Puffing style and human exposure minimally altered by switching to a carbon-filtered cigarette

Latent Class Analysis of E-cigarette Use Sessions in Their Natural Environments

BACKGROUND

Delivery of nicotine and substances from electronic nicotine delivery systems, or e-cigarettes, depends in part on how users puff on the devices. Little is known about variation in puffing behavior to inform testing protocols or understand whether puffing behaviors result in increased exposure to emissions.

METHODS

We analyzed puff topography data collected using a wireless portable use monitor (wPUM) continuously over 2 weeks among 34 current second-generation e-cigarette users in their everyday lives. For each puff, the wPUM recorded date, time, duration, volume, flow rate, and inter-puff interval.

RESULTS

We defined use session and classes at the session level using multilevel latent profile analysis, resulting in two session classes and three person types. Session class 1 ("light") was characterized by 14.7 puffs per session (PPS), low puff volume (59.9 ml), flow rate (28.7 ml/s), and puff duration (202.7 s × 100). Session class 2 ("heavy") was characterized by 16.7 PPS with a high puff volume (290.9 ml), flow rate (71.5 ml/s), and puff duration (441.1 s × 100). Person class 1 had almost exclusively "light" sessions (98.0%), whereas person class 2 had a majority of "heavy" sessions (60.7%) and person class 3 had a majority of "light" sessions (75.3%) but some "heavy" sessions (24.7%).

CONCLUSION

Results suggest there are different session topography patterns among e-cigarette users. Further assessment is needed to determine whether some users have increased exposure to constituents and/or health risks because of e-cigarettes.

IMPLICATIONS

Our study examines topography characteristics in a users' natural setting to identify two classes of e-cigarette session behavior and three classes of users. These results suggest that it is important for studies on the health effects of e-cigarettes to take variation in user topography into account. It is crucial to accurately understand the topography profiles of session and user types to determine whether some users are at greater exposure to harmful or potentially harmful constituents and risks from e-cigarettes as they are used by consumers.

Examining Daily Electronic Cigarette Puff Topography Among Established and Nonestablished Cigarette Smokers in their Natural Environment

Introduction

Understanding exposures and potential health effects of e-cigarettes is complex. Users' puffing behavior, or topography, affects function of e-cigarette devices (eg, coil temperature) and composition of their emissions. Users with different topographies are likely exposed to different amounts of any harmful or potentially harmful constituents (HPHCs). In this study, we compare e-cigarette topographies of established cigarette smokers and nonestablished cigarette smokers.

Methods

Data measuring e-cigarette topography were collected using a wireless hand-held monitoring device in users' everyday lives over 1 week. Young adult (aged 18-25) participants (N = 20) used disposable e-cigarettes with the monitor as they normally would and responded to online surveys. Topography characteristics of established versus nonestablished cigarette smokers were compared.

Results

On average, established cigarette smokers in the sample had larger first puff volume (130.9 mL vs. 56.0 mL, p < .05) and larger puff volume per session (1509.3 mL vs. 651.7 mL, p < .05) compared with nonestablished smokers. At marginal significance, they had longer sessions (566.3 s vs. 279.7 s, p = .06) and used e-cigarettes more sessions per day (5.3 s vs. 3.5 s, p = .14). Established cigarette smokers also used e-cigarettes for longer puff durations (3.3 s vs. 1.8 s, p < .01) and had larger puff volume (110.3 mL vs. 54.7 mL, p < .05) compared with nonestablished smokers. At marginal significance, they had longer puff interval (38.1 s vs. 21.7 s, p = .05).

Conclusions

Our results demonstrate that topography characteristics differ by level of established cigarette smoking. This suggests that exposure to constituents of e-cigarettes depends on user characteristics and that specific topography parameters may be needed for different user populations when assessing e-cigarette health effects.

Implications

A user's topography affects his or her exposure to HPHCs. As this study demonstrates, user characteristics, such as level of smoking, can influence topography. Thus, it is crucial to understand the topography profiles of different user types to assess the potential for population harm and to identify potentially vulnerable populations. This study only looked at topography of cigarette smokers using disposable e-cigarettes. Further research is needed to better understand potential variation in e-cigarette topography and resulting exposures to HPHCs among users of different e-cigarette devices and liquids.

Financial Conflicts of Interest and Stance on Tobacco Harm Reduction: A Systematic Review

Background. Tobacco companies have actively promoted the substitution of cigarettes with purportedly safer tobacco products (e.g., smokeless tobacco, e-cigarettes) as tobacco harm reduction (THR). Given the tobacco, e-cigarette, and pharmaceutical industries' substantial financial interests, we quantified industry influence on support for THR. Objectives. To analyze a comprehensive set of articles published in peer-reviewed journals assessing funding sources and support for or opposition to substitution of tobacco or nicotine products as harm reduction. Search Methods. We searched PubMed, Embase, Web of Science, and PsycINFO with a comprehensive search string including all articles, comments, and editorials published between January 1, 1992, and July 26, 2016. Selection Criteria. We included English-language publications published in peer-reviewed journals addressing THR in humans and excluded studies on modified cigarettes, on South Asian smokeless tobacco variants, on pregnant women, on animals, not mentioning a tobacco or nicotine product, on US Food and Drug Administration-approved nicotine replacement therapies, and on nicotine vaccines. Data Collection and Analysis. We double-coded all articles for article type; primary product type (e.g., snus, e-cigarettes); themes for and against THR; stance on THR; THR concepts; funding or affiliation with tobacco, e-cigarette, pharmaceutical industry, or multiple industries; and each author's country. We fit exact logistic regression models with stance on THR as the outcome (pro- vs anti-THR) and source of funding or industry affiliation as the predictor taking into account sparse data. Additional models included article type as the outcome (nonempirical or empirical) and industry funding or affiliation as predictor, and stratified analyses for empirical and nonempirical studies with stance on THR as outcome and funding source as predictor. Main Results. Searches retrieved 826 articles, including nonempirical articles (21%), letters or commentaries (34%), editorials (5%), cross-sectional studies (15%), systematic reviews and meta-analyses (3%), and randomized controlled trials (2%). Overall, 23.9% disclosed support by industry; 49% of articles endorsed THR, 42% opposed it, and 9% took neutral or mixed positions. Support from the e-cigarette industry (odds ratio [OR] = 20.9; 95% confidence interval [CI] = 5.3, 180.7), tobacco industry (OR = 59.4; 95% CI = 10.1, +infinity), or pharmaceutical industry (OR = 2.18; 95% CI = 1.3, 3.7) was significantly associated with supportive stance on THR in analyses accounting for sparse data. Authors' Conclusions. Non-industry-funded articles were evenly divided in stance, while industry-funded articles favored THR. Because of their quantity, letters and comments may influence perceptions of THR when empirical studies lack consensus. Public Health Implications. Public health practitioners and researchers need to account for industry funding when interpreting the evidence in THR debates.

Cigarette Design Features: Effects on Emission Levels, User Perception, and Behavior

Objectives

This paper describes the effects of non-tobacco, physical cigarette design features on smoke emissions, product appeal, and smoking behaviors - 3 factors that determine smoker's exposure and related health risks.

Methods

We reviewed available evidence for the impact of filter ventilation, new filter types, and cigarettes dimensions on toxic emissions, smoker's perceptions, and behavior. For evidence sources we used scientific literature and websites providing product characteristics and marketing information.

Results

Whereas filter ventilation results in lower machine-generated emissions, it also leads to perceptions of lighter taste and relative safety in smokers who can unwittingly employ more intense smoking behavior to obtain the desired amount of nicotine and sensory appeal. Filter additives that modify smoke emissions can also modify sensory cues, resulting in changes in smoking behavior. Flavor capsules increase the cigarette's appeal and novelty, and lead to misperceptions of reduced harm. Slim cigarettes have lower yields of some smoke emissions, but smoking behavior can be more intense than with standard cigarettes.

Conclusions

Physical design features significantly impact machine-measured emission yields in cigarette smoke, product appeal, smoking behaviors, and exposures in smokers. The influence of current and emerging design features is important in understanding the effectiveness of regulatory actions to reduce smoking-related harm.

Cigarette Filter Ventilation and its Relationship to Increasing Rates of Lung Adenocarcinoma

The 2014 Surgeon General's Report on smoking and health concluded that changing cigarette designs have caused an increase in lung adenocarcinomas, implicating cigarette filter ventilation that lowers smoking machine tar yields. The Food and Drug Administration (FDA) now has the authority to regulate cigarette design if doing so would improve public health. To support a potential regulatory action, two weight-of-evidence reviews were applied for causally relating filter ventilation to lung adenocarcinoma. Published scientific literature (3284 citations) and internal tobacco company documents contributed to causation analysis evidence blocks and the identification of research gaps. Filter ventilation was adopted in the mid-1960s and was initially equated with making a cigarette safer. Since then, lung adenocarcinoma rates paradoxically increased relative to other lung cancer subtypes. Filter ventilation 1) alters tobacco combustion, increasing smoke toxicants; 2) allows for elasticity of use so that smokers inhale more smoke to maintain their nicotine intake; and 3) causes a false perception of lower health risk from "lighter" smoke. Seemingly not supportive of a causal relationship is that human exposure biomarker studies indicate no reduction in exposure, but these do not measure exposure in the lung or utilize known biomarkers of harm. Altered puffing and inhalation may make smoke available to lung cells prone to adenocarcinomas. The analysis strongly suggests that filter ventilation has contributed to the rise in lung adenocarcinomas among smokers. Thus, the FDA should consider regulating its use, up to and including a ban. Herein, we propose a research agenda to support such an effort.

Evaluation of Biomarkers of Exposure in Smokers Switching to a Carbon-Heated Tobacco Product: A Controlled, Randomized, Open-Label 5-Day Exposure Study

Introduction:

Tobacco harm reduction aims to provide reduced risk alternatives to adult smokers who would otherwise continue smoking combustible cigarettes (CCs). This randomized, open-label, three-arm, parallel-group, single-center, short-term confinement study aimed to investigate the effects of exposure to selected harmful and potentially harmful constituents (HPHCs) of cigarette smoke in adult smokers who switched to a carbon-heated tobacco product (CHTP) compared with adult smokers who continued to smoke CCs and those who abstained from smoking for 5 days.

Methods:

Biomarkers of exposure to HPHCs, including nicotine and urinary excretion of mutagenic material, were measured in 24-hour urine and blood samples in 112 male and female Caucasian smokers switching from CCs to the CHTP ad libitum use. Puffing topography was assessed during product use.

Results:

Switching to the CHTP or smoking abstinence (SA) resulted in marked decreases from baseline to Day 5 in all biomarkers of exposure measured, including carboxyhemoglobin (43% and 55% decrease in the CHTP and SA groups, respectively). The urinary excretion of mutagenic material was also markedly decreased on Day 5 compared with baseline (89% and 87% decrease in the CHTP and SA groups, respectively). No changes in biomarkers of exposure to HPHCs or urinary mutagenic material were observed between baseline and Day 5 in the CC group.

Conclusions:

Our results provide clear evidence supporting a reduction in the level of exposure to HPHCs of tobacco smoke in smokers who switch to CHTP under controlled conditions, similar to that observed in SA.

Implications:

The reductions observed in biomarkers of exposure to HPHCs of tobacco smoke in this short-term study could potentially also reduce the incidence of cancer, cardiovascular and respiratory diseases in those smokers who switch to a heated tobacco product.

A systematic review and analysis of data reduction techniques for the CReSS smoking topography device

Introduction: Characterising smoking behaviour in an objective and ecologically valid manner is integral to understanding health complications associated with tobacco use. Smoking topography (ST) provides a representation of the physical attributes of smoking. However, there is no clear guidance on ST data exclusion and reduction techniques and the impact of different techniques.

Methods: A search was conducted using MEDLINE, PubMed, and Scopus and limited to studies published between 2001‒2012. The search identified 23 studies using the CReSS device.

Results: Few studies reported data reduction (n = 9) and exclusion (n = 4) criteria. Four data reduction techniques emerged and were applied to an existing dataset (n = 193, Mage = 38.98, FTND = 5.19, mean 17.23 cigarettes/day). Using repeated measures ANOVA, there were significant (p < 0.05) differences among all techniques for puff volume, peak flow, puff duration and interpuff interval, which were attenuated upon controlling for puff count.

Conclusions: This review highlights the inconsistency in the literature regarding the disclosure of smoking topography data treatment and provides clear evidence that outcomes vary depending on the technique used. Greater transparency is needed and consideration should be given by researchers to the potential impact of methodological decisions on study findings.

Role of cigarette sensory cues in modifying puffing topography

BACKGROUND

Human puffing topography promotes tobacco dependence by ensuring nicotine delivery, but the factors that determine puffing behavior are not well explained by existing models. Chemosensory cues generated by variations in cigarette product design features may serve as conditioned cues to allow the smoker to optimize nicotine delivery by adjusting puffing topography. Internal tobacco industry research documents were reviewed to understand the influence of sensory cues on puffing topography, and to examine how the tobacco industry has designed cigarettes, including modified risk tobacco products (MRTPs), to enhance puffing behavior to optimize nicotine delivery and product acceptability.

METHODS

Relevant internal tobacco industry documents were identified using systematic searching with key search terms and phrases, and then snowball sampling method was applied to establish further search terms.

RESULTS

Modern cigarettes are designed by cigarette manufacturers to provide sensory characteristics that not only maintain appeal, but provide cues which inform puffing intensity. Alterations in the chemosensory cues provided in tobacco smoke play an important role in modifying smoking behavior independently of the central effects of nicotine.

CONCLUSIONS

An associative learning model is proposed to explain the influence of chemosensory cues on variation in puffing topography. These cues are delivered via tobacco smoke and are moderated by design features and additives used in cigarettes. The implications for regulation of design features of modified risk tobacco products, which may act to promote intensive puffing while lowering risk perceptions, are discussed.

Influence of measurement setting and home smoking policy on smoking topography

While cigarette puffing style, measured by smoking topography, is highly variable between individuals, smoking behavior or style tends to vary relatively little within individuals. Recent research has demonstrated that certain situational factors may produce variation in smoking topography, including location of smoking. Smoking topography directly observed by researchers in a laboratory may differ from that indirectly observed via portable measurement devices at participants' homes. The introduction of clean indoor air laws may also influence smokers' puffing styles, as smokers modify their smoking topography to ensure a quicker, more efficient smoking style. The goal of this analysis was to examine whether directly observed laboratory measures are representative of indirectly observed smoking behavior and to examine the influence of smokers' preference for indoor or outdoor home smoking on puffing style. Overall, participants smoked more intensively in the directly observed setting than when in the indirectly observed setting in terms of total volume intake, inter-puff interval, and total time spent smoking. This difference was most pronounced among individuals who reported smoking indoors when at home. The data suggest that adherence to an indoor home smoking policy may further influence an individual's smoking behavior.

Assessing consumer responses to potential reduced-exposure tobacco products: a review of tobacco industry and independent research methods

BACKGROUND

Internal tobacco industry documents and the mainstream literature are reviewed to identify methods and measures for evaluating tobacco consumer response. The review aims to outline areas in which established methods exist, identify gaps in current methods for assessing consumer response, and consider how these methods might be applied to evaluate potentially reduced exposure tobacco products and new products.

METHODS

Internal industry research reviewed included published articles, manuscript drafts, presentations, protocols, and instruments relating to consumer response measures were identified and analyzed. Peer-reviewed research was identified using PubMed and Scopus.

RESULTS

Industry research on consumer response focuses on product development and marketing. To develop and refine new products, the tobacco industry has developed notable strategies for assessing consumers' sensory and subjective responses to product design characteristics. Independent research is often conducted to gauge the likelihood of future product adoption by measuring consumers' risk perceptions, responses to product, and product acceptability.

CONCLUSIONS

A model that conceptualizes consumer response as comprising the separate, but interacting, domains of product perceptions and response to product is outlined. Industry and independent research supports the dual domain model and provides a wide range of methods for assessment of the construct components of consumer response. Further research is needed to validate consumer response constructs, determine the relationship between consumer response and tobacco user behavior, and improve reliability of consumer response measures. Scientifically rigorous consumer response assessment methods will provide a needed empirical basis for future regulation of potentially reduced-exposure tobacco products and new products, to counteract tobacco industry influence on consumers, and enhance the public health.

Reconciling human smoking behavior and machine smoking patterns: implications for understanding smoking behavior and the impact on laboratory studies

BACKGROUND

Recent Food and Drug Administration legislation enables the mandating of product performance standards for cigarette smoke and the evaluation of manufacturers' health claims for modified tobacco products. Laboratory studies used for these evaluations and also for understanding tobacco smoke toxicology use machines to generate smoke. The goal of this review is to critically evaluate methods to assess human smoking behavior and replicate this in the laboratory.

METHODS

Smoking behavior and smoking machine studies were identified using PubMed and publicly available databases for internal tobacco company documents.

RESULTS

The smoking machine was developed to generate smoke to allow for comparing cigarette tar and nicotine yields. The intent was to infer relative human disease risk, but this concept was flawed because humans tailor their smoking to the product, and chemical yields and toxicologic effects change with different smoking profiles. Although smoking machines also allow for mechanistic assessments of smoking-related diseases, the interpretations also are limited. However, available methods to assess how humans puff could be used to provide better laboratory assessments, but these need to be validated. Separately, the contribution of smoke mouth-holding and inhalation to dose need to be assessed, because these parts of smoking are not captured by the smoking machine. Better comparisons of cigarettes might be done by tailoring human puff profiles to the product based on human studies and comparing results across regimens.

CONCLUSIONS

There are major research gaps that limit the use of smoking machine studies for informing tobacco control regulation and mechanistic studies.

Measures for assessing subjective effects of potential reduced-exposure products

Potential reduced-exposure products (PREP) may reduce toxicant exposure and thereby may possibly reduce health risks associated with conventional tobacco use. However, lessened health risk to the individual or harm to the population through the use of PREPs is unknown. Research is being conducted to evaluate the possible health effects associated with PREP use. As part of this evaluation, it is critical to provide sound measures of subjective responses to PREPs to determine the use and the abuse potential of a product, that is, the likelihood that the product will lead to addiction. The goal of this paper is to conduct a systematic review of scales that have been used to measure the subjective responses to PREPs and examine their characteristics. In this article, scales are identified and the items on the scales are described. Scales are also examined to determine whether they are sensitive in testing PREPs. Furthermore, scales to assess PREPs are recommended to investigators. Where no scales exist, items that may be critical for the development and validation of new scales are identified.