The Strategic Dialogue on Tobacco Harm Reduction: a vision and blueprint for action in the US

Does dual use jeopardize the potential role of smokeless tobacco in harm reduction?

INTRODUCTION

The use of smokeless tobacco as part of a strategy to reduce the harm from cigarette smoking is a topic of debate within the tobacco control and public health communities. One concern voiced regarding endorsement of such a tactic is the possibility of actually increasing harm should current smokers adopt dual cigarette/smokeless tobacco use (dual use), which could lead to unintended consequences by perpetuating cigarette smoking, diminishing tobacco cessation, or increasing tobacco-related harm.

METHODS

Here, we review the available literature on health effects and trajectories of use among dual users from a variety of U.S. and European epidemiological studies.

RESULTS

These data suggest that there are not any unique health risks associated with dual use of smokeless tobacco products and cigarettes, which are not anticipated or observed from cigarette smoking alone. Furthermore, studies show that dual users smoke fewer cigarettes than exclusive smokers, and studies of tobacco use patterns over time (tobacco use trajectory data) indicate that dual users are more likely than exclusive cigarette smokers to cease smoking.

CONCLUSIONS

Overall, the concern about dual use appears to be contradicted by the evidence in the literature that dual use of smokeless tobacco and cigarettes may result in reduction in smoking-related harm as smoking intensity is decreased and smoking cessation increases.

Clinical trials methods for evaluation of potential reduced exposure products

Potential reduced exposure products (PREPs) to tobacco toxicants may have promise in reducing tobacco-related morbidity or mortality or may promote greater harm to individuals or the population. Critical to determining the risks or benefits from these products are valid human clinical trial PREP assessment methods. Such an assessment involves determining the effects of these products on biomarkers of exposure and effect, which serve as proxies for harm, and assessing the potential for consumer uptake and abuse of the product. This article identifies critical methodologic issues associated with PREP assessments, reviews the methods that have been used to assess PREPs, and describes the strengths and limitations of these methods. Additionally, recommendations are provided for clinical trial PREP assessment methods and future research directions in this area based on this review and on the deliberations from a National Cancer Institute sponsored Clinical Trials PREP Methods Workshop.

Evaluation of in vitro assays for assessing the toxicity of cigarette smoke and smokeless tobacco

BACKGROUND

In vitro toxicology studies of tobacco and tobacco smoke have been used to understand why tobacco use causes cancer and to assess the toxicologic impact of tobacco product design changes. The need for toxicology studies has been heightened given the Food and Drug Administration's newly granted authority over tobacco products for mandating tobacco product performance standards and evaluate manufacturers' health claims about modified tobacco products. The goal of this review is to critically evaluate in vitro toxicology methods related to cancer for assessing tobacco products and to identify related research gaps.

METHODS

PubMed database searches were used to identify tobacco-related in vitro toxicology studies published since 1980. Articles published before 1980 with high relevance also were identified. The data were compiled to examine (a) the goals of the study, (b) the methods for collecting test substances, (c) experimental designs, (d) toxicologic end points, and (e) relevance to cancer risk.

RESULTS

A variety of in vitro assays are available to assess tobacco smoke that address different modes of action, mostly using non-human cell models. However, smokeless tobacco products perform poorly in these assays. Although reliable as a screening tool for qualitative assessments, the available in vitro assays have been poorly validated for quantitative comparisons of different tobacco products. Assay batteries have not been developed, although they exist for nontobacco assessments. Extrapolating data from in vitro studies to human risks remains hypothetical.

CONCLUSIONS

In vitro toxicology methods are useful for screening toxicity, but better methods are needed for today's context of regulation and evaluation of health claims.

Correlates of individual differences in compensatory nicotine self-administration in rats following a decrease in nicotine unit dose

RATIONALE

The ability of tobacco harm reduction strategies to produce significant reductions in toxin exposure is limited by compensatory increases in smoking behavior. Characterizing factors contributing to the marked individual variability in compensation may be useful for understanding this phenomenon and assessing the feasibility of harm reduction interventions.

OBJECTIVE

The objective of the study was to use an animal model of human compensatory smoking that involves a decrease in unit dose supporting nicotine self-administration (NSA) to examine potential contributors to individual differences in compensation.

METHODS

Rats were trained for NSA during daily 23-h sessions at a unit dose of 0.06 mg/kg/inf until responding was stable. The unit dose was then reduced to 0.03 mg/kg/inf for at least 10 sessions. Following reacquisition of NSA at the training dose and extinction, single-dose nicotine pharmacokinetic parameters were determined.

RESULTS

Decreases in nicotine intake following dose reduction were proportionally less than the decrease in unit dose, indicating partial compensation. Compensatory increases in infusion rates were observed across the course of the 23-h sessions. The magnitude of compensation differed considerably between rats. Rats exhibiting the highest baseline infusion rates exhibited the lowest levels of compensation. Nicotine pharmacokinetic parameters were not significantly correlated with compensation. Infusion rates immediately returned to pre-reduction levels when baseline conditions were restored.

CONCLUSIONS

These findings provide initial insights into correlates of individual differences in compensation following a reduction in nicotine unit dose. The present assay may be useful for characterizing mechanisms and potential consequences of the marked individual differences in compensatory smoking observed in humans.

The relation between smokeless tobacco and cancer in Northern Europe and North America. A commentary on differences between the conclusions reached by two recent reviews

BACKGROUND

Smokeless tobacco is an alternative for smokers who want to quit but require nicotine. Reliable evidence on its effects is needed. Boffetta et al. and ourselves recently reviewed the evidence on cancer, based on Scandinavian and US studies. Boffetta et al. claimed a significant 60-80% increase for oropharyngeal, oesophageal and pancreatic cancer, and a non-significant 20% increase for lung cancer, data for other cancers being "too sparse". We found increases less than 15% for oesophageal, pancreatic and lung cancer, and a significant 36% increase for oropharyngeal cancer, which disappeared in recent studies. We found no association with stomach, bladder and all cancers combined, using data as extensive as that for oesophageal, pancreatic and lung cancer. We explain these differences.

METHODS

For those cancers Boffetta et al. considered, we compared the methods, studies and risk estimates used in the two reviews.

RESULTS

One major reason for the difference is our more consistent approach in choosing between study-specific never smoker and combined smoker/non-smoker estimates. Another is our use of derived as well as published estimates. We included more studies, and avoided estimates for data subsets. Boffetta et al. also included some clearly biased or not smoking-adjusted estimates. For pancreatic cancer, their review included significantly increased never smoker estimates in one study and combined smoker/non-smoker estimates in another, omitting a combined estimate in the first study and a never smoker estimate in the second showing no increase. For oesophageal cancer, never smoker results from one study showing a marked increase for squamous cell carcinoma were included, but corresponding results for adenocarcinoma and combined smoker/non-smoker results for both cell types showing no increase were excluded. For oropharyngeal cancer, Boffetta et al. included a markedly elevated estimate that was not smoking-adjusted, and overlooked the lack of association in recent studies.

CONCLUSION

When conducting meta-analyses, all relevant data should be used, with clear rules governing the choice between alternative estimates. A systematic meta-analysis using pre-defined procedures and all relevant data gives a lower estimate of cancer risk from smokeless tobacco (probably 1-2% of that from smoking) than does the previous review by Boffetta et al.

Receptivity to Taboka and Camel Snus in a U.S. test market

INTRODUCTION

The two largest U.S. cigarette manufacturers introduced Swedish-style low-nitrosamine smokeless tobacco (snus) to several U.S. test markets in summer 2006. Since then, snus brands and test markets have proliferated.

METHODS

This article assesses consumer response by analyzing data from the 2006 and 2007 Indiana Adult Tobacco Survey (IATS), a statewide telephone survey of 3,544 adults. During those years, the IATS included questions on awareness and trial of Camel Snus and Taboka. Analyses examined rates and predictors of awareness and trial statewide, and within the central Indiana test market.

RESULTS

Nineteen percent of Indiana adults were aware of either Taboka or Camel Snus in 2006 and 2007. Estimates are larger (29%) for central Indiana and larger still (70%) for central Indiana smokers. Trial of snus, however, was very low (1.5% statewide), except among male smokers in central Indiana, 20% of whom are estimated to have tried it. Multivariate analyses showed that trial was more likely among men than women (odds ratio [OR] 13.85), residents of central Indiana than those farther from Indianapolis (OR 2.96), recipients than nonrecipients of tobacco promotions (OR 6.08), and those believing that smokeless tobacco is less harmful than cigarettes compared with those who believe it is equally or more harmful (OR 3.86).

DISCUSSION

Results from this study suggest substantial initial interest in the new products among male smokers in this test market, especially those who receive promotional mailings from tobacco companies, which often include coupons for free or discounted products.

Bridging basic and clinical science with policy studies: The Partners with Transdisciplinary Tobacco Use Research Centers experience

INTRODUCTION

The Partners with Transdisciplinary Tobacco Use Research Centers (TTURCs) initiative was a transdisciplinary team-building program, funded by the Robert Wood Johnson Foundation, to expand the policy research capacity of the TTURCs. EXPANSION INTO POLICY RESEARCh: Policy research activities at the TTURCs fell into four broad domains: (a) health services research, (b) examination of the business case for cessation treatment and funding, (c) collaborative teams with key stakeholders, and (d) direct assessment of smoking-related policies. Examples of each domain are presented.

OUTCOMES

Goals of the initiative included efforts to foster collaborative, transdisciplinary research, to bring new investigators into the field, to develop programs of policy research, to answer next-step translational questions, and to enhance awareness of policy relevance. Success at meeting each of these goals is discussed.

RECOMMENDATIONS

We offer recommendations for incorporating programs of policy research into full-spectrum transdisciplinary research initiatives, including the roles of research teams, senior researchers, infrastructure, stakeholders, and communications activities.

CONCLUSIONS

The TTURC Partners initiative represented a first-generation effort to fill the gap between scientific discovery and research translation through expansion into policy studies. While all aspects of the effort were not equally successful, the effort demonstrated that it is possible to develop successful collaborations that extend more basic and applied research into studies that examine their policy and practice implications.