E-Liquid Flavor Preferences and Individual Factors Related to Vaping: A Survey among Dutch Never-Users, Smokers, Dual Users, and Exclusive Vapers

Reducing attractiveness of e-liquids: proposal for a restrictive list of tobacco-related flavourings

OBJECTIVE

Electronic cigarettes are addictive and harmful, and flavour is a key factor determining their abuse liability. Both adult smokers and young non-smokers like sweet and fruity flavours in particular. In order to discourage e-cigarette use among youth, the Dutch government announced in 2020 to only allow tobacco flavours in e-liquids. We propose a restrictive list of flavourings that will only enable the production of e-liquids with a tobacco flavour.

METHODS

We used e-liquid ingredient data notified via the European Common Entry Gate system before the government's announcement. First, we classified all e-liquids into flavour categories, and continued with the set of flavourings present in tobacco e-liquids. Five selection criteria related to prevalence of use, chemical composition, flavour description and health effects were defined to compile a restrictive list of tobacco flavourings.

RESULTS

E-liquids marketed as having tobacco flavour contained 503 different flavourings, some with tobacco flavour, but also other (such as sweet) flavours. We excluded (1) 330 flavourings used in <0.5% of e-liquids, (2) 77 used less frequently in tobacco than in all e-liquids, (3) 13 plant extracts, (4) 60 that are sweet or not associated with a tobacco flavour and (5) 7 flavourings with hazardous properties. This resulted in a final list of 16 flavourings.

CONCLUSIONS

Implementing this restrictive list will likely discourage e-cigarette use among youth, but could also make e-cigarettes less attractive as smoking cessation aid.

An ingredient co-occurrence network gives insight into e-liquid flavor complexity

INTRODUCTION

Part of the appeal of e-cigarettes lies in their available flavors. To achieve attractive flavors, e-liquids contain many different flavoring agents, which allow many flavoring combinations. To advance our knowledge of e-liquid flavors and compositions and to evaluate the effect of legislation, we determined whether there are ingredient combinations that are frequently used together.

METHODS

We used e-cigarette ingredient data from the European Common Entry Gate system (EU-CEG) as available on 31 December 2022.

RESULTS

In e-liquids, we found 214 ingredient pairs with a co-occurrence odds ratio greater than 10. Together, these consisted of 62 unique ingredients. Network analysis revealed that ingredients were grouped together based on their flavor and/or chemical structure. We identified two densely connected regions (clusters) in the network. One consisted of six ingredients with sweet-vanilla-creamy flavors. The second cluster consisted of 13 ingredients. While some of these have fruity flavors, others, such as alkyl carboxylic acids and dimethyl sulfide, are known to have unpleasant flavors. Additional data and literature analyses indicated that alkyl carboxylic acids can contribute to a creamy and sweet-fruity taste, whereas dimethyl sulfide can contribute to a more refined fruity taste.

CONCLUSIONS

These results exemplify that the flavor of e-liquids is not just the sum of its parts. Big data analyses on product data can be used to detect such patterns, but expert knowledge and additional data are needed for further interpretation. Monitoring of e-liquid flavors as well as ingredients will remain important to regulate e-liquid product attractiveness.

Beyond the label: current evidence and future directions for the interrelationship between electronic cigarettes and mental health

Electronic cigarette use has dramatically increased over the last decade. With this recent technological development and wide range of constituents in various products, putative adverse effects on the brain and body have been largely unexplored. Here, we review current evidence linking electronic nicotine cigarette use with potential health consequences and provide evidence supporting an association between drug use and depression in humans. We also examine the biological effects of individual constituents in electronic cigarette aerosols, which include labeled ingredients, such as propylene glycol, vegetable glycerin, nicotine, and flavorants, as well as unlabeled ingredients found in the aerosols, such as carbonyls and heavy metals. Lastly, we examine the effects of electronic cigarette use on endogenous metabolism via changes in cytochrome P450 enzymes, which can thereby impact therapeutic outcomes. While the current evidence offers insight into the potential effects of electronic cigarette use on biological processes, further studies are necessary to determine the long-term clinical relevance of aerosol inhalation.

Effects of electronic cigarette e-liquid flavouring on cigarette craving

BACKGROUND

E-liquid flavour restrictions may discourage electronic cigarette (e-cigarette) uptake among youth. However, possible unintended consequences may include reduced appeal and effectiveness of e-cigarettes for smoking cessation. Non-tobacco flavours appear to be important for smoking cessation, but how and why are currently unclear.

METHODS

We conducted an experimental study in a UK sample of adult daily smokers using an independent groups design (N=84). Participants were randomised to use an e-cigarette with nicotine-containing fruit/sweet-flavoured e-liquid (blackcurrant, strawberry, vanilla, caramel) or unflavoured e-liquid for 1 week. The primary outcomes were average, peak and cue-elicited cigarette craving (the latter was assessed using a cue exposure task). The secondary outcomes were smoking lapse occurrence, enjoyment of the e-cigarette, ease of transitioning from smoking to using an e-cigarette, intentions to continue using an e-cigarette, intentions and motivation to quit smoking, return to smoking, and continuation of e-cigarette use.

RESULTS

E-liquid flavouring did not appear to have an effect on average cigarette craving (b 0.18, 95% CI -0.44 to 0.79, p=0.57), peak cigarette craving (b -0.12, 95% CI -0.59 to 0.35, p=0.62) or cue-elicited cigarette craving (b -0.21, 95% CI -3.86 to 3.43, p=0.91). We did not find evidence of a difference in secondary outcomes.

CONCLUSIONS

We did not find evidence to suggest that nicotine-containing fruit/sweet-flavoured and unflavoured e-liquids have different effects on cigarette cravings after 1 week of use. Further research is needed to establish if differences emerge over longer periods of exposure and extend to smoking cessation outcomes.

E-Cigarette Aerosol Condensate Leads to Impaired Coronary Endothelial Cell Health and Restricted Angiogenesis

Cardiovascular disease (CVD) is a leading cause of mortality worldwide, with cigarette smoking being a major preventable risk factor. Smoking cessation can be difficult due to the addictive nature of nicotine and the withdrawal symptoms following cessation. Electronic cigarettes (e-Cigs) have emerged as an alternative smoking cessation device, which has been increasingly used by non-smokers; however, the cardiovascular effects surrounding the use of e-Cigs remains unclear. This study aimed to investigate the effects of e-Cig aerosol condensate (EAC) (0 mg and 18 mg nicotine) in vitro on human coronary artery endothelial cells (HCAEC) and in vivo on the cardiovascular system using a mouse model of ‘e-vaping’. In vitro results show a decrease in cell viability of HCAEC when exposed to EAC either directly or after exposure to conditioned lung cell media (p < 0.05 vs. control). Reactive oxygen species were increased in HCAEC when exposed to EAC directly or after exposure to conditioned lung cell media (p < 0.0001 vs. control). ICAM-1 protein expression levels were increased after exposure to conditioned lung cell media (18 mg vs. control, p < 0.01). Ex vivo results show an increase in the mRNA levels of anti-angiogenic marker, FKBPL (p < 0.05 vs. sham), and endothelial cell adhesion molecule involved in barrier function, ICAM-1 (p < 0.05 vs. sham) in murine hearts following exposure to electronic cigarette aerosol treatment containing a higher amount of nicotine. Immunohistochemistry also revealed an upregulation of FKBPL and ICAM-1 protein expression levels. This study showed that despite e-Cigs being widely used for tobacco smoking cessation, these can negatively impact endothelial cell health with a potential to lead to the development of cardiovascular disease.

Adverse Maternal and Infant Outcomes of Women Who Differ in Smoking Status: E-Cigarette and Tobacco Cigarette Users

The electronic cigarette (e-cigarette) became commercially available around 2004, yet the characteristics of pregnant women who use these devices and their effects on maternal and infant health remain largely unknown. This study aimed to investigate maternal characteristics and pregnancy outcomes according to maternal smoking status. We conducted a cross-sectional study of Dutch women with reported pregnancies between February 2019 and May 2022, using an online questionnaire to collect data on smoking status and demographic, lifestyle, pregnancy, and infant characteristics. Smoking status is compared among non-smokers, tobacco cigarette users, e-cigarette users, and dual users (tobacco and e-cigarette). We report descriptive statistics and calculate differences in smoking status between women with the chi-square or Fisher (Freeman-Halton) test. Of the 1937 included women, 88.1% were non-smokers, 10.8% were tobacco cigarette users, 0.5% were e-cigarette users, and 0.6% were dual users. Compared with tobacco users, e-cigarette users more often reported higher education, having a partner, primiparity, and miscarriages. Notably, women who used e-cigarettes more often had small infants for gestational age. Despite including few women in the e-cigarette subgroup, these exploratory results indicate the need for more research to examine the impact of e-cigarettes on pregnancy outcomes.

Impact of tobacco flavoring on oral nicotine consumption in C57BL/6J mice

BACKGROUND

The continued use of flavors in tobacco products has been a prominent factor in their popularity, yet little is known regarding their role in nicotine dependence. This study aimed to investigate the impact of tobacco flavoring on oral nicotine consumption in mice using the two-bottle choice (2BC) test and assessed the potential impact of age and sex in their interactions.

METHODS

Adolescent and adult male and female C57BL/6J mice were used. First, voluntary consumption of tobacco flavor concentrate from a commercial electronic cigarette liquid vendor (Avail Vapor LLC) was measured; then, the effects of tobacco flavoring in combination with nicotine were examined. In one approach, tobacco flavor concentration was kept constant while nicotine concentration varied, and in the second, nicotine was kept constant while the tobacco flavor concentration varied.

RESULTS

Overall, tobacco flavoring decreased oral nicotine consumption in mice, and its effects were sex- and age-dependent. Although females consumed the tobacco-flavored solution at a slightly higher rate than males, male mice were more sensitive to the effects of the combination (nicotine + tobacco). Furthermore, adolescent mice showed a starker reduction in nicotine consumption in the presence of tobacco flavoring compared to adult mice. This attenuation was most likely due to a basal aversion to the tobacco flavoring itself, thus, creating a negative synergistic effect with nicotine.

CONCLUSIONS

Tobacco flavoring increases aversion to nicotine in the 2BC test in C57BL6J mice, suggesting that some flavors may diminish rather than enhance oral nicotine consumption in rodents.

Expanding the E-Liquid Flavor Wheel: Classification of Emerging E-Liquid Flavors in Online Vape Shops

INTRODUCTION

Electronic cigarettes are the most popular tobacco product among U.S. youth, and over 80% of current youth users of e-cigarettes use flavored e-cigarettes, with fruit, mint/menthol, and candy/sweets being the most popular flavors. A number of new e-liquid flavors are currently emerging in the online e-cigarette market. Menthol and other flavored e-cigarettes could incentivize combustible tobacco smokers to transition to e-cigarette use.

METHODS

From February to May 2021, we scraped data of over 14,000 e-liquid products, including detailed descriptions of their flavors, from five national online vape shops. Building upon the existing e-liquid flavor wheel, we expanded the semantic databases (i.e., key terms) to identify flavors using WordNet-a major database for keyword matching and group discussion. Using the enriched databases, we classified 14,000+ e-liquid products into the following 11 main flavor categories: "fruit", "dessert/candy/sweets", "coffee/tea", "alcohol", "other beverages", "tobacco", "mint/menthol", "nuts", "spices/pepper", "other flavors", and "unspecified flavor".

RESULTS

We find that the most prominent flavor sold in the five online vape shop in 2021 was fruit flavored products, followed by dessert/candy/other sweets. Online vendors often label a product with several flavor profiles, such as fruit and menthol.

CONCLUSIONS

Given that online stores market products with multiple flavor profiles and most of their products contain fruit flavor, the FDA may have issued marketing denial orders to some of these products. It is important to further examine how online stores respond to the FDA flavor restrictions (e.g., compliance or non-compliance).

General and Device-Specific Reasons for ENDS Use: A Qualitative Study with Adult ENDS Users

BACKGROUND

A scientific consensus on the public health impact of electronic nicotine delivery systems (ENDS) remains elusive. This is partly due to the wide variation in product characteristics often lumped together under one category. Research is needed to better understand what ENDS device type characteristics motivate their use by adults.

METHODS

Nine focus groups of 32 current ENDS users who were 18+ years old, had used ENDS in the previous 30 days, and had been using ENDS for more than two months were held either in person or online between February and June 2020.

RESULTS

Participants' reasons for their choice of ENDS characteristics included both general, applying to all ENDS products, and specific, relating to particular ENDS devices. Health benefits and the lack of offensive odor were commonly identified as important reasons for using ENDS in general. Flavor and product discreteness were both general and device-specific determinants of ENDS use. Conversely, nicotine delivery, cloud size, battery properties, aesthetics, ease of use, and cost were device-specific drivers of participants' choice.

CONCLUSIONS

The reasons that adults choose to use ENDS are complex and sometimes related to both ENDS as a category and as specific ENDS product types. Regulations and public communication campaigns should reflect their ultimate objective and consider both general and specific motivations when attempting to achieve public health objectives.

Smoking cessation aids and strategies: a population-based survey of former and current smokers in Norway

BACKGROUND

In Norway, tobacco consumption is equally divided between combustible (cigarettes) and non-combustible (snus) tobacco. In the process of quitting, people who smoke can choose between several smoking cessation aids and strategies based on what is available on the market or what are recommended as cessation aids. A quit attempt may be planned or unplanned and consist of a gradual decline in consumption or an abrupt quitting. This study explores smoking cessation aids and strategies used at the latest quit attempt among people who have ever smoked. How prevalent is the use of various cessation aids and strategies, and do they correlate with each other? Are there any differences in successful quits depending on the use of a specific cessation aid or strategy?

METHOD

We used repeated cross-sectional representative surveys in Norway for 2017, 2018, 2019 and 2020. The analytic sample consists of people aged 20 years or older who have ever smoked daily, more precisely current daily smokers with at least one quit attempt (n = 476), and former daily smokers who quit in 2012 or later (n = 397). Participants answered questions on cessation aids and strategies used at their last quit attempt. Logistic regression analysis was used to estimate the associations between cessation aids and strategies and sociodemographic and smoking-related variables and successful quit attempts.

RESULTS

Fifty-six percent of people who ever smoked daily reported any use of cessation aids, and nicotine replacement therapy (NRT), snus and e-cigarettes were the most commonly used cessation aids. Snus and web/mobile use was associated with successful quits, while NRT was associated with unsuccessful quit attempts. When exclusive use was separated from the combined use of several aids, only snus was associated with successful quits.

CONCLUSION

Snus use was found to be a "stand-alone" cessation aid, and only weakly associated with the use of other cessation aids. Further investigation of cessation aid preferences is needed, especially among smokers with little or no contact with health services and/or for whom traditional cessation aids have no appeal.

Evolution of tobacco products: recent history and future directions

Declines in cigarette smoking prevalence in many countries and the consolidation of the tobacco industry have prompted the introduction of other forms of nicotine delivery. These include electronic nicotine delivery systems (ENDS), heated tobacco products (HTPs) and oral nicotine products (ONPs). Evolving over time, some of these products now deliver nicotine at levels comparable to cigarettes and may serve as effective substitutes for smokers. However, certain products, especially ENDS like JUUL, have also appealed to youth and non-smokers, prompting concerns about expanding nicotine use (and potentially nicotine addiction). The tobacco industry could shift away from primarily promoting cigarettes to promoting ENDS, HTPs and/or ONPs, though at this time it continues to heavily promote cigarettes in low and middle-income countries. Differing regulatory regimes may place upward and downward pressures on both cigarettes and these newer products in terms of population use, and may ultimately drive the extent to which cigarettes are or are not displaced by ENDS, HTPs and/or ONPs in the coming decade.

Do e-cigarettes attract youths who are otherwise unlikely to use addictive substances? Cross-sectional analyses of Dutch and Flemish secondary school students

INTRODUCTION

E-cigarettes are popular among youth. There are concerns that e-cigarettes attract youth that would otherwise not use addictive substances. While e-cigarettes are thought to be less harmful than tobacco, there is reason for caution. We examined to what extent adolescent e-cigarette users have characteristics associated with increased risk of substance use.

METHODS

We collected cross-sectional survey data in 2018 among 10 schools throughout the Netherlands and Belgium (N=2794; age 10-18 years). We examined differences in characteristics and behaviors between e-cigarette ever users and never users, and former users and current users. We also explored differences in use of flavors and use of nicotine.

RESULTS

Compared to never-users, e-cigarettes users more often were boys, older, had lower education level, non-Dutch or non-Belgian ethnicity, reported more combustible tobacco use, more smoking family members or family with problematic substance use, more smoking friends, more depressive symptoms, more impulsivity, more delinquent behavior, were more susceptible to smoking, had more positive smoking expectancies, and more ever use of substances. Users of non-tobacco flavored e-cigarettes and e-cigarettes without nicotine had fewer characteristics known to be related to an increased risk of substance use, compared to users of tobacco-flavored e-cigarettes and e-cigarettes with nicotine.

CONCLUSIONS

Adolescent e-cigarette users are more like youths who experiment with addictive substances compared to non-users. Thus, e-cigarettes users were more likely to use substances, regardless of whether they used e-cigarettes first. This may not be true for all types of e-cigarettes, as users of e-cigarettes without nicotine or with non-tobacco flavors were less like youths who experiment with substances.

Modification of the Peripheral Olfactory System by Electronic Cigarettes

Electronic cigarettes (e-cigs) are used by millions of adolescents and adults worldwide. Commercial e-liquids typically contain flavorants, propylene glycol, and vegetable glycerin with or without nicotine. These chemical constituents are detected and evaluated by chemosensory systems to guide and modulate vaping behavior and product choices of e-cig users. The flavorants in e-liquids are marketing tools. They evoke sensory percepts of appealing flavors through activation of chemical sensory systems to promote the initiation and sustained use of e-cigs. The vast majority of flavorants in e-liquids are volatile odorants, and as such, the olfactory system plays a dominant role in perceiving these molecules that enter the nasal cavity either orthonasally or retronasally during vaping. In addition to flavorants, e-cig aerosol contains a variety of by-products generated through heating the e-liquids, including odorous irritants, toxicants, and heavy metals. These harmful substances can directly and adversely impact the main olfactory epithelium (MOE). In this article, we first discuss the olfactory contribution to e-cig flavor perception. We then provide information on MOE cell types and their major functions in olfaction and epithelial maintenance. Olfactory detection of flavorants, nicotine, and odorous irritants and toxicants are also discussed. Finally, we discuss the cumulated data on modification of the MOE by flavorant exposure and toxicological impacts of formaldehyde, acrolein, and heavy metals. Together, the information presented in this overview may provide insight into how e-cig exposure may modify the olfactory system and adversely impact human health through the alteration of the chemosensory factor driving e-cig use behavior and product selections. © 2021 American Physiological Society. Compr Physiol 11:2621-2644, 2021.

Critical appraisal of the European Union Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) Preliminary Opinion on electronic cigarettes

BACKGROUND

In preparation for the 2021 revision of the European Union Tobacco Products Directive, the Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) has posted its Preliminary Opinion on Electronic Cigarettes. They concluded that e-cigarettes only achieve a sub-optimal level of protection of human health. In this paper, we provide evidence that the Opinion's conclusions are not adequately backed up by scientific evidence and did not discuss the potential health benefits of using alternative combustion-free nicotine-containing products as substitute for tobacco cigarettes.

METHODS

Searches for articles were conducted in PubMed and by citation chasing in Google Scholar. Articles were also retrieved with a review of references in major publications. Primary data from World Health Organization surveys, the conclusions of reviews, and peer-reviewed non-industry studies were cited to address errors and omissions identified in the Opinion.

RESULTS

The Opinion omitted reporting on the individual and population health benefits of the substitution of e-cigarettes (ENDS) for cigarette smoking. Alternative hypotheses to the gateway theory were not evaluated. Its assessment of cardiovascular risk is contradicted by numerous reviews. It cites ever-use data that do not represent current patterns of use. It did not report non-nicotine use. It presented erroneous statements on trends in ENDS prevalence. It over-emphasized the role of flavours in youth ENDS initiation. It did not discuss cessation in sufficient length.

CONCLUSIONS

For the delivery of a robust and comprehensive final report, the members of the Working Group of the Scientific Committee on Health, Environmental and Emerging Risks will need to consider (1) the potential health benefits of ENDS substitution for cigarette smoking, (2) alternative hypotheses and contradictory studies on the gateway effect, (3) its assessment of cardiovascular risk, (4) the measurements of frequency of use, (5) non-nicotine use, (6) the role of flavours, and (7) a fulsome discussion of cessation.

Both Nonsmoking Youth and Smoking Adults Like Sweet and Minty E-liquid Flavors More Than Tobacco Flavor

Smokers may reduce their health risk by switching to electronic cigarette (e-cigarette) use. As e-cigarettes are not harmless, concerns exist about e-cigarette use by nonsmokers and youth. E-liquids are available in many different flavors that increase sensory appeal. Flavor preferences may differ between user groups, which could open doors for product regulation. We investigated which e-liquid flavors are attractive to specific user groups by comparing liking between adolescent nonsmokers (n = 41; mean age 16.9 ± 0.8), young adult nonsmokers (n = 42; mean age 22.7 ± 1.7), and adult smokers (n = 56; mean age 39.7 ± 11.1). Participants smelled tobacco- (n = 6) and nontobacco (n = 24)-flavored e-liquids and rated liking on a 9-point labeled hedonic scale, and familiarity, overall intensity, perceived sweetness, perceived bitterness, and irritation of the odors on a 100-unit Visual Analog Scale. Mean liking ranged from 2.3 (whiskey) to 6.7 (peppermint). Within all groups, the typically sweet and minty flavors (e.g., wine gum, watermelon, peppermint, menthol) were liked significantly more than the tobacco-flavored e-liquids. The set of tobacco-flavored e-liquids was significantly, but slightly, less disliked by adult smokers (3.9 ± 0.2) than adolescent (3.1 ± 0.3) and young adult (3.4 ± 0.3) nonsmokers (P < 0.001). No between-group differences were observed for sweet and minty flavors. Liking correlated significantly positively with odor sweetness (R = 0.49) and familiarity (R = 0.48) and negatively with odor bitterness (R = -0.58), irritation (R = -0.47), and overall intensity (R = -0.27). Thus, sweet- and minty-flavored e-liquids are liked equally by young nonsmokers and adult smokers, and more than tobacco flavors. Banning all flavors except tobacco will likely reduce e-cigarette appeal; potentially more for young nonsmokers than adult smokers.

ENDS Flavor Preference by Menthol Cigarette Smoking Status among US Adults, 2018-2019

E-cigarette flavor preference may differ among smokers using e-cigarettes, but little information is available on preferences by menthol cigarette status. Using nationally representative data for US adults from the 2018-2019 Tobacco Use Supplement to the Current Population Survey, we analyzed e-cigarette flavor preference by menthol cigarette status and e-cigarette device type for dual-cigarette and e-cigarette users and e-cigarette users who had recently quit smoking by trying to switch to e-cigarettes ("switchers"). Approximately half (52.2%) of dual users of menthol cigarettes and e-cigarettes reported using menthol/mint-flavored e-cigarettes as did 41.4% of "switchers" who had smoked menthol cigarettes; exclusive menthol/mint flavor use was 13.1% for dual users and 21.3% for "switchers." A similar proportion (45.1%) of dual users who smoked nonmenthol cigarettes used tobacco-flavored e-cigarettes, but only 26.7% of "switchers" who had smoked nonmenthol cigarettes used tobacco-flavored e-cigarettes. Approximately 60% of dual users and "switchers" used fruit/other flavors, regardless of menthol cigarette use. By device type, 63.9% of dual users of cartridge-based e-cigarettes and menthol cigarettes used menthol/mint-flavored e-cigarettes. Approximately 75% of dual users and 85% of "switchers" who used tank or mod systems used fruit/other flavors. Menthol cigarette smokers may be particularly likely to use menthol/mint e-cigarettes, and a majority of dual users and "switchers" used fruit/other flavors. These results can inform policy measures concerning flavored electronic nicotine delivery system products.

Flavor-Toxicant Correlation in E-cigarettes: A Meta-Analysis

Flavors in electronic cigarette (ECIG) liquids may increase ECIG aerosol toxicity via intact distillation or chemical transformation. For this report, we performed a meta-analysis of the literature to categorize the compounds found in flavored ECIG liquids into a few chemical classes and to predict their possible chemical transformations upon ECIG liquid aerosolization. This analysis allowed us to propose specific correlations between flavoring chemicals and aerosol toxicants. A literature search was conducted in November 2019 using PubMed. Keywords included terms related to ECIGs and flavors. Studies were included if they reported chemical ingredients of flavored liquids and clearly stated the commercial names of these liquids. The obtained data were visualized on a network diagram to show the common chemical compounds identified in flavored ECIG liquids and categorize them into different chemical classes. The systematic literature review included a total of 11 articles. Analysis of the data reported gave a total of 189 flavored liquids and 173 distinct chemical compounds that were categorized into 22 chemical classes according to their functional groups. The subsequent prediction of chemical transformations of these functional groups highlighted the possible correlation of flavor compounds to aerosol toxicants.

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

INTRODUCTION

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

METHOD

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

RESULTS

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

CONCLUSION

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

GC-MS analysis of e-cigarette refill solutions: A comparison of flavoring composition between flavor categories

OBJECTIVES

Electronic cigarette refill solutions (e-liquids) are available in various flavor descriptions that can be categorized as fruit, tobacco, and more. Flavors increase sensory appeal, thereby stimulating e-cigarette use, and flavoring ingredients can contribute to e-cigarette toxicity. We aim to inform toxicologists, sensory scientists, and regulators by determining flavoring compounds in e-liquids with various flavors, and compare results between flavor categories.

METHODS

Gas chromatography - mass spectrometry (GC-MS) was used to identify 79 flavorings in 320 e-liquids, classified in 15 flavor categories. Ten flavorings highly prevalent in e-liquids according to information from manufacturers were quantified. Flavoring prevalence was defined as the number of e-liquids with the flavoring as percentage of the total number of e-liquids. The method was validated in terms of specificity, linearity, repeatability, recovery, and sensitivity.

RESULTS

The mean number of flavorings per e-liquid was 6 ± 4. Flavoring prevalence was highest for vanillin (creamy/vanilla flavor), ethyl butyrate (ethereal/fruity), and cis-3-hexenol (fresh/green). Based on similarities in flavoring prevalence, four clusters of categories were distinguished: (1) fruit, candy, alcohol, beverages; (2) dessert, coffee/tea, nuts, sweets; (3) menthol/mint; and (4) spices, tobacco, and unflavored. Categories from cluster 4 generally had less flavorings per e-liquid than fruit, candy, alcohol, beverages (cluster 1) and dessert (cluster 2) (p < 0.05). Flavoring concentrations varied between e-liquids within the categories.

CONCLUSIONS

We evaluated flavoring compositions of 320 e-liquids using a simple GC-MS method. Flavoring prevalence was similar within four clusters of typically fresh/sweet, warm/sweet, fresh/cooling, and non-sweet flavor categories. To compare flavoring concentrations between individual flavor categories, additional research is needed.

World vaping update

PURPOSE OF REVIEW

Although death and injury related to e-cigarette use and vaping products has decreased since the peak in 2019, concern over the popularity of electronic nicotine delivery systems (ENDS - a term which includes vape pens, electronic or e-cigarettes, and products that produce vapor for inhaling rather than combusting to produce smoke) continues. ENDS are used as an aid to quit smoking and for harm reduction.

RECENT FINDINGS

This review covers peer-reviewed literature from January 2019 through February 2020 on vaping (the process of using ENDS). Prevalence, risk factors for use, and health risks and benefits from use predominated. Policy articles, commentaries and editorials were excluded from review. E-cigarette or vaping product use-associated lung injury (EVALI)-related injury and death were in the news and literature this year. Because most EVALI-related injury and death occurred among young people who had vaped tetrahydrocannabinol (THC), data from the Healthy Minds (United States) study are reviewed to consider variation in risk factors for vaping THC compared with nicotine.

SUMMARY

Findings provide up-to-date information on vaping as a way to consume a drug, whether THC or nicotine. Harm reduction benefits were shown in a year-long follow-up of smoking cessation; harms continue to accumulate, including from passive consumption.

An Observational Study of Vaping Knowledge and Perceptions in a Sample of U.S. Adults

Background

Vaping is the use of e-cigarettes that contain inhalants such as nicotine, tetrahydrocannabinol, and cannabidiol. Vaping is associated with e-cigarette or vaping product use associated lung injury (EVALI) and is a recognized public health crisis. Despite rising numbers of hospitalizations due to EVALI, public knowledge and perceptions of the dangers of vaping require further investigation.

Objectives

This exploratory study assessed knowledge and perceptions of vaping in U.S. adults.

Methods

This study was approved by an ethical board, and informed consent was obtained from all participants. A cohort of U.S. adults was recruited by shared links on social media. Participants completed an anonymous online survey that contained vaping knowledge and perceptions items. An a priori power analysis was conducted at 95% power and alpha = 0.05. Statistics were calculated using IBM SPSS Statistics Version 26 (IBM Corp., Armonk, NY, USA).

Results

A sample of 413 (N = 413) U.S. adults participated in the survey. The majority of participants (79.18%) were females, and 65.62% were between 18 and 24 years of age. Over half (62.71%) of participants were never asked about vaping use by a clinician at any visit, and 56.51% agreed that vaping can reduce stress. Of all participants, 70.91% agreed that drinking alcohol makes someone more inclined to vape. Significant positive Spearman’s rho correlations were found between vaping and the use of cannabis, cocaine, ecstasy, hallucinogens, and inhalants (p < 0.05).

Conclusions

We found a significant correlation between vaping and drug use. We also found that if the dangers of vaping are discussed by their health care providers, participants are more inclined to quit vaping. Unfortunately, many physicians report that they avoid discussing vaping with their patients due to lack of vaping knowledge. Our results illuminate the communication gap between patients and physicians. All clinicians need to counsel patients on the dangers of vaping, which might help prevent EVALI and related conditions.