The Electronic Cigarette: The Good, the Bad, and the Ugly

A Close Look at Vaping in Adolescents and Young Adults in the United States

Vaping by adolescents and young adults is a legitimate concern as there is a risk that some may start smoking and that electronic cigarette (EC) use may have adverse effects in the developing lungs of adolescents. This commentary provides updated information on vaping patterns among adolescents and young adults in the United States, as well as the impact of EC usage on respiratory health. EC use has surged greatly among high school students and young adults over the last decade but fortunately has declined significantly since its peak in 2019. During the same time period, smoking rates have constantly fallen to new low record levels. These trends argue against EC use as a gateway to smoking. Most EC usage is infrequent and unlikely to increase a person's risk of negative health consequences. Furthermore, the majority of EC usage has happened among those who have previously smoked. There is a dearth of data on the long-term health implications of EC usage in adolescents and young adults. We do not know whether short-term or intermittent use of EC in youth can lead to negative health outcomes in adulthood, and long-term high-quality studies in well-defined groups are needed. Although vaping has been linked to respiratory symptoms, they tend to be transient and of uncertain significance. This commentary provides up-to-date information so health care providers can give objective and responsible medical advice on EC usage.

Approaches to Formaldehyde Measurement: From Liquid Biological Samples to Cells and Organisms

Formaldehyde (FA) is the simplest aldehyde present both in the environment and in living organisms. FA is an extremely reactive compound capable of protein crosslinking and DNA damage. For a long time, FA was considered a “biochemical waste” and a by-product of normal cellular metabolism, but in recent decades the picture has changed. As a result, the need arose for novel instruments and approaches to monitor and measure not only environmental FA in water, cosmetics, and household products, but also in food, beverages and biological samples including cells and even organisms. Despite numerous protocols being developed for in vitro and in cellulo FA assessment, many of them have remained at the “proof-of-concept” stage. We analyze the suitability of different methods developed for non-biological objects, and present an overview of the recently developed approaches, including chemically-synthesized probes and genetically encoded FA-sensors for in cellulo and in vivo FA monitoring. We also discuss the prospects of classical methods such as chromatography and spectrophotometry, and how they have been adapted in response to the demand for precise, selective and highly sensitive evaluation of FA concentration fluctuations in biological samples. The main objectives of this review is to summarize data on the main approaches for FA content measurement in liquid biological samples, pointing out the advantages and disadvantages of each method; to report the progress in development of novel molecules suitable for application in living systems; and, finally, to discuss genetically encoded FA-sensors based on existing natural biological FA-responsive elements.

Perimenstrual Asthma in Adolescents: A Shared Condition in Pediatric and Gynecological Endocrinology

Asthma is a frequent medical condition in adolescence. The worsening of the most common symptoms perimenstrually is defined as perimenstrual asthma (PMA). The cause of PMA remains unclear, but a role for hormonal milieu is plausible. Data on PMA in adolescents are limited, and its management is not fully established. We aimed to discuss the PMA phenomenon in young females from pathophysiology to preventive strategies, focusing on the relationship with the hormonal pattern. The fluctuation of estrogens at ovulation and before menstruation and the progesterone secretion during the luteal phase and its subsequent withdrawal seem to be the culprits, because the deterioration of asthma is cyclical during the luteal phase and/or during the first days of the menstrual cycle. Conventional asthma therapies are not always effective for PMA. Preventive strategies may include innovative hormonal contraception. Even a possible beneficial effect of other hormonal treatments, including estrogens, progestogens, and androgens, as well as leukotriene receptor antagonists and explorative approach using microbial-directed therapy, is considered. The underlying mechanisms, through which sex-hormone fluctuations influence asthma symptoms, represent a challenge in the clinical management of such a distressing condition. Further studies focused on young females are mandatory to promote adolescent health.

Pediatric electronic cigarette or vaping product use-associated lung injury (EVALI): updates in the coronavirus disease 2019 (COVID-19) pandemic era

Electronic cigarette or vaping product use-associated lung injury (EVALI) is a toxic inhalational injury that surged in late 2019 and early 2020, immediately prior to the coronavirus disease 2019 (COVID-19) pandemic. Although EVALI cases have significantly decreased, they are still encountered, especially among adolescents. While several characteristic imaging findings and patterns of EVALI have been described, some of them can overlap with the imaging features of COVID-19 pneumonia. We provide a comprehensive review of EVALI that includes the latest updates and highlight the important role of radiologists as contributors to the appropriate and timely care of pediatric patients with this diagnosis.

The chemistry and toxicology of vaping

Vaping is the process of inhaling and exhaling an aerosol produced by an e-cigarette, vape pen, or personal aerosolizer. When the device contains nicotine, the Food and Drug Administration (FDA) lists the product as an electronic nicotine delivery system or ENDS device. Similar electronic devices can be used to vape cannabis extracts. Over the past decade, the vaping market has increased exponentially, raising health concerns over the number of people exposed and a nationwide outbreak of cases of severe, sometimes fatal, lung dysfunction that arose suddenly in otherwise healthy individuals. In this review, we discuss the various vaping technologies, which are remarkably diverse, and summarize the use prevalence in the U.S. over time by youths and adults. We examine the complex chemistry of vape carrier solvents, flavoring chemicals, and transformation products. We review the health effects from epidemiological and laboratory studies and, finally, discuss the proposed mechanisms underlying some of these health effects. We conclude that since much of the research in this area is recent and vaping technologies are dynamic, our understanding of the health effects is insufficient. With the rapid growth of ENDS use, consumers and regulatory bodies need a better understanding of constituent-dependent toxicity to guide product use and regulatory decisions.

Electronic Cigarettes and Asthma: What Do We Know So Far?

Electronic cigarettes (EC) are a novel product, marketed as an alternative to tobacco cigarette. Its effects on human health have not been investigated widely yet, especially in specific populations such as patients with asthma. With this review, we use the existing literature in order to answer four crucial questions concerning: (1) ECs' role in the pathogenesis of asthma; (2) ECs' effects on lung function and airway inflammation in patients with asthma; (3) ECs' effects on asthma clinical characteristics in asthmatics who use it regularly; and (4) ECs' effectiveness as a smoking cessation tool in these patients. Evidence suggests that many EC compounds might contribute to the pathogenesis of asthma. Lung function seems to deteriorate by the use of EC in this population, while airway inflammation alters, with the aggravation of T-helper-type-2 (Th2) inflammation being the most prominent but not the exclusive effect. EC also seems to worsen asthma symptoms and the rate and severity of exacerbations in asthmatics who are current vapers, whilst evidence suggests that its effectiveness as a smoking cessation tool might be limited. Asthmatic patients should avoid using EC.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Breath analysis of smokers, non-smokers, and e-cigarette users

Solid phase micro extraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) analysis was performed in exhaled breath samples of 48 healthy volunteers: 20 non-smokers, 10 smokers and 18 e-cigarette (EC, vape) users. Each volunteer provided 1 L of exhaled breath in a pre-cleaned Tedlar bag, in which an SPME fiber was exposed to absorb the emitted breath volatile organic compounds (VOCs). The acquired data were processed using multivariate data analysis (MDA) methods in order to identify the characteristic chemicals of the three groups. The results revealed that the breath of non-smokers demonstrated inverse correlation with a variety of molecules related to the breath from smokers including furan, toluene, 2-butanone and other organic substances. Vapers were distinguished from smokers by the chemical speciation of the e-liquids, such as that of esters (e.g. ethyl acetate), terpenes (e.g. α-pinene, β-pinene, d-limonene, p-cymene, etc.) and oxygenated compounds (e.g. 3-hexen-1-ol, benzaldehyde, hexanal, decanal, etc). Two classification models were developed (a) using principal component analysis (PCA) with hierarchical cluster analysis (HCA) and (b) using partial least squares-discriminant analysis (PLS-DA). Both models were validated using 8 new samples (4 vapers and 4 smokers), collected in addition to the 48 samples of the calibration set. The combination of GC/MS breath analysis and MDA contributed successfully in classifying the volunteers into their respective groups and highlighted the relevant characteristic VOCs. The respective dynamic combination (SPME-GC/MS and MDA) provides a means for long term non-invasive monitoring of the population's health status for early detection purposes.

Patients' perspectives on smoking and inflammatory bowel disease: An online survey in collaboration with European Federation of Crohn's and Ulcerative Colitis Associations

BACKGROUND

Smoking has detrimental effects on Crohn’s disease (CD) activity while data on ulcerative colitis (UC) are conflicting. Little is known about the use and impact of alternative smoking products in inflammatory bowel diseases (IBD).

AIM

To understand the patients’ perceptions of the impact of smoking on their IBD and to assess differences between CD and UC patients.

METHODS

The questionnaire was developed by Philip Morris Products SA in cooperation with European Federation of Crohn's and Ulcerative Colitis Associations. The final survey questionnaire consisted of 41 questions divided in 8 categories: (1) Subject screener; (2) Smoking history; (3) Background information; (4) IBD disease background; (5) Current disease status; (6) Current therapeutics and medications; and (7) Current nicotine/cigarettes use and awareness of the impacts of smoking on IBD. The questionnaire was submitted online from 4^th November 2019 to 11th March 2020 through the European Federation of Crohn's and Ulcerative Colitis Associations website to IBD patients who were current smokers or had a history of smoking.

RESULTS

In total 1050 IBD patients speaking nine languages participated to the survey. Among them, 807 (76.9%) patients declared to have ever smoked or consumed an alternative smoking product, with a higher proportion of current cigarette smokers among CD patients (CD: 63.1% vs UC: 54.1%, P = 0.012). About two-thirds of the participants declared to have ever stopped cigarette smoking and restarted (67.0%), with a significantly higher proportion among UC patients compared to CD patients (73.1% vs 62.0%, P = 0.001). We also found significant differences between CD and UC patients in the awareness of the health consequences of smoking in their disease and in the perceived impact of smoking on disease activity, for both cigarettes and alternative smoking products.

CONCLUSION

This survey found significant differences between CD and UC patients in both awareness and perception of the impact of smoking on their disease. Further efforts should be done to encourage smoking cessation for all IBD patients, including UC patients.

Hot Wires and Film Boiling: Another Look at Carbonyl Formation in Electronic Cigarettes

Electronic cigarettes (ECIGs) are a class of tobacco products that emit a nicotine-containing aerosol by heating and vaporizing a liquid. Apart from initiating nicotine addiction in nonsmokers, a persistent concern about these products is that their emissions often include high levels of carbonyl species, toxicants thought to cause most noncancer pulmonary diseases in smokers. This study examined whether the phenomenon of film boiling can account for observations of high carbonyl emissions under certain operating conditions and, if so, whether film boiling theory can be invoked to predict conditions where high carbonyl emissions are likely. We measured the critical heat flux for several common heating materials and liquids and carbonyl emissions for several ECIG types while varying the power. We found that emissions rise drastically whenever the power exceeds the value corresponding to the critical heat flux. While limiting the heat flux to below this threshold can greatly reduce carbonyl exposure, ECIG manufacturer operating instructions often exceed it. Product regulations that limit heat flux may reduce the public health burden of electronic cigarette use.

Potential effects of E-cigarettes and vaping on pediatric asthma

Asthma is the most common chronic disease in childhood and exposure to tobacco smoke has been long recognized as a risk factor for its onset as well as for exacerbations and poor disease control. Since the early 2000s, electronic cigarettes have been marketed worldwide as a non-harmful electronic alternative to combustible cigarettes and as a device likely to help stop smoking, and their use is continuously rising, particularly among adolescents. However, several studies have shown that vape contains many different well-known toxicants, causing significant cytotoxic and pro-inflammatory effects on the airways in-vitro and in animal models. In humans, a variety of harmful lung effects related to vaping, ranging from bronchoconstriction to severe respiratory distress has been already reported. To investigate the potential effects of vaping in pediatric asthma, we searched relevant published studies in the MEDLINE/PubMed database by combining the adequate Medical Subject Headings terms and key words. At the end of our study selection process, five cross-sectional studies focusing on electronic cigarettes use in adolescents and self-reported asthma and/or other respiratory symptoms, one study focusing on the effects of electronic cigarettes second-hand exposure and one case report were retrieved. These preliminary data support a likely detrimental effect of vaping in asthmatic adolescents. Currently available evidence supports that electronic cigarettes are a potential threat to respiratory health, particularly in adolescents with asthma. High-quality studies on larger population assessing the long-term effects of vape exposure, are urgently needed.

Exploring Associations between Susceptibility to the Use of Electronic Nicotine Delivery Systems and E-Cigarette Use among School-Going Adolescents in Rural Appalachia

Electronic nicotine delivery systems (ENDS) use, including e-cigarettes, has surpassed the use of conventional tobacco products. Emerging research suggests that susceptibility to e-cigarette use is associated with actual use among adolescents. However, few studies exist involving adolescents in high-risk, rural, socioeconomically distressed environments. This study examines susceptibility to and subsequent usage in school-going adolescents in a rural distressed county in Appalachian Tennessee using data from an online survey (N = 399). Relying on bivariate analyses and logistic regression, this study finds that while 30.6% of adolescents are ever e-cigarette users, 15.5% are current users. Approximately one in three adolescents are susceptible to e-cigarettes use, and susceptibility is associated with lower odds of being a current e-cigarette user (OR = 0.03; CI: 0.01–0.12; p < 0.00). The age of tobacco use initiation was significantly associated with decreased current use of e-cigarettes (OR = 0.89; CI: 0.83–0.0.97; p < 0.01). Overall, the results of this exploratory study suggest the need for larger studies to identify unique and generalizable factors that predispose adolescents in this high-risk rural, socioeconomically disadvantaged region to ENDS use. Nevertheless, this study offers insight into e-cigarette usage among U.S adolescents in rural, socioeconomically disadvantaged environments and provides a foundation for a closer examination of this vulnerable population.

History repeats itself: Role of characterizing flavors on nicotine use and abuse

The popularity of e-cigarettes has skyrocketed in recent years, and most vapers use flavored e-cigarette products. Consumption of flavored e-cigarettes exceeds that of combustible cigarettes and other tobacco products among adolescents, who are particularly vulnerable to becoming nicotine dependent. Flavorings have been used by the tobacco industry since the 17th century, but the use of flavors by the e-cigarette industry to create products with "characterizing" flavors (i.e. flavors other than tobacco or menthol) has sparked a public health debate. This review addresses the possibility that characterizing flavors make nicotine more appealing, rewarding and addictive. It also discusses ways in which preclinical and clinical studies could improve our understanding of the mechanisms by which flavors may alter nicotine reward and reinforcement. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.

Relation between Tobacco Smoking/Electronic Smoking and Albuminuria/Vascular Stiffness in Young People without Cardiovascular Diseases

INTRODUCTION/OBJECTIVE

Tobacco smoking is a well-known risk factor for cardiovascular and renal diseases. In recent years, alternative types of smoking, including vaping, have been becoming popular. The contribution of vape to vascular and renal injury is not known. We studied the relation between smoking of traditional/electronic cigarettes and arterial stiffness and albuminuria, which is also a vascular dysfunction marker.

METHODS

We examined 270 young volunteers without significant clinical cardiovascular diseases (mean age: 21.2 ± 2.3 years). Twenty-seven percent of the subjects in the study group were smokers; 69.9% of them smoked traditional cigarettes and 30.1% smoked electronic cigarettes. The urine albumin level was assessed by a dipstick test, and the augmentation index was determined by photoplethysmography. A linear correlation test and multiple regression analysis were applied.

RESULTS

The study groups did not differ in basic characteristics. The smokers demonstrated generally higher blood pressure levels and were overweight. Most of the smokers were male. In the groups of smokers, albuminuria was more frequent, especially among vapers (94 vs. 79% in tobacco smokers and 29% in nonsmokers). AU values (median [quartile 25; quartile 75]) were significantly higher in vapers (160 mg/L [150; 207.5]) vs. tobacco smokers (115 mg/L [60; 200]) and vs. nonsmokers (20 mg/L [10; 50]) (р < 0.05). Photoplethysmographic results showed relevant higher augmentation indices among tobacco smokers (-4, [-6.6; -1.9]) and vapers (-5.05 [-13.4; -3.3]) compared to nonsmokers (-16.2 [-23.9; -7]) (р < 0.05). Results of multiple regression analysis demonstrate that smoking of both traditional and electronic cigarettes is related to an increase in the albuminuria level and the augmentation index.

CONCLUSIONS

Smoking of both traditional and electronic cigarettes is related to albuminuria and an increase in the augmentation index, which is a noninvasive marker for arterial stiffness.

Metal/Metalloid Levels in Electronic Cigarette Liquids, Aerosols, and Human Biosamples: A Systematic Review

BACKGROUND

Electronic cigarettes (e-cigarettes) have become popular, in part because they are perceived as a safer alternative to tobacco cigarettes. An increasing number of studies, however, have found toxic metals/metalloids in e-cigarette emissions.

OBJECTIVE

We summarized the evidence on metal/metalloid levels in e-cigarette liquid (e-liquid), aerosols, and biosamples of e-cigarette users across e-cigarette device systems to evaluate metal/metalloid exposure levels for e-cigarette users and the potential implications on health outcomes.

METHODS

We searched PubMed/TOXLINE, Embase®, and Web of Science for studies on metals/metalloids in e-liquid, e-cigarette aerosols, and biosamples of e-cigarette users. For metal/metalloid levels in e-liquid and aerosol samples, we collected the mean and standard deviation (SD) if these values were reported, derived mean and SD by using automated software to infer them if data were reported in a figure, or calculated the overall mean (mean ± SD) if data were reported only for separate groups. Metal/metalloid levels in e-liquids and aerosols were converted and reported in micrograms per kilogram and nanograms per puff, respectively, for easy comparison.

RESULTS

We identified 24 studies on metals/metalloids in e-liquid, e-cigarette aerosols, and human biosamples of e-cigarette users. Metal/metalloid levels, including aluminum, antimony, arsenic, cadmium, cobalt, chromium, copper, iron, lead, manganese, nickel, selenium, tin, and zinc, were present in e-cigarette samples in the studies reviewed. Twelve studies reported metal/metalloid levels in e-liquids (bottles, cartridges, open wick, and tank), 12 studies reported metal/metalloid levels in e-cigarette aerosols (from cig-a-like and tank devices), and 4 studies reported metal/metalloid levels in human biosamples (urine, saliva, serum, and blood) of e-cigarette users. Metal/metalloid levels showed substantial heterogeneity depending on sample type, source of e-liquid, and device type. Metal/metalloid levels in e-liquid from cartridges or tank/open wicks were higher than those from bottles, possibly due to coil contact. Most metal/metalloid levels found in biosamples of e-cigarette users were similar or higher than levels found in biosamples of conventional cigarette users, and even higher than those found in biosamples of cigar users.

CONCLUSION

E-cigarettes are a potential source of exposure to metals/metalloids. Differences in collection methods and puffing regimes likely contribute to the variability in metal/metalloid levels across studies, making comparison across studies difficult. Standardized protocols for the quantification of metal/metalloid levels from e-cigarette samples are needed. https://doi.org/10.1289/EHP5686.

E-cigarette, or vaping, product use-associated lung injury in adolescents: a review of imaging features

BACKGROUND

There has been a recent increase in recognition of lung disease related to the use of electronic cigarettes (called "vaping"). These patients present with acute respiratory illness following exposure to vaporized cannabis or nicotine products and sometimes require hospitalization and intensive care. We describe the imaging findings of this disease entity in the pediatric population.

OBJECTIVE

To describe the radiologic findings of lung injury associated with electronic cigarette use (vaping) in the adolescent pediatric population.

MATERIALS AND METHODS

We identified all adolescents with acute respiratory illness and a history of electronic cigarette use who presented at our institution within a 3-month period (June 2019 through August 2019). We excluded adolescents with potential intercurrent pulmonary disease. We reviewed the charts for symptomatology and laboratory and pathology data. In addition, we reviewed the chest radiographs and chest CTs of these adolescents.

RESULTS

The review group consisted of 12 teenage pediatric patients (10 boys and 2 girls; mean age 16.9 years, range 16.0-17.7 years) with acute respiratory illness found to have a temporal association with electronic cigarette use for cannabis products, nicotine, or both. Other etiologies for illness in these adolescents had been excluded by clinical and laboratory evaluation. All of the adolescents were admitted to the hospital for treatment. The clinical presentations included dyspnea, abdominal pain and constitutional symptoms. Pulmonary function testing that was performed in all patients during admission or follow-up demonstrated reduced diffusion capacity in 4/12 (33%), an obstructive ventilatory pattern in 4/12 (33%), a restrictive pattern in 1/12 (8%), and a mixed obstructive and restrictive pattern in 2/12 (17%) adolescents. Bronchoalveolar lavage studies, performed in 9 of the 12 adolescents, revealed inflammatory cells and lipid-laden macrophages. All of the patients underwent CT of the chest; the findings were notable for centrilobular ground-glass nodules (11/12; 92%) and confluent ground-glass opacities (12/12; 100%), with frequent subpleural sparing (9/12; 75%). Additionally, 6/12 (50%) adolescents demonstrated small pleural effusions; 6/12 (50%) had mild bronchial wall thickening; 9/12 (75%) had enlarged hilar or mediastinal lymph nodes; and 2/12 (17%) had a small pericardial effusion.

CONCLUSION

As seen in our teenage population, e-cigarette, or vaping, product use-associated lung injury (EVALI) is characterized by centrilobular ground-glass nodules and ground-glass opacities with subpleural sparing. The imaging findings are most consistent with acute lung injury resulting from toxic inhalation. Because adolescent pediatric patients might not be forthcoming with their history of electronic cigarette use, it is important for the pediatric radiologist to be aware of the imaging patterns of this disease.

E-cigarettes: Effects in phagocytosis and cytokines response against Mycobacterium tuberculosis

Cigarette smoking and tuberculosis are a significant cause of death worldwide. Several epidemiological studies have demonstrated cigarette smoking is a risk factor for tuberculosis. Electronic cigarettes have recently appeared as a healthier alternative to conventional smoking, although their impact in tuberculosis is not well understood. The aim of this study was to explore the effect of electronic cigarettes in phagocytosis of Mycobacterium tuberculosis and cytokines production. In vitro infection was carried out by exposing THP-1 macrophages to four electronic vapor extracts and the intracellular burden of M. tuberculosis was determined. The percentage of infection was evaluated by confocal microscopy and the cytokine production by Luminex. A reduction of intracellular M. tuberculosis burden in THP-1 macrophages was found after its exposure to electronic vapor extract; the same trend was observed by confocal microscopy when Mycobacterium bovis BCG-GFP strain was used. Electronic cigarettes stimulate a pro-inflammatory cytokine response. We conclude that electronic cigarettes impair the phagocytic function and the cytokine response to M. tuberculosis.

Nicotine in E-cigarette smoke: cancer culprit?

Tobacco smoke's harmful effects are well-known; the harmful effects of tobacco smoke have been well-investigated. Nicotine in tobacco smoke contributes to the pathogenesis of various conditions, such as lung cancer, coronary artery disease and asthma. A decade ago, a seemingly safer alternative to tobacco cigarettes was introduced- the E-cigarette. However, studies have found that E-cigarette smoke (ECS) not only induces DNA damage but also reduces DNA repair activity via BER and NER pathways. Further research conducted with cells damaged by Ultra-Violet (UV) light or hydrogen peroxide (H₂O₂) indicates that ECS can function as a comutagen; nicotine can amplify mutagenic activity by merging with other mutagens. The downstream metabolites derived from nicotine found in ECS put E-cigarette smokers at a higher risk for developing lung or bladder cancers or heart disease than their non-smoking counterparts. Overall, these findings are instrumental in our understanding of the harmful effects of ECS.

Changes in E-Cigarette Use Behaviors and Dependence in Long-term E-Cigarette Users

INTRODUCTION

Little is known about the effects of long-term e-cigarette use, particularly the risks of relapse to cigarette smoking or increased dependence.

METHODS

In a 2012-2014 baseline online e-cigarette survey, 1,863 respondents consented to participate in future research. A follow-up online survey was conducted in 2017-2018 to assess changes in e-cigarette use behaviors and e-cigarette-related dependence. For both surveys, exclusive e-cigarette use was defined as only using e-cigarettes in the past 7 days, and poly use was defined as using both e-cigarettes and other tobacco or nicotine products in the past 7 days. The Penn State Electronic Cigarette Dependence Index (PSECDI) score was calculated for each study subject and was used to evaluate e-cigarette dependence. Paired t-tests or Pearson correlation coefficients were used to examine changes in e-cigarette use behaviors or PSECDI scores between baseline and follow-up. Baseline and follow-up survey data were analyzed in January 2019.

RESULTS

A total of 494 subjects provided complete data on both surveys. At baseline, 402 subjects (81.4%) were exclusive e-cigarette users, and 71 subjects (14.4%) were poly users. Among baseline exclusive e-cigarette users, the majority (88.3%) continued using e-cigarettes exclusively, but 37 users (9.2%) became poly users and 1 returned to cigarette smoking at follow-up. Among baseline poly users, 60.6% became exclusive e-cigarette users at follow-up. The mean PSECDI score remained similar over time (8.4 at baseline vs 8.3 at follow-up).

CONCLUSIONS

Findings suggest that the risk of relapse to cigarette smoking is low, and e-cigarette-related dependence remains stable in long-term e-cigarette users.

Nicotine and Carbonyl Emissions From Popular Electronic Cigarette Products: Correlation to Liquid Composition and Design Characteristics

Introduction

Available in hundreds of device designs and thousands of flavors, electronic cigarette (ECIG) may have differing toxicant emission characteristics. This study assesses nicotine and carbonyl yields in the most popular brands in the U.S. market. These products included disposable, prefilled cartridge, and tank-based ECIGs.

Methods

Twenty-seven ECIG products of 10 brands were procured and their power outputs were measured. The e-liquids were characterized for pH, nicotine concentration, propylene glycol/vegetable glycerin (PG/VG) ratio, and water content. Aerosols were generated using a puffing machine and nicotine and carbonyls were, respectively, quantified using gas chromatograph and high-performance liquid chromatography. A multiregression model was used to interpret the data.

Results

Nicotine yields varied from 0.27 to 2.91 mg/15 puffs, a range corresponding to the nicotine yield of less than 1 to more than 3 combustible cigarettes. Nicotine yield was highly correlated with ECIG type and brand, liquid nicotine concentration, and PG/VG ratio, and to a lower significance with electrical power, but not with pH and water content. Carbonyls, including the carcinogen formaldehyde, were detected in all ECIG aerosols, with total carbonyl concentrations ranging from 3.72 to 48.85 µg/15 puffs. Unlike nicotine, carbonyl concentrations were mainly correlated with power.

Conclusion

In 15 puffs, some ECIG devices emit nicotine quantities that exceed those of tobacco cigarettes. Nicotine emissions vary widely across products but carbonyl emissions showed little variations. In spite of that ECIG users are exposed to toxicologically significant levels of carbonyl compounds, especially formaldehyde. Regression analysis showed the importance of design and e-liquid characteristics as determinants of nicotine and carbonyl emissions.

Implications

Periodic surveying of characteristics of ECIG products available in the marketplace is valuable for understanding population-wide changes in ECIG use patterns over time.

Environmental exposures and mechanisms in allergy and asthma development

Environmental exposures interplay with human host factors to promote the development and progression of allergic diseases. The worldwide prevalence of allergic disease is rising as a result of complex gene-environment interactions that shape the immune system and host response. Research shows an association between the rise of allergic diseases and increasingly modern Westernized lifestyles, which are characterized by increased urbanization, time spent indoors, and antibiotic usage. These environmental changes result in increased exposure to air and traffic pollution, fungi, infectious agents, tobacco smoke, and other early-life and lifelong risk factors for the development and exacerbation of asthma and allergic diseases. It is increasingly recognized that the timing, load, and route of allergen exposure affect allergic disease phenotypes and development. Still, our ability to prevent allergic diseases is hindered by gaps in understanding of the underlying mechanisms and interaction of environmental, viral, and allergen exposures with immune pathways that impact disease development. This Review highlights epidemiologic and mechanistic evidence linking environmental exposures to the development and exacerbation of allergic airway responses.

The Use of E-cigarettes Among School-Going Adolescents in a Predominantly Rural Environment of Central Appalachia

E-cigarette use among youth in the United States (U.S.) continues to increase. In the rural Northeast Tennessee, where prevalence of tobacco use is higher than national and state averages, there is no literature on e-cigarette use to inform policies and programs. This study aimed to estimate the prevalence of e-cigarette use and examine association of e-cigarette use with two tobacco products among school-going adolescents. Data from 894 participants of a school-based survey conducted in 2016 in Northeast Tennessee were analyzed. Descriptive statistics and logistic regression analyses were conducted to estimate the prevalence and delineate the associations between e-cigarette use and other tobacco products. Approximately 11% of the participants currently used e-cigarettes, and 35% had ever used e-cigarettes. About 6% of the participants were current users of both e-cigarettes and cigarettes; 4% were current users of e-cigarettes and smokeless tobacco; 3% were current users of all three products, and 15% had ever tried all three products. More than one-half of current e-cigarette users (52%) also smoked cigarettes. Adjusting for covariates, current e-cigarette use was positively associated with cigarette smoking [Odds Ratio (OR) 27.32, 95% confidence interval (CI) 14.4-51.7] and smokeless tobacco use [OR 7.92, 95% CI 3.8-16.5]. E-cigarette use was more common among the high school students than cigarette and smokeless tobacco use, and a significant proportion of users either smoked cigarettes, used smokeless tobacco, or both. Thus, there is a critical need for preventive policies and programs to address dual and poly-use of these products.

The Relationships of Expectancies With E-cigarette Use Among Hospitalized Smokers: A Prospective Longitudinal Study

Background

Expectancies demonstrate cross-sectional associations with e-cigarette use, but the prospective relationships between expectancies and e-cigarette use are unknown. This study examined the longitudinal associations of expectancies with e-cigarette use among hospitalized tobacco cigarette smokers.

Methods

E-cigarette expectancies (e-cigarette-specific Brief Smoking Consequences Questionnaire-Adult [BSCQ-A]), tobacco cigarette expectancies (tobacco-specific BSCQ-A), and number of days used e-cigarettes in the past 30 days were assessed at baseline hospitalization, 6-months post-hospitalization, and 12-months post-hospitalization among 978 hospitalized tobacco cigarette smokers. Expectancy difference scores (e-cigarette-specific expectancies minus tobacco-specific expectancies) were computed for each of the 10 BSCQ-A scales. Cross-lagged panel models tested the relationships between expectancy difference scores and number of days used e-cigarettes in the past 30 days for each of the 10 BSCQ-A scales.

Results

Though some models revealed partial associations between expectancies and e-cigarette use, only one yielded results consistent with hypotheses. Greater e-cigarette use at baseline predicted greater expectancies that e-cigarettes taste pleasant as compared to tobacco cigarettes at 6 months, which then predicted greater e-cigarette use at 12 months. To a lesser degree greater expectancies that e-cigarettes taste pleasant as compared to tobacco cigarettes at baseline predicted greater e-cigarette use at 6 months, which then predicted greater expectancies that e-cigarettes taste pleasant as compared to tobacco cigarettes at 12 months.

Conclusions

Expectancies that e-cigarettes provide similar or more pleasant taste sensations as compared to tobacco cigarettes may be both a cause and consequence of e-cigarette use. Focusing on the taste experience may prove most effective in modifying e-cigarette use behavior.

Implications

The current study offers the first longitudinal examination of expectancies and e-cigarette use. Results suggest expectancies that e-cigarettes provide similar or more pleasant taste sensations relative to tobacco cigarettes are both a cause and consequence of e-cigarette use. Efforts that focus on the e-cigarette taste experience may prove most effective in modifying e-cigarette use behavior.

Screening for Lung Cancer: Communicating With Patients

OBJECTIVE

The purposes of this article are to detail the experience of a single-center academic institution in applying the patient-centered approach to a lung cancer screening program and to examine how this approach can expand to other aspects of follow-up imaging of lung nodules.

CONCLUSION

As the practice of patient-centered radiology gains attention, diagnostic radiologists are findings new ways to become more involved in patient care. A lung cancer screening program is one opportunity for radiologists to consult with and educate patients.

Burns caused by electronic vaping devices (e-cigarettes): A new classification proposal based on mechanisms

Introduction With more than 10 million of daily users, e-cigarettes encountered a great success. But in the past few years, the number of medical reports of injuries caused by the explosion of e-cigarettes has significantly increased. This article aims at reporting our series and reviewing the literature to propose a new classification based on the mechanisms of injuries related to e-cigarettes that can guide non-specialists and specialists in the management of these patients. Method We performed a retrospective review of our institutional burn database from June 2016 to July 2017 for injuries caused by or in the context of using an e-cigarette. The patients' demographics (age, gender), burn injury mechanisms, depth, localization, surface and interventions were described. Results Ten patients suffered from burns related to the use of e-cigarettes. The burns were located at the thigh (80%) and the hand (50%) with a mean surface of 3% of TBSA. Four different mechanisms could be described: Type A: thermal burns with flames due to the phenomenon of "thermal runaway", Type B: blasts lesions secondary to the explosion, Type C: chemical alkali burns caused by spreading of the electrolyte solution and Type D: thermal burns without flames due to overheating. These different mechanisms suggest specific surgical and non-surgical management. Conclusion Management of injuries sustained from e-cigarettes' explosions should be approached from the standpoint of mechanisms. Different mechanisms could be associated and should be considered in specific management.

Blast Injuries Caused by Vape Devices: 2 Case Reports

Vaporizing devices have become a popular alternative to conventional nicotine products. They are thought to be safer as they produce aerosolized nicotine powered by a lithium ion battery. Many people have used these electronic devices as a tool to quit smoking; however, the batteries can be unstable and explode.We present 2 case reports where explosions of electronic vapor devices caused significant injuries. The first patient sustained a combustion injury to the maxilla resulting in bone and anterior maxillary tooth loss requiring reconstruction. The second patient had a severe blast injury to the hand which ultimately resulted in loss of a digit. Toxicology was consulted due to concerns for systemic absorption of metals in the soft tissue of the hand. Cobalt and manganese were initially elevated but decreased after surgical debridement. The patient did not have any systemic symptoms.Currently, there is no federal regulation of electronic cigarettes or vape devices in the United States. With the increasing use of these devices and no standard regulations, we anticipate more blast injuries occurring in the future. Medical providers will need to be able to be prepared to manage the devastating clinical injuries that ensue.

Behavioral economic substitutability of e-cigarettes, tobacco cigarettes, and nicotine gum

The public health impact of e-cigarettes may depend on their substitutability for tobacco cigarettes. Dual users of e-cigarettes and tobacco cigarettes completed purchasing tasks in which they specified daily use levels under hypothetical conditions that varied the availability and price of e-cigarettes, tobacco cigarettes, and nicotine gum (for those with nicotine gum experience). When either e-cigarettes or tobacco cigarettes were the only available commodity, as price per puff increased, purchasing decreased, revealing similar reinforcement profiles. When available concurrently, as the price of tobacco puffs increased, purchasing of tobacco puffs decreased while purchasing of fixed-price e-cigarette puffs increased. Among those with nicotine gum experience, when the price of tobacco puffs was closest to the actual market value of tobacco puffs, e-cigarette availability decreased median tobacco puff purchases by 44% compared to when tobacco was available alone. In contrast, nicotine gum availability caused no decrease in tobacco puff purchases. E-cigarettes may serve as a behavioral economic substitute for tobacco cigarettes, and may be a superior substitute compared to nicotine gum in their ability to decrease tobacco use. Although important questions remain regarding the health impacts of e-cigarettes, these data are consistent with the possibility that e-cigarettes may serve as smoking cessation/reduction aids.

Type two innate lymphoid cells: the Janus cells in health and disease

Innate lymphoid cells are functionally diverse subsets of immune cells including the conventional natural killer cells, lymphoid tissue inducers, type 1, 2, and 3 with significant roles in immunity and pathogenesis of inflammatory diseases. Type 2 innate lymphoid cells (ILC2s) resemble type 2 helper (Th2) cells in cytokine production and contribute to anti-helminth immunity, maintaining mucosal tissue integrity, and adipose tissue browning. ILC2s play important roles in the pathogenesis of allergic diseases and asthma. Studying the pathways of activation and regulation of ILC2s are currently a priority for giving a better understanding of pathogenesis of diseases with immunological roots. Recently, our laboratory and others have shown several pathways of regulation of ILC2s by co-stimulatory molecules such as ICOS, regulatory T cells and by compounds such as nicotine. In this review, we summarize the current understanding of the mechanisms of activation and regulation of ILC2s and the role of these cells in health and disease.

Electronic cigarettes—A review of the physiological health effects

Electronic cigarettes (ECs) are devices that are used recreationally or as smoking cessation tools, and have become increasingly popular in recent years. We conducted a review of the available literature to determine the health effects caused by the use of these devices. A heating element in the EC aerosolizes a solution of propylene glycol, glycerol, nicotine (optional), and flavouring (optional). These compounds are generally harmless on their own. However, upon heating, they produce various carcinogens and irritants. We found that concentrations of these toxicants vary significantly depending on the type of EC device, the type of EC liquid, and the smoking behaviour of the user. Exposure to these vapours can cause inflammation and oxidative damage to in vitro and in vivo cells. EC aerosol can also potentially affect organ systems and especially cardiovascular and lung function. We concluded that EC use causes acute effects on health but not as severe as those of conventional cigarettes (CCs). These devices could, therefore, be of use for smokers of CCs wishing to quit. However, as EC aerosol introduces new toxicants not found in CCs, long-term studies are needed to investigate possible chronic effects associated with EC use.

Strategies to alter the natural history of childhood asthma

PURPOSE OF REVIEW

Asthma exhibits significant heterogeneity in occurrence and severity over the lifespan. Our goal is to discuss recent evidence regarding determinants of the natural history of asthma during childhood, and review the rationale behind and status of major efforts to alter its course.

RECENT FINDINGS

Variations in microbial exposures are associated with risk of allergic disease, and the use of bacterial lysates may be a promising preventive strategy. Exposure to air pollution appears to be particularly damaging in prenatal and early life, and interventions to reduce pollution are feasible and result in clinical benefit. E-cigarette use may have a role in harm reduction for conventional cigarette smokers with asthma, but has undefined short-term and long-term effects that must be clarified. Vitamin D insufficiency over the first several years of life is associated with risk of asthma, and vitamin D supplementation reduces the risk of severe exacerbations.

SUMMARY

The identification of risk factors for asthma occurrence, persistence and severity will continue to guide efforts to alter the natural history of the disease. We have reviewed several promising strategies that are currently under investigation. Vitamin D supplementation and air pollution reduction have been shown to be effective strategies and warrant increased investigation and implementation.

Overview of Electronic Nicotine Delivery Systems: A Systematic Review

CONTEXT

Rapid developments in e-cigarettes, or electronic nicotine delivery systems (ENDS), and the evolution of the overall tobacco product marketplace warrant frequent evaluation of the published literature. The purpose of this article is to report updated findings from a comprehensive review of the published scientific literature on ENDS.

EVIDENCE ACQUISITION

The authors conducted a systematic review of published empirical research literature on ENDS through May 31, 2016, using a detailed search strategy in the PubMed electronic database, expert review, and additional targeted searches. Included studies presented empirical findings and were coded to at least one of nine topics: (1) Product Features; (2) Health Effects; (3) Consumer Perceptions; (4) Patterns of Use; (5) Potential to Induce Dependence; (6) Smoking Cessation; (7) Marketing and Communication; (8) Sales; and (9) Policies; reviews and commentaries were excluded. Data from included studies were extracted by multiple coders (October 2015 to August 2016) into a standardized form and synthesized qualitatively by topic.

EVIDENCE SYNTHESIS

There were 687 articles included in this systematic review. The majority of studies assessed patterns of ENDS use and consumer perceptions of ENDS, followed by studies examining health effects of vaping and product features.

CONCLUSIONS

Studies indicate that ENDS are increasing in use, particularly among current smokers, pose substantially less harm to smokers than cigarettes, are being used to reduce/quit smoking, and are widely available. More longitudinal studies and controlled trials are needed to evaluate the impact of ENDS on population-level tobacco use and determine the health effects of longer-term vaping.

Asthma in adolescence: Is there any news?

Asthma is a chronic disease that has a significant impact quality of life, which is particularly important in adolescence. We will discuss aspects of epidemiology, the clinical spectrum, diagnostics, and management of asthma in adolescence. In particular, we will highlight the psychological implications of having asthma during this developmental period. Data published in the past 10 years, since we last reviewed the subject, will be the main focus of this paper. The care of the teenager with asthma should take into account the rapid physical, emotional, cognitive, and social changes that occur during normal adolescence. The diagnostic process may be more difficult since teenagers tend to deny their illness. Thus, both under-diagnosis and under-assessment of asthma severity may lead to under-treatment and potentially avoidable morbidity and even mortality. Conversely, teenagers may be often misdiagnosed as having asthma or their asthma severity may be overestimated leading to inappropriate and sometimes excessive treatment. Educational programs, environmental avoidance measures, proper use of medications along with a skilled approach, and a caring attitude of health providers are all very important for successful management. Pediatr Pulmonol. 2017;52:129-138. © 2016 Wiley Periodicals, Inc.

Electronic cigarette initiation among minority youth in the United States

BACKGROUND

Electronic cigarettes (e-cigarette) use among youth is a pressing public health issue, with prevalence of use surpassing that of tobacco cigarettes. While research concerning e-cigarettes has proliferated in recent years, there is a dearth of information regarding those whose first exposure to tobacco products was an e-cigarette.

OBJECTIVES

To examine factors associated with e-cigarette initiation among minority youth in the United States.

METHODS

Data on minority students in middle and high schools in the United States derived from the 2014 National Youth Tobacco Survey (NYTS) were sampled (weighted N = 27,294,454). We examined e-cigarette initiation among minority youth using logistic regression models to identify related factors.

RESULTS

In 2014, 736,158 minority youth were e-cigarette initiators. Odds of e-cigarette initiation was highest among Hispanic youth [adjusted odds ratio (AOR) = 2.70; 95% confidence interval (CI) = 1.60-4.56]. Exposure to e-cigarette advertising (AOR = 1.64; 95% CI = 1.07-2.50), perceptions of little to no harm (AOR = 7.08; 95% CI = 4.03-12.46), and believing e-cigarettes were less addictive than tobacco (AOR = 2.15; 95% CI = 1.52-3.02) were associated with e-cigarette initiation.

CONCLUSIONS

Odds of initiating e-cigarette use was highest among Hispanic youth. Among minority youth, e-cigarette initiation was associated with perceptions of harm and addiction potential, as well as exposure to e-cigarette advertising. Therefore, prevention efforts targeting minority youth who are at risk of becoming e-cigarette initiators may benefit by incorporating these factors into prevention campaigns.

The management of asthmatic smokers

Asthma is still a major public health problem in most countries; new strategies to better control this disease are necessary. Such strategies must include predisposing factors. One of these factors is smoking and a significant fraction of asthmatics are smokers. However, clinical trials studying new drugs or newer therapeutic regimens for asthma generally exclude smokers. Therefore, there is a lack of specific information about the treatment of asthma in smokers. The asthmatic smoker is a special phenotype with important therapeutic and prognostic clinical implications. Any form of tobacco use, especially cigarette smoking, plays an important role in this disease. Asthmatic smokers are prone to several negative outcomes. Smoking cessation results in an improvement of symptoms and pulmonary functioning. Counselling and first-line medications for smoking cessation (nicotine replacement therapy, bupropion and varenicline) significantly increase quitting rates. The role of electronic cigarettes in this group of patients has only begun to be studied. The treatment of asthmatics that smoke has characteristics that need must be well understood by clinicians, especially the poor response to corticosteroids. This condition is not universal and physicians should always consider its inclusion in the treatment of these patients. The association of inhaled corticosteroids (ICS) plus a long-acting beta2 adrenegic (LABA) by smoking asthmatics results in more pronounced improvement in several asthma outcomes compared with the use of corticosteroid alone. Inhaled corticosteroids in extra-fine particles associated with LABA may be a new perspective of treatment. Also the use of leukotriene antagonists may become another therapeutic alternative. The purpose of this narrative review is to discuss the challenges faced by clinicians to control asthma in smokers and to present methods of coping with smoking treatment and avoiding relapses.