Electronic Cigarette Users Research Articles

Changes in Tobacco Use in the Early Phase of Coronavirus Disease 2019 Pandemic in Hong Kong: A Qualitative Study.

IntroductionChanges in tobacco use and related personal and environmental factors amid the coronavirus disease 2019 (COVID-19) pandemic can be captured by qualitative studies, but they are few in non-Western populations.Aims and MethodsWe assessed the perceived links between tobacco use and COVID-19, and changes in the use of cigarettes, electronic cigarettes (ECs), and heated tobacco products (HTPs) in the early phase of the pandemic in Hong Kong, where lockdown was not implemented. Semi-structured telephone interviews were conducted from January to June 2021 in 95 participants (36 EC users, 28 HTP users, and 32 exclusive cigarette users). Transcriptions were coded using deductive and inductive approaches, and factors for changes were nested in the social-ecological model.ResultsTwo-thirds of participants perceived their infection susceptibility was the same as never tobacco users, and 44.2% perceived more severe COVID-19 disease if infected. Amid the pandemic, tobacco use decreased overall but increased indoors for all three products. Increased tobacco use was mostly attributed to increased emotional distress, while decreases were attributed to various personal (health concerns) and environmental factors (e.g., COVID-19 regulations). Perceived convenience and lower costs were reasons for increased EC use. Limited access to HTPs was compensated by cigarette use.ConclusionsMany participants were unaware of the potential harm of tobacco use on COVID-19. Overall tobacco use decreased due to COVID-19 regulations, which may not be sustainable post-pandemic. Indoor consumption increased, supporting a comprehensive smoke-free policy that covers private indoor areas. Better cessation services targeting EC, HTP, and cigarette use are needed.ImplicationsSmokers need better awareness of the risk of tobacco use on COVID-19. Smoking cessation services can be improved by offering brief advice, strengthening advocacy against secondhand smoke, and covering EC and HTP use, highlighting their potential harms to users and others, and their risk of addiction and relapse to cigarette use.

Implications of Electronic Cigarettes on the Safe Administration of Sedation and General Anesthesia in the Outpatient Dental Setting.

Today the number of electronic cigarette users continues to rise as electronic cigarettes slowly, yet steadily overtake conventional cigarettes in popularity. This shift is often attributed to the misconception that electronic cigarettes are "safer" or "less dangerous" than conventional cigarettes. Recent studies have shown that electronic cigarettes are far from safe and that the inhaled agents and byproducts within vaping aerosols can have adverse effects on systemic and oral health like combustible tobacco products. The first electronic cigarettes were originally introduced as a tool for smoking cessation. However, newer iterations of electronic cigarette devices have been modified to allow the user to consume tetrahydrocannabinol (THC), the psychoactive component of cannabis, in addition to nicotine. As the popularity of these devices continues to rise, the number of patients seeking dental treatment who also consume electronic cigarettes will too. This article aims to shed light on the deleterious effects electronic cigarettes can have on systemic and oral health, as well as the special considerations for sedation and anesthesia providers treating patients who use electronic cigarettes.

Biomarkers of Exposure and Potential Harm in Exclusive Users of Electronic Cigarettes and Current, Former and Never-Smokers: A Cross-Sectional Study Protocol

Biomarkers of Exposure and Potential Harm in Exclusive Users of Electronic Cigarettes and Current, Former and Never-Smokers: A Cross-Sectional Study Protocol

The impact of tobacco smoking and electronic cigarette vaping on salivary biomarkers. A comparative study

ObjectivesThis study aimed to investigate the effect of electronic cigarette vaping and cigarette smoking on the levels of interleukin-1β and transforming growth factor‑β salivary biomarkers compared to non-smokers. MethodsOne hundred and fifty people participated in this study; There were 50 participants who smoked traditional cigarettes, 50 who used electronic cigarettes, and 50 healthy people who had never smoked cigarettes (control group). Furthermore, 5 ml of unstimulated whole saliva was sampled and clarified by centrifugation and frozen until analysis. Interleukin-1β and transforming growth factor‑β concentrations were assessed in saliva samples using ELISA. The duplicate readings average was utilized to interpret the data. ResultsWe found that cigarette smokers had significantly higher levels of interleukin-1β and transforming growth factor‑β than non-smokers and electronic cigarette users (p < 0.05). The difference between control participants and electronic cigarette users, as well as that between control participants and traditional cigarette smokers, was statistically significant (p < 0.05). ConclusionElectronic cigarette users have higher levels of inflammatory and cancer risk biomarker than non-smokers, suggesting that electronic cigarettes can pose a risk of developing systemic diseases but less than conventional cigarettes. In conclusion, our study could be regarded as new evidence supporting the hazardous effects of e-cigs using a cost-effective, non-invasive method.

Examining smoking and vaping behaviors, expectancies, and cessation outcomes between bisexual and heterosexual individuals

Prior research indicates bisexual individuals have higher smoking and vaping rates and heightened vulnerability to negative health outcomes. Thus, we compared adult bisexual (n = 294) and heterosexual (n = 2412) participants enrolled in a smoking cessation trial on baseline smoking and vaping use behaviors, motivations, and expectancies/beliefs as well as follow-up smoking and vaping status. This is a secondary analysis of a large randomized controlled trial testing a smoking cessation intervention for dual users of combustible and electronic cigarettes (e-cigarettes) in the United States. Self-reported 7-day point prevalence smoking and vaping abstinence were collected at 3-, 12-, and 24-month assessments. Bisexual and heterosexual participants did not differ in sociodemographic variables or baseline smoking and vaping history and behavior. We found significant differences among bisexual and heterosexual individuals in smoking and vaping beliefs/expectancies. Specifically, bisexual participants expressed overall greater positive expectancies regarding smoking and vaping, such as smoking and vaping to reduce negative affect and stress. There were no differences in smoking at any follow-up assessment. Only at 3 months were bisexual individuals more likely to be abstinent from vaping and less likely to be dual users than heterosexual individuals. Despite similar smoking and vaping status over time, bisexual individuals reported greater positive expectancies regarding smoking and vaping. Our findings revealed few targets for tailoring cessation interventions to bisexual individuals; thus, it is possible that there may be greater utility in targeting the disparities in prevalence (i.e., via prevention efforts).

Identifying prospective subpopulations of combustible and electronic cigarette dual users in the United States via finite mixture modeling.

To identify subpopulations of dual users of combustible and electronic cigarettes using current smoking and vaping behaviors. Secondary analysis of baseline data from a randomized controlled trial testing a smoking cessation intervention for dual users. Finite mixture modeling of frequency, quantity, and dependence on combustible and electronic cigarettes was used to identify classes. Demographics and additional smoking and vaping variables were used to further characterize the classes. United States. A total of 2896 adults who smoked weekly for the past year and vaped weekly for the past month. Self-report baseline measures assessed demographics and smoking and vaping behaviors and characteristics including days of use per week, frequency of use within a day, time to first use after waking, urges to smoke, smoking cessation motivation, self-efficacy to abstain from smoking, months since vaping initiation, reasons for initiating and maintaining vaping, and future plans to stop vaping. Eight probabilistic classes were identified and well-defined (relative entropy = 0.95, Lo-Mendell-Rubin adjusted likelihood ratio test P < 0.0001; class probabilities 0.89-0.97). In general, classes crossed two levels of smoking with four levels of vaping. The largest class (31%) had relatively high levels of smoking (72% daily, 56% 11+ cigarettes per day [CPD], 96% within 30 minutes of waking) and vaping (74% daily, 100% 20+ electronic-CPD, 74% <30 minutes). The next largest class (27%) had relatively high levels of vaping (93% daily, 100% 20+ electronic-CPD, 82% <30 minutes) and very low levels of smoking (28% daily, 12% 11+ CPD, 0% <30 minutes). The six smaller classes (3%-13%) also had distinct smoking and vaping behaviors. All eight classes exhibited distinguishing characteristics beyond current smoking and vaping behaviors. Dual users of combustible and electronic cigarettes are not a homogeneous population, having eight well-defined prospective subpopulations.

Exposure to e-cigarette advertising and provaping websites, and the social acceptability of their use among nicotine users.

ABSTRACTObjectives.To evaluate the prevalence of exposure to Internet communications on and advertising of electronic cigarettes (e-cigarettes) and their association with perceptions of the social acceptability of e-cigarettes in Mexico.Methods.Data were analyzed from eight surveys (2018–2021) of an online sample of Mexican adult (> 18 years) smokers and dual users (of combustible and electronic cigarettes). Self-reported exposure to e-cigarette advertising across various marketing channels was assessed, as well as visits to e-cigarette websites. Logistic regression analysis was used to evaluate the association between perceptions of the social acceptability of e-cigarette use and level of advertising exposure and visits to e-cigarette websites.Results.The Internet and outside e-cigarette stores were where exposure to advertising most occurred, as reported by 47.4% and 46.8% of respondents, respectively. Respondents who noticed e-cigarette advertisements on the Internet (adjusted odds ratio (OR) 1.43, 95% confidence intervals (CI) 1.25, 1.63), outside e-cigarette stores (adjusted OR 1.31, 95% CI 1.14, 1.50), and in temporary outlets (adjusted OR 1.16, 95% CI 1.01, 1.34), and those who visited e-cigarette websites (adjusted OR 1.48, 95% CI 1.25, 1.76) were more likely to perceive e-cigarettes as socially acceptable. Noticing advertisements across more channels was also associated with higher perceived social acceptability of e-cigarette use.Conclusions.Being exposed to e-cigarette marketing, either online or through traditional marketing channels, is associated with perceived social acceptability of e-cigarette use, as is contact with provaping sites. Regulatory options to avoid the proliferation of promotional websites disguised as opinion or user sites need to be considered.

Cardiopulmonary protection against nicotine‐induced pulmonary hypertension and right ventricular remodeling in mice is not mediated by ovarian hormones

IntroductionElectronic cigarette use has increased globally prompting a joint committee of international cardiovascular research organizations to call for improved understanding of the health effects of nicotine. Our group has previously demonstrated that chronic, inhaled nicotine induces pulmonary hypertension (PH) and right ventricular (RV) remodeling in male but not female mice, suggesting sex differences in nicotine‐related pathology. Clinically, biological females develop PH more often, but have less severe disease than biological males, likely due to the cardiopulmonary protective effects of estrogen. Nicotine is also metabolized more rapidly in biological females due to sex hormone‐mediated differences in cytochrome P450 activity. These findings led us to hypothesize that female mice are protected against nicotine‐induced PH by a sex hormone‐dependent mechanism. Here, we assessed the role of ovarian hormones in a murine model of nicotine‐induced PH.MethodsFemale C57BL/6J mice were ovariectomized (OVX) one week prior to nicotine exposure. Intact and OVX mice were exposed to nicotine vapor or room air for 12 hours per day for 8 weeks. Nicotine exposure was measured using serum cotinine, which was comparable to human electronic cigarette users, and was not significantly different between intact (421 ± 101 ng/mL) and OVX (314 ± 61 ng/mL) mice. Cardiac structure and function were assessed using echocardiography and RV catheterization.ResultsIn contrast to previous findings in male mice, inhaled nicotine does not cause PH (measured by RV systolic pressure, RVSP) in intact female mice (24.0 ± 0.5 mmHg, n=7 in air vs. 22.7 ± 0.4 mmHg, n=9 in nicotine). RVSP was also unaffected by OVX (24.4 ± 0.9 mmHg, n=9 in air vs. 23.6 ± 0.6 mmHg, n=10 in nicotine). RV free wall thickness during diastole (RV FWT;d) was not significantly different between air‐exposed intact mice (0.328 ± 0.023 mm, n=8), nicotine‐exposed intact mice (0.292 ± 0.015 mm, n=10), air‐exposed OVX mice (0.315 ± 0.021 mm, n=8), and nicotine‐exposed OVX mice (0.293 ± 0.013 mm, n=10). RV internal diameter during diastole (RVID;d) was, likewise, not significantly different between air‐exposed intact mice (1.30 ± 0.03 mm, n=8), nicotine‐exposed intact mice (1.34 ± 0.04 mm, n=10), air‐exposed OVX mice (1.23 ± 0.05 mm, n=8), and nicotine‐exposed OVX mice (1.24 ± 0.05 mm, n=10).ConclusionIn this study, we found no differences in serum cotinine, RVSP, RV FWT;d, or RVID;d between intact and OVX females, leading us to conclude that ovarian hormones do not mediate cardiopulmonary protection against nicotine‐induced PH. Due to profound sex differences in clinical PH pathogenesis and nicotine metabolism, further studies (including exploration of androgen‐driven RV remodeling) are necessary to illuminate mechanisms underlying protection from nicotine‐induced pathology in female mice.

Attentional Bias in Non-Smoking Electronic Cigarette Users: An Eye-Tracking Study.

This study examined attentional bias (AB) to e-cigarette cues among a sample of non-smoking daily e-cigarette users (n = 27), non-smoking occasional e-cigarette users (n = 32), and control participants (n = 61) who did not smoke or use e-cigarettes. The possibility that e-cigarette users develop a transference of cues to traditional cigarettes was also examined. AB was assessed using a free-viewing eye-gaze tracking methodology, in which participants viewed 180 pairs of images for 4 seconds (e-cigarette and neutral image, e-cigarette and smoking image, smoking and neutral image). Daily and occasional e-cigarette users attended to pairs of e-cigarette and neutral images equally, whereas non-users attended to neutral images significantly more than e-cigarette images. All three groups attended to e-cigarette images significantly more than smoking images, with significantly larger biases for e-cigarette users. There were no between-group differences in attention to pairs of smoking and neutral images. A moderation analysis indicated that for occasional users but not daily users, years of vaping reduced the bias toward neutral images over smoking images. Taken together, the results indicate that the e-cigarette users exhibit heightened attention to e-cigarettes relative to non-users, which may have implications as to how they react to e-cigarette cues in real-world settings. AB for e-cigarettes did not transfer to traditional cigarette cues, which indicates that further research is required to identify the mechanisms involved in the migration of e-cigarettes to traditional cigarettes. This study is the first attempt to examine attentional biases for e-cigarette cues among non-smoking current e-cigarette users using eye-gaze tracking. The results contribute to the growing literature on the correlates of problematic e-cigarette use and indicate that daily and occasional e-cigarette use is associated with attentional biases for e-cigarettes. The existence of attentional biases in e-cigarette users may help to explain the high rate of failure to quit e-cigarettes and provides support for the utility of attentional bias modification in the treatment of problematic e-cigarette use.

Nicotine dependence and intention to quit among electronic, conventional and dual cigarette users in Karachi.

To compare nicotine dependence and intention to quit among different types of smokers. The comparative cross-sectional study was conducted from November 2018 to October 2019 in Karachi after approval from the ethics review committee of the Jinnah Sindh Medical University, and comprised conventional, electronic and dual cigarette users. Data was collected using a structured questionnaire regarding socio-demographics, usage characteristics, and intention to quit. The validated Hooked on Nicotine Checklist was also used. Data was analysed using SPSS 22. Of the 246 subjects, 82(33%) were conventional cigarette users with a mean age of 27.41±8.7 years, 82(33.3%) were electronic cigarette users having mean age of 30.37±9.16 years, and 82(33.3%) were dual cigarette users with a mean age of 28.89±9.07 years. The use of electronic cigarette was more in people with higher age (p=0.01), married (p=0.001) and having higher income (p=0.05). Compared to conventional cigarette users, electronic cigarette users showed lower odds of high nicotine dependence (odds ratio: 0.38, 95% confidence interval: 0.18-0.80). No significant difference was observed in intention to quit among different types of cigarette users (p>0.05). Electronic cigarettes users were comparatively less nicotine-dependent compared to the users of other types of cigarettes. Electronic cigarettes should only be recommended to conventional users with the intention to quit.

Saliva and Lung Microbiome Associations with Electronic Cigarette Use and Smoking.

The microbiome affects cancer and other disease risk. The effects of e-cig usage on the lung microbiome are essentially unknown. Given the importance of lung microbiome dysbiosis populated by oral species which have been observed to drive lung cancer progression, it is important to study effects of e-cig use on microbiome.

Comparative assessment of periodontal treatment needs among the electronic cigarette users and traditional smokers.

It is currently presumptuous that electric cigarettes are less harmful than the conventional ones; this is increasing the consumption of electric cigarettes. Therefore, this study intended to evaluate the periodontal treatment needs among conventional smokers, electronic cigarette smokers and non-smokers. This cross-sectional designed study involved 150 patients with a mean age of 29.88±7.81 years. Among all patients, 50 patients were recruited in each group. The periodontal condition and the treatment need for the patients were assessed using the community periodontal index treatment need (CPITN). Fisher exact test was used to find the significant association of all three groups with the periodontal status and the treatment need. Female patients (12.5%) showed better periodontal status than the male patients (87.5%) and required less complicated periodontal treatment independently from smoking type. Furthermore, deeper pocket depth ≥6 mm (75%) has been found among the conventional cigarette smokers whereas the majority of the electric cigarette smokers (50%) have calculus deposition. Thus, 50% of the electric smokers require professional scaling whereas 57.1% of conventional smokers prerequisite complex periodontal treatment. Besides, there was a significant difference (p≤0.05) observed among all groups in periodontal health index and treatment need. Conventional cigarette consumers need more complicated periodontal treatment compared to the patients who consume electric cigarettes.

Characterization of Baseline Temperature Characteristics Using Thermography in The Clinical Setting.

Thermography is a diagnostic method based on the ability to record infrared radiation emitted by the skin and is unique in its ability to accurately show physiological and/or pathological cutaneous temperature changes in a non-invasive way. This method can be used to indirectly assess changes or impairments in cutaneous perfusion. Significant technological advancements have allowed thermography to be more commonly utilized by clinicians, yet a basic consensus of patient characteristics that may affect temperature recordings is not established. We evaluated cutaneous temperature in a cohort of outpatients to understand what factors, including tobacco use and other high-risk characteristics, contribute to cutaneous tissue perfusion as measured by thermography. Participants were prospectively enrolled if they were a combustible cigarette smoker, an electronic cigarette (e-cigarette) user, or a never smoker. Standardized thermographic images of the subject's facial profiles, forearms, and calves were taken and demographic characteristics, medical comorbidities, and tobacco product use were assessed. These variables were statistically tested for associations with temperature at each anatomic site. We found that gender had a significant effect on thermographic temperature that differed by anatomic site, and we found a lack of significant difference in thermographic temperature by race. Our regression analysis did not support significant differences in thermographic temperatures across smoking groups, while there was a trend for decreased perfusion in smokers relative to non-smokers and e-cigarette users relative to non-smokers. Thermographic imaging is a useful tool for clinical and research use with consideration of sex and other perfusion-affecting characteristics.

Developmental Effects of Electronic Cigarette Use.

Electronic cigarettes have gained widespread acceptance among adolescents and young adults. As a result of this popularity, there are concerns regarding the potential harm of primary, secondhand and thirdhand electronic cigarette exposures on fetal and postnatal development. In vitro studies have shown that constituents in electronic cigarette liquids, including nicotine, flavorings, and carrier agents can alter cellular processes and growth. Additionally, aerosolized electronic cigarette emissions have been shown to disrupt organ development and immune responses in preclinical studies. In clinical studies, an association between electronic cigarette use and frequent respiratory symptoms, greater asthma severity and impaired mucociliary clearance has been demonstrated with adolescent and young adult users of electronic cigarettes having twice the frequency of cough, mucus production, or bronchitis compared to nonusers. Along with the popularity of electronic cigarette use, secondhand electronic cigarette exposure has increased substantially; with almost one-fourth of middle and high school children reporting exposure to secondhand vapors. The health consequences of secondhand electronic cigarette exposure on children and other vulnerable populations are poorly understood but detectable levels of cotinine have been measured in nonusers. Pregnant women and their offspring are another vulnerable group at increased risk for health consequences from electronic cigarette exposure. Nicotine crosses the placenta and can disrupt brain and lung development in preclinical studies. This article will focus on the physiological and health effects associated with primary or secondhand exposure to electronic cigarettes. It is expected that with ongoing availability of electronic cigarettes as well as the accumulation of additional follow-up time for long-term outcomes, the risks associated with exposure will become better clarified. © 2022 American Physiological Society. Compr Physiol 12:3337-3346, 2022.

Smoking Susceptibility in Canadian Adolescent Electronic-Cigarette Users

Background: E-cigarette use is increasing among Canadian youth, with experimentation especially prevalent among never-smoking youth. Among this group, there is concern e-cigarette use contributes to future initiation of smoking through a gateway effect. However, e-cigarette use and smoking share many common risk factors; a postulated mechanism to explain the apparent causal pathway from e-cigarette use to smoking initiation in previously smoking-naïve youth. A better understanding of the relationships between smoking susceptibility and e-cigarette use among never-smoking youth is needed. Purpose/objectives: The primary aim of this study was to gain a deeper understanding of the risk factors associated with smoking susceptibility in youth who have recently used e-cigarettes. Methods: This study used data (n = 40,363) from the 2018/2019 Canadian Student Tobacco Alcohol and Drug Use Survey (CSTADS) to compare the risk factor profiles of susceptible and non-susceptible never-smoking e-cigarette users, as well as susceptible and non-susceptible never-smoking youth who have never used an e-cigarette. Results: E-cigarette use, independent of susceptibility status, was associated with a sociodemographic and behavioral risk factor profile likely to confer a higher risk of initiating smoking. Among e-cigarette users, smoking susceptibility was associated with more smoking risk factors. Conclusions/importance: Study findings support a common risk-factor model, rather than e-cigarette use itself, to explain differences in the likelihood of smoking initiation among e-cigarette users. E-cigarette use and smoking initiation may be interchangeable outcomes amongst those with smoking risk factors. The risks of e-cigarette use, and their regulatory status, need to be balanced with their potential as harm reduction tools.

Oral microbiome of electronic cigarette users: A cross-sectional exploration.

Electronic cigarettes have increased in popularity globally. Vaping may be associated with oral symptoms and pathologies including dental and periodontal damage, both of which have an underlying microbial etiology. The primary aim of this pilot study, therefore, was to compare the oral microbiome of vapers and non-vapers. This secondary data analysis had a cross-sectional comparative descriptive design and included data for 36 adults. Bacterial 16S rRNA genes were extracted and amplified from soft tissue oral swab specimens and taxonomically classified using the Human Oral Microbiome Database. Data for 18 vapers and 18 non-vapers were included in this study. Almost 56% of the vapers also smoked conventional cigarettes. Beta diversity differences were identified between vapers and non-vapers. Vapers had a significantly higher relative abundance of an unclassified species of Veillonella compared with non-vapers. Dual users had higher alpha diversity compared with exclusive vapers. Beta diversity was also associated with dual use. Multiple OTUs were identified to be associated with dual use of e-cigarettes and conventional cigarettes. Vapers exhibit an altered oral microbiome. Dual use of electronic cigarettes and conventional cigarettes is associated with the presence of several known pathogenic microbes.

Non-surgical periodontal therapy with adjunct photodynamic therapy for the management of periodontal inflammation in adults using nicotine-free electronic-cigarette: A randomized control trial

ObjectiveThe aim was to assess the effect of non-surgical periodontal therapy (NSPT) with adjunct photodynamic treatment (PDT) for the management of periodontal inflammation in young electronic cigarette (E-cig) users. MethodsPatients with periodontal inflammation were included. Patient demographics and information related to E-Cig usage were recorded. Scores of plaque index (PI), bleeding index (BI), clinical attachment loss (AL) and probing depth (PD) recorded at baseline and at 3-months’ follow-up. Patients were randomly divided into test (NSPT + PDT) and control groups (NSPT) alone. Sample-size estimation was done using data from a pilot investigation and group comparisons were done. Correlation between periodontal parameters and duration of E-cig use was assessed using regression analysis models. Group-comparisons were done using the Mann Whitney U test; and logistic regression was done to correlate periodontal parameters with age, gender, frequency of vaping, number of puffs inhaled and oral hygiene maintenance protocols. Level of significance was set at P<0.01. ResultsTwenty-three and 23 individuals were randomly allocated to the test- and control-group, respectively. At baseline, PI, BI and PD were comparable in all patients. There was a significant reduction in PI (P<0.01), BI (P<0.01) and PD (P<0.01) in the test and control groups at 3-months’ follow-up when compared with their respective baseline scores. At 3-months’ follow-up, there was no significant difference in PI, BI and PD among patients in the test and control groups. There was no clinical evidence of clinical AL among patients in the test- and control groups at baseline and at 3-months’ follow-up. ConclusionIn the short-term, PDT is as effective as NSPT for the management of periodontal inflammation in young E-Cig users.

The Role of Nicotine and Flavor in the Abuse Potential and Appeal of Electronic Cigarettes for Adult Current and Former Cigarette and Electronic Cigarette Users: A Systematic Review.

Many adult cigarette smokers use electronic cigarettes (e-cigarettes) to cut down on or quit smoking cigarettes. E-cigarettes with higher abuse potential and appeal might facilitate complete switching. E-liquid nicotine concentration and flavor are two of the characteristics that may affect the abuse potential and appeal of e-cigarettes. The objective of this systematic review was to compile results from survey, animal, human laboratory, and clinical studies to understand the possible effects of nicotine concentration and flavor on abuse potential and appeal of e-cigarettes in adult current and former cigarette and e-cigarette users. A comprehensive literature search was conducted in Ovid Medline and PsycINFO followed by citation tracking in Web of Science Core Collection. Peer-reviewed studies published in English between 2007 and August 2020 were selected that analyzed differences between e-liquid nicotine concentration and/or flavors, had outcome measures related to abuse potential and/or appeal, and included adult humans (18+) or animals. A total of 1624 studies were identified and screened. A qualitative synthesis of results was performed. Results from 104 studies included in this review suggest that higher nicotine concentration and access to a variety of flavors are likely to be associated with higher abuse potential and appeal of e-cigarettes for adult current and former cigarette and e-cigarette users. Higher nicotine concentrations and the availability of a variety of flavors in e-cigarettes might facilitate complete substitution for cigarettes. Future e-cigarette regulations should take into account their impact on smokers, for whom e-cigarettes may be a cessation tool or reduced-harm alternative. E-cigarettes may provide a reduced-harm alternative to cigarettes for smokers unwilling/unable to quit or serve as a path for quitting all nicotine products. Higher nicotine concentrations and flavor variety are associated with higher abuse potential and appeal of e-cigarettes. Higher abuse potential and appeal products may help facilitate complete switching from cigarettes to e-cigarettes. Regulation of nicotine concentration and flavors aimed at decreasing naïve uptake may inadvertently decrease uptake and complete switching among smokers, reducing the harm reduction potential of e-cigarettes. Evidence-based effects of regulating nicotine concentration and flavors must be considered for the population as a whole, including smokers.

Assessment of the Exposure to Tobacco-Specific Nitrosamines and Minor Tobacco Alkaloids in Users of Various Tobacco/Nicotine Products.

Tobacco-specific nitrosamines (TSNAs), in particular, the human carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), are important toxicants in tobacco and also (as contaminants) in nicotine products. In a clinical study comprising a period of 74 h under confinement, we investigated the exposure to NNK, NNN, N'-nitrosoanabasine (NAB), and N'-nitrosoanatabine (NAT) as well as to the minor tobacco alkaloids anabasine (AB) and anatabine (AT) by measuring suitable biomarkers in habitual users of combustible cigarettes (CCs), electronic cigarettes (ECs), heated tobacco products (HTPs), oral tobacco (OT), and nicotine replacement therapy products (NRTs). Non-users (NU) of any tobacco/nicotine products served as the (negative) control group. Smokers exhibited the highest levels for all biomarkers measured, except for AB in urine, which was found to be highest in OT users. Somewhat elevated levels compared to NU, EC, and NRT groups were also observed in the users of HTPs. In the users of tobacco-containing products (CC, HTP, and OT), most frequently the biomarkers significantly correlated with the dose markers such as daily consumption, urinary nicotine equivalents (Nequ), and plasma cotinine (CotP). In conclusion, except for smokers (CC) and OT users, exposure of users of ECs, HTPs, and NRTs to TSNAs as well as the minor tobacco alkaloids AB and AT is marginal and statistically not distinguishable from that of NU. Finally, our results for NNN in the saliva provide preliminary evidence for the formation of NNN from the precursor nornicotine in the presence of thiocyanate as a catalyst. The latter hypothesis requires experimental verification.

Increased JUUL Emissions from Initial Puffs after Removing and Reinserting Pod.

Standard laboratory electronic cigarette (ECIG) puffing protocols that do not consider user behaviors, such as removing and resinserting a pod, may underestimate emissions. This study compared JUUL emissions from four 10-puff bout procedures. We generated ECIG aerosol in a chamber using a JUUL device and measured concentrations of particulate matter ≤2.5 μm in diameter (PM2.5). The JUUL pod was removed and reinserted 0 times, 1 time, 4 times, and 9 times in experiments 1-4, respectively. Mean real-time PM2.5 concentration was 65.06 μg/m3 (SD = 99.53) for experiment 1, 375.50 μg/m3 (SD = 346.45) for experiment 2, 501.94 μg/m3 (SD = 450.00) for experiment 3, and 834.69 μg/m3 (SD = 578.34) for experiment 4. In this study, removing and reinserting a JUUL pod resulted in greater PM2.5 concentrations compared to puffing protocols in which the JUUL pod was not removed and reinserted. ECIGs should be examined and evaluated based on ECIG users' real-world behaviors.