Smokeless tobacco mortality risks: an analysis of two contemporary nationally representative longitudinal mortality studies

Oral Cancer Incidence Among Adult Males With Current or Former Use of Cigarettes or Smokeless Tobacco: Population-Based Study

Background

Tobacco use has been identified as a risk factor for oral cancer worldwide. However, relative oral cancer incidence among adults who smoke cigarettes, use smokeless tobacco products (ST), have transitioned from cigarettes to ST, quit cigarettes and/or ST ("quitters"), or never used tobacco has not been well studied.

Objective

We aim to present population-based oral cancer incidence rates for adults who smoke cigarettes, use ST, are former smokers who now use ST, or quit.

Methods

We estimated cross-sectional incidence rates and incidence rate ratios (IRRs) using data from statewide cancer registries (Colorado, Florida, North Carolina, and Texas) and population counts derived from national surveys using combined data from 2014-2017. A random-effect meta-analysis approach was used to summarize estimates among these groups, based on multiple imputation-based IRR estimates by state and age group while considering potential heterogeneity.

Results

A total of 19,536 oral cancer cases were identified among adult males 35 years and older in the study geographies and period. The oral cancer incidence rate among adults who smoke was significantly higher than the ST group (2.6 times higher, 95% CI 2.0-3.3, P<.001), 3.6 (95% CI 3.2-4.1, P<.001) times higher than the never users, and 2.4 (95% CI 1.8-3.1, P<.001) times higher compared to former smokers who now use ST. The IRR among the ST group relative to never users was 1.4 (95% CI 1.1-1.9, P=.02). The IRR between former smokers who now use ST and those who quit was 1.4 (95% CI 1.0-2.1, P=.08).

Conclusions

Findings from this population-based study with a large number of oral cancer cases support significantly high oral cancer incidence among adults who smoke and a lower risk of oral cancer incidence among never users, quitters, users of ST, and former smokers who now use ST compared to cigarettes. Future studies with detailed control of tobacco history and other relevant confounders are needed to confirm these findings.

Modeling the population health impact of accurate and inaccurate perceptions of harm from nicotine

BACKGROUND

Scientific evidence clearly demonstrates that inhaling the smoke from the combustion of cigarettes is responsible for most of the harm caused by smoking, and not the nicotine. However, a majority of U.S. adults who smoke inaccurately believe that nicotine causes cancer which may be a significant barrier, preventing switching to potentially reduced risk, non-combustible products like electronic nicotine delivery systems (ENDS) and smokeless tobacco (ST). We assessed the population health impact associated with nicotine perceptions.

METHODS

Using a previously validated agent-based model to the U.S. population, we analyzed nationally representative data from the Population Assessment of Tobacco and Health (PATH) study to estimate base case rates of sustained (maintained over four waves) cessation and switching to non-combustible product use, by sex. Nicotine perception scenarios were determined from PATH data. The overall switch rate from smoking in Wave 4 to non-combustible product use in Wave 5 (3.94%) was stratified based on responses to the nicotine perception question "Do you believe nicotine is the chemical that causes most of the cancer caused by smoking cigarettes?", (four-item scale from "Definitely not" to "Definitely yes"). The relative percent change between the overall and stratified rates, corresponding to each item, was used to adjust the base case rates of switching, to determine the impact, if all adults who smoke exhibited switching behaviors based on responses to the nicotine perceptions question. The public health impact of nicotine perceptions was estimated as the difference in all-cause mortality between the base case and the four nicotine perception scenarios.

RESULTS

Switch rates associated with those who responded, "Definitely not" (8.39%) resulted in a net benefit of preventing nearly 800,000 premature deaths over an 85-year period. Conversely switch rates reflective of those who responded, "Definitely yes" (2.59%) resulted in a net harm of nearly 300,000 additional premature deaths over the same period.

CONCLUSIONS

Accurate knowledge regarding the role of nicotine is associated with higher switch rates and prevention of premature deaths. Our findings suggest that promoting public education to correct perceptions of harm from nicotine has the potential to benefit public health.

Non-cigarette Tobacco Use and Stroke Among West Africans: Evidence From the SIREN Study

INTRODUCTION

Non-cigarette tobacco (NCT) represents a form of tobacco use with a misperceived significance in chronic disease events. Whether NCT use is sufficient to promote stroke events, especially among Africans, is yet to be understood. This study assessed the relationship between NCT use and stroke among indigenous Africans.

METHODS

A total of 7617 respondents (NCT users: 41 vs. non-NCT: 7576) from the Stroke Investigative Research and Educational Network (SIREN) study were included in the current analysis. NCT use was defined as self-reported use of smoked (cigars or piper) or smokeless (snuff or chewed) tobacco in the past year preceding stroke events. Stroke was defined based on clinical presentation and confirmed with a cranial computed tomography/magnetic resonance imaging. Multivariable-adjusted logistic regression was applied to estimate the odds ratio (OR) and 95% confidence interval (CI) for the relationship of NCT with stroke at a two-sided p < .05.

RESULTS

Out of the 41 (0.54%) who reported NCT use, 27 (65.9%) reported using smokeless NCT. NCT users were older than non-NCT users (62.8 ± 15.7 vs. 57.7 ± 14.8 years). Overall, NCT use was associated with first-ever stroke (OR: 2.08; 95% CI: 1.02, 4.23) in the entire sample. Notably, smokeless NCT use was independently associated with higher odds of stroke (OR: 2.74; 95% CI: 1.15, 6.54), but smoked NCT use (OR: 0.16; 95% CI: 0.02, 1.63) presented a statistically insignificant association after adjusting for hypertension and other covariates.

CONCLUSIONS

NCT use was associated with higher odds of stroke, and public health interventions targeting NCT use might be promising in reducing the burden of stroke among indigenous Africans.

IMPLICATIONS

A detailed understanding of the relationship between NCT use and stroke will likely inform well-articulated policy guidance and evidence-based recommendations for public health prevention and management of stroke on the African continent.

Exploring factors associated with smokeless tobacco use among young people: A systematic scoping review

PURPOSE

While smoking is declining among young people, smokeless tobacco use is increasing. Identifying who is using smokeless tobacco and why is essential in preventing smokeless tobacco use. This study aimed to comprehensively explore the factors of young people's use of smokeless tobacco in western countries and identify research gaps.

METHODS

We conducted a systematic scoping review of studies that examined factors associated with smokeless tobacco use among young people (ages 13-29) from western countries published between January 2011 and September 2021. Searches were conducted in CINAHL, Medline, and Scopus. Studies on adults, total tobacco use (i.e., did not differentiate between tobacco product types), dual and multiple uses of tobacco, and studies on smokeless tobacco cessation programs were excluded.

RESULTS

A total of 160 studies were included in this scoping review. The studies were primarily undertaken in the US and the Scandinavian countries, and the majority explored smokeless tobacco use without distinguishing between the specific types. Smokeless tobacco users were more likely to be male, non-Hispanic white, engaging in physical activity, and using other substances, including cigarettes and alcohol. The role of friends and family were identified as critical factors that were related to the use of smokeless tobacco.

CONCLUSIONS

This scoping review suggests that preventative measures against smokeless tobacco use should focus on peer and family members' roles and that these measures may benefit from targeting males. Additional research, including systematic reviews on this area to validate the identified associated factors, would improve the understanding of smokeless tobacco use.

Review with meta-analysis relating North American, European and Japanese snus or smokeless tobacco use to major smoking-related diseases

BACKGROUND

While extensive information exists relating cigarette smoking to the risk of lung cancer, chronic obstructive pulmonary disease (COPD), ischaemic heart disease (IHD) or acute myocardial infarction (AMI), and stroke, far less information is available on risks from moist snuff (“snus”) or smokeless tobacco (ST) in United States/Canada, Europe or Japan.

AIM

To summarize data from the selected countries on risks of the four diseases associated with current ST or snus use.

METHODS

Publications in English in 1990-2020 were considered that, based on epidemiological studies in North America, Europe or Japan, estimated risks of lung cancer, COPD, IHD/AMI, or stroke according to use of ST or snus. The studies should involve at least 100 cases of the disease considered, and not be restricted to those with specific other diseases. Medline literature searches were conducted, selecting papers initially from examination of titles and abstracts, and then from full texts. Further papers were sought from reference lists in selected papers, reviews and meta-analyses. For each disease, relative risk estimates adjusted at least for age were extracted relating ST or snus use to risk, and combined using random-effects meta-analysis. The estimates were mainly for current vs. never or non-current use, but results for ever vs never use were also considered.

RESULTS

Seven publications reported results for ST use from six United States studies. The most useful results came from four studies which provided results for current vs. never use. Random-effects meta-analyses of these results showed an increased risk for each disease, clearest for lung cancer (relative risk 1.59, 95% confidence interval 1.06-2.39, based on 4 estimates) and COPD (1.57, 1.09-2.26, n = 3), but also significant (at P < 0.05) for IHD (1.26, 1.10-1.45, n = 4) and stroke (1.27, 1.03-1.57, n = 4). Also including results for ever vs. never use from two other studies increased the lung cancer estimate to 1.80 (1.23-2.64, n = 6), but had little effect on the other estimates. For snus, 16 publications described results from 12 studies, one in Norway and the rest in Sweden. There were no results for COPD, and only three for lung cancer, with these reporting a relative risk of 0.80 (0.40-1.30) for current vs never use. More extensive data were available for IHD/AMI and stroke. Using the latest results from each study, combined estimates for current vs. never use were 1.00 (0.91-1.11, n = 5) for IHD/AMI and 1.05 (0.95-1.17, n = 2) for stroke, while for current vs. non-current use they were 1.10 (0.92-1.33, n = 9) for IHD/AMI and 1.12 (0.86-1.45, n = 9) for stroke. Meta-analyses including earlier results from some studies also showed no significant association between snus use and IHD/AMI or stroke. No relevant results were found for Japan.

CONCLUSION

Risks of smoking-related diseases from snus use in Scandinavia are not demonstrated, while those from ST use in the United States are less than from smoking.

Associations of Smokeless Tobacco Use With Cardiovascular Disease Risk: Insights From the Population Assessment of Tobacco and Health Study

INTRODUCTION

Cigarette smoking is strongly associated with the development of cardiovascular disease (CVD). However, evidence is limited as to whether smokeless tobacco (ST) use is associated with CVD.

AIMS AND METHODS

Using data from 4347 adults in the Population Assessment of Tobacco and Health Study (2013-2014), we compared geometric mean concentrations of CVD-related harm biomarkers and biomarkers of exposure among exclusive ST users and exclusive cigarette smokers-in relation to recent nicotine exposure-and never tobacco users, adjusting for age, sex, race/ethnicity, income, body mass index, and CVD. Biomarker levels among exclusive ST users who were former established cigarette smokers were compared with exclusive cigarette smokers.

RESULTS

Compared with cigarette smokers, ST users had significantly higher concentrations of total nicotine equivalents (TNE) but lower concentrations of inflammatory (high-sensitivity C-reactive protein, interleukin-6, intercellular adhesion molecule, fibrinogen) and oxidative stress (8-isoprostane) biomarkers (all p < .05). Biomarker levels among ST users were similar to never smokers. ST users who were former cigarette smokers had lower levels of inflammatory and oxidative stress biomarkers and biomarkers of exposure (cadmium, lead, 1-hydroxypyrene, acrylonitrile, and acrolein), compared with cigarettes smokers (p < .05), despite having higher TNE levels (p < .05). Among cigarette smokers, but not among ST users, inflammatory biomarkers and TNE were highly correlated.

CONCLUSIONS

ST use is not associated with increases in biomarkers of CVD-related harm and exposure, compared with never smokers, despite exposure to nicotine at levels higher than those observed among cigarette smokers. These findings support the concept that increases in CVD risk among cigarette smokers is caused primarily by constituents of tobacco smoke other than nicotine.

IMPLICATIONS

Despite having higher levels of nicotine and compared with exclusive cigarette smokers, exclusive ST users (including those who were former cigarette smokers) had significantly lower concentrations of inflammatory and oxidative stress biomarkers, comparable to levels observed among never tobacco users. These findings suggest that increases in CVD risk among cigarette smokers is caused primarily by tobacco constituents other than nicotine and that switching to ST is likely associated with lower CVD risk.

Smoking and snus use among Norwegian students: Demographic, personality and substance use characteristics

Background and aim:

Smoking rates are decreasing in Norway while the use of snus has increased. We aimed to investigate the co-occurrence of, and the socio-demographics, personality and substance use characteristics associated with, student smoking and snus use.

Methods:

Survey data were collected among students in higher education in Bergen, Norway in 2015 (N = 11,236, response rate 39.4%). Multinomial regression analyses comparing snus users and smokers to non-users and non-smokers, respectively, on demographic, personality and substance use variables were conducted. Regression analyses comparing current dual users to current smokers and current snus users and comparing daily smokers to daily snus users, on demographic, personality and substance use variables were also conducted.

Results:

In total 67.9% of ever snus users identified themselves as non-smokers (past and current). Several demographic, personality and substance use characteristics associated with smoking and snus use were identified (all = p < .05), some of which were common for both (e.g., use of cannabis) and some which were exclusively associated with either smoking (e.g., neuroticism) or snus use (e.g., extroversion).

Conclusion:

The current study contributes with several novel findings regarding traits associated with smoking and snus use. Though limited by a cross-sectional design, the current findings may suggest that the group of students using snus consists of a combination of previous smokers, students who would have smoked if snus was not available and a new segment who may not have used nicotine if snus was not available.

The health impact of smokeless tobacco products: a systematic review

INTRODUCTION

The objective was to systematically review studies on health outcomes from smokeless tobacco (SLT) products.

METHODS

We analysed published literature on the health outcomes from SLT use between 01/01/2015 to 01/02/2020, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol using PubMed, Embase, Scopus, and Google Scholar.

RESULTS

Of 53 studies included, six were global, 32 from Asia, Middle East and Africa (AMEA), nine from USA and six from Europe. 'Poor'-rated studies predominated (23;43%), in particular, for global (4;66%) and AMEA (16;50%). Health outcomes differed between SLT-products and regions; those in AMEA were associated with higher mortality (overall, cancer, Coronary heart disease (CHD), respiratory but not cardiovascular disease (CVD)), and morbidity (CVD, oral and head and neck cancers), with odds ratios up to 38.7. European studies showed no excess mortality (overall, CVD, from cancers) or morbidity (ischemic heart disease (IHD), stroke, oral, head and neck, pancreatic or colon cancers) from several meta-analyses; single studies reported elevated risk of rectal cancer and respiratory disorders. Pooled study data showed protection against developing Parkinson's disease. US studies showed mixed results for mortality (raised overall, CHD, cancer and smoking-related cancer mortality; no excess risk of respiratory or CVD mortality). Morbidity outcomes were also mixed, with some evidence of increased IHD, stroke and cancer risk (oral, head and neck). No studies reported on switching from cigarettes to SLT-products.

CONCLUSION

Our review demonstrates stark differences between different SLT-products in different regions, ranging from zero harm from European snus to greatly increased health risks in AMEA. The literature on the safety profile for SLT-products for harm reduction is incomplete and potentially misinforming policy and regulation.

Modeling mortality risk effects of cigarettes and smokeless tobacco: results from the National Health Interview Survey Linked Mortality File Data

BACKGROUND

Cigarettes and smokeless tobacco (SLT) products are among a wide range of tobacco products that are addictive and pose a significant health risk. In this study, we estimated smoking- and SLT use-related mortality hazard ratios (HRs) among U.S. adults by sex, age group, and cause of death, for nine mutually exclusive categories of smoking and/or SLT use.

METHODS

We used data from the public-use National Health Interview Survey Linked Mortality with mortality follow-up through 2015. We used Cox proportional hazard models to estimate mortality HRs, adjusted by race/ethnicity, education, poverty level, body mass index, and tobacco-use status.

RESULTS

With never users as reference group, HRs for smoking-related diseases for male exclusive current smokers aged 35-64 and 65+ were 2.18 (95% confidence interval [CI]: 1.79-2.65), and 2.45 (95% CI: 2.14-2.79), respectively. Similar significant HR estimates were found for females and for all-cause mortality (ACM) and other-cause mortality (OCM) outcomes. HRs for exclusive current SLT users were only significant for males aged 35-64 for ACM (HR: 2.04, 95% CI: 1.27-3.27) and OCM (HR: 2.80, 95% CI: 1.50-5.25). HRs for users who switched from cigarettes to SLT products were significant for males aged 65+ for smoking-related diseases (HR: 2.06, 95% CI: 1.47-2.88), SLT-related diseases (HR: 1.99, 95% CI: 1.36-2.89), and ACM (HR: 1.63, 95% CI: 1.21-2.19).

CONCLUSIONS

Male exclusive current SLT users aged 35-64 had a significant HR for ACM and OCM outcomes, suggesting that deaths not attributed to SLT use could be contributing to the ACM elevated HR for exclusive current SLT users.

Assessing quality-adjusted years of life lost associated with exclusive cigarette smoking and smokeless tobacco use

The main purpose of this analysis is to quantify quality adjusted life years (QALYs) lost associated with lifetime exclusive cigarette or smokeless tobacco use among U.S. adults. Multiple waves of National Health Interview Survey (NHIS) data linked to death certificate records were used to define current exclusive cigarette and smokeless tobacco use and associated mortality risks. NHIS data were used to assess health-related quality of life (HRQOL). Regression and Cox proportional hazard modeling were used to adjust HRQOL and mortality risk associated with tobacco use for age, sex, race/ethnicity, body mass index, education, and household poverty level. QALYs were estimated based on adjusted HRQOL and mortality risks. All analyses were initiated in 2019 and completed in 2020. Male current exclusive cigarette smokers, aged 25 to 29 years would lose 8.1 QALYs (SE = 0.09), and male current exclusive smokeless tobacco users aged 25 to 34 would lose 4.1 QALYs (SE = 0.22), compared to never users of tobacco. Current exclusive cigarette or smokeless tobacco use is associated with QALY loss. QALYs lost can be lessened through preventing the initiation of tobacco product use or helping tobacco product users quit as early in life as possible.

Harm reduction for smokers living with HIV

Tobacco use is now a leading cause of death in people living with HIV in the USA. Increasing cessation rates in this group is a public health priority, yet the results of clinical trials aimed at optimising tobacco treatment strategies have been largely disappointing. Combinations of behavioural and pharmacological cessation therapies in people living with HIV have yielded increases in short-term quit rates, but few have shown long-term efficacy. Even with aggressive therapy combining intensive behavioural treatment with pharmacological agents, most smokers living with HIV continue to smoke. The generalised approach to tobacco treatment that prevails in guidelines and in clinical practices might do a disservice to these individuals, who represent a sizable segment of the population of people living with HIV. Harm reduction is a sensible and needed approach for smokers living with HIV who are unable or unwilling to quit. In this Viewpoint, we take an expansive view of harm reduction to include not only cutting down on cigarette intake for persistent smokers, but also reducing smoking's downstream health effects by increasing lung cancer screening and by controlling concurrent cardiovascular risk factors, especially hypertension and hyperlipidaemia.

A comparison of tobacco product prevalence by different frequency of use thresholds across three US surveys

BACKGROUND

With the increasing changes in tobacco use patterns, "current use" definition and the survey used may have important implications for monitoring population use trends.

METHODS

Using three US surveys (2014/15 TUS-CPS, NHIS and PATH), we compared the adult (age 18+) prevalence of four product groups (cigarettes, other combustibles, smokeless tobacco, and e-cigarettes) based on three past 30-day frequency of use thresholds: 1+, 10+, and 25+ days. We also examined mutually exclusive single, dual, and polytobacco users as a percentage of total users for each product group.

RESULTS

Regardless of threshold or product, the prevalence was higher in PATH followed by NHIS and TUS-CPS, in some cases by large percentages. The differences in cigarette and smokeless tobacco use prevalence in going from the 1+ to 10+ days and to the 25+ days threshold were minimal. Applying different frequency thresholds had the largest impact on other combustibles prevalence, with a 60% reduction with the 10+ days threshold and a 80% reduction with the 25+ days threshold, compared to the 1+ days threshold, followed by e-cigarettes with 40 and 60% reductions, respectively. The proportion of dual and polytobacco users decreased considerably when using the 10+ vs. the 1+ days threshold and polytobacco use was almost non-existent with the 25+ days threshold.

CONCLUSION

The estimated prevalence of each tobacco product use depends largely on the survey and frequency of use threshold adopted. The choice of survey and frequency threshold merits serious consideration when monitoring patterns of tobacco use.

Determination of Nicotine-Related Impurities in Nicotine Pouches and Tobacco-Containing Products by Liquid Chromatography–Tandem Mass Spectrometry

Smokeless tobacco products and nicotine-containing tobacco-free oral pouches have increased in popularity in recent years. They are associated with far fewer health hazards compared to cigarettes. Nicotine pouches are filled with non-tobacco filler and nicotine. The nicotine used in nicotine pouches usually comes from the extraction of tobacco; thus, related alkaloids may be found as impurities at low levels. Moreover, nicotine degradation products are formed because of microbial action, flavor oxidation, exposure to high temperatures etc. Currently, there are no published or recommended methods for the analysis of nicotine degradants in nicotine pouches. Here, we present a sensitive and selective liquid chromatography–tandem mass spectrometry method for the simultaneous determination of seven nicotine-related impurities. All seven analytes and corresponding deuterated internal standards were separated within 3.5 min, including 1 min equilibration. The method was fully validated, showing good linearity with correlation coefficients >0.996 for all analytes, good extraction yields ranging from 78% to 110%, limits of detection between 0.08 and 0.56 µg/g and limits of quantification between 0.27 and 2.04 µg/g. Although the method was mainly developed to determine the degradants of nicotine in nicotine pouches, it was validated and performed well on a broader range of tobacco-containing products.

Dissolution Testing of Nicotine Release from OTDN Pouches: Product Characterization and Product-to-Product Comparison

In recent years, oral tobacco-derived nicotine (OTDN) pouches have emerged as a new oral tobacco product category. They are available in a variety of flavors and do not contain cut or ground tobacco leaf. The on!® nicotine pouches fall within this category of OTDN products and are currently marketed in seven (7) flavors with five (5) different nicotine levels. Evaluation of the nicotine release from these products is valuable for product assessment and product-to-product comparisons. In this work, we characterized the in vitro release profiles of nicotine from the 35 varieties of on!® nicotine pouches using a fit-for-purpose dissolution method, employing the U.S. Pharmacopeia flow-through cell dissolution apparatus 4 (USP-4). The nicotine release profiles were compared using the FDA’s Guidance for Industry: Dissolution Testing of Immediate Release Solid Oral Dosage Forms. The cumulative release profiles of nicotine show a dose dependent response for all nicotine levels. The on!® nicotine pouches exhibit equivalent percent nicotine release rates for each flavor variant across all nicotine levels. Furthermore, the nicotine release profiles from on!® nicotine pouches were compared to a variety of other commercially available OTDN pouches and traditional pouched smokeless tobacco products. The percent nicotine release rates were found to be dependent on the product characteristics, showing similarities and differences in the nicotine release profiles between the on!® nicotine pouches and other compared products.

Mortality among male smokers and smokeless tobacco users in the USA

BACKGROUND

One published study simultaneously reported the mortality associated with cigarette smoking and smokeless tobacco (ST) use in the USA. In this study, we focus only on men ages 40-79 years old and extend the follow-up by 4 years.

METHODS

We used selected years (1987-2010) of National Health Interview Survey (NHIS) Linked Mortality Files to classify 46,104 men age 40-79 years with respect to 7 categories of smoking and/or ST use. We used Cox proportional hazards models adjusted for age, race/ethnicity, marital status, education, income, health status, body mass index, and region to estimate hazard ratios (HRs; 95% confidence intervals, CI) for mortality from all causes, heart diseases, malignant neoplasms, and two mutually exclusive categories: smoking-related and other diseases.

RESULTS

There were 15,540 deaths from all causes, including 3476 never tobacco users, 4782 exclusive smokers, and 210 exclusive ST users. The latter had significant excess mortality from all causes (HR = 1.25, CI = 1.08-1.46), but not from heart diseases (HR = 1.16, CI = 0.85-1.59), malignant neoplasms (HR = 1.17, CI = 0.83-1.67), and all smoking-related diseases (HR = 1.19, CI = 0.97-1.46). However, they had higher mortality for all other causes (1.39, CI = 1.10-1.74), which was largely seen in age 40-59 years (HR = 1.68, CI = 1.11-2.54). Current smokers, with or without ST use, also had significantly elevated HRs for other causes (1.70 and 1.57, respectively), in addition to significant increases in mortality from heart diseases (1.98 and 2.00), malignant neoplasms (2.60 and 2.84), and all smoking-related diseases (2.32 and 2.47).

CONCLUSIONS

This is the first simultaneous mortality follow-up study of older American male smokers and ST users. ST users did not have excess mortality from any smoking-related diseases, but younger users had an elevation in deaths from other causes.

A Computational Model for Assessing the Population Health Impact of Introducing a Modified Risk Claim on an Existing Smokeless Tobacco Product

Computational models are valuable tools for predicting the population effects prior to Food and Drug Administration (FDA) authorization of a modified risk claim on a tobacco product. We have developed and validated a population model using best modeling practices. Our model consists of a Markov compartmental model based on cohorts starting at a defined age and followed up to a specific age accounting for 29 tobacco-use states based on a cohort members transition pathway. The Markov model is coupled with statistical mortality models and excess relative risk ratio estimates to determine survival probabilities from use of smokeless tobacco. Our model estimates the difference in premature deaths prevented by comparing Base Case ("world-as-is") and Modified Case (the most likely outcome given that a modified risk claim is authorized) scenarios. Nationally representative transition probabilities were used for the Base Case. Probabilities of key transitions for the Modified Case were estimated based on a behavioral intentions study in users and nonusers. Our model predicts an estimated 93,000 premature deaths would be avoided over a 60-year period upon authorization of a modified risk claim. Our sensitivity analyses using various reasonable ranges of input parameters do not indicate any scenario under which the net benefit could be offset entirely.