Serum cotinine levels and nicotine addiction potential of e-cigarettes: an NHANES analysis

The rodent electronic nicotine delivery system: Apparatus for voluntary nose-only e-cigarette aerosol inhalation

Tobacco use is the leading cause of death globally and in the United States. After decades of decline, driven by decreases in combusted tobacco use, nicotine product use has increased due to electronic nicotine delivery systems, also known as e-cigarettes or vapes. Preclinical models of nicotine self-administration can serve as important lodestars in the search for effective intervention and prevention tactics. Current variants of the preclinical models have substantial limitations, however. Therefore, we created the rodent electronic nicotine delivery system (RENDS), a novel low-cost nonproprietary nose-only preclinical model of nicotine aerosol self-administration. We confirmed that RENDS sequesters nicotine aerosol in the nose port by measuring fine particulate matter (PM <2.5 microns) generated by e-cigarettes. We also showed that rats robustly self-administer flavored nicotine aerosol, resulting in high blood levels of cotinine (the major nicotine metabolite) and spontaneous somatic withdrawal symptoms. Thus, we provide validation of the operation and function of the RENDS, opening the door to an open-source preclinical aerosol model of nicotine self-administration that is relatively low in cost. Four existing operant chambers can be retrofitted with the RENDS for less than $325/chamber. All RENDS diagrams and plans for custom-designed components are on Open Science Framework (https://osf.io/x2pqf/?view_only=775b55435b8e428f98e6da384ef7889d).

The Rodent Electronic Nicotine Delivery System: Apparatus for Voluntary Nose-Only E-Cigarette Aerosol Inhalation

Tobacco use is the leading cause of death globally and in the U.S. After decades of decline, driven by decreases in combusted tobacco use, nicotine product use has increased due to Electronic Nicotine Delivery Systems, also known as e-cigarettes or vapes. Preclinical models of nicotine self-administration can serve as important lodestars in the search for effective intervention and prevention tactics. Current variants of the task have substantial limitations, however. Therefore, we created the Rodent Electronic Nicotine Delivery System, a novel low-cost non-proprietary nose-only preclinical model of nicotine aerosol self-administration. We confirmed that RENDS sequesters nicotine aerosol in the nose port by measuring fine particulate matter (PM < 2.5 microns) generated by e-cigarettes. We also showed that rats robustly self-administer flavored nicotine aerosol, resulting in high blood levels of cotinine (the major nicotine metabolite) and spontaneous somatic withdrawal symptoms. Thus, we provide strong validation of the operation and function of the RENDS, opening the door to an open-source preclinical aerosol model of nicotine self-administration that is relatively low cost. Four existing operant chambers can be retrofitted with the RENDS for less than $325/chamber. All RENDS diagrams and plans for custom designed components are on Open Science Framework (https://osf.io/x2pqf/?view_only=775b55435b8e428f98e6da384ef7889d).

Sex- and age-dependent impacts of nicotine and ethanol binge drinking on the brain: Insights from preclinical research

Electronic cigarette use among adolescents is a growing concern, not only due to the high incidence of co-use with other substances, such as alcohol, but also due to the fact brain is still maturing during this period. Combined exposure to alcohol and nicotine leads to plastic adaptation of crucial circuits in the brain, which can contribute to the development of addiction. It is well established that nicotine exposure can facilitate alcohol binge drinking, and vice-versa, in a sex-, age- and exposure-dependent manner. Nonetheless, the central mechanisms underlying the synergistic relationship between these two substances and the emergence of differential behavioural traits dependent on these factors remain underexplored. Preclinical studies continue to provide valuable insights into such mechanisms. Here, we discuss recent preclinical findings that report behavioural changes characteristic of addiction following nicotine consumption, primarily in models of vaping and alcohol use; and insights into the neural mechanisms impacted by intake of these two substances, with a focus on the adolescent brain.

Myocardial Infarction Injury Is Exacerbated by Nicotine in Vape Aerosol Exposure

BACKGROUND

Vaping is touted as a safer alternative to traditional cigarette smoking, but the full spectrum of harm reduction versus comparable risk remains unresolved. Elevated bioavailability of nicotine in vape aerosol together with known risks of nicotine exposure may result in previously uncharacterized cardiovascular consequences of vaping. The objective of this study is to assess the impact of nicotine exposure via vape aerosol inhalation upon myocardial response to infarction injury.

METHODS AND RESULTS

Flavored vape juice containing nicotine (5 mg/mL) or vehicle alone (0 mg) was delivered using identical 4-week treatment protocols. Mice were subjected to acute myocardial infarction injury and evaluated for outcomes of cardiac structure and function. Findings reveal that nicotine exposure leads to worse outcomes with respect to contractile performance regardless of sex. Nonmyocyte interstitial cell accumulation following infarction significantly increased with exposure to vape aerosol alone, but a comparable increase was not present when nicotine was included.

CONCLUSIONS

Myocardial function after infarction is significantly decreased after exposure to nicotine vape aerosol irrespective of sex. Comparable loss of contractile function was not observed in mice exposed to vape aerosol alone, highlighting the essential role of nicotine in loss of contractile function. Increased vimentin immunoreactivity was observed in the vape alone group compared with control and vape nicotine. The correlation between vaping, interstitial cell responses, and cardiac remodeling leading to impaired contractility warrants further investigation. Public health experts seeking to reduce vaping-related health risks should consider messaging that highlights the increased cardiovascular risk especially with nicotine-containing aerosols.

Serum cotinine levels and adolescents' sleep health outcomes from NHANES 2005 to 2018

The association between tobacco smoke exposure and sleep has been widely discussed, but the correlation between serum cotinine levels and sleep health outcomes in adolescents has not been well described. This study aimed to further evaluate the association between serum cotinine levels and sleep health outcomes in adolescents using data from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. This cross-sectional study included participants aged 16-19 years from the NHANES 2005-2018. A weighted multivariate logistic regression model was used for the primary analysis. A restricted cubic spline (RCS) model was employed to investigate the non-linear association between serum cotinine levels and trouble sleeping. Subgroup analyses based on population characteristics were also conducted. In total, 2630 participants were included, which are representative of the 11.5 million US adolescents. Higher serum cotinine levels (≥ 3 ng/ml) were significantly associated with trouble sleeping in the fully adjusted model (odds ratio [OR] 1.817). The RCS model revealed a non-linear relationship between serum cotinine levels and trouble sleeping. Subgroup analyses indicated that this relationship was consistent and stable across various population characteristics. Serum cotinine levels are associated with sleep health outcomes in adolescents, with high serum cotinine levels being linked to increased trouble sleeping and longer or shorter sleep duration.

Health outcomes of electronic cigarettes

ABSTRACT

The usage of electronic cigarettes (e-cigarettes) sparked an outbreak of unidentified vaping-related lung disease in the US during late 2019. With e-cigarettes becoming more and more popular, smokers have more options other than conventional cigarettes. Under these circumstances, a comprehensive evaluation of the general safety of new tobacco and tobacco-related products, represented by e-cigarettes, to human health is necessary. In this review, we summarize the current research on potential negative impacts of e-cigarette exposure on human health. In particular, studies detailing the relationship between e-cigarettes and the digestive system are summarized, with mechanisms mainly including hepatic metabolic dysfunction, impaired gut barrier, and worsened outcomes of inflammatory bowel disease (IBD). Although believed to be safer than traditional cigarettes, e-cigarettes exert adverse effects on systemic health and induce the development of multiple diseases including asthma, cardiovascular disease, and IBD. Moreover, nicotine-containing e-cigarettes have a negative impact on the childhood development and increase the risk of arterial stiffness compared to the non-nicotine e-cigarettes. However, non-nicotine e-cigarette components have detrimental effects including promoting liver damage and metabolic disorders.

Fruit flavors in electronic cigarettes (ECIGs) are associated with nocturnal dry cough: A population longitudinal analysis

Evidence from in vitro and animal models has identified the pulmonary toxicity of flavors in electronic cigarettes (ECIGs); however, less is known from epidemiological studies about the effects of flavors in the respiratory health. This study examined the longitudinal association between exposure to ECIGs flavors and nocturnal dry cough among ECIGs users. A secondary analysis of data from the Population Assessment of Tobacco and Health Study (2014-2019) was conducted. The study population included adults who provided information (n = 18,925) for a total of 38,638 observations. Weighted-incidence estimates and weighted- generalized estimating equation models were performed to assess unadjusted and adjusted associations. The weighted incidence proportion (WIP) of nocturnal dry cough was significantly higher among current (WIP:16.6%; 95%CI 10.5, 21.2) and former fruit flavored ECIGs users (WIP:16.6%; 95%CI 11.3, 21.9) as compared to non-ECIGs users (WIP:11.1%; 95%CI 10.6, 11.6). Current ECIGs users of fruit flavors showed 40% higher risk of reporting cough than non-ECIGs users (aRR:1.40, 95%CI 1.01, 1.94). Former ECIGs users of multiple flavors and other flavors had 300% and 66% higher risk to develop cough, respectively (aRR:3.33, 95%CI 1.51, 7.34 and aRR:1.66, 95%CI 1.0.9, 2.51), relative to non-ECIGs users. We observed a significantly higher risk of developing nocturnal dry cough in the past 12 months in current and former ECIGs users of fruit flavors and in former ECIGs users of multiple flavors. To the extent that cough may serve as an early indicator of respiratory inflammation and potential disease risk, the association between ECIGs use and cough raises potential concerns.

Nicotine is associated with smoking dependence and vascular inflammation through cotinine: A mediation analysis

INTRODUCTION

The main alkaloid component in cigarettes is nicotine. Cotinine, a metabolite of nicotine, is capable of causing dependence effects through endless mechanisms modulated by the ion channel nicotinic acetylcholine receptors nAChRs. Nicotine and cotinine can also cause damage to blood vessels through a chronic inflammatory process mediated by the Ligand-Tie2 Angiopoietin Receptor system. Hypoxic conditions that occur due to vascular inflammation cause a decrease in the concentration of nitric oxide (NO). This study aimed to evaluate the relationship between NO levels and cotinine through the expression of nAChRs that mediate the nicotine dependence mechanism and Tie2 (Tyrosine Kinase 2) expression.

METHODS

A cross-sectional study was conducted with 200 participants grouped into two groups based on their smoking status: 100 smokers and 100 non-smokers. All participants were men aged 20-40 years with no history of cardiovascular disease, diabetes mellitus, or dyslipidemia, and were not currently on medication. According to the parameters used, all blood samples were taken from peripheral blood for analysis using the ELISA kit or Colorimetric Assay Kit.

RESULTS

Cigarette consumption increases blood cotinine concentrations in smokers and causes dependence by modulating nAChRs. The study indicates an emerging cycle regarding nicotine-cotinine consumption and nAChRs expression. In addition, the data in this study showed a significant relationship (p<0.001) regarding the cycle formed with decreased NO levels as a result of damage caused by Tie2-mediated inflammation.

CONCLUSIONS

There is a relationship between NO levels and cotinine through nAChRs, which mediate the nicotine dependence mechanism and Tie2 expression.

Pembrolizumab monotherapy for non-small cell lung cancer (NSCLC): can patient stratification be improved in the UK Tayside population? A retrospective cohort study

OBJECTIVE

Pembrolizumab is a programmed cell death protein-1 (PD-1) inhibitor used to treat advanced patients with non-small cell lung cancer (NSCLC) with a programmed cell death ligand-1 (PD-L1) tumour proportion score (TPS) ≥50. Further sub-division of TPS-based stratification has not been evaluated in the UK, although smoking-induced tumour mutational burden and the immunogenic effects of prior radiotherapy are suggested to improve response.

AIMS

To investigate if PD-L1 TPS ≥80%, smoking status or radiotherapy before or within 2 months of treatment influenced progression-free survival (PFS) in patients with NSCLC treated with pembrolizumab monotherapy.

METHODS

PD-L1 TPS, smoking status and radiotherapy exposure were compared in patients with NSCLC in National Health Service (NHS) Tayside (n=100) treated with pembrolizumab monotherapy between 1 November 2017 and 18 February 2022. Survival estimates were compared using log-rank analysis, and Cox proportional hazards analysis was used to investigate the influence of potential confounding factors, including tumour stage and performance status.

RESULTS

PFS was not significantly different (log-rank HR=0.330, p=0.566) comparing patients with PD-L1 TPS 50-79% and PD-L1 TPS ≥80%. Smokers had significantly improved PFS (log-rank HR=4.867, p=0.027), while patients receiving radiotherapy had significantly decreased PFS (log-rank HR=6.649, p=0.012). A Cox regression model confirmed that both radiotherapy (p=0.022) and performance status (p=0.009) were independent negative predictors of PFS.

CONCLUSIONS

More rigorous PD-L1 TPS stratification did not influence survival outcomes. Smoking history improved PFS, although it was not an independent response predictor, while radiotherapy and performance status independently influenced clinical response. We suggest that further stratification of PD-L1 TPS is not warranted, while performance status and radiotherapy treatment may be additional clinically useful biomarkers of response to pembrolizumab in patients with NSCLC.

Pharmacological effects of nicotine salts on dopamine release in the nucleus accumbens

With the growing number of individuals regularly using e-cigarettes, it has become increasingly important to understand the psychobiological effects of nicotine salts. Nicotine increases the release of dopamine (DA) into the nucleus accumbens (NAc), causing feelings of satisfaction. However, the differences in the DA-increasing effects of different nicotine salts have not been reported. In this study, we used a G protein-coupled receptor-activated DA fluorescent probe (GRABDA1m) and optical fiber photometric recording equipment to monitor the dynamic changes and kinetics of DA release in the NAc of mice exposed to different e-cigarette aerosols, including nicotine, nicotine benzoate, nicotine tartrate, nicotine lactate, nicotine levulinic acid, nicotine malate, and nicotine citrate. The results of this study were as follows: 1) Different types of nicotine salts could increase the release of DA in the NAc. 2) The slopes and half-effective concentrations of the fitted curves were different, suggesting that each nicotine salt had a difference in the efficiency of increasing DA release with concentration changes. 3) The absorption rates of different nicotine salts containing the same original nicotine concentration were significantly different by measuring the blood nicotine content. The effect of nicotine salts on increasing DA was directly proportional to the blood nicotine level. In conclusion, by observing the effects of nicotine salts on DA release in real time in vivo, differences in the pharmacological effects of nicotine salts are revealed to better understand the mechanism underlying the regulatory effects of nicotine salts on the brain.

Independent and Combined Associations of Blood Manganese, Cadmium and Lead Exposures with the Systemic Immune-Inflammation Index in Adults

Manganese (Mn), cadmium (Cd) and lead (Pb) have toxic effects on the immune system. However, their independent and combined effects on immune-inflammation responses are unclear. In recent years, the systemic immune-inflammation index (SII) has been developed as an integrated and novel inflammatory indicator. A retrospective cross-sectional study of 2174 adults ≥20 years old from the National Health and Nutrition Examination Survey (NHANES) 2015-2016 was conducted. Generalized linear models were used to evaluate the independent and combined associations of SII with blood Mn, Cd and Pb levels. As continuous variables, both blood Cd and Mn showed dose-dependent relationships with the SII before and after adjusting for all potential confounding factors. Metal concentrations were then converted into categorical variables. Compared with the adults in the lowest Cd or Mn tertile, those in the highest tertile had higher risks of elevated SII. Furthermore, co-exposure to Mn and Cd also showed a positive relationship with the SII after adjusting for all confounding factors. However, the single effect of Pb exposure and the joint effect of Pb and other metal exposures on the SII were not observed. This study provides important epidemiological evidence of the associations of SII with single and co-exposure effects of blood Mn, Cd, and Pb.

Genotoxicity and hypomethylation of LINE-1 induced by electronic cigarettes

Currently, the marketing of electronic cigarettes as a safe alternative to smoking has increased, which is associated with greater use of these devices, especially among young people and smokers interested in quitting tobacco cigarettes. Given the growing use of this type of product, there is a need to determine the consequences of electronic cigarettes on human health, especially since many of the compounds contained in the aerosol and liquid of these devices have a high potential to be carcinogenic and genotoxic. Additionally, many of these compounds' aerosol concentrations exceed the safe limits. We have evaluated the levels of genotoxicity and changes in DNA methylation patterns associated with vaping. We analyzed a total of 90 peripheral blood samples from a population of vapers (n = 32), smokers (n = 18), and controls (n = 32), in which the frequencies of genotoxicity were determined by the cytokinesis-blocking micronuclei (CBMN) assay and the patterns of methylation of the repetitive elements of LINE-1 through the Quantitative Methylation Specific PCR (qMSP) assay. Here we show an increase in genotoxicity levels associated with vaping habits. Additionally, the group of vapers showed changes at the epigenetic level specifically associated with the loss of methylation of the LINE-1 elements. These changes in LINE-1 methylation patterns were reflected in its representative RNA expression detected in vapers.

Sex Differences in the Impact of Electronic Nicotine Vapor on Corticotropin-Releasing Factor Receptor 1 Neurons in the Mouse Ventral Tegmental Area

Nicotine engages dopamine neurons in the ventral tegmental area (VTA) to encode reward and drive the development of nicotine addiction, however how nicotine alters a stress associated VTA population remains unclear. Here, we used male and female CRF1-GFP mice and nicotine vapor exposure to examine the effects of nicotine in VTA corticotropin-releasing factor receptor 1 (CRF1) neurons. We use immunohistochemistry and electrophysiology to examine neuronal activity, excitability, and inhibitory signaling. We found that VTA CRF1 neurons are mainly dopaminergic and project to the nucleus accumbens (NAc; VTA-NAcCRF1 neurons). VTA-NAcCRF1 neurons show greater phasic inhibition in naive females and greater focal nicotine-induced increases in firing in naive males. Following acute nicotine vapor exposure, phasic inhibition was not altered, but focal nicotine-induced tonic inhibition was enhanced in females and diminished in males. Acute nicotine vapor exposure did not affect firing in VTA-NAcCRF1 neurons, but females showed lower baseline firing and higher focal nicotine-induced firing. Activity (cFos) was increased in the CRF1 dopaminergic VTA population in both sexes, but with greater increases in females. Following chronic nicotine vapor exposure, both sexes displayed reduced basal phasic inhibition and the sex difference in tonic inhibition following acute vapor exposure was no longer observed. Additionally, activity of the CRF1 dopaminergic VTA population was no longer elevated in either sex. These findings reveal sex-dependent and exposure-dependent changes in mesolimbic VTA-NAc CRF1 neuronal activity, inhibitory signaling, and nicotine sensitivity following nicotine vapor exposure. These changes potentially contribute to nicotine-dependent behaviors and the intersection between stress, anxiety, and addiction.SIGNIFICANCE STATEMENT Nicotine is known to engage reward systems in the brain historically centering the neurotransmitter dopamine however, how nicotine impacts other neurons in the reward pathway is less clear. The current study investigates the impact of acute and chronic electronic nicotine vapor exposure in a genetically-defined cell population containing the stress receptor corticotropin-releasing factor 1 (CRF1) that is located in the reward circuitry. This study employs functional measures of neuronal activity and identifies important sex differences in nicotine's effects across time and exposure.

A pilot randomized controlled trial of automated and counselor-delivered text messages for e-cigarette cessation

INTRODUCTION

Automated text messaging programs show promise for e-cigarette cessation. Adding live text counseling could make them more engaging. We developed Quit the Vape (QTV), an automated e-cigarette cessation text messaging program, designed to be delivered as stand-alone or with counselor-delivered messages (QTV-C), and evaluated the acceptability and preliminary efficacy of QTV and QTV-C.

METHODS

Between May and August 2021, we recruited 58 e-cigarette users, aged 20-43 years, 53.5% male, 63.8% non-Hispanic White, from an ongoing cohort study in the United States. Inclusion criteria were: using nicotine-containing e-cigarettes on ≥4 days per month; smartphone ownership; and not receiving tobacco cessation treatment. Motivation to quit did not impact eligibility. Participants were randomized to QTV (n=20), QTV-C (n=19), or control (link to e-cigarette cessation website, n=19). At end-of-treatment, we assessed program engagement and satisfaction, and self-reported quitting behaviors (e.g. point prevalence abstinence, PPA).

RESULTS

At baseline, average past-month e-cigarette use was 26.8 days (SD=6.2). At follow-up at 4 weeks, among QTV and QTV-C participants, ≥85% replied to ≥1 message, ≥35% set a quit date, and ≤15% opted out. More QTV and QTV-C participants (55.6%) versus control (17.7%) reported program satisfaction (p=0.034). QTV-C participants (vs QTV and control) trended more favorably on 7-day e-cigarette PPA [27.8% (95% CI: 11.5-53.3) vs 11.1% (95% CI: 2.6-37.0) and 5.9% (95% CI: 0.7-34.5)] and quit attempts [66.7% (95% CI: 41.6-84.9) vs 50.0% (95% CI: 27.4-72.6) and 52.9% (95% CI: 29.2-75.5)].

CONCLUSIONS

Adding live text counseling to an automated text messaging program is acceptable and shows promise for e-cigarette cessation. A larger trial is warranted to assess its efficacy.

Increased serum cotinine and obesity negatively impact asthma exacerbations and hospitalizations: A cross-sectional analysis of NHANES

Background

Asthma is the most common non-communicable chronic airway disease worldwide. Obesity and cigarette use independently increase asthma morbidity and mortality. Current literature suggests that obesity and smoking synergistically increase asthma-related wheezing.

Objective

To assess whether increased serum cotinine and obesity act synergistically to increase the likelihood of having an asthma exacerbation, emergency department (ED) visit, or hospitalization.

Methods

A cross-sectional analysis of the 2011-2015 iterations of NHANES database was performed. Patients aged 18 years or greater with asthma were included. Serum cotinine was utilized as an accurate measurement of cigarette use. Logistic regression models were constructed to determine whether elevated serum cotinine and obesity were associated with self-reported asthma exacerbations, asthma-specific ED usage, and hospitalizations for any reason in the past year. Odds ratios were adjusted for age, gender, race, and ethnicity. Interactions were assessed by multiplying the adjusted effect sizes for elevated cotinine and obesity.

Results

We identified 2179 (N = 32,839,290) patients with asthma, of which 32.2% were active smokers and 42.7% were obese. Patients with an elevated cotinine and asthma were significantly more likely to have had an asthma-related ED visit in the past year (adjusted odds ratio [AOR] 1.82; 95% CI 1.19-2.79), have a physician-prescribed asthma medication (AOR 2.04; 95% CI 1.11-3.74), and have a hospitalization for any reason (AOR 3.65; 95% CI 1.88-7.07) compared to those with low cotinine. Patients with asthma and obesity were more likely to have an asthma-related ED visit (AOR 1.67; 95% CI 1.06-2.62) or hospitalization for any reason in the past year compared to non-obese patients (AOR 2.76; 95% CI 1.69-4.5). However, a statistically significant interaction between obesity and cotinine was only identified in patients who currently have asthma compared to a previous asthma diagnosis (AOR 1.76; 95% CI 1.10-2.82). There were no synergistic interactions among ED usage or asthma exacerbations.

Conclusion

Nearly one-third of patients with asthma were current smokers, and almost half were obese. This study identified elevated serum cotinine, a metabolite of cigarette use, and obesity as key risk factors for asthma exacerbations, asthma-related ED visits, and hospitalizations for any reason. Elevated serum cotinine and obesity were not found to act synergistically in increasing asthma exacerbations or ED visits. However, the presence of both risk factors increased the risk of currently having asthma (compared to a previous diagnosis) by 76%. Serum cotinine may be useful in predicting asthma outcomes.

E-Cigarette Quit Attempts and Experiences in a Convenience Sample of Adult Users

Most e-cigarette users report planning to quit, but there is a paucity of evidence-based interventions for e-cigarette cessation. In the absence of interventions for e-cigarette cessation, we sought to understand how and why e-cigarette users attempt to quit on their own. Participants were recruited from Amazon Mechanical Turk, an online crowdsourcing platform. Those who reported they had ever used e-cigarettes regularly and had attempted to quit e-cigarette use were eligible for participation. Measures included demographic characteristics, other tobacco product use, e-cigarette device characteristics, barriers to quitting e-cigarettes, and facilitators to quitting e-cigarettes. A content analysis was conducted on twotwo open-ended questions that asked about advice respondents had for others trying to quit vaping and resources they wished they had during their quit attempt. Descriptive analyses were performed (means/standard errors; frequencies/proportions). A total of 89.0% reported using an e-cigarette with nicotine, 20.2% reported a nicotine concentration of 4-6 mg/mL%, 32.8% reported using multiple flavors, and 77.7% reported using their e-cigarette every day or some days. The primary reason reported for wanting to quit e-cigarettes was health concerns (42.2%), and 56.7% reported trying to quit "cold turkey". During quit attempts, 41.0% reported intense cravings and 53.1% reported stress as a trigger. From the content analysis, the most commonly cited suggestion for those wanting to quit e-cigarettes was distractions/hobbies (19.9%), followed by reducing/tapering down nicotine (16.9%). Descriptive information on demographics, e-cigarette use, device characteristics, barriers, facilitators, and quit methods provides a first step in identifying factors that contribute to successful interventions designed for e-cigarette cessation.

E-cigarette vapor exposure in utero causes long-term pulmonary effects in offspring

The in utero environment is sensitive to toxicant exposure, altering the health and growth of the fetus, and thus sensitive to contaminant exposure. Though recent clinical data suggest that e-cigarette use does no further harm to birth outcomes than a nicotine patch, this does not account for the effects of vaping during pregnancy on the long-term health of offspring. Pregnant mice were exposed to: 1) e-cigarette vapor with nicotine (PV + Nic; 2% Nic in 50:50 propylene glycol: vegetable glycerin), 2) e-cigarette vapor without nicotine [PV; (50:50 propylene glycol:vegetable glycerin)], or 3) HEPA filtered air (FA). Dams were removed from exposure upon giving birth. At 5 mo of age, pulmonary function tests on the offspring revealed female and male mice from the PV group had greater lung stiffness (Ers) and alveolar stiffness (H) compared with the FA group. Furthermore, baseline compliance (Crs) was reduced in female mice from the PV group and in male mice from the PV and PV + Nic groups. Lastly, female mice had decreased forced expiratory volume (FEV0.1) in the PV group, but not in the male groups, compared with the FA group. Lung histology revealed increased collagen deposition around the vessels/airways and in alveolar tissue in PV and PV + Nic groups. Furthermore, goblet hyperplasia was observed in PV male and PV/PV + Nic female mice. Our work shows that in utero exposure to e-cigarette vapor, regardless of nicotine presence, causes lung dysfunction and structural impairments that persist in the offspring to adulthood.

Predictors of electronic nicotine product quit attempts and cessation: Analysis of waves 3 and 4 of the PATH study

INTRODUCTION

Identifying theory-based predictors of electronic nicotine product (ENP) quit attempts and cessation can guide the development of effective vaping cessation interventions, which are currently limited. This study examined predictors of ENP quit attempts and cessation among adult ENP users.

METHODS

Using data from wave 3 (W3; 2015-2016) current established ENP users in the Population Assessment of Tobacco and Health study, we used multivariable logistic regression to identify predictors of (i) wave 4 (W4; 2016-2018) quit attempts (unweighted n = 1,135); and (ii) W4 cessation among those who made a quit attempt (unweighted n = 610). Predictors included Social Cognitive Theory (SCT)-based cognitive (interest in quitting, self-efficacy to quit, outcome expectancies, risk perception), behavioral (smoking status, and use of combustibles, non-combustibles, cannabis, and alcohol), and socio-environmental (perceived disapproval, household rules, exposure to advertising) factors.

RESULTS

Between W3 and W4, 51.7% of W3 ENP users made a quit attempt. Among those who tried quitting, 68.4% stopped using ENPs. SCT-based predictors of ENP quit attempts included higher interest in quitting ENPs (aOR = 1.18), greater self-efficacy to quit ENPs (aOR = 1.31), and currently using cigarettes (vs non-smoker; aOR = 1.71), non-combustibles (aOR = 2.25), and cannabis (aOR = 1.80). Predictors of ENP cessation included greater self-efficacy to quit ENPs (aOR = 1.33), greater perceived risk of ENPs (aOR = 1.35), and being a current smoker (vs non-smoker; aOR = 3.28).

CONCLUSIONS

ENP cessation interventions should address cognitive factors, particularly self-efficacy, as it predicted quit attempts and cessation. Cigarette smoking among dual users should be monitored and addressed to ensure that those who quit using ENPs do not maintain cigarette use.

Neural-hematopoietic-inflammatory axis in nonsmokers, electronic cigarette users, and tobacco smokers

Amygdala activity in context of the splenocardiac model has not been investigated in healthy, young adults and has not been compared between nonsmokers, electronic cigarette users, and smokers. The purpose of the current study was to determine whether fluorodeoxyglucose positron emission tomography/computer tomography (FDG PET/CT) scans would demonstrate positively correlated metabolic activity in the amygdala, bone marrow, spleen, and aorta, elucidating activation of the splenocardiac axis in otherwise healthy young people who use tobacco products compared to nonusers. Moreover, the study was conducted to evaluate whether electronic cigarette users and tobacco smokers have similar levels of inflammation compared to nonusers. In 45 healthy adults (mean age = 25 years), including nonsmoker (n = 15), electronic cigarette user (n = 16), and smoker (n = 14) groups, metabolic activity in the amygdala, spleen, aorta, bone marrow of thoracic vertebrae, and adjacent erector spinae skeletal muscle was quantified through visualization of radioactive glucose (18 FDG) uptake by FDG-PET/CT. The maximum standardized uptake value for each region was calculated for correlation analyses and comparisons between groups. In correlation analyses, metabolic activity of the amygdala correlated with metabolic activity in the aorta (r = 0.757), bone marrow (r = 0.750), and spleen (r = 0.665), respectively. Metabolic activity in the aorta correlated with 18 FDG uptake in the thoracic vertebrae (r = 0.703) and spleen (r = 0.594), respectively. Metabolic activity in the spleen also correlated with 18 FDG uptake in the bone marrow (r = 0.620). Metabolic activity in the adjacent erector spinae skeletal muscle (our control tissue) was not positively correlated with any other region of interest. Finally, there were no statistically significant mean differences in metabolic activity between the three groups: nonsmokers, electronic cigarette users, and smokers in any target tissue. Amygdala metabolic activity, as measured by 18 FDG uptake in FDG-PET/CT scans, positively correlated with inflammation in the splenocardiac tissues, including: the aorta, bone marrow, and spleen, underscoring the existence of a neural-hematopoietic-inflammatory axis in healthy, young adults.

Cardiopulmonary Consequences of Vaping in Adolescents: A Scientific Statement From the American Heart Association

Although the US Food and Drug Administration has not approved e-cigarettes as a cessation aid, industry has at times positioned their products in that way for adults trying to quit traditional cigarettes; however, their novelty and customizability have driven them into the hands of unintended users, particularly adolescents. Most new users of e-cigarette products have never smoked traditional cigarettes; therefore, understanding the respiratory and cardiovascular consequences of e-cigarette use has become of increasing interest to the research community. Most studies have been performed on adult e-cigarette users, but the majority of these study participants are either former traditional smokers or smokers who have used e-cigarettes to switch from traditional smoking. Therefore, the respiratory and cardiovascular consequences in this population are not attributable to e-cigarette use alone. Preclinical studies have been used to study the effects of naive e-cigarette use on various organ systems; however, almost all of these studies have used adult animals, which makes translation of health effects to adolescents problematic. Given that inhalation of any foreign substance can have effects on the respiratory and cardiovascular systems, a more holistic understanding of the pathways involved in toxicity could help to guide researchers to novel therapeutic treatment strategies. The goals of this scientific statement are to provide salient background information on the cardiopulmonary consequences of e-cigarette use (vaping) in adolescents, to guide therapeutic and preventive strategies and future research directions, and to inform public policymakers on the risks, both short and long term, of vaping.

Serum Concentrations of Cotinine and Trans-3'-Hydroxycotinine in US Adults: Results From Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study

INTRODUCTION

The Population Assessment of Tobacco and Health (PATH) Study is a nationally representative cohort of tobacco product users and nonusers. The study's main purpose is to obtain longitudinal epidemiologic data on tobacco use and exposure among the US population.

AIMS AND METHODS

Nicotine biomarkers-cotinine (COT) and trans-3'-hydroxycotinine (HCT)-were measured in blood samples collected from adult daily tobacco users and nonusers during Wave 1 of the PATH Study (2013-2014; n = 5012; one sample per participant). Participants' tobacco product use and exposure to secondhand smoke were categorized based on questionnaire responses. Nonusers were subdivided into never users and recent former users. Daily tobacco users were classified into seven tobacco product use categories: exclusive users of cigarette, smokeless tobacco, electronic cigarette, cigar, pipe, and hookah, as well as polyusers. We calculated sample-weighted geometric mean (GM) concentrations of cotinine, HCT, and the nicotine metabolite ratio (NMR) and evaluated their associations with tobacco use with adjustment for potential confounders.

RESULTS

The GMs (95% confidence intervals) of COT and HCT concentrations for daily tobacco users were 196 (184 to 208) and 72.5 (67.8 to 77.4) ng/mL, and for nonusers they were 0.033 (0.028 to 0.037) and 0.021 (0.018 to 0.023) ng/mL. Exclusive smokeless tobacco users had the highest COT concentrations of all user groups examined. The GM NMR in daily users was 0.339 (95% confidence interval: 0.330 to 0.350).

CONCLUSIONS

These nationally representative estimates of serum nicotine biomarkers could be the basis for reference ranges characterizing nicotine exposure for daily tobacco users and nonusers in the US adult population.

IMPLICATIONS

This report summarizes the serum nicotine biomarker measurements in Wave 1 of the PATH Study. We are reporting the first estimates of HCT in serum for daily tobacco users and nonusers in the noninstitutionalized, civilian US adult population; the first nationally representative serum COT estimates for daily exclusive users of different tobacco products and daily polyusers; and the first nationally representative estimate of the serum NMR in daily tobacco users by age, race/ethnicity, and sex.

Efficacy of a group-based brief tobacco intervention among young adults aged 18-20 years in the US Air Force

INTRODUCTION

Most smokers begin using tobacco before the age of 25 years, making it important to reduce tobacco use during adolescence and early adulthood. Rates of use are historically higher among military personnel. While 'Tobacco 21' made it illegal for US retailers to sell tobacco to those aged <21 years, the policy did not address cessation for current youth and young adult tobacco users. Additionally, there is limited research on cessation interventions among young adults under 21 years. The current study evaluated the efficacy of a group-based Brief Tobacco Intervention (BTI) among US Air Force trainees, who are predominantly aged 18-20 years and directly impacted by Tobacco 21 legislation.

METHODS

Participants were 2969 US Air Force Trainees from April 2017 through January 2018 cluster randomized to three conditions: 1) BTI + Airman's Guide to Remaining Tobacco Free (AG), 2) AG alone, and 3) the National Cancer Institute's Clearing the Air (CTA) pamphlet. To assess the efficacy of the interventions among people aged 18-20 years, a domain analysis (<21 years, n=2117; and ≥21 years, n=852) of a multinomial logistic regression model was run.

RESULTS

Mono tobacco users aged <21 years at baseline who received the BTI+AG had higher odds of quitting tobacco at 3 months (OR=2.13; 95% CI: 1.02-4.46). Dual and poly users aged <21 years at baseline who received the BTI+AG intervention had higher odds of reducing the number of tobacco products used at 3 months (OR=2.94; 95% CI: 1.03-8.37).

CONCLUSIONS

The BTI was effective for people aged 18-20 years. The current study offers insight into components of interventions that might be successful in helping this age group decrease tobacco use.

Changes in E-Cigarette Perceptions Over Time: A National Youth Tobacco Survey Analysis

INTRODUCTION

This multiyear, cross-sectional study explores the changes over time in how U.S. middle- and high-school students perceive the harm and addiction risk of E-cigarettes.

METHODS

This study analyzed 83,779 participants in the National Youth Tobacco Survey from 2015 to 2019. Associations of survey year with perceived harm and addiction risk of E-cigarettes were assessed using multivariable multinomial logistic regression models, adjusted for sociodemographic characteristics.

RESULTS

Smoking decreased over the 5 years (-1.85 percentage points, p=0.07); vaping increased (9.03 percentage points, p<0.01). Perceived harm of both combustible cigarettes and E-cigarettes increased with time. Male, older, and non-White students perceived less harm from smoking or vaping. Perceptions of the addictiveness of E-cigarettes increased over time: 26.31% of students considered E-cigarettes to be more addictive than combustible cigarettes in 2019, compared with 7.26% in 2016. Female and non-White students were more likely to think that E-cigarettes were at least as addictive as combustible cigarettes but also reported less knowledge about them.

CONCLUSIONS

The perceptions of both harm and addictiveness of E-cigarettes have increased over time, independent of current use. Perceptions vary on the basis of age, sex, race/ethnicity, and current use. Efforts should be made to further educate adolescents about E-cigarettes and to regulate their sale and advertisement. Efforts to reduce the uptake of combustible cigarettes among adolescents have been successful and should be duplicated for E-cigarettes.

E-cigarette use and combustible tobacco cigarette smoking uptake among non-smokers, including relapse in former smokers: umbrella review, systematic review and meta-analysis

OBJECTIVE

To review and summarise the current evidence on the uptake of combustible cigarette smoking following e-cigarette use in non-smokers-including never-smokers, people not currently smoking and past smokers-through an umbrella review, systematic review and meta-analysis.

DESIGN

Umbrella review, systematic review and meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science, PsychINFO (Ovid), Medline (Ovid) and Wiley Cochrane Library up to April 2020.

RESULTS

Of 6225 results, 25 studies of non-smokers-never, not current and former smokers-with a baseline measure of e-cigarette use and an outcome measure of combustible smoking uptake were included. All 25 studies found increased risk of smoking uptake with e-cigarette exposure, although magnitude varied substantially. Using a random-effects model, comparing e-cigarette users versus non-e-cigarette users, among never-smokers at baseline the OR for smoking initiation was 3.25 (95% CI 2.61 to 4.05, I2 85.7%) and among non-smokers at baseline the OR for current smoking was 2.87 (95% CI 1.97 to 4.19, I2 90.1%). Among former smokers, smoking relapse was higher in e-cigarette users versus non-users (OR=2.40, 95% CI 1.50 to 3.83, I2 12.3%).

CONCLUSIONS

Across multiple settings, non-smokers who use e-cigarettes are consistently more likely than those avoiding e-cigarettes to initiate combustible cigarette smoking and become current smokers. The magnitude of this risk varied, with an average of around three times the odds. Former smokers using e-cigarettes have over twice the odds of relapse as non-e-cigarettes users. This study is the first to our knowledge to review and pool data on the latter topic.

PROSPERO REGISTRATION NUMBER

CRD42020168596.

Recent updates on biomarkers of exposure and systemic toxicity in e-cigarette users and EVALI

Electronic nicotine delivery systems (ENDS), or e-cigarettes, are emerging tobacco products that produce aerosols by heating e-liquids, which most often consist of propylene glycol and vegetable glycerin along with various flavoring compounds, bypassing the combustion that occurs in the use of traditional tobacco cigarettes. These products have seen a drastic increase in popularity in recent years both as smoking cessation devices as well as among younger generations, due in large part to the widespread perception among consumers that e-cigs are significantly less harmful to health than traditional tobacco cigarettes. Due to the novelty of ENDS as well as their rapidly increasing use, research into biomarkers of e-cig exposure and toxicity have lagged behind their popularity, leaving important questions about their potential toxicity unanswered. Research into potential biomarkers of acute and chronic e-cig use, and e-cigarette- or vaping-associated lung injury is necessary for informing both clinical and regulatory decision-making. We aim to provide an updated review of recent research into potential circulating, genomic, transcriptomic, and epigenetic biomarkers of exposure to and toxicity of e-cigs. We additionally highlight research areas that warrant additional study to gain a better understanding of health risks associated with ENDS use, as well as to provide validation of existing data and methods for measuring and analyzing e-cig-associated biomarkers in human and animal biofluids, tissues, and cells. This review also highlights ongoing efforts within the WNY Center for Research on Flavored Tobacco for research into novel biomarkers in extracellular vesicles that may be associated with short- and long-term ENDS use.

Trends in Tobacco Use among Young Adults Presenting for Military Service in the United States Air Force between 2013 and 2018

Background: The US military has historically higher tobacco use compared to civilians, and tobacco use increases following enlistment. While the military is vulnerable to tobacco use, current surveillance of tobacco among this high-risk population is lacking. Methods: Recently enlisted Airmen (N = 43,597) between 2013 and 2018 were asked about tobacco use prior to enlistment across ten products: (1) cigarettes/roll your own tobacco, (2) smokeless tobacco/snus, (3) cigars, cigarillos/little cigars, (4) hookah/pipe, and (5) e-cigarettes. Results: Hookah/pipe use, cigarettes/roll your own, smokeless tobacco/snus, and cigars/little cigars/cigarillos use decreased significantly between 2013 and 2018, while the prevalence of e-cigarette use increased (p's < 0.0001). The relationships between the time and each tobacco product(s) use outcomes were influenced differently by different age, race, education and marital status. Conclusion: While e-cigarette use has increased in the civilian sector, the use of e-cigarettes among new recruits increased much more drastically (i.e. prevalence 15.3% in 2018). Further, demographic characteristics influenced tobacco trends; specifically, recruits of racial minorities increased their use of e-cigarettes over the past five years faster than Whites. Of concern is what impact this dramatic increase in e-cigarette use will have on overall health and later initiation of combustible tobacco products in the military.

Association between Perceived Discrimination and Vaping among College Students

Perceived discrimination has been associated with a higher prevalence of e-cigarette use among adult samples. However, little is understood about the relationship between discrimination and various vaping behaviors among college students. Methods: College students completed an online survey about e-cigarette use (N = 488; 73.2% women; 52.7% White, 30.5% Black/African American, 6.1% Asian, 5.3% other races, 3.9% Multiracial). Participants completed the Everyday Discrimination Scale and identified which of their identities discrimination was most directed toward. Regressions, controlling for significant covariates of outcomes, examined discrimination in relation to e-cigarette ever use, current use, and frequency of use. Results: A higher discrimination score predicted greater odds of ever vaping compared with never use (OR = 1.21, p=.03). Controlling for race (p=.003), greater discrimination was related to increased likelihood of established vaping (100+ times) versus lighter levels of use (AOR = 1.22, p=.04). Discrimination was not associated with likelihood of current vaping (p>.05). Among e-cigarette users, greater perceived discrimination was related to an increased time spent vaping per day (β =1.69, SE = 0.204, p=.05). Conclusions/Importance: Greater perceived discrimination was associated with more frequent vaping among college students. Current results extend previous findings by suggesting that among college e-cigarette users, those who experience discrimination are more likely to use these products frequently rather than experimentally. Findings can inform the identification and development of resources for students experiencing discrimination to prevent the uptake of e-cigarette use.