) and Eastern Europe (22·5%), and the lowest but still substantial potential for further prevention in Northern Europe (12·5%). In women, among whom lung cancer incidence is expected to increase, we estimated somewhat larger proportions of preventable lung cancer cases ranging from 9·9 to 33·9% as compared to men (8·6-28·5%). In the final year of study period (2037), these proportions even exceed 50% in women for some countries.

INTERPRETATION

Improved and expanded implementation of evidence-based tobacco control policies at the most comprehensive level could reduce future lung cancer incidence considerably across Europe.

FUNDING

The study was funded by the German Cancer Aid ("Deutsche Krebshilfe"), grant number 70112097.