NIH electronic cigarette workshop: developing a research agenda

Level and timing of product substitution in a trial of e-cigarettes for smokers not interested in quitting

INTRODUCTION

The e-cigarette market is large and diverse. Traditional smoking cessation trials involving a control group and a 6-month observation period are an inefficient methodology for testing the multiple treatment options e-cigarettes provide for harm reduction in cigarette smokers. We determined when product substitution occurred in the e-cigarette provision arm of an e-cigarette substitution trial for cigarette smokers who were not interested in quitting.

METHODS

We conducted a secondary analysis of 120 cigarette smokers with severe mental illness (recruitment 2017-2020) who were given disposable e-cigarettes for 8 weeks and assessed at weeks 0 (t0), 2, 4, 6, and 8. We explored product substitution through visit-to-visit correlations in change in product use, then developed a dual process growth model for cigarette and e-cigarette use to test the association between increases in e-cigarette use and concurrent decreases in cigarettes smoked.

RESULTS

Mean age of the participants was 45.9 years, and 42.7% smoked ≥20 cigarettes per day. Almost all product substitution occurred between t0 and t2. For the average smoker (18 cigarettes per day), t2 cigarette frequency decreased by 0.39 (95% CI: -0.56 - -0.22) cigarettes for each additional e-cigarette session. There was effect modification (p=0.033), such that baseline light smokers (<10 cigarettes/day) had no significant decrease in t2 cigarette frequency, regardless of their initial increase in e-cigarette use, while heavy smokers (38 cigarettes/day) switched products nearly on a one-to-one basis.

CONCLUSIONS

In this study, most product substitution occurred early, and heavier smokers had larger t2 decreases in cigarettes/day with increased e-cigarette use. If confirmed with replication studies, the findings could suggest establishment of a novel outcome for e-cigarette studies - early product substitution - and support the value of short-term comparative effectiveness trials that compare multiple potentially lower harm tobacco products.

CLINICAL TRIAL REGISTRATION

The study was registered on the official website of ClinicalTrials.gov.

IDENTIFIER

ID NCT03050853.

Susceptibility to Electronic Cigarette and Consumption Patterns in Adolescents

The use of electronic cigarettes (ECs) is a major problem globally. Susceptibility and curiosity are important factors that develop prior to the onset of substance use, such as ECs, and are therefore considered as predictors. Both factors are used to obtain an extended index of susceptibility (ESIe-c), which allows the identification of adolescents who are at risk of starting to use these devices. The aim of this study was to determine the prevalence of EC consumption and to assess the association of possible predictors with susceptibility to use and experimentation with ECs among adolescents. A cross-sectional study was carried out in 377 adolescents (53.0% female). Participants were compared according to their experimentation with ECs. A total of 45.9% had already used electronic cigarettes, and 20.8% were current users. Among those who had not tried electronic cigarettes, 43.3% had a medium-high susceptibility to EC initiation. Consumption among close friends, receiving offers of consumption and alcohol consumption were associated with initiation. There was an inverse association between a medium susceptibility index electronic cigarette score and the consumption of cigarettes and positive affect; on the other hand, the lack of premeditation was associated with a higher susceptibility index score. Intrapersonal factors and social factors seem to influence the ESIe-c and onset of EC use, respectively. The main conclusion in this study is that susceptibility is influenced by intrapersonal factors such as affectivity and impulsivity through the lack of premeditation, and by social factors such as EC consumption by best friends.

An Evaluation of the Contextual Factors Associated With the Use of Either Tobacco or Electronic Cigarettes in Individuals Who Dual Use

INTRODUCTION

Little is known about patterns of dual use of tobacco and electronic cigarettes (e-cigarettes), especially regarding the factors that lead people to choose either product in particular situations. Identifying contextual factors that are associated with product use would enhance understanding of the maintenance of dual product use.

METHODS

Individuals who dual use (N = 102) completed ecological momentary assessment surveys via text message regarding the recent use of tobacco and e-cigarettes for 2 weeks. Product legality, availability, craving, the presence of other people who smoke/vape, and social disapproval were assessed. Data were analyzed using hierarchical logistic regression to identify factors associated with the likelihood of tobacco versus e-cigarette use.

RESULTS

Contexts associated with increased likelihood of using tobacco rather than e-cigarettes included being in the presence of other people who smoke (odds ratio [OR] = 3.50, p < .0001) and experiencing elevated tobacco cigarette craving (OR = 3.51, p < .0001). Decreased likelihood of tobacco over e-cigarette use was associated with smoking restrictions (OR = 0.26, p = .003), the presence of other people who vape (OR = 0.38, p < .001), and experiencing elevated e-cigarette craving (OR = 0.23, p < .0001). The legality of e-cigarettes, social disapproval, and the availability of the alternative product were not significantly associated with the use of one product over the other. An individual difference score of relative tobacco (vs. e-cigarette) use pattern did not significantly moderate these effects.

CONCLUSIONS

This study provided essential information regarding behavioral patterns of dual use, which informs our understanding of people who dual use. Contexts such as smoking restrictions, craving, and social context significantly differentiated between the use of tobacco and e-cigarettes. This suggests product-specific motivations for dual use of tobacco and e-cigarettes in people who use both.

IMPLICATIONS

This study assessed the relationship between momentary contextual factors and dual use in a nationally recruited sample of people who dual use. Assessments of dual use in daily life provided novel information regarding patterns of dual use as well as differential use-motivations for each product. This information will be essential to build a theoretical framework of dual use of tobacco and e-cigarettes.

Differential Toxicity of Electronic Cigarette Aerosols Generated from Different Generations of Devices In Vitro and In Vivo

Electronic cigarettes (e-cigs) have become increasingly popular, especially among youth, raising concerns about their potential health risks. JUUL and Tank devices are two common types of e-cigs that deliver aerosols with varying nicotine levels and flavors. However, the differences in the aerosols generated from different devices and their corresponding cytotoxicity and pulmonary injury effects remain poorly understood. This study addresses these knowledge gaps by characterizing the aerosols of JUUL and Tank e-cig devices and testing their toxic effects on THP-1 and BEAS-2B human cell lines as well as the C57BL/6J mouse model. In our study, the lower-voltage device, the 3.7 V JUUL generates 2.72 mg/puff aerosols by using e-liquid containing 3% nicotine salt (i.e., nicotine benzoate), which is less than the 11.06 mg/puff aerosols generated by the 7.5 V Tank using e-liquid containing 2.4% freebase nicotine. Yet, the cytotoxicity results reveal that JUUL aerosols induced higher toxicity and increased production of pro-inflammation cytokines compared to Tank aerosols per puff. Additionally, we observed that JUUL induced more severe pulmonary inflammation and DNA damage compared to Tank after normalizing for cotinine, a nicotine metabolite, in vivo. Our findings suggest that the device design plays a more important role in e-cig aerosol-induced toxicity than the composition of the e-liquid or voltage. These results provide valuable insights into the health risks associated with various electronic-cig devices and offer an approach for evaluating them.

Preliminary assessment of the subjective effects of electronic-cigarettes in young-adult low-dose electronic-cigarette users: Effects of nicotine dose and e-liquid flavor

OBJECTIVE

The present study evaluated the effects of nicotine concentration (0-10 mg/ml) and flavor (gummy bear vs unflavored) on the subjective experiences of vaporized nicotine in young adult low-dose nicotine (3 mg/ml) ECIG users.

PARTICIPANTS

Eight young adult ECIG users were recruited.

METHODS

A single blinded crossover study was used. Participants were instructed to take ten 1.5 second puffs, each separated by 20 seconds. After self-administration, heart rate was recorded, and participants completed the Drug Effects, Direct Effects of Nicotine, and Direct Effects of ECIG questionnaires.

RESULTS

ECIG user's standard daily nicotine dose influenced the rewarding and aversive effects of nicotine as the 10 mg/ml dose was found to be aversive in this user group. The combination of flavor and nicotine increased the subjective effects of ECIGs.

CONCLUSIONS

Flavored e-liquids contribute to the reinforcing properties of nicotine by enhancing the subjective effects, which may lead to continued ECIG use.

Birth Outcomes Associated With E-Cigarette and Non-E-Cigarette Tobacco Product Use During Pregnancy: An Examination of PATH Data Waves 1-5

OBJECTIVES

To examine associations of prenatal e-cigarette use to pregnancy and birth outcomes.

METHODS

Currently pregnant women (n = 1 037) from Waves 1 through 4 of the Population Assessment of Tobacco and Health Study who had pregnancy or live birth outcome data in a subsequent wave (Waves 2-5; 2013 to 2019). Weighted bivariate and multivariable models\ examined associations between past 30-day tobacco use assessed during pregnancy (any past 30-day e-cigarette use, any past 30-day non-e-cigarette tobacco use, or no past 30-day tobacco use) with adverse pregnancy (miscarriage, abortion, ectopic or tubal pregnancy, stillbirth) and birth outcomes (preterm birth, low birth weight, birth defect, placenta previa, placental abruption, pre-eclampsia) reported in the subsequent wave.

RESULTS

Approximately 1% of pregnant women reported past 30-day exclusive e-cigarette use and 3.2% used e-cigarettes and one other tobacco product. Compared to no tobacco use, past 30-day e-cigarette use (exclusive or use with another tobacco product) during pregnancy was not associated with increased odds of an adverse pregnancy or birth outcome in bivariate or multivariable models. Past 30-day non-e-cigarette tobacco use was associated with increased odds of an adverse pregnancy outcome in multivariable models, but not an adverse live birth outcome. Compared to past 30-day cigarette use, past 30-day e-cigarette use during pregnancy was not associated with lowered odds of a birth or pregnancy outcome.

CONCLUSIONS

E-cigarette use during pregnancy is rare. Understanding the positive and negative impacts of pre-natal e-cigarette use on women's health may guide public health messaging campaigns.

IMPLICATIONS

Results showed that past 30-day e-cigarette use during pregnancy was low, with cigarette smoking remaining the most prevalent form of tobacco use during pregnancy. Current e-cigarette use during pregnancy used either exclusively or with another tobacco product, was not associated with increased risk of an adverse pregnancy, or birth outcome. A small sample size of e-cigarette users and limited information on quantity and frequency of e-cigarette use before and during pregnancy may limit conclusions. Healthcare providers may use this information when discussing the harms and consequences associated with e-cigarette and tobacco use during pregnancy.

Biomarkers of Electronic Nicotine Delivery Systems (ENDS) Use

This perspective summarizes available evidence on biomarkers of exposure in electronic nicotine delivery system (ENDS) users to aid the overall assessment of the health consequences of using ENDS. Identification of novel biomarkers of exposure specific to ENDS use remains challenging because chemicals emitted from ENDS devices have many familiar sources. The biomarker levels of many tobacco-related toxicants measured in biological samples collected from ENDS users did not differ significantly from non-users, except for nicotine metabolites and a small number of biomarkers of exposure to volatile organic compounds and tobacco-specific tobacco nitrosamines. Several studies have shown that while exposed to nicotine, long-term exclusive ENDS users showed significantly lower levels of toxicant biomarkers than cigarette smokers. Studies have also shown that concurrent users of ENDS and combustible cigarettes ('dual users') are not reducing overall exposure to harmful toxicants compared to exclusive cigarette smokers. Because of an absence of validated ENDS-specific biomarkers, we recommend combining several biomarkers to differentiate tobacco product user groups in population-based studies and monitor ENDS compliance in randomized controlled trials. Using a panel of biomarkers would provide a better understanding of health effects related to ENDS use.

Unintended Side Effects of Electronic Cigarettes in Otolaryngology: A Scoping Review

OBJECTIVE

Electronic cigarettes (E-cigs) are nicotine delivery systems with increasing popularity. The US Food and Drug Administration defines side effects as unwanted or unexpected events or reactions. Our objective was to examine the unintended otolaryngology-related side effects associated with E-cigs.

DATA SOURCES

Medline, EMBASE, CINAHL, Web of Science, and CENTRAL databases.

REVIEW METHODS

Study selection was independently performed by 2 authors in accordance with the PRISMA-ScR statement (Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews); discrepancies were resolved by the senior author. English studies from database inception to May 1, 2020, with a sample size >5 were included. In vitro, animal, and lower respiratory tract studies were excluded. The main outcome was defined as otolaryngology-related side effects following E-cig use. Levels of evidence per the Oxford Centre for Evidence-Based Medicine were used to determine study quality.

RESULTS

From 1788 articles, 32 studies were included. The most common unintended side effects were throat irritation (n = 16), cough (n = 16), mouth irritation (n = 11), and oral mucosal lesions (n = 8). A large proportion of participants also reported conventional tobacco use in addition to E-cigs. Eight studies investigated the effectiveness of vaping on smoking cessation. The quality of the literature was level 2 to 4. Given the significant heterogeneity in the studies, meta-analysis was not performed.

CONCLUSION

The most reported side effects were throat and mouth irritation, followed by cough. The long-term impact of E-cigs is not known given the recent emergence of this technology. Future studies are warranted.

Targeting ion channels for the treatment of lung cancer

Lung cancer is caused by several environmental and genetic variables and is globally associated with elevated morbidity and mortality. Among these variables, membrane-bound ion channels have a key role in regulating multiple signaling pathways in tumor cells and dysregulation of ion channel expression and function is closely related to proliferation, migration, and metastasis of lung cancer. This work reviews and summarizes current knowledge about the role of ion channels in lung cancer, focusing on the changes in the expression and function of various ion channels in lung cancer and how these changes affect lung cancer cell biology both in vitro and in vivo as evidenced by both genetic and pharmacological studies. It can help understand the molecular mechanisms of various ion channels influencing the initiation and progression of lung cancer and shed new insights into their roles in the development and treatment of this deadly disease.

Electronic cigarettes consumption and associated factors among general population in Western Saudi Arabia

Background: In recent years, consumption of e-cigarettes has increased dramatically. Several studies have focused on the prevalence of e-cigarettes among specific groups of people, using it as a substitute to traditional cigarettes, or the participant knowledge regarding risks. This research was aimed on E-cigarettes’ prevalence and its association to several factors in the general population of Western Saudi Arabia.

Design and methods: Using an observational cross-sectional study, data were collected from (n=465) above 18 years old smokers during the survey at public attractions. A validated self-administered questionnaire acquired from previous studies was employed to insure the suitability for the general population of Jeddah Saudi Arabia. Sample size was calculated via Raosoft^® and adults of either gender were included in the study. Descriptive or inferential statistical analysis was performed using SPSS.

Results: The preponderance of e-cigarette smokers used entertainment as the reason for smoking, with an average of (33.9%). Although one reason for e-cigarette consumption was to cease traditional smoking, results showed an average of (49.4%), which is the majority of those who attempted to cease traditional smoking via e-cigarette, did not succeed in quitting traditional smoking. This study also demonstrated that participant that believed that ecigarette is beneficial had a higher chance to cease conventional smoking than who did not (32.1% versus 14.6%) which is significant (p<0.001).

Conclusions: In conclusion, this study estimated the prevalence of e-cigarette consumption among the population of Jeddah, Saudi Arabia along with assessment of elements which help increase the overall e-cigarette consumption in Jeddah.

Nicotine-free vapor inhalation produces behavioral disruptions and anxiety-like behaviors in mice: Effects of puff duration, session length, sex, and flavor

Electronic-cigarette's (ECIGs) popularity has grown over the last decade and changed the way individuals administer nicotine. Preclinical research is imperative for understanding the addictive properties and health-risks associated with ECIG use; however, there is not a standard dosing regimen used across research laboratories. The main objective was to determine how vapor puff durations, administration session length, and flavored e-liquid alter general and mood-disorder related behaviors while providing a foundation of vapor administration parameters. Adult male and female C57BL/6 mice were exposed to several nicotine-free unflavored vapor puff durations (1, 3, 6, or 10 s) and vapor administration session lengths (10 and 30 min) then measured on the following assays: locomotor activity (LMA), tail suspension test (TST), and light-dark test. The effects of mecamylamine and the time-course of vapor-induced depression of LMA also were assessed. Additionally, mice were exposed to flavored (strawberry and adventurers tobacco blend) vapor inhalation and measured on locomotor activity, tail suspension test, and light-dark test. Following both 10 and 30 min vapor administration session, there was a puff duration-dependent decrease in distance traveled, time in center, and rearing. The vapor-induced depression of LMA was not mediated by nicotine or nicotinic acetylcholine receptor (nAChR) activation and lasted 60-90 min. The 10 s puff duration produced an anxiogenic-like effect in the light-dark test by decreasing the time spent in the light side. Vapor inhalation did not significantly alter TST behavior. No significant effects of sex or flavor were found. The anxiogenic-like effects of nicotine-free vapor inhalation are concerning as many adolescents vape nicotine-free flavored e-liquid, and there is an association between ECIGs and mood disorders. Additionally, these studies demonstrate that vapor puff duration, but not vapor administration session length, is an important variable to consider during research design as it can become a confounding variable and alter baseline behaviors.

Nicotinic α7 acetylcholine receptor (α7nAChR) in human airway smooth muscle

Diseases such as asthma are exacerbated by inflammation, cigarette smoke and even nicotine delivery devices such as e-cigarettes. However, there is currently little information on how nicotine affects airways, particularly in humans, and changes in the context of inflammation or asthma. Here, a longstanding assumption is that airway smooth muscle (ASM) that is key to bronchoconstriction has muscarinic receptors while nicotinic receptors (nAChRs) are only on airway neurons. In this study, we tested the hypothesis that human ASM expresses α7nAChR and explored its profile in inflammation and asthma using ASM of non-asthmatics vs. mild-moderate asthmatics. mRNA and western analysis showed the α7 subunit is most expressed in ASM cells and further increased in asthmatics and smokers, or by exposure to nicotine, cigarette smoke or pro-inflammatory cytokines TNFα and IL-13. In these effects, signaling pathways relevant to asthma such as NFκB, AP-1 and CREB are involved. These novel data demonstrate the expression of α7nAChR in human ASM and suggest their potential role in asthma pathophysiology in the context of nicotine exposure.

Toxicological assessment of electronic cigarette vaping: an emerging threat to force health, readiness and resilience in the U.S. Army

The U.S. Army and U. S. Army Public Health Center are dedicated to protecting the health, and readiness of Department of the Army Service Members, civilians, and contractors. Despite implementation of health programs, policies and tobacco control interventions, the advent of electronic nicotine delivery systems (ENDS), including electronic cigarettes (e-cigs), represent unregulated and poorly defined systems to supplant or substitute use of conventional nicotine products (e.g., cigarettes and pipe tobacco). E-cigs present unique challenges to healthcare officials vested in preventive medicine. The health impact of an e-cig and vaping on an individual's acute or chronic disease susceptibility, performance and wellness, is fraught with uncertainty. Given the relatively recent emergence of e-cigs, high-quality epidemiological studies, and applied biological research studies are severely lacking. In sparsely available epidemiological studies of short-term cardiovascular and respiratory health outcomes, any attempt at addressing the etiology of acute and chronic health conditions from e-cig use faces incredible challenges. Until relatively recently, this was complicated by an absent national regulatory framework and health agency guidance on the manufacture, distribution, selling and use of e-cigs or similar ENDS devices and their chemical constituents. Two key issues underpin public health concern from e-cig use: 1) continued or emergent nicotine addiction and potential use of these devices for vaping controlled substances; and 2) inadvertent sudden-onset or chronic health effects from inhalational exposure to low levels of complex chemical toxicants from e-cig use and vaping the liquid. Herein, the health impacts from e-cig vaping and research supporting such effects are discussed.

Critical appraisal of the European Union Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) Preliminary Opinion on electronic cigarettes

BACKGROUND

In preparation for the 2021 revision of the European Union Tobacco Products Directive, the Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) has posted its Preliminary Opinion on Electronic Cigarettes. They concluded that e-cigarettes only achieve a sub-optimal level of protection of human health. In this paper, we provide evidence that the Opinion's conclusions are not adequately backed up by scientific evidence and did not discuss the potential health benefits of using alternative combustion-free nicotine-containing products as substitute for tobacco cigarettes.

METHODS

Searches for articles were conducted in PubMed and by citation chasing in Google Scholar. Articles were also retrieved with a review of references in major publications. Primary data from World Health Organization surveys, the conclusions of reviews, and peer-reviewed non-industry studies were cited to address errors and omissions identified in the Opinion.

RESULTS

The Opinion omitted reporting on the individual and population health benefits of the substitution of e-cigarettes (ENDS) for cigarette smoking. Alternative hypotheses to the gateway theory were not evaluated. Its assessment of cardiovascular risk is contradicted by numerous reviews. It cites ever-use data that do not represent current patterns of use. It did not report non-nicotine use. It presented erroneous statements on trends in ENDS prevalence. It over-emphasized the role of flavours in youth ENDS initiation. It did not discuss cessation in sufficient length.

CONCLUSIONS

For the delivery of a robust and comprehensive final report, the members of the Working Group of the Scientific Committee on Health, Environmental and Emerging Risks will need to consider (1) the potential health benefits of ENDS substitution for cigarette smoking, (2) alternative hypotheses and contradictory studies on the gateway effect, (3) its assessment of cardiovascular risk, (4) the measurements of frequency of use, (5) non-nicotine use, (6) the role of flavours, and (7) a fulsome discussion of cessation.

Factors associated with smoking susceptibility among high school students in western Spain

The Expanded Susceptibility to Smoking Index (ESSI) is based on the combination of susceptibility to smoking and curiosity about smoking. The ESSI can identify young people who are at risk of starting to smoke cigarettes and related products. The objective of this study was to analyse the ESSI results and to examine factors associated with ESSI scores in students between 12 and 16 years of age. Sociodemographic, social/environmental and personal variables were analysed, and the ESSI value was determined for non-smoking students recruited from three schools in western Spain. Regression models were used to examine the factors associated with smoking for the entire sample and the factors associated with ESSI scores in the non-smoking population. Of the 377 participants who were analysed, 20.4% were smokers. Among the non-smokers, 53.5% and 55.3% presented medium-high ESSI scores for cigarettes and e-cigarettes, respectively, and 39.8% presented medium-high ESSI scores for hookah use. A higher ESSI score was associated with greater exposure to people smoking in the home, having more friends who smoke, alcohol consumption, and a higher impulsivity scale score. These findings reinforce the importance of reducing peer pressure and suggest the important role of resolve under conditions of positive affect on reducing impulsivity. Approaches based on self-efficacy could be addressed in preventive programmes developed in educational settings.

Worry and e-cigarette cognition: The moderating role of sex

As electronic cigarette (e-cigarette) use continues to rise, it is important to identify individual characteristics that may influence e-cigarette use behavior and potential group-level moderators of effects, such as sex. Initial evidence has suggested that worry, defined as excessive, unrealistic thoughts focused on the possibility of future negative events, may contribute to e-cigarette use behavior. Yet, how these established relations differ across groups, such as male and female e-cigarette users, has not been explored. The present study evaluated the effect of worry on perceived barriers for quitting e-cigarettes, perceptions of benefits for e-cigarette use, and perceived negative consequences of e-cigarette use across sex. The sample included 584 current e-cigarette users (52.2% female, M_age = 35.15 years, SD = 10.27). Analyses indicated a significant interaction between sex and worry on each criterion variable (perceived benefits: b = 0.02, SE = 0.01, t = -2.73, p = .01; perceived barriers for quitting e-cigarettes: b = -0.45, SE = 0.08, t = -5.70, p ≤ 0.001; negative consequences to use: b = -0.033, SE = 0.01, t = -4.50, p < .001), such that worry was more strongly related to each outcome among males than females. These findings suggest that sex plays a role in e-cigarette use behaviors and that males may constitute a group that is especially vulnerable to the effects of worry on both positive and negative e-cigarette use perceptions and perceived barriers for quitting e-cigarettes.

A review of the analysis of biomarkers of exposure to tobacco and vaping products

Quantification of exposure to different chemicals from both combustible cigarettes and vaping products is important in providing information on the potential health risks of these products. To assess the exposure to tobacco products, biomarkers of exposure (BOEs) are measured in a variety of biological matrices. In this review paper, current knowledge on analytical methods applied to the analysis of biomarkers of exposure to tobacco products is discussed. Numerous sample preparation techniques are available for the extraction and sample clean up for the analysis of BOEs to tobacco and nicotine delivery products. Many tobacco products-related exposure biomarkers have been analyzed using different instrumental techniques, the most common techniques being gas and liquid chromatography coupled with mass spectrometry (GC-MS, GC-MS/MS and LC-MS/MS). To assess exposure to emerging tobacco products and study exposure in dual tobacco users, the list of biomarkers analyzed in urine samples has been expanded. Therefore, the current state of the literature can be used in preparing a preferred list of biomarkers based on the aim of each study. The information summarized in this review is expected to be a handy tool for researchers involved in studying exposures to tobacco products, as well as in risk assessment of biomarkers of exposure to vaping products.

Where college students look for vaping information and what information they believe

Objective: This convergent mixed methods study examined how information sources influence college students' beliefs and knowledge about vaping. Participants: College students either completed a survey (n = 522; January-April, 2016) or were interviewed (n = 33; 2015-2016). Methods: College students completed an online survey asking 'where' students had heard about e-cigarette and 'what' they had heard. Responses were quantified and a chi-square analysis was conducted. Additional college student e-cigarette users were interviewed about the credibility of information sources. Thematic analysis was conducted with the coded interviews. Results: There was a significant relationship between information sources for e-cigarettes (social sources, media, advertising, education/research) and the messages they recalled. Friends who vaped and e-cigarette users were the most credible information sources. Confirmation bias and scientific impotence bias characterized assessment of e-cigarette information. Conclusions: Health education specialists working on college campuses should provide accurate information via communication channels most unitized by college students.

Biomarkers of Tobacco Exposure Decrease After Smokers Switch to an E-Cigarette or Nicotine Gum

Introduction

The aerosol composition of electronic cigarettes (ECs) suggests that exposure to toxicants during use is greatly reduced compared to exposure from combustible cigarettes (CCs).

Methods

This randomized, parallel-group, clinical study enrolled smokers to switch to Vuse Solo (VS) Digital Vapor Cigarettes (Original or Menthol) or Nicorette 4 mg nicotine gum (NG) in a controlled setting. Subjects who smoked CCs ad libitum for 2 days during a baseline period were then randomized to ad libitum use of either VS or NG for 5 days. Biomarkers of 23 toxicants were measured in 24-hour urine samples and blood collected at baseline and following product switch.

Results

A total of 153 subjects completed the study. Total nicotine equivalents decreased in all groups, but higher levels were observed in the VS groups compared to the NG groups, with decreases of 38% and 60%–67%, respectively. All other biomarkers were significantly decreased in subjects switched to VS, and the magnitude of biomarker decreases was similar to subjects switched to NG. Decreases ranged from 30% to greater than 85% for constituents such as benzene and acrylonitrile.

Conclusions

These results indicate that exposure to toxicants when using VS is significantly reduced compared to CC smoking, and these reductions are similar to those observed with use of NG. Although statistically significantly decreased, nicotine exposure is maintained closer to CC smoking with VS use compared to NG use. This research suggests that use of VS exposes consumers to fewer and lower levels of smoke toxicants than CCs while still providing nicotine to the consumer.

Implications

This is the first study to report changes in nicotine delivery and biomarkers of tobacco exposure following a short-term product switch from CCs to either an EC or NG in a controlled environment. The study shows that nicotine exposure decreased in both groups but was maintained closer to CC smoking with the EC groups. Biomarkers of tobacco combustion decreased to similar levels in both EC and gum groups.

Vaping, Smoking, and the Physical Fitness of Active Young Men

INTRODUCTION

Adverse effects of cigarette smoking on physical performance are well studied. Because of the recent rise in popularity of vaping, it is important to evaluate its effect on fitness both independently and in conjunction with traditional cigarette use.

METHODS

This was a secondary analysis performed in 2018 on data collected from U.S. Army Soldiers during 2016. All metrics were self-reported via an electronic questionnaire. Personal characteristics of current ENDS users, smokers, and dual users were compared with a reference group that reported no history of use. Adjusting for age and physical training habits, an ANCOVA was used to compare Army physical fitness test results. A Fisher's exact test determined specific mean differences between groups.

RESULTS

This study population consisted of 2,854 men aged 24.6 years on average. Differences in physical training and fitness were shown between the groups. Never users averaged the most total physical training, followed by ENDS users, smokers, and then dual users. Compared with never users on the fitness tests, ENDS users had an adjusted mean difference of +27 seconds on the 2-mile run, -4.56 push-ups, and -2.01 sit-ups; smokers averaged +8 seconds, -2.15 push-ups, and -1.44 sit-ups; and dual users averaged +32 seconds, -5.17 push-ups, and -3.88 sit-ups. Dual users had significantly (p<0.05) lower scores than current smokers and never users on all 3 fitness events.

CONCLUSIONS

This study suggests that individuals who use e-cigarettes and tobacco cigarettes average a lower level of fitness than individuals who abstain.

Non-nicotine constituents in e-cigarette aerosol extract attenuate nicotine's aversive effects in adolescent rats

BACKGROUND

Development of preclinical methodology for evaluating the abuse liability of electronic cigarettes (ECs) in adolescents is urgently needed to inform FDA regulation of these products. We previously reported reduced aversive effects of EC liquids containing nicotine and a range of non-nicotine constituents (e.g., propylene glycol, minor tobacco alkaloids) compared to nicotine alone in adult rats as measured using intracranial self-stimulation. The goal of this study was to compare the aversive effects of nicotine alone and EC aerosol extracts in adolescent rats as measured using conditioned taste aversion (CTA), which can be conducted during the brief adolescent period.

METHODS AND RESULTS

In Experiment 1, nicotine alone (1.0 or 1.5 mg/kg, s.c.) produced significant CTA in adolescent rats in a two-bottle procedure, thereby establishing a model to study the effects of EC extracts. At a nicotine dose of 1.0 mg/kg, CTA to Vuse Menthol EC extract, but not Aroma E-Juice EC extract, was attenuated compared to nicotine alone during repeated two-bottle CTA tests (Experiment 2a). At a nicotine dose of 0.5 mg/kg, CTA to Vuse Menthol EC extract did not differ from nicotine alone during the first two-bottle CTA test but extinguished more rapidly across repeated two-bottle tests (Experiment 2b).

CONCLUSIONS

Non-nicotine constituents in Vuse Menthol EC extracts attenuated CTA in a two-bottle procedure in adolescents. This model may be useful for anticipating the abuse liability of ECs in adolescents and for modeling FDA-mandated changes in product standards for nicotine or other constituents in ECs.

Abuse liability assessment of an electronic cigarette in combustible cigarette smokers

Under certain conditions, electronic cigarettes (e-cigs) can deliver nicotine to and suppress tobacco abstinence symptoms in cigarette smokers. Growing popularity of e-cigs raises abuse liability concerns. This study's purpose was to compare the abuse liability of an e-cig (1.5 Ohm, 3.3 V) filled with 36 mg/mL or 0 mg/mL nicotine to an Food and Drug Administration (FDA)-approved nicotine inhaler (IN) and participants' own brand (OB) of cigarettes. Smokers (N = 24) completed four sessions in which they completed the multiple-choice procedure, and plasma nicotine concentration and subjective effects were measured. Mean (SD) multiple-choice procedure crossover point was $0.87 (1.0) for the 36-mg/mL nicotine e-cig and $0.96 (1.2) for the 0-mg/mL e-cig, significantly higher than the IN mean of $0.32 (0.6) but significantly lower than the OB cigarette mean of $1.42 (1.4). Ten puffs from an own-brand cigarette increased mean plasma nicotine concentration from 3.55 (2.8) to 13.64 (9.8) ng/mL, as compared to an increase from 3.16 (1.8) to 8.51 (5.4) ng/mL for the 36-mg/mL e-cig. The 36-mg/mL e-cig reduced nicotine abstinence symptoms more than the 0-mg/mL e-cig, and both e-cigs were rated as more reinforcing than the inhaler but less reinforcing than participants' OB cigarettes (ps < .05). Results suggest that the e-cig examined had higher abuse liability than the IN but lower than combustible cigarettes. These data and methods may be useful for policymakers by revealing how e-cig abuse liability compares to tobacco/nicotine products with abuse liability profiles that are well established. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

An Examination of the Variation in Estimates of E-Cigarette Prevalence among U.S. Adults

Introduction: Accurate estimates of e-cigarette use are needed to gauge its impact on public health. We compared the results of online and traditional, large scale surveys and provide additional estimates from the Population Assessment of Tobacco and Health (PATH) survey, with the aim of assessing the extent of variation in prevalence estimates. Materials and Methods: We searched the peer-reviewed literature for nationally representative estimates of U.S. adult e-cigarette prevalence, and developed our own estimates from waves one, two, and three of the PATH survey. We compared estimates by age, gender, cigarette smoking status, and e-cigarette use intensity both between online and traditional surveys and among the traditional surveys. Results: For specific years, online surveys generally yielded higher adult use rates than most traditional surveys, but considerable variation was found among traditional surveys. E-cigarette prevalence was greater for less intensive than for more intensive use. Levels of use were higher among current and recent former cigarette smokers than among former smokers of longer quit duration and never smokers, and by those of younger ages. Conclusions: Considerable variation in e-cigarette use estimates was observed even for a specific year. Further study is needed to uncover the source of variation in e-cigarette prevalence measures, with a view towards developing measures that best explain regular use and transitions between the use of e-cigarettes and other tobacco products.

The relationship between nicotine metabolism and nicotine and carcinogen exposure among American Indian commercial cigarette smokers and electronic nicotine delivery system users

BACKGROUND

In American Indian (AI) tobacco users from the southern plains region of the US, we examined the relationship between nicotine and carcinogen exposure and nicotine metabolism.

METHODS

Smokers (n = 27), electronic nicotine delivery system (ENDS) users (n = 21), and dual users (n = 25) of AI descent were recruited from a southern plains state. Urinary biomarkers of nicotine metabolism (nicotine metabolite ratio [NMR]), nicotine dose (total nicotine equivalents [TNE]), and a tobacco-specific lung carcinogen (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides [total NNAL] were measured.

RESULTS

The geometric mean of NMR was 3.35 (95% Confidence Interval(CI): 2.42, 4.65), 4.67 (95% CI: 3.39, 6.43), and 3.26 (95% CI: 2.44, 4.37) among smokers, ENDS users, and dual users. Each of the three user groups had relatively low levels of TNE, indicative of light tobacco use. Among smokers, there were inverse relationships between NMR and TNE (r = -0.45) and between NMR and NNAL (r = -0.50). Among dual users, NMR and TNE, and NMR and NNAL were not associated. Among ENDS users, NMR and TNE were not associated.

CONCLUSIONS

AI tobacco users with higher NMR did not have higher TNE or NNAL exposure than those with lower NMR. This supports prior work among light tobacco users who do not alter their tobacco consumption to account for nicotine metabolism.

IMPACT

The high prevalences of smoking and ENDS among AI in the southern plains may not be related to nicotine metabolism. Environmental and social cues may play a more important role in light tobacco users and this may be particularly true among AI light tobacco users who have strong cultural ties.

Prospective study of dual use of e-cigarettes and other tobacco products among school-going youth in rural Appalachian Tennessee

INTRODUCTION

E-cigarettes have emerged as the most commonly used tobacco or nicotine products among youth in the United States (US), and usage with other products (dual use) is not well understood. This study assessed dual use and identified associated factors of usage in school-going youth in the high tobacco burdened region of rural Appalachian Tennessee.

METHODS

Two waves of data for the same cohort of students were collected in 2014 (Wave 1) and 2016 (Wave 2). Dual use of e-cigarettes with any other tobacco product was the dependent variable. The independent variables consisted of exposure to tobacco use at home, home smoking rules, smoking inside the vehicle, attitudes toward smoking, exposure to tobacco industry marketing/promotion, and peer/family pressure. Descriptive statistics and multivariate logistic regression analyses were conducted to determine the prevalence of dual use and delineate factors associated with usage.

RESULTS

Dual use increased from 13.3% in Wave 1 to 18.6% in Wave 2. Results of logistic regression show that exposure to tobacco industry marketing/promotion was significantly associated with dual use in the two waves, odds ratio (OR) = 4.18 (confidence interval [CI] = 1.69-10.38) and OR = 4.43 (CI = 2.03-9.67), respectively. While allowing smoking inside the vehicles, sometimes, significantly increased dual use in Wave 1 (OR = 3.18 [CI = 1.19-8.48]), exposure to tobacco use at home (OR = 2.94 [1.24-6.97]), and peer/family pressure (OR = 2.92 [1.87-7.19]) increased usage in Wave 2.

CONCLUSION

The increasing trend in dual use of e-cigarettes and other tobacco products among youth in Appalachia Tennessee suggests a critical need for comprehensive tobacco control programs to avert exacerbating disparities in tobacco use and tobacco-related diseases in the US.

Longitudinal Tobacco Use Transitions Among Adolescents and Young Adults: 2014-2016

INTRODUCTION

Among youth, the frequency and prevalence of using more than one tobacco (small cigar, cigarette, and hookah) or nicotine-containing product (e-cigarettes-ENDS) are changing. These shifts pose challenges for regulation, intervention, and prevention campaigns because of scant longitudinal data on the stability of use patterns in this changing product landscape.

METHODS

A nationally representative longitudinal survey of 15- to 21-year olds (n = 15,275) was used to describe transitions between never use, noncurrent use, and past 30-day use of combustible tobacco, e-cigarettes (ENDS), and dual use of both kinds of products. A multistate model was fit to observations collected every 6 months across 2.5 years to estimate the probability of transitions between states (TPs), the average time in state (sojourn time), and the effect of age on transitions.

RESULTS

Current state strongly predicted future state over time intervals of 1 year or less, but only weakly predicted future state at longer intervals: TP to noncurrent use was higher for ENDS-only than combustible-only users over a 6-month interval but was similar for both groups over a 2-year interval. Sojourn time was significantly longer for combustible-only (0.52 years) and dual use (0.55 years) than ENDS-only use (0.27 years); older youth were more likely than younger youth to stay combustible tobacco users or noncurrent users.

CONCLUSIONS

The dynamics of transitions between combustible tobacco products and ENDS in a population of youth and young adults suggest that policy and prevention efforts must consider the frequent changes and instability over a 1-year or less time period in use patterns among young people.

IMPLICATIONS

The study addresses an urgent need in public health for timely information on how youth and young adults use tobacco and nicotine products. We found that youth, particularly adolescents, moved frequently between using ENDS and combustible tobacco products either alone or together. Importantly, the utility of current-use states for predicting future use states declined for time horizons longer than 1 year. Our results demonstrate a need for caution in interpreting product transitions. Longitudinal data with frequent observations and coverage of a wide range of possible product types is required to fully characterize usage patterns in youth.

E-cigarettes and Atherosclerotic Cardiovascular Disease: What Clinicians and Researchers Need to Know

PURPOSE OF REVIEW

Electronic cigarettes, commonly known as electronic nicotine delivery systems (ENDS), e-cigarettes, or vapes, are growing in use and popularity. E-cigarettes are not one distinct type of product. These devices have evolved from the initial "cigarette-alike" designs to larger tank-style devices and most recently, smaller "mod-pods" that can be easily hidden. E-cigarettes can deliver nicotine at levels similar to conventional cigarettes.

RECENT FINDINGS

As with conventional cigarettes, e-cigarettes expose users to chemicals and particulates that affect many biological systems including the heart, lungs, and circulation. Most e-cigarettes contain and emit potentially toxic but highly variable substances. Only by using them in total abstinence from combustible tobacco products can users reduce (not eliminate) their exposure to these harmful chemicals. However, most adults smoking e-cigarettes are dual users, meaning they smoke both conventional and e-cigarettes. This review of the current cardiovascular-specific literature related to e-cigarette use explores what is known (and unknown) about the short- and long-term effects of using these devices. Specifically, the effects of nicotine, oxidizing agents, and particulates in e-cigarettes are examined in the context of cardiovascular and lung health. The goal is to assist clinicians when discussing e-cigarettes with their patients and to help them analyze the impact of use on cardiovascular health. Recommendations are provided related to clinical treatment and research to address gaps in the literature.

Are we guilty of errors of omission on the potential role of electronic nicotine delivery systems as less harmful substitutes for combusted tobacco use?

Two of the more controversial tobacco control and regulatory strategies in recent years are the nicotine reduction and tobacco harm reduction (THR) strategies. They have become inextricably intertwined as a successful nicotine reduction policy might only be possible in an environment in which alternative, noncombusted forms of nicotine like electronic nicotine delivery systems (ENDS) are available to address the needs of those who were unable or unwilling to completely give up nicotine. Unfortunately, ENDS have emerged as particularly controversial, in part, because they are the first product to carry reduced risk potential while being broadly appealing to cigarette smokers across demographic groups and subpopulations, and to a much smaller extent nonsmokers including, and most controversial, adolescents. In an effort to better understand some of the reasons that make this a controversial topic, we review some of the relevant history and discuss a broader dilemma that faces practitioners and policy developers of medical and public health interventions, namely, weighing the potential consequences of errors of commission versus omission. Commission errors involve a salient, direct link between an action and associated adverse or unintended consequences while omission errors are typically less salient with a more indirect link between inaction and associated adverse consequences. Decision-making research demonstrates that humans have a bias towards avoidance of commission errors and insensitivity to omission errors. This bias may be contributing to some of the aforementioned difficulties in finding common ground regarding the potential contribution of ENDS to reducing the harm of combusted tobacco use.

Regulation of Sox2 and stemness by nicotine and electronic-cigarettes in non-small cell lung cancer

Background

Lung cancer is the leading cause of cancer related deaths and its incidence is highly correlated with cigarette smoking. Nicotine, the addictive component of tobacco smoke, cannot initiate tumors, but can promote proliferation, migration, and invasion of cells in vitro and promote tumor growth and metastasis in vivo. This nicotine-mediated tumor promotion is facilitated through the activation of nicotinic acetylcholine receptors (nAChRs), specifically the α7 subunit. More recently, nicotine has been implicated in promoting self-renewal of stem-like side-population cells from lung cancers. This subpopulation of cancer stem-like cells has been implicated in tumor initiation, generation of the heterogeneous tumor population, metastasis, dormancy, and drug resistance. Here we describe the molecular events driving nicotine and e-cigarette extract mediated stimulation of self-renewal of stem-like cells from non-small cell lung cancer.

Methods

Experiments were conducted using A549 and H1650 non-small cell lung cancer cell lines and human mesenchymal stem cells according to protocols described in this paper. 2 μM nicotine or e-cigarette extracts was used in all relevant experiments. Biochemical analysis using western blotting, transient transfections, RT-PCR and cell biological analysis using double immunofluorescence and confocal microscopy, as well as proximity ligation assays were conducted.

Results

Here we demonstrate that nicotine can induce the expression of embryonic stem cell factor Sox2, which is indispensable for self-renewal and maintenance of stem cell properties in non-small cell lung adenocarcinoma (NSCLC) cells. We further demonstrate that this occurs through a nAChR-Yap1-E2F1 signaling axis downstream of Src and Yes kinases. Our data suggests Oct4 may also play a role in this process. Over the past few years, electronic cigarettes (e-cigarettes) have been promoted as healthier alternatives to traditional cigarette smoking as they do not contain tobacco; however, they do still contain nicotine. Hence we have investigated whether e-cigarette extracts can enhance tumor promoting properties similar to nicotine; we find that they can induce expression of Sox2 as well as mesenchymal markers and enhance migration and stemness of NSCLC cells.

Conclusions

Our findings shed light on novel molecular mechanisms underlying the pathophysiology of smoking-related lung cancer in the context of cancer stem cell populations, and reveal new pathways involved that could potentially be exploited therapeutically.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0901-2) contains supplementary material, which is available to authorized users.

Using the Ecological Model to understand influences on college student vaping

Objective The Ecological Model was used to examine the social and environmental influences of the college environment on e-cigarette use (vaping) among college students.

PARTICIPANTS

Undergraduate college student e-cigarette users (vapers) across three large college campuses in the southwest US from Jan 2015- Aug 2016.

METHODS

Thirty-three interviews were conducted. Transcribed interviews were coded then analyzed for themes.

RESULTS

College student vapers report multiple levels of influence on their vaping beyond personal beliefs and peer influences, including parents, explicit campus and community messaging, community member requests, and respect for others. College student vapers also describe constant associations with smokers in allowable public places to vape.

CONCLUSIONS

Parents, community members, campus policy, and the physical environment all influence where and when college students vape. Health communication messages to prevent college student vaping should incorporate alternative messages that are important to college students, such as respect for others and social image.

Characterization of puff topography of a prototype electronic cigarette in adult exclusive cigarette smokers and adult exclusive electronic cigarette users

Puff topography is an important measure of how consumers use e-vapor products. The purpose of this study was to evaluate the feasibility of using SODIM Smoking Puff Analyzer Mobile Device (SPA/M) to measure puff topography during use of a prototype e-cigarette (e-cig) in exclusive cigarette smokers (CS) and e-cig users (EC) under ad lib conditions in a clinic. Adult CS (n = 13) and EC (EC; n = 10) completed a 7-hr use session with the e-cig (2% tobacco-derived nicotine by weight, cartridge based system approximately the size of a king size cigarette). E-liquid usage was determined from cartridge weight. CS also smoked a single cigarette with the SPA/M. The SPA/M reliably recorded puff parameters throughout the study period, with CS puffs averaging 47.9 ± 18.2 ml volume, 2.3 ± 0.8 s duration, and 21.5 ± 4.6 ml/s flow rate. EC puffs averaged 53.4 ± 19.2 ml volume, 3.0 ± 1.3 s duration, and 19.6 ± 5.0 flow rate. CS average e-liquid use was 292 ± 214 mg and EC averaged 415 ± 305 mg over 7 h. When compared to a single use of their own brand cigarettes, CS took longer (2.3 ± 0.8 vs.1.7 ± 0.4 s) puffs with similar puff volume (47.9 ± 18.2 vs. 44.1 ± 10.5 ml) from the e-cig prototype. The puff duration, flow rate and peak flow were significantly lower (p < 0.05) with the e-cigs compared to cigarettes. Experienced EC and CS appeared to use the e-cig prototype differently, which is consistent with the literature. The SPA/M could be a useful tool in assessing e-cig use behavior for regulatory purposes.

Differences in vaping topography in relation to adherence to exclusive electronic cigarette use in veterans

Background

Understanding vaping patterns of electronic cigarette (EC) use is important to understand the real-life exposure to EC vapor. Long term information on vaping topography in relation to tobacco cigarette (TC) smoking cessation success has not been explored.

Methods

Observational non-blinded study where active TC smokers were asked to replace TC with EC over 4 weeks (replacement phase, RP) followed by exclusive EC use for an additional 12 weeks (maintenance phase, MP). TC use and EC compliance was monitored weekly. Subjects were classified as success or failure whether or not they completed the protocol. Vaping information was stored and downloaded directly from the EC device and averaged per calendar day for analysis.

Results

From 25 subjects that followed the protocol, sixteen succeeded in completing the RP and 8 the MP (32%). No significant differences in baseline characteristics were noted between subjects in the success and failure groups including markers of nicotine addiction, plasma cotinine levels or smoking history. Success subjects showed significantly longer puff duration (seconds per vape) and total overall vapor exposure (number of vapes x average vape duration or vape-seconds) in both study phases. Furthermore, subjects in the success group continued to increase the number of vapes, device voltage and wattage significantly as they transitioned into the MP. After an initial drop, subjects in the success group were able to regain plasma cotinine levels comparable to their TC use while subjects in the failure group could not. Cotinine levels significantly correlated with the average number of daily vapes and vapes-seconds, but not with other vaping parameters.

Conclusion

The topography of smokers who adhere to exclusive EC use reflects a progressive and dynamic device adaptation over weeks to maintain baseline cotinine levels. The higher inhaled volume over time should be considered when addressing the potential toxic effects of EC and the variable EC adherence when addressing public health policies regarding their use.

Pennsylvania policymakers' knowledge, attitudes and likelihood for action regarding waterpipe tobacco smoking and electronic nicotine delivery systems

INTRODUCTION

Use of waterpipe tobacco smoking (WTS, or hookah smoking) and electronic nicotine delivery systems (ENDS, such as e-cigarettes) is rapidly increasing. However, legislatures have been slow to update policy measures related to them. Therefore, we aimed to assess knowledge, attitudes and likelihood to take future action regarding WTS and ENDS among Pennsylvania legislators.

METHODS

We approached all Standing Members of key Pennsylvania House and Senate health and welfare committees to complete a survey about substances of abuse, including WTS and ENDS. Closed-ended knowledge, attitude and action items used a 100-point scale. Responses to open-ended items were assessed using thematic analysis by three independently working researchers.

RESULTS

We received responses from 13 of 27 eligible policymakers (48%). Participants answered a mean of only 27% (SD=20%) of knowledge items correctly. When asked to rank by priority eight issues in substance abuse, WTS ranked eighth (least urgent) and ENDS ranked fifth. Participants reported low likelihood to introduce legislation on WTS (mean=29, median=25) and/or ENDS (mean=28, median=10). Thematic analysis revealed that participants readily acknowledged lack of understanding of WTS and ENDS, and were eager for additional information.

CONCLUSIONS

Policymakers exhibit a lack of knowledge concerning newer forms of tobacco and nicotine delivery systems and consider them to be relatively low legislative priorities. However, respondents expressed a desire for more information, suggesting the potential for public health entities to promote effective policy development via improved dissemination of information.

Establishing consensus on survey measures for electronic nicotine and non-nicotine delivery system use: Current challenges and considerations for researchers

The development and validation of survey measures for electronic nicotine and non-nicotine delivery system (ENDS) use has not kept pace with the burgeoning research on them. This, along with the diverse and evolving nature of ENDS, presents several unique measurement challenges and hampers surveillance and tobacco regulatory research efforts. In this commentary, we identify four important areas related to ENDS use (describing ENDS products; defining current use; evaluating frequency and quantity of use; and characterizing devices and e-liquids) and summarize a selective review of the measurement and definitions of these constructs across prominent national tobacco use surveys and 30 projects within the 14 federally-funded Tobacco Centers of Regulatory Science. Across these national, regional, and local studies, there was considerable variability and relatively little consensus in ENDS use measures - thus highlighting the need for caution when comparing findings across studies or over time until more research is available to evaluate the sensitivity of findings to differing measures. Drawing from the nascent ENDS use measurement research literature and our experiences, we conclude with general considerations for measuring ENDS use for tobacco researchers as an initial step towards the development of consensus measures.

Harm Minimization and Tobacco Control: Reframing Societal Views of Nicotine Use to Rapidly Save Lives

Inhalation of the toxic smoke produced by combusting tobacco products, primarily cigarettes, is the overwhelming cause of tobacco-related disease and death in the United States and globally. A diverse class of alternative nicotine delivery systems (ANDS) has recently been developed that do not combust tobacco and are substantially less harmful than cigarettes. ANDS have the potential to disrupt the 120-year dominance of the cigarette and challenge the field on how the tobacco pandemic could be reversed if nicotine is decoupled from lethal inhaled smoke. ANDS may provide a means to compete with, and even replace, combusted cigarette use, saving more lives more rapidly than previously possible. On the basis of the scientific evidence on ANDS, we explore benefits and harms to public health to guide practice, policy, and regulation. A reframing of societal nicotine use through the lens of harm minimization is an extraordinary opportunity to enhance the impact of tobacco control efforts.

Effects of nicotine-containing and "nicotine-free" e-cigarette refill liquids on intracranial self-stimulation in rats

BACKGROUND

Animal models are needed to inform FDA regulation of electronic cigarettes (ECs) because they avoid limitations associated with human studies. We previously reported that an EC refill liquid produced less aversive/anhedonic effects at a high nicotine dose than nicotine alone as measured by elevations in intracranial self-stimulation (ICSS) thresholds, which may reflect the presence of behaviorally active non-nicotine constituents (e.g., propylene glycol) in the EC liquids. The primary objective of this study was to assess the generality of our prior ICSS findings to two additional EC liquids. We also compared effects of "nicotine-free" varieties of these EC liquids on ICSS, as well as binding affinity and/or functional activity of nicotine alone, nicotine-containing EC liquids, and "nicotine-free" EC liquids at nicotinic acetylcholine receptors (nAChRs).

METHODS AND RESULTS

Nicotine alone and nicotine dose-equivalent concentrations of both nicotine-containing EC liquids produced similar lowering of ICSS thresholds at low to moderate nicotine doses, indicating similar reinforcement-enhancing effects. At high nicotine doses, nicotine alone elevated ICSS thresholds (a measure of anhedonia-like behavior) while the EC liquids did not. Nicotine-containing EC liquids did not differ from nicotine alone in terms of binding affinity or functional activity at nAChRs. "Nicotine-free" EC liquids did not affect ICSS, but bound with low affinity at some (e.g., α4ß2) nAChRs.

CONCLUSIONS

These findings suggest that non-nicotine constituents in these EC liquids do not contribute to their reinforcement-enhancing effects. However, they may attenuate nicotine's acute aversive/anhedonic and/or toxic effects, which may moderate the abuse liability and/or toxicity of ECs.

Initiation of Traditional Cigarette Smoking after Electronic Cigarette Use Among Tobacco-Naïve US Young Adults

BACKGROUND

Although electronic cigarettes (e-cigarettes) may help some smokers quit, some young adult never-smokers are now using e-cigarettes recreationally, potentially increasing their risk for initiation of smoking. We aimed to determine the association between baseline e-cigarette use and subsequent initiation of cigarette smoking among initially never-smoking young adults.

METHODS

We conducted a prospective cohort study with assessments at baseline (March 2013) and follow-up (October 2014). We used sampling frames representing 97% of the US population to recruit a nationally representative sample of never-smoking young adults aged 18 to 30 years. The independent variable was baseline ever use of e-cigarettes. The main outcome measure was initiation of traditional cigarette smoking between baseline and 18-month follow-up.

RESULTS

Baseline surveys were completed by 1506 never-smoking young adults, of whom 915 (60.8%) completed follow-up. There were no demographic differences between responders and nonresponders. After applying survey weights-which accounted for both nonresponse and overcoverage or undercoverage-2.5% of the represented population of never-smokers (801,010 of 32,040,393) used e-cigarettes at baseline. Cigarette smoking was initiated by 47.7% of e-cigarette users and 10.2% of nonusers (P = .001). In fully adjusted multivariable models, e-cigarette use at baseline was independently associated with initiation of smoking at 18 months (adjusted odds ratio, 6.8; 95% confidence interval, 1.7-28.3). Results remained similar in magnitude and statistically significant in all sensitivity analyses.

CONCLUSIONS

Baseline e-cigarette use was independently associated with initiation of traditional cigarette smoking at 18 months. This finding supports policy and educational interventions designed to decrease use of e-cigarettes among nonsmokers.

Biomarkers of Exposure in ENDS Users, Smokers, and Dual Users of American Indian Descent

Objectives

We measured biomarkers of exposure among American Indian (AI) ENDS users, smokers, and dual users.

Methods

Urine was analyzed for total nicotine equivalents (TNE) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol(NNAL). Expired-air carbon monoxide (CO) was collected. Two analyses were performed. "CO analysis" included smokers and dual users whose CO was ≥ 6 ppm and ENDS users whose CO was < 6 ppm. "NNAL analysis" included smokers and dual users whose NNAL was ≥ 47.3 pg/mg, and ENDS users whose NNAL was < 47.3 pg/mg. Biomarkers were summarized by geometric means (GM) and compared with nonparametric tests.

Results

In both analyses, TNE was no different across the groups, and NNAL and CO were lower in ENDS users. In the NNAL analysis the GM of NNAL was 261.4, 6.1, and 228.0 pg/mg among smokers, ENDS users, and dual users (p < .001). Also in the NNAL analysis, the GM of CO was 14.7, 2.4, and 16.8 ppm among smokers, ENDS users, and dual users (p < .001).

Conclusions

ENDS users did not differ in nicotine and had lower exposure to a lung carcinogen and a cardiovascular toxicant than smokers or dual users. Dual users and smokers did not differ in biomarker levels. Results should be used to inform tribal regulations and to educate the AI community on ENDS.

American pediatric society's 2017 John Howland award acceptance lecture: a tale of two toxicants: childhood exposure to lead and tobacco

This article summarizes the presentation of the 2017 Howland Award to Michael Weitzman, MD, at the Annual Pediatric Academic Society Meetings. It summarizes the remarkable advances in understanding the effects and pathways of exposure of the two most common and pernicious of our nation's child environmental exposures, namely lead and tobacco. It also summarizes the profound effect of the translation of these findings into prudent and effective clinical and public health policies such that exposure to both has dramatically decreased over the past 40 years due to the tenacious activities of pediatricians, other child-related professionals, government agencies at all levels, and the American Academy of Pediatrics. Research and clinical activities, although essential, were not sufficient to produce these successes, but required extensive mentoring to produce a generation of academic pediatricians capable of conducting the requisite research, and extensive advocacy by pediatricians and others to overcome the formidable inertia and outright opposition to efforts to protect our children from these exposures. Moreover, the article highlights that both of these environmental exposures have roots in social and environmental injustice and neither is solved, and that there is no safe level of exposure to either of these toxicants.

Electronic nicotine delivery system use behaviour and loss of autonomy among American Indians: results from an observational study

OBJECTIVE

American Indians (AI) have a high prevalence of electronic nicotine delivery system (ENDS) use. However, little information exists on (ENDS) use, either alone or in combination with cigarettes (dual use), among AI. The objective of this small-scaled study was to examine use behaviours and dependence among exclusive ENDS users and dual users of AI descent. Exclusive smokers were included for comparison purposes.

SETTING

Oklahoma, USA.

PARTICIPANTS

Adults of AI descent who reported being exclusive ENDS users (n=27), dual users (n=28) or exclusive cigarette smokers (n=27).

MEASURES

Participants completed a detailed questionnaire on use behaviours. The Hooked on Nicotine Checklist (HONC) was used to assess loss of autonomy over cigarettes and was reworded for ENDS. Dual users completed the HONC twice. Sum of endorsed items indicated severity of diminished autonomy. Comparisons were made with non-parametric methods and statistical significance was defined as P<0.05.

RESULTS

Median duration of ENDS use was 2 years among ENDS users and 1 year among dual users. Most ENDS and dual users reported <20 vape sessions per day (72.0% vs 72.0%) with ≤10 puffs per vape session (70.4% vs 69.2%). Severity of diminished autonomy over ENDS was similar among ENDS and dual users (medians: 4 vs 3; P=0.6865). Among dual users, severity of diminished autonomy was lower for ENDS than cigarettes (medians: 3 vs 9; P=<0.0001). Comparing ENDS users with smokers, ENDS users had a lower severity of diminished autonomy (4 vs 8; P=0.0077). Comparing dual users with smokers, median severity of diminished autonomy over cigarettes did not differ (P=0.6865).

CONCLUSIONS

Severity of diminished autonomy was lower for ENDS than cigarettes in this small sample of AI. Future, adequately powered studies should be conducted to fully understand ENDS use patterns and dependence levels in this population.

A Naturalistic, Randomized Pilot Trial of E-Cigarettes: Uptake, Exposure, and Behavioral Effects

Background: Most studies of electronic nicotine delivery systems (ENDS) compare self-selected users versus nonusers. The few randomized studies to date generally support a positive impact on reducing smoking behavior, but these studies are focused on guided ENDS use. This study presents a randomized, naturalistic trial of ENDS with prospective outcomes of uptake and behavioral changes in smoking.Methods: Adult smokers with minimal ENDS history were randomized in a 2:1 ratio to receive product for 3 weeks (n = 46), or not (n = 22). Changes in nicotine delivery (16 vs. 24 mg), midway through the study allowed a compelling opportunity to examine two ENDS products compared with the control group. Primary outcomes, assessed via daily diaries during sampling period and in-person laboratory visits over 4 months, included uptake and usage of ENDS, cessation-related outcomes, and exposure to smoke constituents.Results: All ENDS participants tried product at least once, with 48% of 24 mg and 30% of 16 mg using their assigned product for the entire sampling period. Within the 24 mg ENDs group, 57% made an independent purchase of ENDS, versus 28% of 16 mg, and 14% of control participants (P = 0.01). Smokers in both ENDS groups significantly reduced their smoking, whereas control participants did not (P = 0.03). Cessation behaviors (quit attempts, biologically verified abstinence) numerically but not statistically favored ENDS participants.Conclusions: Results suggest that cigarette smokers are willing to use ENDS with trends toward reduced cigarette smoking and positive changes in cessation-related behaviors.Impact: Randomized, naturalistic trials such as presented herein are needed to understand the population impact of e-cigarettes. Cancer Epidemiol Biomarkers Prev; 26(12); 1795-803. ©2017 AACR.

A comparison of nicotine dependence among exclusive E-cigarette and cigarette users in the PATH study

Electronic cigarettes ("e-cigs") have recently gained in popularity, but their health risks, including dependence potential are unclear. This study analyzed the adult database from the Wave 1 Population Assessment of Tobacco and Health (PATH) Study, a nationally representative survey of tobacco use in the United States, to assess the relative level of dependence among adult, exclusive everyday users of e-cigarettes and cigarettes. Of the total 32,320 observations from the Wave 1 PATH adult database, 3586 (5.9%, weighted) were eligible for our analysis population. Among those who met the eligibility criteria, 156 (4.6%) were exclusive e-cig users, and 3430 (95.4%) were exclusive cigarette smokers. Our results show that e-cig users reported a significantly longer time-to-first-use of the day after waking (measured in minutes) compared to cigarette smokers after adjusting for confounders (adjusted geometric mean [95% confidence limits (CL)]: 29.2 [24.4-34.9] vs. 20.0 [18.7, 21.5]). In addition, cigarette smokers were significantly more likely to consider themselves addicted (Adj. Odds Ratio [95% CL]: 6.9 [4.5-10.7]); have strong cravings (2.9 [1.9-4.2]); find it difficult in the past 12months to refrain from using their product in places where it was prohibited (6.4 [2.9-14.3]); and feel like they really needed to use their product (3.9 [2.4-6.4]). These results are consistent with previous studies, in finding that exclusive daily e-cigarette users are less dependent on their respective product than comparable cigarette smokers.

Similar precipitated withdrawal effects on intracranial self-stimulation during chronic infusion of an e-cigarette liquid or nicotine alone

The FDA recently extended their regulatory authority to electronic cigarettes (ECs). Because the abuse liability of ECs is a leading concern of the FDA, animal models are urgently needed to identify factors that influence the relative abuse liability of these products. The ability of tobacco products to induce nicotine dependence, defined by the emergence of anhedonia and other symptoms of nicotine withdrawal following cessation of their use, contributes to tobacco abuse liability. The present study compared the severity of precipitated withdrawal during chronic infusion of nicotine alone or nicotine-dose equivalent concentrations of three different EC refill liquids in rats, as indicated by elevations in intracranial self-stimulation (ICSS) thresholds (anhedonia-like behavior). Because these EC liquids contain constituents that may enhance their abuse liability (e.g., minor alkaloids), we hypothesized that they would be associated with greater withdrawal effects than nicotine alone. Results indicated that the nicotinic acetylcholine receptor antagonist mecamylamine precipitated elevations in ICSS thresholds in rats receiving a chronic infusion of nicotine alone or EC liquids (3.2mg/kg/day, via osmotic pump). Magnitude of this effect did not differ between formulations. Our findings indicate that nicotine alone is the primary CNS determinant of the ability of ECs to engender dependence. Combined with our previous findings that nicotine alone and these EC liquids do not differ in other preclinical addiction models, these data suggest that product standards set by the FDA to reduce EC abuse liability should primarily target nicotine, other constituents with peripheral sensory effects (e.g. flavorants), and factors that influence product appeal (e.g., marketing).

Initiation of Electronic Cigarette Use by Age Among Youth in the U.S

INTRODUCTION

The rapid increase in electronic cigarette (e-cigarette) smoking among U.S. youth requires data regarding the age pattern of initiation risk for effective tobacco use prevention.

METHODS

Data from the 2014 National Youth Tobacco Survey (N=20,680, aged 11-19 years, 50.6% male) were analyzed using survival analysis in 2016 to quantify the likelihood of e-cigarette use initiation by age, overall and by gender and racial/ethnic groups.

RESULTS

The estimated mean age of e-cigarette initiation was 17.50 (95% CI=17.47, 17.52) years. The estimated hazards of e-cigarette use initiation were 0 up to age 6 years, increased slowly from age 7 to 11 years, and continued with an accelerated increase up to age 17 years before it slowed down. There were significant gender (male > female) and racial/ethnicity (from high to low: multiracial, white, Hispanic, African, and Asian) differences in the age pattern.

CONCLUSIONS

E-cigarette smoking is initiated as young as age 7 years. Different from conventional cigarette smoking with peak initiation risk at age 14-15 years, the likelihood of initiating e-cigarette smoking continues to increase up to age 18 years. The unique age pattern and significant gender and racial/ethnic differences provide useful data to support further research to strengthen tobacco use prevention in the U.S.

Correlates of Electronic Cigarettes Use Before and During Pregnancy

Introduction

Electronic cigarette use is rapidly gaining in popularity. However, little is known about correlates and reasons for electronic cigarette use by women of reproductive age, a group for which the safety and efficacy of electronic cigarette use is of particular interest.

Methods

As part of a clinical trial for smoking cessation, we surveyed pregnant smokers about their lifetime use of electronic cigarettes, previous use of any adjunctive treatments for smoking cessation, and use of electronic cigarettes during pregnancy. We examined associations between electronic cigarette use and participant characteristics.

Results

Fifty-three percent (55/103) of participants had previously tried electronic cigarettes. Ever users smoked more cigarettes per day before pregnancy (p = .049), had a greater number of previous quit attempts (p = .033), and were more likely to identify as being Hispanic or non-Hispanic white than never users (p = .027). Fifteen percent of participants (15/103) reported previous use of electronic cigarettes for smoking cessation, which was more common than the use of any specific FDA-approved smoking cessation medication. Fourteen percent of participants (14/103) reported electronic cigarette use during pregnancy, most commonly to quit smoking. A history of substance abuse (p = .043) and more previous quit attempts (p = .018) were associated with electronic cigarette use during pregnancy.

Conclusions

Use of electronic cigarettes to quit smoking may be common in women of reproductive age, including those who are pregnant. More research is needed to determine the risks and benefits of electronic cigarette use in this population of smokers.

Implications

This study shows that electronic cigarettes are used by women of reproductive age, including pregnant smokers. The implications of this finding are that there is an urgent need to examine the risks and benefits of electronic cigarette use, especially by pregnant women. The study also shows that electronic cigarettes are commonly used as a smoking cessation aid in women of reproductive age. The greater likelihood of electronic cigarette use compared to proven adjunctive smoking treatments suggests that electronic cigarettes should be examined as a potential aid to cessation in this population.

Tobacco, e-cigarettes, and child health

PURPOSE OF THE REVIEW

The availability of the Children's Health Exposure Assessment Resource funded by the National Institute of Environmental Health Sciences provides new opportunities for exploring the role of tobacco smoke exposure in causing harm to children.

RECENT FINDINGS

Children of smokers are exposed to nicotine and other harmful tobacco smoke chemicals in utero as well as in their environment. This passive exposure to tobacco smoke has a variety of negative effects on children. In-utero exposure to tobacco smoke causes poor birth outcomes and influences lung, cardiovascular, and brain development, placing children at increased risk of a number of adverse health outcomes later in life, such as obesity, behavioral problems, and cardiovascular disease. Furthermore, most smokers start in their adolescence, an age of increased nicotine addiction risk. Biomarkers of tobacco exposure helps clarify the role tobacco chemicals play in influencing health both in childhood and beyond. Although electronic cigarettes (e-cigarettes) appear to be a nicotine delivery device of reduced harm, it appears to be a gateway to the use of combustible cigarette smoking in adolescents.

SUMMARY

Pediatric researchers interested in elucidating the role of tobacco smoke exposure in adverse outcomes in children should incorporate biomarkers of tobacco exposure in their studies.

Effect of tobacco and electronic cigarette use on cough reflex sensitivity

Multiple previous studies have shown that otherwise healthy tobacco cigarette smokers have suppressed cough reflex sensitivity compared with nonsmokers and furthermore, that smoking cessation, even after years of tobacco use, leads to prompt enhancement of cough reflex sensitivity. Thus, cough reflex sensitivity is demonstrated to be a dynamic phenomenon, responding to the presence or absence of influences such as tobacco smoke. These studies, however, were unable to identify whether it was the influence of nicotine, or one or more of the numerous components of tobacco cigarette smoke, that were responsible for this effect. More recently, it has been shown that a single exposure to electronic cigarette (e-cig) vapor causes inhibition of cough reflex sensitivity in healthy lifetime nonsmokers. An identical study employing a non-nicotine containing e-cig confirmed an absence of effect on cough reflex sensitivity, thus implicating nicotine as the causative agent of these findings. Recent animal studies demonstrate cough suppression after injection of nicotine into the brains of cats, thus supporting a centrally-mediated antitussive effect of nicotine to explain the results of the aforementioned studies of tobacco smoke and e-cig vapor exposure in humans.

Documenting the emergence of electronic nicotine delivery systems as a disruptive technology in nicotine and tobacco science

BACKGROUND

The emergence of electronic nicotine delivery systems (ENDS, or "e-cigarettes") has resulted in nicotine and tobacco scientists committing increased resources to studying these products. Despite this surge of research on various topics related to e-cigarettes, it is important to characterize the evolving e-cigarette research landscape as a way to identify important future research directions. The purpose of this review was to broadly categorize published scholarly work on e-cigarettes using a structured, multi-level coding scheme.

METHODS

A systematic literature search was conducted to collect articles on e-cigarettes that were published in peer-reviewed journals from 2006 through 2014. Studies were classified through 3 coding waves. Articles were first divided into research reports, literature reviews and opinions/editorials. Research reports were further categorized to determine the proportion of these studies using human participants. Finally, human studies were classified based on their methodologies: descriptive, predictive, explanatory, and intervention.

RESULTS

Research reports (n=224) and opinions/editorials (n=248) were published at similar rates during this time period. All types of articles showed exponential rates of increase in more recent years. 76.4% of human research studies were descriptive in nature, with very little research employing experimental (6.8%) or intervention-based methodologies (5.4%).

CONCLUSIONS

This review reinforces the idea that e-cigarettes are a disruptive technology exerting substantial influence on nicotine and tobacco science. This review also suggests that opinions on e-cigarettes may be outpacing our scientific understanding of these devices. Our findings highlight the need for more e-cigarette research involving experimental, intervention, and longitudinal designs.

Exposure to Nicotine and Selected Toxicants in Cigarette Smokers Who Switched to Electronic Cigarettes: A Longitudinal Within-Subjects Observational Study

INTRODUCTION

Electronic cigarettes (e-cigarettes) are purported to deliver nicotine aerosol without any toxic combustion products present in tobacco smoke. In this longitudinal within-subjects observational study, we evaluated the effects of e-cigarettes on nicotine delivery and exposure to selected carcinogens and toxicants.

METHODS

We measured seven nicotine metabolites and 17 tobacco smoke exposure biomarkers in the urine samples of 20 smokers collected before and after switching to pen-style M201 e-cigarettes for 2 weeks. Biomarkers were metabolites of 13 major carcinogens and toxicants in cigarette smoke: one tobacco-specific nitrosamine (NNK), eight volatile organic compounds (1,3-butadiene, crotonaldehyde, acrolein, benzene, acrylamide, acrylonitrile, ethylene oxide, and propylene oxide), and four polycyclic aromatic hydrocarbons (naphthalene, fluorene, phenanthrene, and pyrene). Changes in urine biomarkers concentration were tested using repeated measures analysis of variance.

RESULTS

In total, 45% of participants reported complete abstinence from cigarette smoking at 2 weeks, while 55% reported continued smoking. Levels of total nicotine and some polycyclic aromatic hydrocarbon metabolites did not change after switching from tobacco to e-cigarettes. All other biomarkers significantly decreased after 1 week of using e-cigarettes (p < .05). After 1 week, the greatest percentage reductions in biomarkers levels were observed for metabolites of 1,3-butadiene, benzene, and acrylonitrile. Total NNAL, a metabolite of NNK, declined by 57% and 64% after 1 and 2 weeks, respectively, while 3-hydroxyfluorene levels declined by 46% at week 1, and 34% at week 2.

CONCLUSIONS

After switching from tobacco to e-cigarettes, nicotine exposure remains unchanged, while exposure to selected carcinogens and toxicants is substantially reduced.

IMPLICATIONS

To our knowledge, this is the first study that demonstrates that substituting tobacco cigarettes with an e-cigarette may reduce user exposure to numerous toxicants and carcinogens otherwise present in tobacco cigarettes. Data on reduced exposure to harmful constituents that are present in tobacco cigarettes and e-cigarettes can aid in evaluating e-cigarettes as a potential harm reduction device.