Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks

Smoking Cessation for Preoperative Optimization

Cigarette smoking is associated with pulmonary and cardiovascular disease and confers increased postoperative morbidity and mortality. Smoking cessation in the weeks before surgery can mitigate these risks, and surgeons should screen patients for smoking before a scheduled operation so that appropriate smoking cessation education and resources can be given. Interventions that combine nicotine replacement therapy, pharmacotherapy, and counseling are effective to achieve durable smoking cessation. When trying to stop smoking in the preoperative period, surgical patients experience much higher than average cessation rates compared with the general population, indicating that the time around surgery is ripe for motivating and sustaining behavior change. This chapter summarizes the impact of smoking on postoperative outcomes in abdominal and colorectal surgery, the benefits of smoking cessation, and the impact of interventions aimed to reduce smoking before surgery.

What drives public perceptions of e-cigarettes? A mixed-methods study exploring reasons behind adults' perceptions of e-cigarettes in Northern England

BACKGROUND

Despite growing evidence that e-cigarettes are likely less harmful than cigarettes, perceptions of equal or more harm have increased worldwide. This study aimed to identify the most common reasons behind adults' perceptions of the (i) relative harm of e-cigarettes compared with cigarettes and (ii) effectiveness of e-cigarettes for smoking cessation.

METHODS

Adults (N = 1646) from Northern England were recruited through online panels from December-March 2017/2018, using quota sampling to guarantee socio-demographic representativeness. Qualitative content analysis of open-ended responses was performed with codes representing reasons for a given perception about e-cigarettes. Percentages of participants who gave each reason for each perception were calculated.

RESULTS

823 (49.9%) participants agreed that e-cigarettes were less harmful than cigarettes, 283 (17.1%) disagreed, and 540 (32.8%) were undecided. The most common reasons for agreeing that e-cigarettes were less harmful than cigarettes were that they produce no smoke (29.8%) and fewer toxins (28.9%). Those who disagreed were most concerned about a perceived lack of trustworthy research (23.7%) and safety issues (20.8%). Lacking knowledge (50.4%) was the most common reason for being undecided. 815 (49.5%) of participants agreed that e-cigarettes were an effective smoking cessation aid, 216 (13.2%) disagreed, and 615 (37.4%) were undecided. The most common reasons participants gave for agreeing were related to e-cigarettes being successful smoking replacements (50.3%) and advice from family, friends or health professionals (20.0%). Respondents who disagreed were most concerned about e-cigarettes being addictive (34.3%) and containing nicotine (15.3%). Lacking knowledge (45.2%) was the most common reason for being undecided.

CONCLUSIONS

Negative perceptions of e-cigarette harm were driven by concerns about a perceived lack of research and safety issues. Adults who viewed e-cigarettes as ineffective for smoking cessation feared that they perpetuate nicotine addiction. Campaigns and guidelines that address these concerns may help promote informed perceptions.

Occurrence of metals in e-cigarette liquids: Influence of coils on metal leaching and exposure assessment

Electronic cigarettes are generally recognized as a safer alternative than conventional cigarettes. Nevertheless, previous research suggests metal (loid) leaching due to coil contact, potentially transferring to the e-liquid and its aerosolized form. In this study, Cr, Cd, Ni, and Pb levels were measured by inductively coupled plasma mass spectrometry (ICP-MS) on 17 samples of e-liquids with different chemical properties (e.g., pH, nicotine content, flavoring, free-base, and nicotine salts). Twelve e-liquids were then put in contact with 36-gauge Kanthal A-1, Nichrome 80, Stainless steel 317 L and disposable coils such as Juul, and Aspire BVC for three days at 200-250 °C for 1 h each day. Metal levels expressed as mean (standard deviation) metal concentration, were below detection (Cd) to very low in bottle samples (Ni ≤ 76 (18); Pb ≤ 16 (1.5); and Cr ≤ 386 (15.6) μg/kg). In the coil extracts, varying concentrations of the same metal (loid) were found, indicating that metal leaching capacity may differ per sample. All samples contained Ni and Cr, followed by Pb to a much lesser extent. Cd levels were mostly below detection limits. Coil + e-liquid combinations with the highest Ni, Cr, and Pb concentrations were: Aspire BVC + Melon 0 mg/mL: Ni = 1.22 E+04 (281); Aspire BVC + Hit Nicotine 40 mg/mL: Cr = 864 (116); and Nichrome 80 + Melon 0 mg/mL: Pb = 56 (5) μg/kg. Overall, results suggest that nicotine salts at 40 mg/mL enhance Cr and Ni transfer. Stainless steel 317 L released very low metal concentrations. A conservative screening level risk characterization showed that 10.5% and 3.5% of the coil extracts may exceed Ni and Cr (III) safe concentrations, respectively. In the aerosol phase, 8.8% of samples might be above Ni equivalent daily dose for chronic exposure and 1.8% for intermediate exposure. Further studies on coil metal leaching could aid in establishing coil manufacturing regulations.

Chemical Profiles and Toxicity of Electronic Cigarettes: An Umbrella Review and Methodological Considerations

BACKGROUND

Electronic cigarettes (ECs) are often marketed as a safer alternative to combustible tobacco products. The global EC market has rapidly expanded since their introduction, creating an urgent need for research describing the toxicity and chemical composition of ECs. We conducted an umbrella review to summarize the evidence from existing systematic reviews (SRs).

METHODS

The search for SRs was conducted across four electronic databases through 25 January 2022. Methodological quality was assessed using the AMSTAR-2 quality appraisal tool.

RESULTS

Twenty-five SRs were included in our umbrella review. Chemical profiles widely varied across studies included in the reviews, which was mainly attributed to the lack of standardized protocols investigating the constituents, and differences in EC devices and e-liquids tested. Metals were more abundant in some EC aerosols than cigarettes, while carbonyls were typically found at lower levels. There was consistent evidence of in vitro toxicity from EC aerosol and e-liquid exposure. AMSTAR-2 revealed important limitations across reviews.

CONCLUSIONS

While most reviews concluded that ECs were likely less harmful than cigarettes, there was hesitancy to draw clear conclusions due to variable analytical procedures and inconsistent findings among the included studies. Future SRs with improved methodology and reporting are needed to adequately inform tobacco regulatory actions.

Exposure-response analysis of the association of maternal smoking and use of electronic cigarettes (vaping) in relation to preterm birth and small-for-gestational-age in a national US sample, 2016-2018

Introduction

The US experienced a surge in use of e-cigarettes. Smoking women may consider e-cigarettes during pregnancy as an alternative to smoking. E-cigarettes typically contain nicotine, an established cause of reduction in fetal growth in animal studies.

Methods

This cohort study included 99,201 mothers who delivered live singletons in 2016-2018 from the Pregnancy Risk Assessment Monitoring System. We created exposure categories based on self-reported number of cigarettes smoked per day and vaping frequency and evaluated their associations with preterm birth and small-for-gestational-age (SGA) birth (two established cigarette smoking-related risks).

Results

Dual users in late pregnancy were a heterogeneous group: 29% lightly smoked and occasionally vaped; 19% lightly smoked and frequently vaped; 36% heavily smoked and occasionally vaped; and 15% heavily smoked and frequently vaped. While dual users who heavily smoked and occasionally vaped had the highest adjusted OR for SGA (3.4, 95% CI 2.0, 5.7), all the dual users had, on average, about twice the odds of having SGA than non-users. While the risks of preterm birth were higher among sole light smokers (adjusted OR 1.3, 95% CI 1.1, 1.5) and sole heavy smokers (adjusted OR 1.5. 95% CI 1.2, 1.8) than non-users, the adjusted odds of preterm birth for dual users were not noticeably higher than those of non-users.

Conclusion

Relative to non-users, both smoking and vaping during pregnancy appear to increase risk of SGA, but excess risk of preterm birth appears to be primarily attributable to smoking alone. Higher levels of exposure tended to confer more risk.

Chemical characterisation of the vapour emitted by an e-cigarette using a ceramic wick-based technology

Fourth-generation ‘pod’ e-cigarette devices have been driven by technological advances in electronic atomization of the e-liquid. Use of microporous ceramic as a wicking material improves heating efficiency, but how it affects the chemical emissions of these devices is unclear. We assessed the emissions of a pod e-cigarette with innovative ceramic wick-based technology and two flavoured e-liquids containing nicotine lactate and nicotine benzoate (57 and 18 mg mL⁻¹ nicotine, respectively). Among the studied harmful and potentially harmful constituents (HPHCs) listed by the US FDA and/or WHO TobReg, only 5 (acetone, acetaldehyde, formaldehyde, naphthalene and nornicotine) were quantified at levels of 0.14 to 100 ng puff⁻¹. In the combustible cigarette (Kentucky reference 1R6F), levels were from 0.131 to 168 µg puff⁻¹. Nicotine levels ranged 0.10–0.32 mg puff⁻¹ across the 3 study products. From the 19 proposed HPHCs specifically of concern in e-cigarettes, only 3 (glycerol, isoamyl acetate and propylene glycol) were quantified. The low/undetectable levels of HPHCs reflect not only the optimal operating conditions of the e-cigarette, including an efficient supply of e-liquid by the ceramic wick without overheating, but also the potential of the e-cigarettes to be used as an alternative to combustible cigarettes.

Risk and safety profile of electronic nicotine delivery systems (ENDS): an umbrella review to inform ENDS health communication strategies

OBJECTIVES

This umbrella review aims to summarise the evidence about electronic nicotine delivery systems' (ENDS) risk and safety health profile to inform ENDS health communication strategies.

DATA SOURCES AND STUDY SELECTION

Six databases were searched for systematic reviews presenting evidence on ENDS-related health effects. Ninety reviews divided into five categories were included: toxicity=20, health effects=40, role in smoking cessation=24, role in transition to combustible cigarettes (CCs)=13 and industry marketing claims=4.

DATA EXTRACTION

Findings were synthesised in narrative summaries. Meta-analyses were conducted by study type when appropriate. Quality assessment was conducted using the Measurement Tool to Assess Systematic Reviews. The Institute of Medicine's Levels of Evidence Framework was used to classify the evidence into high-level, moderate, limited-suggestive and limited-not-conclusive.

DATA SYNTHESIS

We found high-level evidence that ENDS exposes users to toxic substances; increases the risk of respiratory disease; leads to nicotine dependence; causes serious injuries due to explosion or poisoning; increases smoking cessation in clinical trials but not in observational studies; increases CC initiation; and exposure to ENDS marketing increases its use/intention to use. Evidence was moderate for ENDS association with mental health and substance use, limited-suggestive for cardiovascular, and limited-not-conclusive for cancer, ear, ocular and oral diseases, and pregnancy outcomes.

CONCLUSIONS

As evidence is accumulating, ENDS communication can focus on high-level evidence on ENDS association with toxicity, nicotine addiction, respiratory disease, ENDS-specific harm (explosion, poisoning) and anti-ENDS industry sentiment. Direct comparison between the harm of CCs and ENDS should be avoided.

PROSPERO REGISTRATION NUMBER

CRD42021241630.

DNA damage, DNA repair and carcinogenicity: Tobacco smoke versus electronic cigarette aerosol

The allure of tobacco smoking is linked to the instant gratification provided by inhaled nicotine. Unfortunately, tobacco curing and burning generates many mutagens including more than 70 carcinogens. There are two types of mutagens and carcinogens in tobacco smoke (TS): direct DNA damaging carcinogens and procarcinogens, which require metabolic activation to become DNA damaging. Recent studies provide three new insights on TS-induced DNA damage. First, two major types of TS DNA damage are induced by direct carcinogen aldehydes, cyclic-1,N2-hydroxy-deoxyguanosine (γ-OH-PdG) and α-methyl-1, N2-γ-OH-PdG, rather than by the procarcinogens, polycyclic aromatic hydrocarbons and aromatic amines. Second, TS reduces DNA repair proteins and activity levels. TS aldehydes also prevent procarcinogen activation. Based on these findings, we propose that aldehydes are major sources of TS induce DNA damage and a driving force for carcinogenesis. E-cigarettes (E-cigs) are designed to deliver nicotine in an aerosol state, without burning tobacco. E-cigarette aerosols (ECAs) contain nicotine, propylene glycol and vegetable glycerin. ECAs induce O6-methyl-deoxyguanosines (O6-medG) and cyclic γ-hydroxy-1,N2--propano-dG (γ-OH-PdG) in mouse lung, heart and bladder tissues and causes a reduction of DNA repair proteins and activity in lungs. Nicotine and nicotine-derived nitrosamine ketone (NNK) induce the same types of DNA adducts and cause DNA repair inhibition in human cells. After long-term exposure, ECAs induce lung adenocarcinoma and bladder urothelial hyperplasia in mice. We propose that E-cig nicotine can be nitrosated in mouse and human cells becoming nitrosamines, thereby causing two carcinogenic effects, induction of DNA damage and inhibition of DNA repair, and that ECA is carcinogenic in mice. Thus, this article reviews the newest literature on DNA adducts and DNA repair inhibition induced by nicotine and ECAs in mice and cultured human cells, and provides insights into ECA carcinogenicity in mice.

Electronic Cigarette or Vaping Product Use-Associated Lung Injury in a Previously Healthy Young Male

Vaping (i.e., the use of electronic cigarettes) has been gaining popularity among people for the past few years, perhaps due to the misconception that its use is less harmful than traditional cigarettes. Although the long-term effects of these products are still unknown, it has been shown that they can be implicated in acute lung injury in healthy people. In 2019, an epidemic of severe acute lung injury was reported in the United States, and it was linked to vaping or electronic cigarette use and was referred to as e-cigarette or vaping product use-associated lung injury (EVALI). Here, we present the first case of EVALI in the state of Qatar.

ECAM: A low-cost vaping device for generating and collecting electronic cigarette condensate for in vitro studies

The use of electronic cigarettes (ECs) has become widespread despite many unknowns around their long-term health impact. ECs work by vapourising a liquid, known as an e-liquid, typically consisting of propylene glycol, glycerol, flavourings and nicotine. The chemical constituents and resultant impact on cells and tissue are dependent on several factors, including the flavourings used, the vaping topography/use pattern, and the device used. ECAM (Electronic Cigarette Aerosol Machine) is an open source, portable device for creating EC aerosol - for condensate collection and in vitro studies - using a controlled methodology. ECAM was developed as a low cost, automated, and customisable alternative to commercial devices. ECAM consists of a micro diaphragm gas pump to draw air/EC aerosol through the system. The device is automated using an Arduino and solenoid pinch valves are used to alternate between air and EC vapour. Condensate is collected in a vial within a cold-water bath. Each ECAM unit uses a temperature/humidity sensor to measure ambient air conditions and a differential pressure sensor to determine the pressure within the system. ECAM is programmed to adhere to International Standards Organisation 20768:2018. The design files, source code, and build instructions for this device can be found at https://dx.doi.org/10.17605/OSF.IO/3NGU4.

Analysis of electric cigarette liquid effect on mouse brain tumor growth through EGFR and ERK activation

Introduction

Recently, electric cigarettes with liquid (e-liquid) were introduced as an alternative to tobacco smoking. They were promoted as possible cessation aids and were considered to be potentially less harmful than traditional tobacco-based cigarettes. However, there is little information on the toxicants present in e-liquids and their possible carcinogenic effects.

Methods

Western blot analysis was performed to identify the protein levels of cancer progression related signal transducers. Patient-derived brain tumor cells (CSC2) were injected into mouse brains and tumor growth was then observed by performing magnetic resonance imaging (MRI) and hematoxylin and eosin (H&E) staining of the whole brain. Immunohistochemistry (IHC) staining and Immunofluorescence staining were performed to study the expression of pEGFR and pERK.

Results

Western blotting revealed that e-liquids increased pEGFR and pERK expression in a dose dependent manner. Animal experiments revealed that the e-liquid treated group had accelerated tumor growth and poor prognosis compared to the vehicle group. Histological staining showed activation of pEGFR and pERK in the e-liquid treated group.

Conclusion

Our study revealed that e-liquid activates pEGFR and pERK, leading to accelerated brain tumor growth and poor prognosis.

Smoking Addiction and Strategies for Cessation

Cigarette smoking is the leading cause of chronic obstructive pulmonary disease (COPD) worldwide. Smoking cessation is thus integral to the treatment of COPD. Nicotine addiction is a disease dependent on the complex interactions of neurotransmitter pathways, conditioned behaviors, environmental cues, genetic predisposition, and personal life circumstances, which render some more susceptible to tobacco abuse than others. The most successful smoking cessation programs are individualized, comprehensive, and utilize combinations of clinician counseling, behavioral reinforcement, community resources, advanced technology support (eg, smartphone apps, and Internet Web sites), and pharmacotherapy (both nicotine-based and nonnicotine medications). E-cigarettes were introduced to the US market in 2006 and touted as a safer alternative to tobacco cigarette smoking. Unfortunately, over the last 5 to 10 years, recreational e-cigarette use, or "vaping," has increased in popularity, especially among adolescents. This has introduced nicotine addiction to an entire generation of nonsmokers and resulted in numerous cases of acute lung disease, now known as e-cigarette or vape product use-associated lung injury (EVALI). In light of these adverse events, e-cigarettes and vape products are not currently recommended as a smoking cessation aid.

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

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

Vape-Associated Pulmonary Injury (VAPI) Presenting With a "Miliary" Pattern on Imaging

Electronic (E)-cigarette use or vaping is associated with pulmonary injury. Users can present with wide-ranging symptoms, varying degrees of pulmonary injury, and respiratory distress. Lung injury secondary to vaping is associated with a variety of patterns on pulmonary imaging. Typical radiographic findings are consistent with bilateral, basilar ground-glass opacities and or consolidation with septal thickening. We present a case of vape-associated pulmonary injury (VAPI) in a previously healthy adult who was found to have atypical radiographic findings. A 34-year-old male presented with a chief complaint of a two-week history of malaise, nausea, cough, and worsening shortness of breath. A chest CT scan without contrast revealed diffuse nodules in a miliary pattern. The patient reported a six-month history of tetrahydrocannabinol (THC) vape use. Bronchoscopy with cytologic analysis confirmed findings consistent with the VAPI. To our knowledge, this is the first report of a "miliary" pattern of infiltrates and nodules in a patient with VAPI. This pattern on CT imaging led to increased suspicion for other possible etiologies, including tuberculosis. Thus, moving forward, we believe that VAPI needs to be considered in the differential diagnosis if a patient presents with radiographic findings consistent with a miliary or diffuse micronodular pattern.

Incarceration exposure and electronic cigarette use during pregnancy: Findings from the pregnancy risk assessment monitoring system, 2016-2018

Smoking during pregnancy is a serious public health concern that poses risks for maternal and infant health. Considering the rise of electronic cigarette use in recent years, there is also growing concern about electronic cigarette use during pregnancy. Recent research has begun to explore correlates of electronic cigarette use among pregnant women. While research has revealed a strong connection between incarceration and smoking, scholars have yet to examine the connection between a woman's exposure to incarceration in the year prior to birth - either personally or vicariously through her husband or partner - and prenatal electronic cigarette use. The current study uses data from 74,554 recent mothers from the 2016-2018 Pregnancy Risk Assessment Monitoring System. Logistic regression and multinomial logistic regression models were used to assess the association between incarceration exposure and electronic cigarette use. The findings indicate a robust association between incarceration exposure and electronic cigarette use during pregnancy. Specifically, analyses demonstrate that incarceration-exposed women were approximately 2.7 times (AOR = 2.699, 95% CI = 1.939, 3.755) as likely to use electronic cigarettes after adjusting for a host of demographic, economic, health, and pregnancy related characteristics. Additional analyses reveal this association remains after accounting for conventional cigarette use during pregnancy. Considering the potential harmful health ramifications for electronic cigarette use during pregnancy, these findings suggest a need for interventions targeting electronic cigarette use among incarceration-exposed populations and point to electronic cigarette use among pregnant women in particular as an important area of focus for both criminal justice and public health practitioners.

Responsibility, normalisation and negotiations of harm: E-cigarette users' opinions and experiences of vaping around children

BACKGROUND

Concern about youth uptake of vaping is widespread. Regulation and education campaigns aim to protect children from initiating use, yet it is likely that children will be primarily influenced by the behaviour of people in their immediate environment. This is the first known study exploring e-cigarette users' views and reported experiences of vaping around children.

METHODS

Following informed consent, semi-structured qualitative interviews were conducted with 40 adults who had attempted to give up smoking by vaping. Participants were recruited from England as part of a wider study into e-cigarette use trajectories and smoking relapse (ECtra study). Data were extracted from 28 interviews where participants had spontaneously discussed vaping around children. Extracted data were analysed thematically and situated in previous analysis of vaping identity which distinguished between recreational and medicinal vapers.

RESULTS

Vaping behaviour around children was in part a habituated replication of smoking norms but also guided by broad vaping identity; recreational users were more permissive and medicinal users more secretive. Vaping in the home appeared to be determined by caregivers' need to reconcile vaping behaviour so that it was congruent with parental identity as a responsible caregiver. Participant perspectives reflected existing moral discourses applied to e-cigarettes around the use of "harm reduction for smokers" and "potential for youth harm".

CONCLUSION

Vaping is likely to be role modelled within the community and home despite attempts by e-cigarette users to conceal the behaviour. The ambivalent contextualisation of e-cigarettes means that e-cigarette users may lack a clear narrative to draw on when discussing vaping with children. Public health guidance for vaping around children could be helpful, but to be most effective, should take into consideration users' vaping identity.

E-Cigarette or Vaping Product Use-Associated Lung Injury: A Review for Pathologists

CONTEXT.—

Vaping is the inhalation of heated aerosol from a small battery-powered device as a method to deliver nicotine or other substances. A recent outbreak of severe respiratory illness primarily in the United States has put a spotlight on vaping and its potential risks.

OBJECTIVE.—

To familiarize pathologists with vaping, the cytologic and histopathologic features of vaping-associated acute lung injury, and the role of pathology in this diagnosis.

DATA SOURCES.—

A targeted literature review was performed.

CONCLUSIONS.—

Most cases of vaping-associated lung injury have been linked to vaping products containing tetrahydrocannabinol or other cannabinoids. Lung biopsies show a spectrum of nonspecific acute lung injury patterns (organizing pneumonia, diffuse alveolar damage, acute fibrinous, and organizing pneumonia, or combinations of the above), accompanied by prominent, foamy macrophage accumulation. Injury is usually accentuated around small airways. Lipid-laden macrophages can be identified in bronchioloalveolar lavage fluid in most patients and these can be highlighted using lipid stains, such as oil red O, but the clinical utility of this finding remains unclear, as lipid-laden macrophages can be seen in a wide variety of processes and should not be relied upon to make the diagnosis. Classic histologic features of exogenous lipoid pneumonia have not been identified in tissue samples. Lightly pigmented macrophages, similar to those seen with traditional cigarette smoking, are present in some cases but are usually a minor feature. To date, no specific pathologic features for vaping-related injury have been identified, and it remains a diagnosis of exclusion that requires clinicopathologic correlation.

An Unrecognized Hazard in E-Cigarette Vapor: Preliminary Quantification of Methylglyoxal Formation from Propylene Glycol in E-Cigarettes

Up to 95% of the liquid volume in an e-cigarette consists of propylene glycol. Previous research has shown that propylene glycol can generate diacetyl and formaldehyde when heated. New research shows that propylene glycol can also generate methylglyoxal, an alpha di-carbonyl compound recently shown to cause epithelial necrosis at even lower concentrations than diacetyl, the flavoring chemical associated with bronchiolitis obliterans ("Popcorn Lung"). We analyzed chemical emissions from 13 JUUL pod flavors. Diacetyl and methylglyoxal was detected in 100% of samples with median concentration (range) of 20 µg/m3 (less than limit of quantification: 54 µg/m3) and 4219 µg/m3 (677-15,342 µg/m3), respectively. We also detected acetaldehyde (median concentration: 341 µg/m3) and propionaldehyde (median concentration: 87 µg/m3) in all samples. The recent evidence that methylglyoxal is more cytotoxic to airway epithelial cells than diacetyl makes this an urgent public health concern. Current smokers considering e-cigarettes as a smoking cessation tool, and never users, who may be under the impression that e-cigarettes are harmless, need information on emissions and potential risks to make informed decisions.

Addressing the challenges of E-cigarette safety profiling by assessment of pulmonary toxicological response in bronchial and alveolar mucosa models

Limited toxicity data on electronic cigarette (ECIG) impede evidence-based policy recommendations. We compared two popular mixed fruit flavored ECIG-liquids with and without nicotine aerosolized at 40 W (E-smoke) with respect to particle number concentrations, chemical composition, and response on physiologically relevant human bronchial and alveolar lung mucosa models cultured at air–liquid interface. E-smoke was characterized by significantly increased particle number concentrations with increased wattage (25, 40, and 55 W) and nicotine presence. The chemical composition of E-smoke differed across the two tested flavors in terms of cytotoxic compounds including p-benzoquinone, nicotyrine, and flavoring agents (for example vanillin, ethyl vanillin). Significant differences in the expression of markers for pro-inflammation, oxidative stress, tissue injury/repair, alarm anti-protease, anti-microbial defense, epithelial barrier function, and epigenetic modification were observed between the flavors, nicotine content, and/ or lung models (bronchial or alveolar). Our findings indicate that ECIG toxicity is influenced by combination of multiple factors including flavor, nicotine content, vaping regime, and the region of respiratory tree (bronchial or alveolar). Toxic chemicals and flavoring agents detected in high concentrations in the E-smoke of each flavor warrant independent evaluation for their specific role in imparting toxicity. Therefore, multi-disciplinary approaches are warranted for comprehensive safety profiling of ECIG.

Development of a novel method to measure material surface staining by cigarette, e-cigarette or tobacco heating product aerosols

Tobacco smoke (CS) may visually stain indoor surfaces including ceilings, walls and soft furnishings over time. Potentially reduced risk products (PRRPs) such as e-cigarettes (EC) and tobacco heating products (THP) produce chemically less complex aerosols with significantly reduced levels of toxicants, particles and odour. However, the potential effects of EC and THP aerosols on the staining of indoor surfaces are currently unknown. In this study, an exposure chamber was developed as a model system to enable the accelerated staining of wallpaper and cotton samples by a scientific reference cigarette (3R4F), three THP (glo™, glo™ pro, glo™ sens) and an e-cigarette (iSwitch Maxx).

Exposure to 3R4F reference cigarettes caused the greatest level of staining, which was significantly higher than glo™, glo™ pro, glo™ sens or iSwitch Maxx aerosols, all of which showed relatively little colour change. Exposure to 200–1000 puffs of 3R4F cigarette smoke resulted in a visible dose response effect to wallpaper and cotton samples which was not observed following exposure to glo™, glo™ pro, glo™ sens or iSwitch Maxx aerosols. Aging of the samples for 4 weeks post-exposure resulted in changes to the staining levels, however PRRP staining levels were minimal and significantly lower than 3R4F exposed samples.

For the first time, diverse PRRPs across the tobacco and nicotine products risk continuum have been assessed in vitro for their impact on surface staining. CS exposure significantly increased the level of wallpaper and cotton staining, whereas exposure to glo™, glo™ pro, glo™ sens or iSwitch Maxx aerosols resulted in significantly reduced levels of staining, staining levels were also comparable to untreated control samples.

The Year in Cardiothoracic Critical Care: Selected Highlights from 2019

In 2019, cardiothoracic and vascular critical care remained an important focus and subspecialty. This article continues the annual series to review relevant contributions in postoperative critical care that may affect the cardiac anesthesiologist. Herein, the pertinent literature published in 2019 is explored and organized by organ system.

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

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

Characterization of Volatile Organic Compound Metabolites in Cigarette Smokers, Electronic Nicotine Device Users, Dual Users, and Nonusers of Tobacco

INTRODUCTION

Limited research exists about the possible cardiovascular effects of electronic nicotine delivery systems (ENDS). We therefore sought to compare exposure to known or potentially cardiotoxic volatile organic compounds (VOCs) in ENDS users, smokers, and dual users.

METHODS

A total of 371 individuals from the Cardiovascular Injury due to Tobacco Use study, a cross-sectional study of healthy participants aged 21-45 years, were categorized as nonusers of tobacco (n = 87), sole ENDS users (n = 17), cigarette smokers (n = 237), and dual users (n = 30) based on 30-day self-reported tobacco product use patterns. Participants provided urine samples for VOC and nicotine metabolite measurement. We assessed associations between tobacco product use and VOC metabolite measures using multivariable-adjusted linear regression models.

RESULTS

Mean (SD) age of the population was 32 (±6.8) years, 55% men. Mean urinary cotinine level in nonusers of tobacco was 2.6 ng/mg creatinine, whereas cotinine levels were similar across all tobacco product use categories (851.6-910.9 ng/mg creatinine). In multivariable-adjusted models, sole ENDS users had higher levels of metabolites of acrolein, acrylamide, acrylonitrile, and xylene compared with nonusers of tobacco, but lower levels of most VOC metabolites compared with cigarette smokers or dual users. In direct comparison of cigarettes smokers and dual users, we found lower levels of metabolites of styrene and xylene in dual users.

CONCLUSION

Although sole ENDS use may be associated with lower VOC exposure compared to cigarette smoking, further study is required to determine the potential health effects of the higher levels of certain reactive aldehydes, including acrolein, in ENDS users compared with nonusers of tobacco.

IMPLICATIONS

ENDS use in conjunction with other tobacco products may not significantly reduce exposure to VOC, but sole use does generally reduce some VOC exposure and warrants more in-depth studies.

Three Patients With Acute Pulmonary Damage Following the Use of E-Cigarettes-A Case Series

BACKGROUND

The use of e-cigarettes is on the rise around the world. Many case reports of acute lung injury due to e-cigarette use have been published in recent months in the USA, but no comparable cases have emerged in Germany up to the present report. The use of e-cigarettes has risen very rapidly in the USA in recent years, simultaneously with the legalization of marijuana sale in many American states. Most of the cases described there involved the use, not only of nicotine, but of tetrahydrocannabinol (THC, the psychoactive ingredient in marijuana) as well, though some of the patients had indeed not used additives (e.g. THC).

METHODS

We report three cases in Germany of acute pulmonary illness that we consider to have been caused by the use of e-cigarettes.

RESULTS

All three patients were hospitalized for acute shortness of breath. Two displayed partial respiratory insufficiency and bilateral pulmonary infiltrates. All three stated that they had used ordinary, commercially available e-cigarettes every day for at least the past three months. In the first patient, a 48-year-old man, the complete blood count and bronchial lavage findings indicated eosinophilic inflammation. The second patient, a 22-year-old man, developed multiple episodes of hemoptysis, with computed tomography (CT) showing diffuse alveolar bleeding; his complete blood count also revealed eosinophilic inflammation. The third patient, a 34-year-old man, displayed acute ground-glass lung opacities as well as fibrosing changes on CT corresponding to pulmonary sarcoidosis. All three recovered on high-dose systemic corticosteroid treatment and were discharged from the hospital in 2 to 12 days.

CONCLUSION

In the first two cases, acute pulmonary injury was very likely due to e-cigarette consumption, as all other possible causes were ruled out. A possible link to e-cigarette use was present in the third case. We thus describe the first three suspected cases of acute lung disease due to e-cigarette use in Germany. These patients do not share any common, typical clinical picture; rather, their symptoms represent different components of the wide spectrum of interstitial lung disease. A uniform national registry should be established to improve our understanding of the adverse effects of e-cigarettes and the resulting acute and chronic changes in the lungs.

Review of Cases of E-Cigarette or Vaping Product Use-Associated Lung Injury (EVALI) and Brief Review of the Literature

Since the appearance of the E-Cigarette in the early 2000s, its industry, popularity, and prevalence have risen dramatically. In the past, E-Cigarette use with the vaping of nicotine or cannabis products had been associated with a few reported cases of lung injury. However, in 2019, thousands of cases of E-Cigarette or vaping product use-associated lung injury (EVALI) were reported in the United States. Evidence linked this outbreak with vaping of tetrahydrocannabinol (THC). We report two confirmed cases of EVALI and their associated clinical, radiologic, and pathologic features. This report supports the growing body of information regarding EVALI. It also discusses various substances, particularly vitamin E acetate, which has been suggested as a causative agent.

Characterization of the Spatial and Temporal Dispersion Differences Between Exhaled E-Cigarette Mist and Cigarette Smoke

Introduction

There are fundamental differences between electronic cigarettes (e-cigarettes) and conventional cigarette product categories with regards to potential environmental exposures, notably that e-cigarettes do not contain tobacco or generate side-stream emissions. Here we assess the spatial and temporal patterns of exhaled e-cigarette aerosol at a bystander’s position, and compare it with conventional cigarette smoke emissions.

Methods

Smokers were asked to use e-cigarettes or smoke conventional cigarettes in a room-simulating chamber. Volunteers used the products at different distances from a heated mannequin, representing a bystander, and under different room ventilation rates. Aerosol particle concentrations and size distributions at the bystander’s position were measured.

Results

For both product categories, the particle concentrations registered following each puff were in the same order of magnitude. However, for e-cigarettes the particle concentration returned rapidly to background values within seconds; for conventional cigarettes it increased with successive puffs, returning to background levels after 30–45 minutes. Unlike for the e-cigarette devices tested, such temporal variation was dependent on the room ventilation rate. Particle size measurements showed that exhaled e-cigarette particles were smaller than those emitted during smoking conventional cigarettes and evaporated almost immediately after exhalation, thus affecting the removal of particles through evaporation rather than displacement by ventilation.

Conclusions

Significant differences between emissions from the tested e- and conventional cigarettes are reported. Exhaled e-cigarette particles are liquid droplets evaporating rapidly; conventional cigarette smoke particles are far more stable and linger.

Implications

• Several factors potentially influencing particle behavior after exhalation of e-cigarette aerosols or emitted during smoking conventional cigarettes were studied.

• Differences in particle size between those exhaled following use of e-cigarettes and those emitted during smoking of conventional cigarettes were observed.

• E-cigarette particle concentrations decreased rapidly following exhalation due to evaporation.

• The removal of particles following smoking conventional cigarettes was much slower and was dependent on the room ventilation rate.

Smoking and use of electronic cigarettes (vaping) in relation to preterm birth and small-for-gestational-age in a 2016 U.S. national sample

Women who smoke may be motivated to switch to vaping (use electronic cigarettes, e-cigs) around pregnancy in seeking to alleviate known hazards of smoking. E-cigs typically contain nicotine but either eliminates or greatly reduces exposure to the combustion products of tobacco. We studied a U.S.-wide representative sample of 31,973 live singleton births in 2016. In the three months before pregnancy, 5029 (14%) mothers exclusively smoked tobacco ("sole smokers") and 976 (3%) used both tobacco and e-cigs ("dual-users"). Among pre-pregnancy sole smokers, 44% continued to only smoke while 1% became dual-users in late pregnancy. Logistic regression models were used to assess the adjusted odds ratios (aOR) for preterm and small-for-gestational-age (SGA) by reported smoking or vaping in late pregnancy. Compared to women who used neither product ("non-users"), late-pregnancy sole smokers had increased risks for preterm birth (aOR 1.6, 95% CI 1.2-2.0) and SGA (aOR 2.4, 95% CI 1.8-2.9), after adjusting for their pre-pregnancy smoking or vaping status and other confounders. The adjusted models also showed that late-pregnancy sole vapers had similar risk of preterm birth as non-users (aOR 1.2, 95% CI 0.5-2.7). Late-pregnancy dual-users also had similar risk of preterm birth as non-users (aOR 1.3, 95% CI 0.8-2.3). However, late-pregnancy sole vapers and dual-users had increased risk of SGA compared to non-users (aOR 2.4, 95% CI 1.0-5.7 for sole vapers, and aOR 2.3 95% CI 1.3-4.1 for dual-users). These findings suggest that vapers during pregnancy had similar risk of preterm as non-users but still had elevated risk for restricted fetal growth.

Neuroinflammatory and Behavioral Outcomes Measured in Adult Offspring of Mice Exposed Prenatally to E-Cigarette Aerosols

BACKGROUND

In an effort to decrease the rates of smoking conventional tobacco cigarettes, electronic cigarettes (e-cigarettes) have been proposed as an effective smoking cessation tool. However, little is known about their toxicological impacts. This is concerning given that e-cigarette use is perceived as less harmful than conventional tobacco cigarettes during pregnancy for both the mother and fetus.

OBJECTIVE

The goal of this study was to test the neurodevelopmental consequences of maternal e-cigarette use on adult offspring behavior and neuroimmune outcomes.

METHODS

Pregnant female CD-1 mice were randomly assigned to one of three treatment groups (n=8-10 per group) and exposed daily to either filtered air, propylene glycol and vegetable glycerol (50:50 PG/VG vehicle), or to PG/VG with 16mg/mL nicotine (+Nic). Whole-body exposures were carried out for 3 h/d, 7 d/week, from gestational day (GD)0.5 until GD17.5. Adult male and female offspring (8 weeks old) were assessed across a battery of behavioral assessments followed by region-specific quantification of brain cytokines using multiplex immunoassays.

RESULTS

Adult offspring of both sexes exposed to +Nic exhibited elevated locomotor activity in the elevated plus maze and altered stress-coping strategies in the forced swim task. Moreover, male and female offspring exposed to PG/VG with and without nicotine had a 5.2% lower object discrimination score in the novel object recognition task. In addition to differences in offspring behavior, maternal e-cigarette exposure with nicotine led to a reduction in interleukin (IL)-4 and interferon-gamma (IFNγ) in the diencephalon, as well as lower levels of hippocampal IFNγ (females only). E-cigarette exposure without nicotine resulted in a 2-fold increase of IL-6 in the cerebellum.

DISCUSSION

These findings support previous adverse findings of e-cigarette exposure on neurodevelopment in a mouse model and provide substantial evidence of persistent adverse behavioral and neuroimmunological consequences to adult offspring following maternal e-cigarette exposure during pregnancy. https://doi.org/10.1289/EHP6067.

Pulmonary Illness Related to E-Cigarette Use in Illinois and Wisconsin - Final Report

BACKGROUND

E-cigarettes are battery-operated devices that heat a liquid and deliver an aerosolized product to the user. Pulmonary illnesses related to e-cigarette use have been reported, but no large series has been described. In July 2019, the Wisconsin Department of Health Services and the Illinois Department of Public Health received reports of lung injury associated with the use of e-cigarettes (also called vaping) and launched a coordinated public health investigation.

METHODS

We defined case patients as persons who reported use of e-cigarette devices and related products in the 90 days before symptom onset and had pulmonary infiltrates on imaging and whose illnesses were not attributed to other causes. Medical record abstraction and case patient interviews were conducted with the use of standardized tools.

RESULTS

There were 98 case patients, 79% of whom were male; the median age of the patients was 21 years. The majority of patients presented with respiratory symptoms (97%), gastrointestinal symptoms (77%), and constitutional symptoms (100%). All case patients had bilateral infiltrates on chest imaging. A total of 95% of the patients were hospitalized, 26% underwent intubation and mechanical ventilation, and two deaths were reported. A total of 89% of the patients reported having used tetrahydrocannabinol products in e-cigarette devices, although a wide variety of products and devices was reported. Syndromic surveillance data from Illinois showed that the mean monthly rate of visits related to severe respiratory illness in June through August of 2019 was twice the rate that was observed in the same months in 2018.

CONCLUSIONS

Case patients presented with similar clinical characteristics. Although the definitive substance or substances contributing to injury have not been determined, this initial cluster of illnesses represents an emerging clinical syndrome or syndromes. Additional work is needed to characterize the pathophysiology and to identify the definitive causes.

Electronic cigarettes containing nicotine increase endothelial and platelet derived extracellular vesicles in healthy volunteers

BACKGROUND AND AIMS

E-cigarette use is increasingly common. Whether e-cigarettes are harmful to human health is an intensely debated subject. In order to investigate whether e-cigarettes with and without nicotine cause different vascular responses, we obtained blood samples from healthy young volunteers who performed brief active e-cigarette inhalations. Extracellular vesicles (EVs) of endothelial and platelet origin were measured to determine vascular changes.

METHODS

Using a randomized, double-blind, crossover design, 17 healthy occasional smokers inhaled 30 puffs of e-cigarette vapor during 30 min. Blood samples were collected at baseline, as well as at 0, 2, 4 and 6 h post-exposure. EVs from platelets and endothelial cells were measured by flow cytometry.

RESULTS

Platelet and endothelial derived EVs were significantly increased with peak levels seen at 4 h following exposure to active inhalation of e-cigarette vapor with nicotine. Moreover, platelet derived EVs, expressing platelet activation marker P-selectin and the inflammation marker, CD40 ligand, were also significantly increased following inhalation of e-cigarette vapor with nicotine. In addition, platelet derived EVs expressing CD40 ligand was increased after inhalation of e-cigarette vapor without nicotine.

CONCLUSION

As few as 30 puffs of nicotine-containing e-cigarette vapor caused an increase in levels of circulating EVs of endothelial and platelet origin, which may signify underlying vascular changes. Although e-cigarette vapor without nicotine caused an increase in platelet EVs expressing CD40 ligand, nicotine, as a component in the vapor, seems to have a more compelling effect on extracellular vesicle formation and protein composition.

Investigating E-Cigarette Particle Emissions and Human Airway Depositions under Various E-Cigarette-Use Conditions

E-cigarette use is dramatically increasing, particularly with adolescents. While the chemical composition of e-liquids and e-vapor is well characterized, the particle size distribution and the human airways deposition patterns of e-cigarette particles are understudied and poorly understood despite their likely contribution to adverse health effects from e-cigarette usage. In this study, we examined the impacts of e-cigarette device power, e-liquid composition, and vaping topography on e-cigarette particle sizes and their deposition in human airways. In addition, we observed that particle measurement conditions (dilution ratio, temperature, and humidity) significantly affect measured e-cigarette particle sizes. E-cigarette power output significantly increased particle count median diameters (CMD) from 174 ± 13 (particles generated under 6.4 W) to 236 ± 14 nm (particles generated under 31.1 W). E-cigarette particles generated from propylene glycol-based e-liquids (CMD = 145 ± 8 nm and mass median diameter [MMD] = 3.06 ± 0.17 μm) were smaller than those generated from vegetable glycerin-based e-liquids (CMD = 182 ± 9 nm and MMD = 3.37 ± 0.21 μm). Puff volume also impacted vapor particle size: CMD and MMD were 154 ± 11 nm and 3.50 ± 0.27 μm, 163 ± 6 nm and 3.35 ± 0.24 μm, and 146 ± 12 nm and 2.95 ± 0.14 μm, respectively, for 35, 90, and 170 mL puffs. Estimated e-cigarette particle mass deposition fractions in tracheobronchial and bronchoalveolar regions were 0.504-0.541 and 0.073-0.306, respectively. Interestingly, e-cigarette particles are smaller than the particles generated from cigarette smoking but have similar human airway deposition patterns.

Social Influence in the Uptake and Use of Electronic Cigarettes: A Systematic Review

CONTEXT

E-cigarettes were introduced to support smoking cessation, but their popularity has increased among nonsmokers, challenging current perspectives on their safety and effectiveness as a public health intervention. The objective of this systematic review was to identify and synthesize current evidence on the influence of social factors on e-cigarette intentions and use.

EVIDENCE ACQUISITION

MEDLINE, CINAHL, PsycINFO, and Embase were searched for studies of the effects of social factors on e-cigarette intention or use in February 2019. Studies were included if they used experimental, longitudinal, qualitative, or mixed methods designs. Advertising, social interactions, and social norms were considered as social factors; social media was considered a conduit for other social factors. Two reviewers screened all studies; bias risk was evaluated for all RCTs using the Cochrane risk of bias tool.

EVIDENCE SYNTHESIS

This review included 43 studies: 9 experimental, 11 longitudinal, 22 qualitative, and 1 mixed method. All experimental studies examined advertising and consistently showed that exposure increased intentions to use e-cigarettes. Evidence of the influence of social interactions and social norms came from longitudinal and qualitative studies, suggesting that these factors could increase e-cigarette use. Most participants were nonsmokers (81%; 22,233 of 27,303). Studies rarely considered differences in the effects of social factors on smokers and nonsmokers.

CONCLUSIONS

Given the increased popularity among nonsmokers and the potential for advertising to increase e-cigarette use, closer public health monitoring of e-cigarette uptake by nonsmokers is warranted. Future primary research should be designed to measure how social factors affect smokers and nonsmokers differently.

Examining the Association Between Physical Activity, Sedentary Behavior and Sport Participation With E-Cigarette Use and Smoking Status in a Large Sample of Canadian Youth

INTRODUCTION

Youth e-cigarette use is common worldwide, but the profile of e-cigarette users compared with tobacco users is unclear. This study examines how sport participation and activity levels among youth differ between e-cigarette users and smokers.

METHODS

Using Canadian data from 38977 grade 9 to 12 students who participated in Year 3 (2014-15) of the COMPASS study, logistic regression models were used to examine the likelihood of sport participation and activity level based on e-cigarette use and smoking status. Pearson's chi-square tests were used to examine subgroup differences by gender.

RESULTS

E-cigarette users are more likely to participate in intramural, competitive, and team sports compared to non-users. Current and former smokers are less likely to participate in those sports than non-smokers. Youth e-cigarette users are more likely than non-users to meet the physical activity guidelines. Current smokers are more likely than non-smokers to undertake physical activity at least 60 min daily but less likely than non-smokers to tone at least 3 times per week. Youth e-cigarette users are less likely than non-users to be sedentary less than 2 h daily. Gender differences among males and females show that male e-cigarettes users drive the general relationship.

CONCLUSION

Results suggest that e-cigarette users are more likely to engage in physical activity compared to non e-cigarette users. Youth e-cigarette users are more likely to be physically active while the opposite is true for smokers. Although e-cigarettes may be less harmful to health compared to cigarette smoking, the increased uptake among youth of differing profiles should be considered in prevention efforts.

IMPLICATIONS

These results highlight the importance of addressing e-cigarette use in youth who undertake health promoting behaviors. Prevention efforts should not focus only on youth who may undertake riskier health habits; e-cigarette prevention programs should go beyond the domain of tobacco control.

Electronic Cigarette or Vaping-associated Lung Injury (EVALI): The Tip of the Iceberg

The Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, and state and local health departments have begun an investigation into the lung injury attributed to the use of electronic cigarette (e-cigarette) or vaping products. A clinical case of a 24-year-old man who used e-cigarette products regularly and presented with shortness of breath, productive cough, chest pain, and fever for 1 week was discussed. Radiographic and CT findings in that patient were reviewed. Recent cases of e-cigarette-associated lung injury from the literature were summarized to continue the dialogue and encourage radiologists to research this relatively new and specific type of lung injury. © RSNA, 2019.

Characterization of the Spatial and Temporal Dispersion Differences Between Exhaled E-Cigarette Mist and Cigarette Smoke

INTRODUCTION

There are fundamental differences between electronic cigarettes (e-cigarettes) and conventional cigarette product categories with regards to potential environmental exposures, notably that e-cigarettes do not contain tobacco or generate side-stream emissions. Here we assess the spatial and temporal patterns of exhaled e-cigarette aerosol at a bystander's position, and compare it with conventional cigarette smoke emissions.

METHODS

Smokers were asked to use e-cigarettes or smoke conventional cigarettes in a room-simulating chamber. Volunteers used the products at different distances from a heated mannequin, representing a bystander, and under different room ventilation rates. Aerosol particle concentrations and size distributions at the bystander's position were measured.

RESULTS

For both product categories, the particle concentrations registered following each puff were in the same order of magnitude. However, for e-cigarettes the particle concentration returned rapidly to background values within seconds; for conventional cigarettes it increased with successive puffs, returning to background levels after 30-45 minutes. Unlike for the e-cigarette devices tested, such temporal variation was dependent on the room ventilation rate. Particle size measurements showed that exhaled e-cigarette particles were smaller than those emitted during smoking conventional cigarettes and evaporated almost immediately after exhalation, thus affecting the removal of particles through evaporation rather than displacement by ventilation.

CONCLUSIONS

Significant differences between emissions from the tested e- and conventional cigarettes are reported. Exhaled e-cigarette particles are liquid droplets evaporating rapidly; conventional cigarette smoke particles are far more stable and linger.

IMPLICATIONS

• Several factors potentially influencing particle behavior after exhalation of e-cigarette aerosols or emitted during smoking conventional cigarettes were studied.• Differences in particle size between those exhaled following use of e-cigarettes and those emitted during smoking of conventional cigarettes were observed.• E-cigarette particle concentrations decreased rapidly following exhalation due to evaporation.• The removal of particles following smoking conventional cigarettes was much slower and was dependent on the room ventilation rate.

Main and side stream effects of electronic cigarettes

Over the last decade there has been a significant boost towards the use of electronic cigarettes (e-cigarettes), especially among youth. Different concentrations of propylene glycol (PG) or vegetable glycerin (VG), flavors and nicotine are mixed in plastic cartridges and commercially offered or privately produced by the vapers. During vaping, a mixture of air and vapors is inhaled to the lungs. Since the ingredients of the e-cigarettes are not burned but vaporized (heated), fewer chemicals are emitted. The levels of potentially toxic compounds (e.g. volatile organic compounds (VOCs), particulate matter (PM), metals, radicals, nitrosamines, etc.) emitted from vaping appear to be lower compared to that of tobacco smoking (from combustible cigarettes). Nevertheless, measurable toxic elements and VOCs are still released (e.g. acetaldehyde, formaldehyde, acrolein, benzene, etc.) along with other volatiles associated with e-liquid flavoring and device variability with PG and VG. The wide range of available flavors at various purities along with the heating temperature are important parameters affecting the evolution of VOCs and aerosols. There is lack of standardized short- and long-term epidemiological medical data (chronic exposure) on e-cigarettes effects to users, non-users and the human micro-environment (second- or third-hand exposure). Therefore, the potential health, safety and environmental effects of vaping are reviewed, examined and discussed.

Effectiveness and safety of nicotine patches combined with e-cigarettes (with and without nicotine) for smoking cessation: study protocol for a randomised controlled trial

INTRODUCTION

Evidence indicates e-cigarettes can help people quit smoking; however, more confirmatory trials are needed. To date, no trials have evaluated the effectiveness and safety of combining nicotine patches with e-cigarettes (with and without nicotine) for smoking cessation.

METHODS AND ANALYSIS

This study is a pragmatic, three-arm, community-based, single-blind, randomised trial undertaken in New Zealand. Eligible participants are daily/non-daily smokers, aged ≥18 years, naive e-cigarette users and motivated to quit smoking in the next 2 weeks. Participants (n=1809), recruited using multi-media advertising, are randomised to 14 weeks of (1) 21 mg nicotine patches (n=201); (2) 21 mg nicotine patches+18 mg/mL nicotine e-cigarette (n=804); or (3) 21 mg nicotine patches+nicotine free e-cigarette (n=804). Participants receive weekly withdrawal-oriented behavioural support calls for 6 weeks post-randomisation. The primary outcome is self-reported biochemically verified continuous abstinence (CA) at 6 months post quit-date. The primary comparison is nicotine patch + nicotine e-cigarette versus nicotine patch + nicotine free e-cigarette, and the secondary comparison is nicotine patch versus nicotine patch +nicotine e-cigarette (90% power, p=0.05, to detect an absolute difference in 6 month CA rates of 8% and 15% respectively). Secondary outcomes, collected by phone interview at quit date, then 1, 3, 6 and 12 months post-quit date, include self-reported CA, 7 day point prevalence abstinence, cigarettes per day (if smoking, or when smoking for non-daily smokers), time to relapse (if returned to smoking), belief in ability to quit, use of other cessation support, side effects/serious adverse events, treatment compliance, seeking additional support around e-cigarette use, daily use of both e-cigarettes and cigarettes, use of treatment past 14 weeks, views on treatment and recommendation to others, weight and cost-per-quitter.

ETHICS AND DISSEMINATION

The Northern A Health and Disability Ethics Committee approved the trial. Findings will be disseminated through publication, conference/meeting presentations, and media.

TRIAL REGISTRATION NUMBER

NCT02521662; Pre-results.

A Deliberate Choice? Exploring the Decision to Switch from Cigarettes to E-Cigarettes

E-cigarettes are increasingly popular among both cigarette smokers and non-users. Although smoking cessation yields the most individual and population health benefits, switching to exclusive e-cigarette use offers some individual health benefits for cigarette smokers. However, e-cigarette use is not harmless, and its use among non-cigarette smokers should be prevented. Our study aims to explore the decision-making process about e-cigarettes among an e-cigarette users, cigarette smokers, and non-users. We conducted 12 semi-structured focus group interviews with e-cigarette users, cigarette smokers, and non-users. We performed a thematic analysis of the interview transcripts. First, knowledge reported by e-cigarette users was mainly based on other users’ experiences. Second, cigarette smokers and non-users were more negative towards e-cigarettes than e-cigarette users. Third, e-cigarette users considered switching from cigarette smoking to e-cigarette use by deliberating relevant information, and weighing up the benefits and disadvantages of e-cigarette use versus smoking. Additionally, important factors in the decision-making process were a perception of risks and benefits of e-cigarettes compared to cigarettes, a supportive social environment about e-cigarette use, and trust in information offered about the risks and benefits of e-cigarettes. Our findings provide insight into what we can learn from the conscious decision-making process of e-cigarette users who switched from cigarettes to e-cigarettes. This information can be considered to develop targeted communications strategies to stimulate a conscious decision-making process, these may highlight benefits of switching to e-cigarettes for cigarette smokers, discussing the risks of smoking, and correcting misperceptions about the perceived risks and benefits of e-cigarette use.

Youth perspectives on concurrent smoking and vaping: Implications for tobacco control

Most people who smoke cigarettes begin young. Consequently, public health efforts directed at youth are a priority. The increasing popularity of electronic nicotine delivery systems (ENDS) among youth in the United States has raised concerns in the public health community about the potential of ENDS to renormalize cigarette smoking and perpetuate nicotine addiction, creating dual users who both vape and smoke. Despite limited and inconclusive evidence about dual use for young people, restrictive approaches towards ENDS have shaped tobacco control agendas in the United States. Based on analysis of 26 interviews with young dual users in California, we explored the meanings young people ascribe to their dual using practices and how those meanings relate to the broader tobacco control environment which structures their lives. Results suggest that dual users of ENDS and cigarettes overwhelmingly perceive a utilitarian meaning of dual use and view vaping as a tool for reducing smoking-related harm in the near term and facilitating quitting smoking in the long term. Also, participants' narratives related to Tobacco 21 laws, which prohibit sales of both ENDS and cigarettes to individuals under 21 years of age, revealed concerns about restrictive policies that limit access to less harmful tobacco products. Results of this study raise important questions about whether we are working towards further reductions in the prevalence of smoking and tobacco-related diseases.

IQOSTM vs. e-Cigarette vs. Tobacco Cigarette: A Direct Comparison of Short-Term Effects after Overnight-Abstinence

Introduction: Research from Philip Morris International's science division on its Heat-not-Burn product IQOSTM focused on its chemical, toxicological, clinical, and behavioral aspects. Independent research on the experiences and behavioral aspects of using IQOSTM, and how it compares to e-cigarettes, is largely lacking. The current randomized, cross-over behavioral trial tried to bridge the latter gaps. Methods: Participants (n = 30) came to the lab on three consecutive days after being overnight smoking abstinent. During each session, participants used one of three products (cigarette, e-cigarette, or IQOSTM) for five minutes. Exhaled CO (eCO) measurements and questionnaires were repeatedly administered throughout the session. Results: Smoking a cigarette for five minutes resulted in a significant increase of eCO, whereas using an IQOSTM resulted in a small but reliable increase (0.3 ppm). Vaping did not affect eCO. Cigarette craving reduced significantly after product use, with the decline being stronger for smoking than for e-cigarettes or IQOSTM. Withdrawal symptoms declined immediately after smoking or using IQOSTM, and with some delay after vaping. IQOSTM scored higher in terms of subjective reward/satisfaction and was slightly preferred to the e-cigarette. Discussion: Short-term use of IQOSTM has a minimal impact on eCO, is equally effective in reducing cigarette craving and withdrawal symptoms as an e-cigarette, and is slightly preferred.

An evaluation of school-based e-cigarette control policies' impact on the use of vaping products

INTRODUCTION

Electronic cigarette (e-cigarette) use among youth is common, and so efforts to regulate its use and availability are continually being made. The school environment represents an important domain for advancing health policy among youth populations. This study examines the impact of school-based e-cigarette control policies on student e-cigarette use in the context of a natural experiment.

METHODS

Using three years of longitudinal student and school level data (2013/2014 to 2015/2016), from a sample of 69 secondary schools in Ontario, Canada, a generalized estimating equation approach examined the impact of school-based e-cigarette control policy changes on the prevalence of youth e-cigarette use. The main outcome of interest was current e-cigarette use, while covariates included age, gender, ethnicity, and amount of spending money in dollars per week the student has. Tests of proportion (t-tests) were used to examine whether there were any significant differences in the changes for each intervention school relative to the sample of schools that report no changes in school-level e-cigarette control policies.

RESULTS

Estimates from the generalized estimating equation approach suggest that students had lower odds of using e-cigarettes in schools where an e-cigarette control policy was implemented. That is, the e-cigarette control policy decreased the adjusted odds of being an e-cigarette user (OR=0.68; 95% CI: 0.48–0.97). Examining school-specific impact, at four of six schools that had an e-cigarette control policy, the ban on the use of e-cigarettes may have lowered the prevalence of e-cigarette use.

CONCLUSIONS

This is the first study to use longitudinal data to study school-level e-cigarette use and the impact of e-cigarette control policy. These results provide new evidence that school-level policies banning the use of e-cigarettes on school property may be effective in reducing e-cigarette use (or preventing it) in their current form, as seen in this natural experiment.