Electronic cigarettes: what are they and what do they do?

Secondary indoor air pollution and passive smoking associated with cannabis smoking using electric cigarette device-demonstrative in silico study

With electronic (e)-liquids containing cannabis components easily available, many anecdotal examples of cannabis vaping using electronic cigarette devices have been reported. For electronic cigarette cannabis vaping, there are potential risks of secondary indoor air pollution from vapers. However, quantitative and accurate prediction of the inhalation and dermal exposure of a passive smoker in the same room is difficult to achieve due to the ethical constraints on subject experiments. The numerical method, i.e., in silico method, is a powerful tool to complement these experiments with real humans. In this study, we adopted a computer-simulated person that has been validated from multiple perspectives for prediction accuracy. We then conducted an in silico study to elucidate secondary indoor air pollution and passive smoking associated with cannabis vaping using an electronic cigarette device in an indoor environment. The aerosols exhaled by a cannabis vaper were confirmed to be a secondary emission source in an indoor environment; non-smokers were exposed to these aerosols via respiratory and dermal pathways. Tetrahydrocannabinol was used as a model chemical compound for the exposure study. Its uptake by the non-smoker through inhalation and dermal exposure under a worst-case scenario was estimated to be 5.9% and 2.6% of the exhaled quantity from an e-cigarette cannabis user, respectively.

How can we best mitigate unintended passive smoking in an indoor environment? As marijuana tends to be legalized in more countries, there is an increasing number of cases of vaping cannabis using e-cigarette devices. E-cigarette vaping is presumed to cause relatively low levels of indoor air pollution due to the absence of a direct combustion process. In this study, we developed a numerical simulation model to quantitatively predict the impact of first- and second-hand cannabis vaping in an indoor environment. The study was conducted in response to vulnerable residents who are concerned regarding the deterioration of indoor air quality and informs policymakers of the potential risk of second-hand cannabis vaping exposure.

Electrical features, liquid composition and toxicant emissions from 'pod-mod'-like disposable electronic cigarettes

INTRODUCTION

Use of flavoured pod-mod-like disposable electronic cigarettes (e-cigarettes) has grown rapidly, particularly among cost-sensitive youth and young adults. To date, little is known about their design characteristics and toxicant emissions. In this study, we analysed the electrical and chemical characteristics and nicotine and pulmonary toxicant emission profiles of five commonly available flavoured disposable e-cigarettes and compared these data with those of a JUUL, a cartridge-based e-cigarette device that pod-mod-like disposables emulate in size and shape.

METHODS

Device construction, electrical power and liquid composition were determined. Machine-generated aerosol emissions including particulate matter, nicotine, carbonyl compounds and heavy metals were also measured. Liquid and aerosol composition were measured by high-performance liquid chromatography, gas chromatography-mass spectrometry/flame ionisation detection, and inductively coupled plasma mass spectrometry.

RESULTS

We found that unlike JUUL, disposable devices did not incorporate a microcontroller to regulate electrical power to the heating coil. Quality of construction varied widely. Disposable e-cigarette power ranged between 5 and 9 W and liquid nicotine concentration ranged between 53 and 85 mg/mL (~95% in the protonated form). In 15 puffs, total nicotine yield for the disposables ranged between 1.6 and 6.7 mg, total carbonyls ranged between 28 and 138 µg, and total metals ranged between 1084 and 5804 ng. JUUL emissions were near the floors of all of these ranges.

CONCLUSIONS

Disposable e-cigarettes are designed with high nicotine concentration liquids and are capable of emitting much higher nicotine and carbonyl species relative to rechargeable look-alike e-cigarettes. These differences are likely due to the lower quality in construction, unreliable labelling and lack of temperature control regulation that limits the power during operation. From a public health perspective, regulating these devices is important to limit user exposure to carbonyls and nicotine, particularly because these devices are popular with youth and young adults.

Synthetic cannabinoids in e-liquids: A proton and fluorine NMR analysis from a conventional spectrometer to a compact one

The ¹H NMR profiles of 13 samples of e-liquids supplied by French customs were obtained with high-field and low-field NMR. The high-field ¹H NMR spectra allowed the detection of matrix signals, synthetic cannabinoids, and flavouring compounds. Quantitative results were obtained for the five synthetic cannabinoids detected: JWH-210, 5F-MDMB-PICA, 5F-ADB, 5F-AKB48, and ADB-FUBINACA. Conventional GC-MS analysis was used to confirm compound identification. Fluorine-19 NMR was proposed for the quantification of fluorinated synthetic cannabinoids and was successfully implemented on both 400 MHz and 60 MHz NMR spectrometers. This study based on few examples explored the potentiality of low-field NMR for quantitative and quantitative analysis of synthetic cannabinoids in e-liquids.

High-School Students Rarely Use E-Cigarettes Alone: A Sociodemographic Analysis of Polysubstance Use Among Adolescents in the United States

INTRODUCTION

Most adolescents reporting e-cigarette use have also used combustible tobacco; however, the extent to which they use other substances is less clear. This study assessed e-cigarette use with tobacco, alcohol, or cannabis and quantified the risk of polysubstance use among adolescents overall and by sociodemographic characteristics.

AIMS AND METHODS

Using 2017 Youth Behavioral Risk Factor Surveillance System data from adolescents (grades 9-12) with complete substance use information (n = 11 244), we examined e-cigarette poly-use status (none [referent], e-cigarettes only, or e-cigarettes + other substances). We estimated the prevalence of substance use and modeled odds of e-cigarette use, alone or with other substances, by several sociodemographic characteristics. Analyses were completed in Stata version 15.1 using survey procedures to account for the complex survey design.

RESULTS

Approximately 12% of adolescents reported past 30-day e-cigarette use. Almost all (93%) e-cigarette users also reported other substance use; alcohol appeared most frequently in combinations. Odds of e-cigarette single use and e-cigarette poly-use (vs. no use) were higher for males and adolescents with lower grades (odds ratios [ORs] = 1.44-2.31). Racial/ethnic minorities had lower odds of e-cigarette poly-use than White peers (ORs = 0.18-0.61), and bisexual (vs. straight) adolescents were more likely to be e-cigarette poly-users (OR = 1.62). E-cigarette use increased from 9th grade (7%) to 12th grade (16%).

CONCLUSIONS

Polysubstance use is highly prevalent among adolescents who use e-cigarettes. Therefore, e-cigarette screening should include the assessment of other substances, especially alcohol. Early and comprehensive prevention efforts to reduce e-cigarette and other substance use could have a substantial beneficial impact on population health over time.

IMPLICATIONS

This study extends knowledge about e-cigarette use among adolescents by exploring its use with alcohol, cannabis, and other tobacco products. We found that e-cigarettes were very rarely used alone, and our analysis identified several sociodemographic factors associated with greater odds of e-cigarette polysubstance use. In response, we recommend that prevention interventions address multiple substances concurrently, screen repeatedly to detect new initiation as age increases, focus on e-cigarette use as a less stigmatized entry point to discussions of substance use, and target priority population subgroups.

E-cigarette Solvent Ratio and Device Power Influence Ambient Air Particulate Matter

OBJECTIVES

Electronic cigarette (ECIG)-generated aerosol contains particulate matter with a diameter less than 2.5 microns (PM2.5). Particles of this size may be injurious to the health of those who inhale them. Few studies have assessed the relationship between ECIG aerosol PM2.5 and ECIG liquid ingredients or ECIG device power.

METHODS

Two studies were conducted in which participants generated aerosols with ECIGs: in one, ECIG liquids contained various vegetable glycerin/propylene glycol ratios and in the other, ECIG devices varied by electrical power output.

RESULTS

Results indicate that, in general, PM2.5 increases as the ratio of vegetable glycerin to propylene glycol increases, or as device power increases.

CONCLUSIONS

Regulating ECIG PM2.5 emissions to protect non-users requires an understanding of all the factors that influence these emissions.

Association of e-cigarette advertising with e-cigarette and cigarette use among US adults

AIMS

To estimate the association of e-cigarette advertisement exposure with e-cigarette and cigarette use behavior among US adults.

DESIGN

Data from the 2013-14 National Adult Tobacco Survey (NATS) were linked to Kantar Media and National Consumer Study data to construct measures of e-cigarette advertisements on TV and in magazines. The relationship between advertisement measures and outcomes was estimated using logistic and Poisson regressions, controlling for socio-demographics, state cigarette taxes and state and year fixed-effects.

SETTING

United States.

PARTICIPANTS/CASES

A total of 98 746 adults aged ≥ 18 years who responded to the 2013-14 NATS.

MEASUREMENTS

The independent variables of interest were the number of e-cigarette advertisements in magazines to which an adult was exposed in the past 6 months and the number of e-cigarette advertisements on TV to which an adult was exposed in the past 6 months. Outcomes were awareness of e-cigarettes, ever e-cigarette use, current e-cigarette use, current cigarette use and number of cigarettes smoked per month.

FINDINGS

Exposure to one additional e-cigarette advertisement on TV was associated with a 0.18, 0.13 and 0.03 percentage point increase, respectively, in awareness, ever use and current use of e-cigarettes among all adults (P < 0.05). This exposure also was associated with a 0.11 percentage point increase in current cigarette use among all adults and an increase in cigarette consumption of 2.24 cigarettes per month among adults aged ≥ 45 (P < 0.05).

CONCLUSIONS

Exposure to e-cigarette advertising appears to be positively associated with the use of e-cigarettes and cigarettes among adults of all ages, and with increased cigarette consumption among older adults.

Antioxidants in smokers

Cigarette smoke (CS) is likely the most common preventable cause of human morbidity and mortality worldwide. Consequently, inexpensive interventional strategies for preventing CS-related diseases would positively impact health systems. Inhaled CS is a powerful inflammatory stimulus and produces a shift in the normal balance between antioxidants and oxidants, inducing oxidative stress in both the respiratory system and throughout the body. This enduring and systemic pro-oxidative state within the body is reflected by increased levels of oxidative stress and inflammation biomarkers seen in smokers. Smokers might benefit from consuming antioxidant supplements, or a diet rich in fruit and vegetables, which can reduce the CS-related oxidative stress. This review provides an overview of the plasma profile of antioxidants observable in smokers and examines the heterogeneous literature to elucidate and discuss the effectiveness of interventional strategies based on antioxidant supplements or an antioxidant-rich diet to improve the health of smokers. An antioxidant-rich diet can provide an easy-to-implement and cost-effective preventative strategy to reduce the risk of CS-related diseases, thus being one of the simplest ways for smokers to stay in good health for as long as possible. The health benefits attributable to the intake of antioxidants have been observed predominantly when these have been consumed within their natural food matrices in an optimal antioxidant-rich diet, while these preventive effects are rarely achieved with the intake of individual antioxidants, even at high doses.

Risk of smoking relapse with the use of electronic cigarettes: A systematic review with meta-analysis of longitudinal studies

INTRODUCTION

The use of e-cigarettes has been the subject of a public health debate on their possibility of undermining efforts for tobacco control. The aim of this study was to synthesize the risk of smoking relapse with the use of e-cigarettes by former smokers.

METHODS

MEDLINE, EMBASE, PsycInfo and LILACS were searched without restriction to language or date of publication. Longitudinal observational studies evaluating the association between e-cigarette use and smoking relapse were selected by two independent reviewers, and disagreements solved by discussion with a third researcher. Data extraction and risk of bias assessment were also carried out by two independent reviewers. The meta-analysis was performed using the random effect Mantel-Haenszel model.

RESULTS

From 632 retrieved records, six studies were eligible and described, while three were included in the quantitative synthesis. The studies were conducted in the USA, UK and France, with final sample size varying from 374 to 4094 former smokers. Risk of relapse was 2.03 (95% CI: 1.39–2.96) among former smoker users than non-users of e-cigarettes, and 1.38 (95% CI: 1.11–1.65) when pooling the adjusted association measures. Long-term former smokers were the main contributors for the higher relapse risk, while the impact of frequency of exposure to e-cigarettes (past, non-daily, daily) was uncertain.

CONCLUSIONS

Considering the growing popularity of e-cigarettes among former smokers, our results point to the great potential for an increase in the frequency of relapse to conventional smoking and vaping for those who move to regular use of e-cigarettes.

Assessment of Serum Concentrations of 12 Aldehydes in the U.S. Population from the 2013-2014 National Health and Nutrition Examination Survey

Aldehydes are known carcinogens and irritants that can negatively impact health. They are present in tobacco smoke, the environment, and food. The prevalence of aldehyde exposure and potential health impact warrants a population-wide study of serum aldehydes as exposure biomarkers. We analyzed 12 aldehydes in sera collected from 1843 participants aged 12 years or older in the 2013-2014 National Health and Nutrition Examination Survey. Several aldehydes were detected at high rates, such as isopentanaldehyde (99.2%) and propanaldehyde (88.3%). We used multiple linear regression models to examine the impact of tobacco smoke and dietary variables on serum concentrations of isopentanaldehyde and propanaldehyde. Although 12 serum aldehydes were analyzed and compared to tobacco smoke exposure, only isopentanaldehyde and propanaldehyde showed any significant association with tobacco smoke exposure. Survey participants who smoked 1-10 cigarettes per day (CPD) had 168% higher serum isopentanaldehyde and 28% higher propanaldehyde compared with nonusers. Study participants who smoked 11-20 CPD had higher serum isopentanaldehyde (323%) and propanaldehyde (70%). Similarly, study participants who smoked >20 CPD had 399% higher serum isopentanaldehyde and 110% higher serum propanaldehyde than nonexposed nonusers. The method could not, however, differentiate between nonexposed nonusers and nonusers exposed to secondhand smoke for either of these two aldehydes. No dietary variables were consistently predictive of serum isopentanaldehyde and propanaldehyde concentrations. This report defines baseline concentrations of serum aldehydes in the U.S. population and provides a foundation for future research into the potential health effects of aldehydes. In addition, this study suggests that tobacco smoke is a significant source of exposure to some aldehydes such as isopentanaldehyde and propanaldehyde.

Effect of an electronic nicotine delivery system with 0, 8, or 36 mg/mL liquid nicotine versus a cigarette substitute on tobacco-related toxicant exposure: a four-arm, parallel-group, randomised, controlled trial

BACKGROUND

Electronic nicotine delivery systems (ENDSs) are used by some smokers to reduce cigarette consumption, but their effectiveness is uncertain. We aimed to examine the extent to which ENDSs or a non-nicotine cigarette substitute influence tobacco-related toxicant exposure and cigarette consumption in smokers interested in smoking reduction.

METHODS

We did a four-arm, parallel-group, randomised controlled trial at two sites in the USA (Penn State University, Hershey, PA, and Virginia Commonwealth University, Richmond, VA). We enrolled adults aged 21-65 years who smoked more than nine cigarettes per day (for at least the past year), with exhaled CO of more than 9 parts per million at screening, who were not currently using an ENDS, and who were interested in reducing smoking but not quitting. Participants were randomised (site-specific with allocation concealment; 1:1:1:1) to receive either a cartomiser-based, pen-style ENDS (eGo-style) paired with 0, 8, or 36 mg/mL liquid nicotine (participants and researchers masked to concentration) or a non-ENDS cigarette-shaped plastic tube that delivered no nicotine or aerosol (cigarette substitute; unmasked) for 24 weeks. Conditions were chosen to reflect a range of nicotine delivery including none (cigarette substitute and 0 mg/mL ENDS), low (8 mg/mL), and cigarette-like (36 mg/mL), and all conditions were paired with smoking reduction instructions. The primary outcome was concentration of the tobacco-specific carcinogen metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL; urinary total) collected at randomisation and at 4, 12, and 24 weeks. Multiple imputation with and without covariate adjustment was used in addition to sensitivity analyses. This trial is registered with ClinicalTrials.gov, NCT02342795.

FINDINGS

Between July 22, 2015, and Nov 16, 2017, 684 individuals were screened and 520 (76%) were enrolled and randomised. 188 (36%) of 520 participants were lost to follow-up by week 24; attrition did not differ by study group (39 [30%] of 130 in the cigarette substitute group, 56 [43%] of 130 in the ENDS with 0 mg/mL nicotine group, 49 [38%] of 130 in the ENDS 8 mg/mL group, and 44 [34%] of 130 in the ENDS 36 mg/mL group). Urinary total NNAL at 24 weeks in the ENDS with 36 mg/mL nicotine group was 210·80 pg/mg creatinine (95% CI 163·03-274·42) compared with 346·09 pg/mg creatinine (265·00-455·32) in the cigarette substitute group (p=0·0061). No other significant differences between groups were observed for any time point for urinary total NNAL. Serious adverse event frequency was similar across groups (12 events in 12 participants [9%] in the ENDS with 36 mg/mL nicotine group, seven events in six participants [5%] in the 8 mg/mL group, 11 events in ten participants [8%] in the 0 mg/mL group, and 13 events in 13 participants [10%] in the cigarette substitute group), and all of these were deemed unrelated or unlikely to be related to study product use. There was one death between randomisation and 24 weeks (suicide; in the ENDS with 0 mg/mL nicotine group).

INTERPRETATION

Use of an ENDS with cigarette-like nicotine delivery can reduce exposure to a major pulmonary carcinogen, NNAL, even with concurrent smoking. Future ENDS trials should involve products with well characterised nicotine delivery, including those with nicotine delivery approaching that of a cigarette.

FUNDING

National Institutes of Health, US Food and Drug Administration.

"Taking Up a New Problem": Context and Determinants of Pod-Mod Electronic Cigarette Use Among College Students

In this article, we explore the context and determinants of pod-mod electronic cigarette (ECIG) use among college students aged 18 to 24 in the United States. We conducted semi-structured interviews with 55 students (M age = 20 years, 56% female, 65% White) on three campuses in the Northwest, Midwest, and Southeast. We performed a thematic analysis. Students described ECIG use by peers, increased ECIG exposure and prevalence in college, and school-related stress as reasons for vaping. Pod-mod features such as convenience, design, easy concealment, and flavors made vaping more appealing. Negative aspects of vaping included addiction, cost, and possible health consequences. Most viewed vaping as a college behavior and intended to quit after graduation. Our results show that the college environment plays a major role in young adult ECIG use. These findings can inform the development of targeted interventions to prevent and control uptake of ECIGs by young adults.

Knowledge, attitudes, and practices of young adults regarding the impact of electronic cigarette use on oral health

BACKGROUND

The popularity and prevalence of electronic cigarette (EC) usage has continued to surge to 35 million worldwide, with one-half of users younger than 34 years. Despite emerging research suggesting deleterious oral health effects, the perceptions of EC users concerning oral health effects remain unknown. The purpose of this study was to explore knowledge, attitudes, and practices of young adults regarding the impact of EC use on oral health.

METHODS

A cross-sectional survey used a validated tool to investigate vaping and oral health knowledge, attitudes, and practices among a convenience sample of EC users (N = 220). Outcomes were analyzed using descriptive and inferential statistics.

RESULTS

People 18 through 24 years (N =168) indicated a lack of knowledge (mean [standard deviation {SD}], 2.9 [1.7]) and familiarity with oral health effects of vaping (mean [SD], 2.7 [1.7]). Participants expressed willingness to discuss oral health effects of vaping with dental care professionals (n = 111 [66%]), and most (n = 109 [65%]) would potentially reduce (30%) or quit (24%) if they believed it was harmful to their oral health. Participants 18 through 24 years were more likely to agree they would quit (n = 54 [68%]) than those 25 through 34 years (n = 36 [42%]; χ² = 11.03; P = .004; φ = 0.26). Those who visit their dental care professional every 6 months (n = 82 [57%]) agreed they would quit vaping versus those who do not (n = 26 [37%]; χ² = 9.84; P = .007; φ, 0.22).

CONCLUSIONS

Respondents reported low knowledge regarding the implications of vaping on oral health but expressed a willingness to discuss vaping with their dental care professionals.

PRACTICAL IMPLICATIONS

Most EC users are willing to accept guidance from dental care professionals regarding quitting use.

Effect of Ethanol Extract of Mangosteen Peel on Serum Malondialdehyde and Leukotriene B4 Levels in Male White Rats (Rattus norvegicus) Wistar Strain Exposed with Electric Cigarette Smoke

This study aims to analyze the administration of mangosteen peel ethanol extract at different doses can reduce levels of malondialdehyde (MDA) and leukotriene B4 (LTB4) serum in male white rats (Rattus norvegicus) Wistar strains exposed to electric cigarette smoke. Electric cigarette induces mitochondrial ROS production and triggers oxidative stress. Antioxidants are needed by the body if there are many free radicals, for example mangosteen peel. This laboratory experimental study uses a randomized post test only control group design. Thirty male white rats were divided into 5 groups randomly (KK, KR, P1, P2, P3). KK given 0.5% Na-CMC, KR given smoke and 0.5% Na-CMC, P1, P2, P3 given smoke and mangosteen peel ethanol extract 100, 200, 300 mg / kg weight. Data were tested for normality and homogeneity tests. Data distribution was found not normal. Data were tested by Kruskal-Wallis Test and Mann-Whitney. Kruskal-Wallis Test results showed significant differences in MDA and LTB4 levels in each experimental group (KS, KR, P1, P2 and P3), p <0.05. Mann-Whitney test results showed a significant difference in the MDA levels of the KR against P3 and in the LTB4 level of the KR against P2 (p <0.05). The conclusion of the study was the administration of mangosteen peel ethanol extract can reduce MDA and LTB4 levels serum in male white rats (Rattus norvegicus) Wistar strains exposed to electric cigarette smoke.

Electronic Cigarettes Associated With Incident and Polysubstance Use Among Youth

PURPOSE

Electronic cigarette (e-cigarette) use has increased exponentially among the youth in the United States and may increase the incidence of substance use.

METHODS

Youth participants (12-17 years) were surveyed through the Population Assessment of Tobacco and Health study over a three-year time period. Youth with any baseline substance use or diagnosis of an attention deficit disorder were excluded from the analysis. Multivariable logistic regressions were used to assess the association between e-cigarette use at Wave 1 and incident substance use (marijuana, painkillers, sedatives, or tranquilizers and Ritalin/Adderall) and polysubstance use at Wave 2 or 3, and marijuana use in the electronic nicotine device at Wave 3.

RESULTS

Baseline ever e-cigarette users who had no history of marijuana, nonprescribed drugs and illicit substance use in Wave 1 had increased odds of reporting incident use of marijuana (odds ratio 2.59, 95% confidence interval: 1.90-3.52), nonprescribed Ritalin/Adderall use (1.89, 1.09-3.28), or polysubstance use (2.09, 1.43-3.05) in Wave 2 or 3 compared to never e-cigarette users. They were also more likely to report use of marijuana in the electronic nicotine product (2.26, 1.56-3.27) in Wave 3 compared to never e-cigarette users. There was no statistically significant association between baseline e-cigarette use and incident use of painkillers, sedatives, or tranquilizers in Wave 2 or 3 (1.21, .79-1.87).

CONCLUSIONS

E-cigarette use is associated with incident use of marijuana, marijuana in electronic nicotine devices, Ritalin/Adderall, and polysubstance use but not painkillers, sedatives, or tranquilizers. Results indicate that e-cigarettes are associated with subsequent additional risky health behaviors in youth.

A Gut Feeling: Abdominal Symptoms as an Initial Presentation of EVALI

Electronic cigarette or vaping product use-associated lung injury (EVALI) is a disease process that has become prevalent in the United States.¹ The Centers for Disease Control and Prevention reported there have been almost 2700 cases of this condition in the United States as of January 14, 2020, with >50% of these patients aged ≤24.² We present a 13-year-old boy with a history of functional abdominal pain who presented with recurrent episodes of nausea, emesis, periodic fevers, and severe episodic abdominal pain after a 12-month history of significant electronic cigarette use. On admission, he had severe abdominal pain and appeared anxious. A computed tomography scan of the abdomen was unremarkable, but a computed tomography scan of the chest demonstrated both multifocal ground-glass and crazy-paving pulmonary opacities bilaterally, with scattered septal thickening and dependent bibasilar opacities associated with volume loss. Inflammatory markers were significantly elevated, and cell counts were remarkable for leukocytosis and neutrophilia. The patient was ultimately diagnosed with EVALI and treated with intravenous methylprednisolone, resulting in improvement. This is an example of a case of EVALI in an adolescent, in which the presenting symptoms are largely gastrointestinal. It is important to keep EVALI in the differential diagnosis of patients who exhibit gastrointestinal symptoms, have markers of increased systemic inflammation, and endorse a history of vaping or are in the age range of electronic cigarette users. Although obtaining an accurate history of vaping can be challenging in the pediatric population, it is especially critical to do so.

Response to Flavored Cartridge/Pod-Based Product Ban among Adult JUUL Users: "You Get Nicotine However You Can Get It"

In order to curb increasing youth electronic cigarette (e-cig) use, the United States Food and Drug Administration (FDA) banned the sale of flavored cartridge/pod-based products in February 2020. This mixed-methods study aimed to evaluate the impact of the FDA ban on adult JUUL users. The samples of current adult JUUL users were surveyed via Amazon Mechanical Turk at three time-points n = 76 (Sample 1); n = 128 (Sample 2); n = 86 (Sample 3) before and after the FDA flavored/pod ban. The participants were asked to report the JUUL flavored pod used most often and answer questions on purchasing generic pods or refilling (Quantitative). JUUL users were then interviewed in order to explore their perceptions and behaviors related to the FDA ban of flavored cartridge/pod-based products (Qualitative; n = 16). Quantitative data analysis evaluated the differences in variables by time-point. Qualitative data were coded into themes while using the constant comparative method. We found a significant decrease in the use of mint pods (43.4%, 22.7%, 16.3%) (p < 0.01), while there was a significant increase in the use of menthol pods (6.6%, 26.6%, 37.2%) (p < 0.01). Themes that emerged from the qualitative data included switching from mint to menthol pods, refilling pods, and switching to other products that are available in the desired flavors, such as generic pods or disposable e-cigs. Future research is needed in order to evaluate the impact of these behaviors on public health.

Do Not Huff, Puff, or Vape That Stuff: Interstitial Airspace Disease in a Teenager

A 17-year-old previously healthy male was admitted to the hospital for intractable and persistent vomiting, fever, cough, abdominal pain, and intermittent diarrhea and dehydration. He presented with severe chest pain and O₂ desaturations up to 80% on room air. An infectious (including a nasopharyngeal swab), GI, and cardiac workup was completed and was negative except for elevated inflammatory markers with a C-reactive protein (CRP) level of 261 mg/L, erythrocyte sedimentation rate (ESR) of 53 mm/hr, and a D-dimer level of 0.93 mcg/ml. Chest X-ray showed diffuse multifocal infiltrates. The patient was treated with ceftriaxone and azithromycin initially for a suspected pneumonia. He was also started on 4L of nasal cannula O₂ supplementation. Due to persistent hypoxic respiratory failure, worsening respiratory distress clinically, with tachypnea and retractions, and lab findings of elevated D-dimer, a chest CT was performed to rule out a pulmonary embolism (PE). Computed tomography (CT) findings were negative for PE but notable for diffuse airspace opacities, primarily within the lower lobes, with a ground-glass appearance concerning for ARDS. Upon further investigation of the social history, the patient admitted to vaping nicotine products for the past 4 years and tetrahydrocannabinol (THC) products within the last several months. He was immediately started on prednisone 30 mg BID for a diagnosis of e-cigarette or vaping product use-associated lung injury (EVALI) and started showing clinical improvement. The patient was able to be weaned off of supplemental oxygen to room air, and clinical symptoms of respiratory distress began to improve over the next 24 hours.

Exclusive E-Cigarette Users Report Lower Levels of Respiratory Symptoms Relative to Dual E-Cigarette and Cigarette Users

INTRODUCTION

Exclusive e-cigarette use has been shown to be associated with reduced levels of respiratory symptoms relative to smoking combustible cigarettes; this association has been less frequently studied in smokers using advanced-generation e-cigarette devices. Advanced-generation devices generate denser vapor than either early generation or pod-style devices, and engender longer inhalations; these vaping topography patterns may contribute to respiratory symptoms.

METHODS

In a single-session, cross-sectional study of exclusive e-cigarette users (N = 59) and dual users of e-cigarettes and cigarettes (N = 54), participants completed questionnaires, including the American Thoracic Society Questionnaire (ATSQ) and were videotaped vaping their own device in the lab for 1 hour. Using a hierarchical regression method, we examined whether topography variables, level of nicotine concentration used in their e-cigarette device in the past month, e-cigarette dependence, amount of e-cigarette use in the past month, and smoking status (any smoking in the last month vs. none) predicted ATSQ score severity.

RESULTS

There was a significant mean difference in ATSQ score across smoking status, with greater ATSQ scores for vapers who also smoked cigarettes (19.0, SD = 6.7) than for exclusive vapers (13.4, SD = 5.3). In the final model, of the predictors of interest, only cigarette smoking status predicted significantly greater ATSQ scores (overall F = 2.51, p = .006; R2 = .26; smoking status β = 0.39, p < .0001).

CONCLUSIONS

Findings suggest that differences in respiratory symptoms between dual and exclusive e-cigarette users appear to be attributable to combustible cigarette smoking, rather than more intense or frequent e-cigarette use across groups.

IMPLICATIONS

In this comparison of exclusive advanced-generation vape device users (N = 59) versus dual users of these devices and combustible cigarettes (N = 54), we set out to determine the extent to which smoking status and e-cigarette use variables predicted self-reported respiratory symptom severity. We found that dual users showed greater respiratory symptom severity (ATSQ scores) than exclusive vapers. Despite examining vaping topography and other variables, smoking status and race were the only significant predictor of respiratory symptoms. We conclude that combustible cigarette use, not individual vaping topography, likely accounts for differences in respiratory symptoms between dual users and exclusive vapers.

User-Perceived Negative Respiratory Symptoms Associated with Electronic Cigarette Use

INTRODUCTION

Electronic cigarettes (ECIGs) expose users to an aerosol containing chemicals, which could affect the respiratory system negatively. This study examined negative respiratory symptoms associated with ECIG use.

METHODS

In 2019, adult current ECIG users from 24 US states who reported experiencing negative respiratory symptoms from ECIG use (n = 49; 44.9% women; mean age = 35.2, SD = 11.5) completed an online survey and brainstormed statements that completed the prompt: "A specific negative effect or symptom related to my breathing, nose, mouth, throat, or lungs that I have experienced from vaping/using my e-cigarette is..." Participants sorted the final list of 56 statements into groups of similar content and rated statements on how true they were for them. Multidimensional scaling analysis identified thematic clusters.

RESULTS

Eight ECIG use respiratory symptom clusters identified in analysis included Mucus and Congestion, Fatigue, Throat Symptoms, Breathing Problems, Mouth Symptoms, Chest Symptoms, Illness Symptoms, and Nose and Sinus Symptoms. Highly rated (ie, most common) symptoms included dry throat or mouth, fatigue during physical activity, coughing, shortness of breath, excessive phlegm, and bad taste in mouth. Mean cluster ratings did not differ based on lifetime cigarette smoking status (100 lifetime cigarettes smoked), but current cigarette smokers (ie, dual users) rated the Fatigue, Breathing Problems, Mucus and Congestion, and Nose and Sinus Symptoms clusters higher than noncurrent cigarette smokers.

CONCLUSIONS

Participant-identified respiratory symptoms perceived to be ECIG related, many similar to cigarette smoking symptoms. Future research should assess if these symptoms are associated with other negative health outcomes.

IMPLICATIONS

ECIG use exposes users to chemicals that may have negative health impacts on the respiratory system. Limited research has examined the broad range of negative respiratory symptoms associated with e-cigarette use. This study identified that ECIG-cigarette users perceive their ECIG use to be associated with negative respiratory symptoms. Many e-cigarette user-reported negative respiratory symptoms are similar to those associated with cigarette smoking, though some appear unique to e-cigarette use. Future research should continue to monitor respiratory symptoms reported by ECIG users and whether these are associated with health outcomes over time.

Prevalence and risk factors of e-cigarette use among working-age adults with and without disabilities in 2017-2018

BACKGROUND

Despite rapid growth in the use of electronic cigarettes (ECIGs) in the U.S., few studies have examined the national prevalence of ECIG use among adults with disabilities.

OBJECTIVE

To assess the national prevalence of and risk factors for ECIG use among working-age (18-64 years) adults with and without disabilities.

METHODS

This observational study relied on a sample of 560,858 working-age adults from the 2017-2018 Behavioral Risk Factor and Surveillance System (BRFSS). We conducted descriptive analyses to estimate the prevalence of ECIG use and multivariate logistic regression models to examine factors associated with ECIG use among adults with and without disabilities.

RESULTS

ECIG use was more prevalent among adults with a cognitive disability (12.0%), an independent living disability (11.0%), or two or more disabilities (9.2%), compared to adults without disabilities (4.8%). In the multivariate analysis, adults with a cognitive disability (OR = 1.45; p < .001), ambulatory disability (OR = 1.23; p < .05), and those with two or more disabilities (OR = 1.49; p < .001) had an increased likelihood of ECIG use compared to those without disabilities. Current smokers had greater odds of using ECIGs compared to never smokers (OR = 8.53, p < .001).

CONCLUSIONS

Adults with cognitive disabilities and independent living disabilities had more than twice the prevalence of ECIG use compared to adults without disabilities. Future studies should monitor the rising prevalence and risk factors for ECIG use as well as examine longitudinal associations between using ECIGs, dual use with cigarette smoking, and health outcomes among adults with disabilities.

A comparison of product dependence among cigarette only, ENDS only, and dual users: Findings from Wave 3 (2015-2016) of the PATH study

INTRODUCTION

Little is known about differences in tobacco product dependence among people who use two tobacco products versus one. Self-reported product dependence among individuals using cigarettes only, electronic nicotine delivery systems (ENDS) only, and both cigarettes and ENDS (dual users) was compared.

METHOD

PATH Wave 3 data were collected between 2015 and 2016. We used 11 Wisconsin Inventory of Smoking Dependence Motives items to assess cigarette and ENDS dependence, averaged to generate Cigarette Dependence (CD) and ENDS Dependence (ED) scores. Linear regression models were used to assess the association between tobacco use groups and the two dependence scores.

RESULTS

Our analytic sample included 5538 (91.5 %) cigarette only, 399 (6.7 %) ENDS only, and 108 (1.8 %) dual users. There was no difference in CD between cigarette only and dual users. ENDS only users' ED (2.11, SE = 0.05) was higher than dual users' ED (1.67, SE = 0.04) (p < 0.05). Dual users' mean ED (1.70, SE = 0.09) was significantly lower than their CD (3.03, SE = 0.11) (p < 0.001), and ENDS only users' ED (2.34, SE = 0.05) was significantly lower than cigarette only users' CD (2.94, SE = 0.02) (p < 0.001).

CONCLUSION

While there was no difference in CD between dual and cigarette only users, dual users' ED was lower than that for ENDS only users. ENDS appeared to produce less dependence than cigarettes among dual users. Given the high nicotine concentration ENDS products that entered the market after PATH Wave 3 data were collected, future research should examine ED among ENDS only and dual users.

E-Cigarette or Vaping Product Use-associated Lung Injury: Developing a Research Agenda. An NIH Workshop Report

The NHLBI convened a working group on October 23, 2019, to identify the most relevant and urgent research priorities and prevailing challenges in e-cigarette or vaping product use-associated lung injury (EVALI). Experts across multiple disciplines discussed the complexities of the EVALI outbreak, identified research priorities, and recommended strategies to address most effectively its causal factors and improve diagnosis, treatment, and prevention of this disease. Many research priorities were identified, including the need to create national and international registries of patients with EVALI, to track accurately those affected and assess outcomes. The group concluded that biospecimens from subjects with EVALI are urgently needed to help define EVALI pathogenesis and that vaping has disease risks that are disparate from smoking, with the occurrence of EVALI highlighting the importance of broadening e-cigarette research beyond comparators to smoking-related diseases.

Characterization of E-cigarette coil temperature and toxic metal analysis by infrared temperature sensing and scanning electron microscopy - energy-dispersive X-ray

INTRODUCTION

Electronic cigarettes (e-cigarettes) have rapidly evolved since their introduction to the U.S. market. The rebuildable atomizer (RBA) offers user-driven modification to the heating element (coil) and wicking systems. Different coil materials can be chosen based on user needs and preferences. However, the heating element of an e-cigarette is believed to be one-source for toxic metal exposure.

METHODS

E-cigarette coils from Kanthal and nichrome wires were constructed in a contact and non-contact configuration and heated at four voltages. The maximum temperatures of the coils were measured by infrared temperature sensing when dry and when saturated with 100% vegetable glycerin or 100% propylene glycol. The metal composition of each coil was analyzed with Scanning Electron Microscopy-Energy-Dispersive X-Ray (SEM-EDX) when new, and subsequently after 1, 50, and 150 heat cycles when dry.

RESULTS

The coils reached temperatures above 1000 °C when dry, but were below 300 °C in both liquid-saturated mediums. Metal analysis showed a decrease of 9-19% chromium and 39-58% iron in Kanthal wire and a decrease of 12-14% iron and 39-43% nickel in nichrome wire after 150 heat cycles. Significant metal loss was observed after one heat cycle for both coil alloys and configurations.

CONCLUSIONS

The loss of metals from these heat cycles further suggests that the metals from the coils are potentially entering the aerosol of the e-cigarette, which can be inhaled by the user.

What factors reliably predict electronic cigarette nicotine delivery?

BACKGROUND

The ability of an electronic cigarette (e-cigarette) to deliver nicotine effectively may be dependent on features of the device, the liquid and the user. Some of these features have been examined in previous work (eg, liquid nicotine concentration and puff topography), while others have not (eg, nicotine dependence and demographic characteristics). The purpose of this secondary analysis is to examine such features as predictors of e-cigarette nicotine delivery using a relatively large sample.

METHODS

Four studies were combined in which e-cigarette-experienced users (n=63; 89% men; 75% white) and e-cigarette-naïve cigarette smokers (n=67; 66% men; 54% white) took 10 puffs from an eGo-style e-cigarette (~7.3 watts) filled with liquid that had a nicotine concentration of 18, 25 or 36 mg/mL. Thus, held constant across all studies were device features of battery/cartomiser style and power level and the topography parameters of puff number and interpuff interval. Blood was sampled before and after use, and puff topography was measured. Three general linear models were conducted to predict plasma nicotine concentrations (pre-post increase) for: (1) e-cigarette users only, (2) smokers only and (3) both groups combined. Predictor variables included puff duration, puff volume, liquid nicotine concentration, presession plasma nicotine concentration, nicotine dependence score (smokers only), gender and race.

RESULTS

In all models tested, longer puff durations and higher liquid nicotine concentrations were associated significantly with increased nicotine delivery (ps<0.05). For e-cigarette users only, higher presession nicotine concentration was associated significantly with increased nicotine delivery (p<0.05).

CONCLUSIONS

Puff duration and liquid nicotine concentration may be among the more important factors to consider as regulators attempt to balance e-cigarette safety with efficacy. These findings should be interpreted in the context of devices with relatively low power output, a variable not studied here but likely also directly relevant to product regulation.

Variable Voltage, Tank-Style ENDS Do Not Always Deliver Nicotine

Objective

This study's objective was to characterize the nicotine delivery profile of a variable voltage, tank-style electronic nicotine delivery system (ENDS).

Methods

Ten cigarette smokers (8 men, 2 women) completed this within-subject study assessing effects of 2 device power settings (15 W, 45 W) and 3 liquid nicotine concentrations (0, 3, and 6 mg/ml) using a tank-style ENDS. Participants completed one directed (10 puffs) and one ad libitum use period for each condition, with blood sampled throughout.

Results

Plasma nicotine concentration did not increase significantly at 15 W regardless of liquid nicotine concentration. At 45 W, mean plasma nicotine increased (not significantly compared to 0 mg/ml) from 2.24 ng/ml (SD=0.2) at baseline to 3.4 ng/ml (SD=0.6) in the 3 mg/ml condition. In the 6 mg/ml, 45 W condition, mean plasma nicotine increased significantly (compared to 0 mg/ml) from 2.0 ng/ml (SD=0) at baseline to 5.96 ng/ml (SD=1.3) after 10 puffs. In general, puff duration and volume decreased as device power and nicotine concentration increased.

Conclusions

Despite using a variable wattage, tank-style device, nicotine delivery was minimal. These results, when combined with results from other studies using tank-style devices, highlight ENDS performance heterogeneity. Regulation may play a role in standardizing ENDS nicotine delivery.

Optimization of aqueous aerosol extract (AqE) generation from e-cigarettes and tobacco heating products for in vitro cytotoxicity testing

Electronic cigarettes (e-cigarettes) and tobacco heating products (THPs) have reduced yields of toxicants and have recently emerged as a potentially safer alternative to combustible cigarettes. To understand if reduced toxicant exposure is associated with reductions in biological responses, there is a need for high-quality pre-clinical in vitro studies. Here, we investigated the cytotoxic response of human umbilical vein endothelial cells to conventional cigarette aqueous aerosol extracts (AqE) and highly concentrated AqEs from e-cigarettes (two generations of atomisers) and THPs (two variants). All AqE samples were generated by a standardized methodology and characterized for nicotine, propylene glycol and vegetable glycerol. The cigarette AqE caused a maximum 100 ± 0.00 % reduction in cell viability at 35 % dose (2.80 puffs) as opposed to 96.63 ± 2.73 % at 50 % (20 puffs) and 99.85 ± 0.23 % at 75 % (30 puffs) for the two THP variants (glo Bright Tobacco, glo Rich Tobacco), and 99.07 ± 1.61 % at the neat ePen2.0 e-cigarette (200 puffs). The AqE of the remaining e-cigarettes either resulted in an incomplete dose-response or did not elicit any response. The methods utilized were suitably sensitive to not only differentiate between cigarette, THP and e-cigarette aerosols but also to distinguish between products within each product category.

Associated factors for depression, suicidal ideation and suicide attempt among asthmatic adolescents with experience of electronic cigarette use

INTRODUCTION

While electronic cigarette (EC) use is rapidly increasing among asthmatic adolescents, little is known about the links between EC use and depression or suicidality. We assessed associated factors for depression and suicidality in asthmatic adolescents with experience of EC use.

METHODS

We analyzed the data from the 11th to 13th Korea Youth Risk Behavior Web-based Surveys, which were completed from 2015 to 2017. Data were obtained from a stratified, multistage, clustered sample. Students supplied ‘yes or no’ answers to questions about previous asthma diagnosis by a doctor. Associated factors for depression and suicidality were evaluated by logistic regression models after controlling for potential confounding factors. We targeted 203336 adolescents, and 195847 completed the survey.

RESULTS

The proportion of asthma among the respondents was 8.9%. The rate of experience of EC use was higher among asthmatic respondents than non-asthmatic respondents (10.3% vs 8.6%). Asthmatic respondents with experience of EC use had a much higher proportion of negative mental health states including depression and suicidality than subjects without EC experience. In our adjusted models, perception of stress was most strongly associated with depression (adjusted odds ratio, AOR=4.79; 95% CI: 4.12–5.58), and perception of unhappiness was most strongly associated with suicidal ideation (AOR=5.24; 95% CI: 4.51–6.09) and suicide attempt (AOR=4.37; 95% CI: 3.36–5.69).

CONCLUSIONS

Many Korean asthmatic adolescents with experience of EC use report relatively high depression and suicidal behaviors. A multidisciplinary approach, including psychological help, may be required to prevent suicide among this population, especially those who report associated factors.

Validation of an E-cigarette Purchase Task in Advanced Generation Device Users

INTRODUCTION

Behavioral economic purchase tasks are used to estimate the reinforcing value of drugs by asking participants how much they would purchase across a range of increasing prices. We sought to validate such a task for e-cigarettes in experienced users of advanced generation, tank-style devices.

METHODS

Dual users of cigarettes and e-cigarettes (N = 54) and exclusive e-cigarette users (N = 59) attended one session during which they completed assessments including two versions of the E-cigarette Purchase Task: one that asked how many puffs of their e-cigarette they would purchase in 24 hours at varying prices and one that asked how many mLs of e-liquid they would purchase. We correlated purchase task outcomes with other measures of e-cigarette use. We also compared the tasks across dual and exclusive users.

RESULTS

Indices derived from the mLs-based task were more likely to be correlated with self-reported use rates, e-cigarette dependence, and cotinine levels than the puffs-based task. Exclusive users showed greater demand on than dual users only on the mLs version when using an F-test comparison method, while multivariate analysis of variance (MANOVA) results showed that dual users showed greater demand only on the puffs task.

CONCLUSIONS

Results indicate that the mLs version had greater validity than the puffs version in terms of clinical indices. Dual users may still be on a trajectory to fully switching to e-cigarettes; thus, puffs as a measure may be more intuitive, as this measure is shared by cigarettes and e-cigarettes. For exclusive users, the unit they purchase their e-liquid in may be the most relevant unit and better capture their demand for that product.

IMPLICATIONS

Behavioral economic purchase tasks have been widely used to understand nicotine use. We have developed two versions of a purchase task for e-cigarette use and compared the two versions in users of advanced generation e-cigarette devices. We found that the mLs version of the task better-reflected use patterns relative to a puffs version, which suggests that participants struggle to place monetary value on a unit of consumption (ie, puffs). Validated measures of e-cigarette reinforcement will be important as researchers and regulators determine which features of these products contribute to reinforcing efficacy.

Collecting e-cigarette aerosols for in vitro applications: A survey of the biomedical literature and opportunities to increase the value of submerged cell culture-based assessments

Electronic nicotine delivery systems (ENDS) are being developed as potentially reduced‐risk alternatives to the continued use of combustible tobacco products. Because of the widespread uptake of ENDS—in particular, e‐cigarettes—the biological effects, including the toxic potential, of their aerosols are under investigation. Preclinically, collection of such aerosols is a prerequisite for testing in submerged cell culture‐based in vitro assays; however, despite the growth in this research area, there is no apparent standardized collection method for this application. To this end, through an Institute for in vitro Sciences, Inc. workshop initiative, we surveyed the biomedical literature catalogued in PubMed® to map the types of methods hitherto used and reported publicly. From the 47 relevant publications retrieved, we identified seven distinct collection methods. Bubble‐through (with aqueous solvents) and Cambridge filter pad (CFP) (with polar solvents) collection were the most frequently cited methods (57% and 18%, respectively), while the five others (CFP + bubble‐through; condensation; cotton filters; settle‐upon; settle‐upon + dry) were cited less often (2–10%). Critically, the collected aerosol fractions were generally found to be only minimally characterized chemically, if at all. Furthermore, there was large heterogeneity among other experimental parameters (e.g., vaping regimen). Consequently, we recommend that more comprehensive research be conducted to identify the method(s) that produce the fraction(s) most representative of the native aerosol. We also endorse standardization of the aerosol generation process. These should be regarded as opportunities for increasing the value of in vitro assessments in relation to predicting effects on human health.

Collection of e‐cigarette aerosols is a prerequisite to enable testing in submerged culture‐based in vitro assays; however, there is no standardized method for this. Thus, we surveyed the biomedical literature to map the types of published methods. Bubble‐through and Cambridge filter pad methods were most common, although there was heterogeneity among other parameters, and moreover, the resulting fractions were only minimally characterized. Comprehensive research is required to identify the method(s) that produce the fraction(s) most representative of the native aerosol.

People smoke for nicotine, but lose sexual and reproductive health for tar: a narrative review on the effect of cigarette smoking on male sexuality and reproduction

PURPOSE

To systematically review the impact of smoking habits on cardiovascular (CV) as well as on male sexual and reproductive function and to provide updated evidence on the role of electronic cigarettes (e-Cig) on the same topics.

METHODS

A comprehensive Medline, Embase, and Cochrane search was performed including the following words: smoking, CV system, CV risk, erectile dysfunction (ED), and male fertility. Publications from January 1, 1969 up to February 29, 2020 were included.

RESULTS

Smoking has a tremendous negative impact on CV mortality and morbidity. Current smoking behavior is also negatively associated with erectile dysfunction (ED) and impaired sperm parameters. E-Cig can release significantly lower concentrations of harmful substances when compared to regular combustible cigarettes. Whether or not the latter can result in positive CV, sexual, and fertility outcomes is still under study. Preliminary studies showed that exposure to e-Cig leads to lower vascular damage when compared to the traditional cigarette use. However, data on the long-term effects of e-Cig are lacking. Similarly, preliminary data, obtained in animal models, have suggested a milder effect of e-Cig on erectile function and sperm parameters.

CONCLUSION

Available evidence showed that e-Cig are much less dangerous when compared to the traditional tobacco use. However, it should be recognized that the risk related to e-Cig is still higher when compared to that observed in non-smoking patients. Hence, e-Cig should be considered as a potential tool, in the logic of harm reduction, to reduce the CV, sexual and fertility risk in patients refractory to the fundamental, healthy choice to definitively quit smoking.

Nicotine forms: why and how do they matter in nicotine delivery from electronic cigarettes?

INTRODUCTION

Unregulated e-cigarette devices and their nicotine content have amplified the potential of e-cigarettes as addictive agents. Several e-cigarette-related parameters have been identified altering nicotine's absorption profile, so their potential effects on addiction should be considered. Of these factors, nicotine forms (protonated and free base) play a significant role in the addiction potential yet their impact on nicotine's absorption has been studied with limited research.

AREAS COVERED

Current review aims to emphasize on the possible mechanism behind different absorption profiles of nicotine forms considering their physical states (droplet and vapor phase) and the aerosol particle size, their analysis in e-cigarette research and the regulatory attention warranted by them to combat nicotine addiction in the population due to e-cigarettes.

EXPERT OPINION

The protonated form of nicotine is being correlated with the smooth sensory effects and high nicotine absorption as compared to free base nicotine. With the introduction of nicotine salts, which yield mostly the protonated form, the youth popularity of e-cigarettes has spiked exponentially. While it is important to control nicotine levels in e-cigarette products, attention should also be given to the nicotine forms present in these products in order to address nicotine addiction in the population.

Are E-cigarette Users a Unique Group of Smokers? Latent Class Analysis of the National Youth Tobacco Survey

We used data from the 2014 National Youth Tobacco Survey to examine patterns of cigarette smoking behavior and tobacco use. In light of the recent upsurge in e-cigarette use, we modeled current use and future intentions to use vape products along with combustible cigarette smoking and other tobacco products (i.e., cigars, cigarillos, chew, snuff, and dip). Latent class analyses indicated four discrete classes of smokers including a nominally involved class with very modest levels of tobacco product use, a class blending e-cigarette and cigars, a class of youth who predominantly use combustible cigarettes, and a group reporting indiscriminate use of almost all tobacco products excluding chew. Tests of invariance in item response probabilities and latent class proportions showed little variation across race and gender, albeit a new class of combustible cigarette and e-cigarette users emerged when examined by grade. Members of the heavy smoking and tobacco use class were more likely to be male, White, and older. Predictors of class membership included expectancies (perceived benefits of use), perceived harm (risk), media exposure, tobacco dependence, and the desire to quit. Findings are discussed in terms of characterizing risk among already smoking youth and how actionable prevention measures can be incorporated into existing universal and indicated programs that target reducing tobacco use and smoking behaviors.

A simple predictive model for estimating relative e-cigarette toxic carbonyl levels

E-cigarette devices are wide ranging, leading to significant differences in levels of toxic carbonyls in their respective aerosols. Power can be a useful method in predicting relative toxin concentrations within the same device, but does not correlate well to inter-device levels. Herein, we have developed a simple mathematical model utilizing parameters of an e-cigarette’s coil and wick in order to predict relative levels of e-liquid solvent degradation. Model 1, which is coil length/(wick surface area*wraps), performed in the moderate-to-substantial range as a predictive tool (R² = 0.69). Twelve devices, spanning a range of coil and wick styles, were analyzed. Model 1 was evaluated against twelve alternative models and displayed the best predictability. Relationships that included power settings displayed weak predictability, validating that power levels cannot be reliably compared between devices due to differing wicking and coil components and heat transfer efficiencies.

Beliefs about the Harmfulness of Heated Tobacco Products Compared with Combustible Cigarettes and Their Effectiveness for Smoking Cessation among Korean Adults

Heated tobacco products (HTPs) have been widely used in Korea since their introduction in 2017. In this study, we investigated the perceptions of their relative harmfulness and smoking cessation effects. We performed an online survey in 7000 Koreans in 2018 (2300 males and 4700 females aged 20-69 years) by matching their age, sex, and provincial distribution. To investigate the factors causing HTPs to be perceived as less harmful than combustible cigarettes (CCs) and helpful for smoking cessation, we used multivariable logistic regression analyses. HTPs were less harmful than CCs in 16.8% of participants, particularly among HTP-only users and dual and triple users of HTPs, electronic cigarettes (ECs), or CCs than among CC-only users, those who were aged ≤ 34 years, males, and those with higher incomes. HTPs were reportedly helpful for smoking cessation in 11.2% of participants. Similar perceptions were more likely among HTP-only users, as well as dual and triple users than among CC-only users and adults with higher education/incomes. Although Korean adults generally had negative perceptions of the harmfulness and smoking cessation effects of HTPs compared with CCs, dual and triple users were more likely to have positive perceptions. Monitoring the use of multiple tobacco products and HTPs is a new challenge for Korean policymakers.

Recent findings in the pharmacology of inhaled nicotine: Preclinical and clinical in vivo studies

INTRODUCTION

The rise of vaping in adolescents, the recent entrance of new inhaled nicotine products such as iQOS on the market and e-cigarette or vaping product use-associated lung injury cases has created concern for the use of inhaled non-combustible nicotine products. This narrative review discusses recent experimental in vivo studies that utilize human, rat and mouse models to understand the pharmacological impact of nicotine from non-combustible products.

METHODS

The search engine PubMed was utilized with the following search terms: inhaled nicotine, nicotine e-cigarette, heated tobacco products, iQOS, electronic cigarette, nicotine inhaler, nicotine vaping. This review highlights recent primary in vivo studies of inhaled nicotine administration experimental paradigms that occurred in laboratory settings using human and rodent (rats and mice) models that have been published from January 2017-December 2019.

RESULTS

The pharmacokinetics of nicotine via e-cigarettes is influenced by the PG/VG and flavor constituents in e-liquids, the presence of nicotine salts in e-liquids, puff topography of nicotine and tobacco product users and the power of the e-cigarette device. The pharmacodynamic impact of inhaled nicotine has cardiovascular, pulmonary and central nervous system implications.

CONCLUSION

The articles reviewed here highlight the importance of both animal and human models to fully understand the impact of inhaled nicotine pharmacology There is a need for more rodent pharmacokinetic inhaled nicotine studies to understand the influences of factors such as flavor and nicotine salts. Additionally, consensus on nicotine measurement in both human and rodent studies is greatly needed.

The analysis of commercially available natural products recommended for use in electronic cigarettes

RATIONALE

Natural plant products have been used to promote health, prevent sickness, and treat various ailments. These products often consist of leaves, flowers, bark, roots, seeds, and/or other parts of the plant. Many of the pharmacologically active constituents of these products are known, but the pharmacology of these constituents may not be fully elucidated. Natural plant-based products are also available in various forms other than the raw plant material. A wide array of commercial products such as capsules, powders, extracts, and electronic cigarette (e-cigarette) electronic liquids (e-liquids) are readily available and can be purchased from various outlets, both store-based retailers and online. Newer e-cigarettes are often advertised as "heat not burn" and are used for "vaping" various forms of extracts including "waxes" and "dabs" and raw plant material.

METHODS

A single manufacturer was found online selling "24 different herbs" in powders, extracts, or e-liquids. These were advertised as "legal in the USA" and each product listed multiple effects. Eight e-liquids, six extracts (resins), and four powders from eight different "herbs," namely African dream, areca nut, blue lotus, damiana, kra thum na, kra thum kok, klip dagga, and wild lettuce, were purchased. An advertisement for these products stated, "Most people use the leaves, powder or resin in vaporizers." Direct analysis in real time AccuTOF™ mass spectrometry (DART-MS) was used to identify the psychoactive components in the natural products.

RESULTS

The psychoactive compounds that were identified in only two of the eight e-liquids, three of the five resins, and three of the four powders were arecaidine, arecoline, coumarin, entadamide, mitragynine, 7-hydroxymitragynine, and nuciferine.

CONCLUSIONS

Psychoactive and potentially harmful substances were present in the powders and resins of the natural products. The newer types of e-cigarettes made for consuming natural products may increase their abuse potential.

Vaping implications for children and youth

PURPOSE OF REVIEW

The development and uptake of E cigarettes are a relatively recent phenomenon. Because of aggressive marketing, attractive designs, enticing flavors and primarily reactionary legislation, we are now seeing soaring rates of adolescent vaping with associated consequences. This review explores how E cigarettes work, their health implications, epidemiology among youth and current regulatory strategies.

RECENT FINDINGS

Recently, the Center for Disease Control and Prevention reported that 27% of high school students had used a tobacco product within the last month, the majority being E-cigarettes in 20.8% of high school students. Vaping has managed to reverse a decades long trend of declining nicotine use among youth. Long-term addiction is not the only concern related to youth vaping; there are also increasing reports of short-term health consequences, such as seizures, acute nicotine toxicity, burns and lung injury.

SUMMARY

Industry has created and aggressively marketed a product that is enticing to adolescents. E cigarettes have sleek designs, desirable flavors and social acceptability with perceived safety among youth. This has resulted in epidemic E cigarette use in youth with resultant significant short-term and long-term health concerns. Legislation must include regulations that strictly avoid marketing and sales to youth, as well as reducing access to these products.

Association of Electronic Nicotine Delivery System Use With Cigarette Smoking Relapse Among Former Smokers in the United States

IMPORTANCE

Relapse to smoking among former smokers is a serious clinical concern, and use of electronic nicotine delivery systems (ENDS) has been proposed as a new risk factor for relapse. Understanding the specificity of this risk can help guide clinical practice and lead to improved health outcomes.

OBJECTIVE

To assess the associations of ENDS use with cigarette smoking relapse among adult former cigarette smokers.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study examined data from the Population Assessment of Tobacco and Health Study, waves 1 to 4 (2013-2018). Cox proportional hazards models were developed. This is an ongoing, nationally representative, longitudinal cohort study in the US. Participants included adult (≥18 years) former cigarette smokers who reported no tobacco product use at wave 1 (unweighted n = 2273), separated into recent former cigarette smokers (last smoked ≤12 months previously) and long-term former smokers (last smoked >12 months previously). Data analysis was conducted from July to August 2019.

EXPOSURES

Self-reported use of cigarettes, ENDS, and other tobacco products (ie, cigars, pipe tobacco, hookah, snus tobacco, other smokeless tobacco, and dissolvable tobacco) was assessed.

MAIN OUTCOMES AND MEASURES

Self-reported current (every day or some days) use of cigarettes at follow-up interviews.

RESULTS

Of 2273 adult former cigarette smokers, 51.8% (95% CI, 49.7%-53.8%) were women, 65.0% (95% CI, 62.6%-67.4%) were older than 50 years, and 79.5% (95% CI, 77.8%-81.2%) were non-Hispanic white participants. Use of ENDS was associated with significant risk of cigarette smoking relapse among recent former smokers (adjusted hazard ratio [AHR], 1.63; 95% CI, 1.04-2.53; unweighted n = 304) and among long-term former smokers (AHR, 3.79; 95% CI, 1.75-8.20; unweighted n = 1554). Use of other tobacco products was also associated with significant risk for cigarette smoking relapse among recent former smokers (AHR, 1.97; 95% CI, 1.27-3.05) and among long-term former smokers (AHR, 3.82; 95% CI, 1.91-7.66).

CONCLUSIONS AND RELEVANCE

In this study, use of ENDS and other tobacco products was associated with increased risk of cigarette smoking relapse among former cigarette smokers who did not use any tobacco product at wave 1 of the PATH Study. For clinicians treating former smokers who have successfully quit all nicotine products, the implications are that use of ENDS products should be discouraged, just as use of all other tobacco products is discouraged.

Orthodox and Unorthodox Uses of Electronic Cigarettes: A Surveillance of YouTube Video Content

INTRODUCTION

Open electronic cigarette (e-cigarette) systems are customizable by consumers and often allow for potential "unorthodox" use of the product; that is, use not as intended by the manufacturer. Little is known about the types and prevalence of unorthodox uses and how these practices are transmitted via popular social media.

METHODS

Monthly searches of YouTube were conducted from June through November 2016 using the following search terms: "e-cigarettes," "vaping," and "e-juice." After collecting static and dynamic data on the 150 videos identified, two coders independently coded videos for general information, unorthodox use behaviors, health claims, and production quality and characteristics for orthodox and unorthodox use. Intercoder reliability was high (Cohen's κ 0.81, p < .001).

RESULTS

One hundred fifty videos were included in the study with a total of 115 551 563 views. We identified nine categories of unorthodox uses of e-cigarettes. Unorthodox use was three times as prevalent as orthodox use. Seventy-seven percent of the unorthodox use videos included recreational e-cigarette use, 57% included modification of mechanical parts and components, and 44.6% included unorthodox substance application (dripping). There were more than twice as many social media links in videos depicting unorthodox compared to orthodox use, but the level of engagement was lower for unorthodox use.

CONCLUSIONS

E-cigarette unorthodox use on YouTube is more prevalent than orthodox use, suggesting the need to further investigate the prevalence of unorthodox use among e-cigarette users and the influence of social media on consumer uptake of unorthodox and orthodox uses of e-cigarettes.

IMPLICATIONS

The US Food and Drug Administration has regulatory authority over e-cigarettes, parts and components. Many e-cigarettes currently marketed are open systems. Closed systems may allow less manipulation and may influence the safety of these products. This study provides valuable information on ways that open system e-cigarettes are used and it can inform safety tests that can be conducted by the US Food and Drug Administration to determine whether or not these products should remain on the market. In addition, our definitions of unorthodox use can be incorporated into the Population Assessment of Tobacco on Health Study to better understand the prevalence of these behaviors.

Differential effects of nicotine delivery rate on subjective drug effects, urges to smoke, heart rate and blood pressure in tobacco smokers

RATIONALE

The nicotine delivery rate is a key feature of tobacco product design, yet there have been limited human studies examining the effects of nicotine as a function of delivery rate.

OBJECTIVE

We developed an intravenous nicotine infusion protocol to evaluate differential effects of nicotine delivery rate on subjective drug effects, smoking urges, abstinence symptoms, heart rate, and blood pressure.

METHODS

Eighteen non-treatment seeking, overnight abstinent male and female smokers (18 to 30 years old), who smoked ≥ 5 cigarettes per day for the past year completed four sessions, in which they were randomly assigned to a saline infusion, or a 1 mg per 70-kg body weight dose of nicotine delivered over 1, 5, or 10 min at rates of 0.24, 0.048, or 0.024 μg/kg/s, respectively.

RESULTS

Smoking urges, as assessed by the Brief Questionnaire of Smoking Urges, were reduced relative to placebo for the 1- and 5-min infusion, but not the 10-min infusion. Although the 1- and 5-min infusions reduced smoking urges to a similar extent, the 1-min infusion induced a greater heart rate and blood pressure increase. Changes to subjective drug effects, heart rate, and blood pressure delineate the differential effects of nicotine delivery rate for these outcomes.

CONCLUSIONS

We have characterized the delivery rate-response curve for a nicotine dose that is roughly the amount of nicotine (~ 1 mg) delivered by smoking a standard tobacco cigarette. Our findings reinforce the importance of nicotine delivery rate when evaluating the potential effects of nicotine from tobacco products.

Perioperative Implications of Vaping

Over the past 10 - 15 years, there has been a significant increase in the use of electronic cigarettes. These devices are generally used to deliver nicotine through inhalation by aerosolization. While the long-term risk of lung cancer is yet to be known, the chemicals and impurities in the solutions may have other acute and chronic effects on the respiratory system including respiratory failure from adult respiratory distress syndrome. Recent concerns have been raised regarding the potential for significant acute and chronic health care risks of these devices including pneumonitis, airway reactivity and respiratory failure. Given that many of the acute effects are related to the respiratory system, anesthetic care may be required during diagnostic procedures including bronchoscopy to investigate the etiology of acute respiratory symptomatology. We present an adolescent who presented to the operating room for bronchoscopy and bronchoalveolar lavage to investigate the etiology of respiratory involvement following an episode of vaping. The healthcare and end-organ effects of nicotine, tobacco smoke and vaping are discussed, and potential anesthetic implications are presented.

Longitudinal Analysis of Associations Between Reasons for Electronic Cigarette Use and Change in Smoking Status Among Adults in the Population Assessment of Tobacco and Health Study

INTRODUCTION

Electronic cigarette (ECIG) use and changes in cigarette smoking status may be influenced by self-reported reasons for using ECIGs.

METHODS

We analyzed adult current and former cigarette smokers who were also current or former ECIG users at wave 1 (n = 3044) using wave 1 and wave 2 Population Assessment of Tobacco and Health Study data (2013-2015). Prevalence of reporting 13 reasons for ECIG use at wave 1 was examined and weighted logistic regressions were conducted predicting smoking status changes from wave 1 to wave 2.

RESULTS

Reasons for ECIG use ranged from 18.1% (people in the media or public figures use them) to 82.5% (they might be less harmful to people around me than cigarettes). From wave 1 to wave 2, 27.2% of former smokers (n = 249) became current smokers and 11.6% of current smokers (n = 246) became former smokers. Among wave 1 former smokers, using ECIGs because of the availability of flavors (AOR = 0.57, 95% CI = 0.39-0.85) or because they don't smell (AOR = 0.64, 95% CI = 0.42-0.97) was associated with lower odds of relapse to smoking, but using ECIGs because using them helps people quit smoking (AOR = 1.55, 95% CI = 1.01-2.38) was associated with greater odds of relapse. Among wave 1 current smokers, using ECIGs because they can be used where smoking is not allowed (AOR = 0.56, 95% CI = 0.38-0.85) was associated with reduced odds of quitting cigarettes.

CONCLUSIONS

Some reasons for ECIG use are associated with changes in self-reported smoking status. Researchers should examine ECIG user characteristics when assessing associations between ECIG use and smoking status transitions.

IMPLICATIONS

Given that certain reasons for ECIG use, such as using ECIGs in locations are where smoking is not allowed, may inhibit smoking reduction, policies may be developed to prevent ECIG use in locations where smoking is banned. In addition, because certain reasons for ECIG use may aid in relapse prevention, such as availability of desired flavors, efforts should be made to identify ECIG device characteristics that are appealing to smokers but not youth or nontobacco users. These results provide support for future research on reasons for ECIG use to inform regulatory policies.

Perception of E-cigarette Use among Adult Users in China: A Mixed-method Study

The use of electronic cigarettes (ECs) is increasing rapidly in China, but the perception of these products and their health impact among Chinese users have received little research attention. This study collected semi-structured in-depth interview data from experienced adult EC (including heated tobacco products also named ECs on the Chinese market) users in the Shanghai area. The subjects were recruited from those who participated in a previous online survey on EC use. A thematic narrative approach was used to analyze the data. Thirty current EC users were interviewed for evaluation of their perception of EC use in a variety of categories, including reasons for using, concerns, social acceptance, satisfaction, and health impacts. Participants' common reasons for using ECs were the ease of use and carrying, hygiene, no fire hazard, reduced smoke exposure, aiding quitting smoking, reduced health hazard, palatable flavor, being fashionable, and substituting cigarettes in non-smoking areas. Most (90%; 27/30) participants reduced (77%) or quit smoking (13%) after using ECs, and 80% were willing to recommend these products to others. Most (90%) of the participants reportedly noticed positive health changes after using ECs. Regulatory concerns were expressed by 33% participants. Participants predominately viewed ECs as a viable substitute for smoking, with substantial effects on tobacco harm reduction. These findings lend support to EC use as a promising opportunity for public health promotion in China through engaging smokers in smoking cessation attempts. However, overall public health benefits/risks of EC use, and its regulatory affairs need to be considered.

Effect of electronic cigarette aerosol exposure during gestation and lactation on learning and memory of adult male offspring rats

INTRODUCTION

Electronic cigarette (ECIG) use has increased worldwide, including among pregnant and breastfeeding women. In this study, we examined the effect of ECIG aerosol exposure during gestation and lactation on learning and memory of adult male offspring rats.

METHODS

Rats were exposed to either fresh air or ECIG aerosol for one hour daily during gestational period as well as days 4-21 of lactation. Male offspring were followed through 19 weeks and then spatial learning and memory were tested by radial arm water maze (RAWM). The hippocampus was examined for biomarkers of harm, including oxidative stress, superoxide dismutase, catalase, glutathione peroxidase and thiobarbituric acid reactive substances and brain derived neurotrophic factor (BDNF).

RESULTS

Relative to exposure to fresh air, exposure to ECIG aerosol during gestation/lactation impaired long-term memory in adult offspring (P < 0.05). This impairment was associated with increased activity of superoxide dismutase in the hippocampus (P < 0.05). BDNF and the other tested oxidative stress biomarkers were not affected by ECIG aerosol exposure (p > 0.05).

CONCLUSIONS

In conclusion, ECIG aerosol exposure during gestation and lactation impaired long-term memory and increased the activity of superoxide dismutase in the hippocampus of offspring adult rats. These results support the development of strategies to enhance ECIG cessation during pregnancy and breastfeeding.

Urinary biomonitoring of subjects with different smoking habits. Part I: Profiling mercapturic acids

BACKGROUND

While tobacco smoke contains thousands of chemicals, some of which are carcinogenic to humans, the content of electronic cigarette smoke is less known. This work aimed to assess and compare the exposure associated with different smoking habits by profiling urinary mercapturic acids as biomarkers of toxic compounds.

METHODS

In this pilot study, sixty-seven healthy adults with different smoking habits were investigated: 38 non-smokers (NS), 7 electronic cigarette users (ECU), and 22 traditional tobacco smokers (TTS). Seventeen urinary mercapturic acids, metabolites of 1,3-butadiene (DHBMA, MHBMA), 4-chloronitrobenze (NANPC), acrolein (3-HPMA), acrylamide (AAMA, GAMA), acrylonitrile (CEMA), benzene (SPMA), crotonaldehyde (CMEMA, HMPMA), ethylating agents (EMA), methylating agents (MMA), ethylene oxide (HEMA), N,N-dimethylformamide (AMCC), propylene oxide (2-HPMA), styrene (PHEMA), and toluene (SBMA), were quantified, along with urinary nicotine and cotinine.

RESULTS

Median urinary cotinine was 0.4, 1530 and 1772 μg/L in NS, ECU and TTS, respectively. Most mercapturic acids were 2-165 fold-higher in TTS compared to NS, with CEMA, MHBMA, 3-HPMA and SPMA showing the most relevant increases. Furthermore, some mercapturic acids were higher in ECU than NS; CEMA and 3-HPMA, in particular, showed significant increases and were 1.8 and 4.9 fold-higher, respectively.

CONCLUSIONS

This study confirms that tobacco smoking is a major source of carcinogenic chemicals such as benzene and 1,3-butadiene; electronic cigarette use is a minor source, mostly associated with exposure to chemicals with less carcinogenic potential such as acrylonitrile and acrolein.

Effects of Electronic Cigarettes on Indoor Air Quality and Health

With the rapid increase in electronic cigarette (e-cig) users worldwide, secondhand exposure to e-cig aerosols has become a serious public health concern. We summarize the evidence on the effects of e-cigs on indoor air quality, chemical compositions of mainstream and secondhand e-cig aerosols, and associated respiratory and cardiovascular effects. The use of e-cigs in indoor environments leads to high levels of fine and ultrafine particles similar to tobacco cigarettes (t-cigs). Concentrations of chemical compounds in e-cig aerosols are generally lower than those in t-cig smoke, but a substantial amount of vaporized propylene glycol, vegetable glycerin, nicotine, and toxic substances, such as aldehydes and heavy metals, has been reported. Exposures to mainstream e-cig aerosols have biologic effects but only limited evidence shows adverse respiratory and cardiovascular effects in humans. Long-term studies are needed to better understand the dosimetry and health effects of exposures to secondhand e-cig aerosols.

Effects of Electronic Cigarettes on Indoor Air Quality and Health

With the rapid increase in electronic cigarette (e-cig) users worldwide, secondhand exposure to e-cig aerosols has become a serious public health concern. We summarize the evidence on the effects of e-cigs on indoor air quality, chemical compositions of mainstream and secondhand e-cig aerosols, and associated respiratory and cardiovascular effects. The use of e-cigs in indoor environments leads to high levels of fine and ultrafine particles similar to tobacco cigarettes (t-cigs). Concentrations of chemical compounds in e-cig aerosols are generally lower than those in t-cig smoke, but a substantial amount of vaporized propylene glycol, vegetable glycerin, nicotine, and toxic substances, such as aldehydes and heavy metals, has been reported. Exposures to mainstream e-cig aerosols have biologic effects but only limited evidence shows adverse respiratory and cardiovascular effects in humans. Long-term studies are needed to better understand the dosimetry and health effects of exposures to secondhand e-cig aerosols.

Abuse liability of electronic cigarettes in men who are experienced electronic cigarette users

Most electronic cigarettes (e-cigs) aerosolize a nicotine-containing liquid that users inhale. Few experimental studies have examined e-cig abuse liability (the extent to which use of these products may lead to persistent and/or problematic use). In this study, 24 experienced male e-cig users completed 4 sessions that differed byproduct used: own e-cig (OWN), an eGo e-cig filled with participants' own brand/flavor liquid in 0 mg/mL nicotine (e-cig0), an eGo e-cig filled with the highest nicotine concentration available in participants' own brand/flavor (e-cighighest), and a U.S. Food and Drug Administration-approved nicotine inhaler (IN). Outcome measures included crossover point on the multiple-choice procedure, plasma nicotine delivery, and subjective effect profile. After 10 puffs, a significantly higher mean crossover point was observed for OWN at $1.35 (SD = 0.90) compared to e-cighighest at $0.88 (SD = 0.89), e-cig0 at $0.83 (SD = 0.79), and IN at $0.72 (SD = 0.84). Significant increases in mean plasma nicotine concentration were observed for OWN at 7.94 ng/mL (SD = 6.19) and e-cighighest at 7.51 ng/mL (SD = 5.39). Significant reductions in abstinence symptom suppression and higher ratings of satisfaction were observed for OWN and e-cighighest, with significantly less suppression and lower ratings of satisfaction for e-cig0 and IN. These findings suggest that human laboratory methods can be used to assess e-cig abuse liability and that nicotine-containing e-cigs have greater abuse liability than nicotine-free e-cigs and the IN. Potential regulations intended to limit e-cig abuse liability should be tested using these or similar procedures. (PsycInfo Database Record (c) 2020 APA, all rights reserved).