Electronic Liquid Research Articles

A Social Media Study on the Associations of Flavored Electronic Cigarettes With Health Symptoms: Observational Study.

BackgroundIn recent years, flavored electronic cigarettes (e-cigarettes) have become popular among teenagers and young adults. Discussions about e-cigarettes and e-cigarette use (vaping) experiences are prevalent online, making social media an ideal resource for understanding the health risks associated with e-cigarette flavors from the users’ perspective.ObjectiveThis study aimed to investigate the potential associations between electronic cigarette liquid (e-liquid) flavors and the reporting of health symptoms using social media data.MethodsA dataset consisting of 2.8 million e-cigarette–related posts was collected using keyword filtering from Reddit, a social media platform, from January 2013 to April 2019. Temporal analysis for nine major health symptom categories was used to understand the trend of public concerns related to e-cigarettes. Sentiment analysis was conducted to obtain the proportions of positive and negative sentiment scores for all reported health symptom categories. Topic modeling was applied to reveal the topics related to e-cigarettes and health symptoms. Furthermore, generalized estimating equation (GEE) models were used to quantitatively measure potential associations between e-liquid flavors and the reporting of health symptoms.ResultsTemporal analysis showed that the Respiratory category was consistently the most discussed health symptom category among all categories related to e-cigarettes on Reddit, followed by the Throat category. Sentiment analysis showed higher proportions of positive sentiment scores for all reported health symptom categories, except for the Cancer category. Topic modeling conducted on all health-related posts showed that 17 of the top 100 topics were flavor related. GEE models showed different associations between the reporting of health symptoms and e-liquid flavor categories, for example, lower association of the Beverage flavors with Respiratory compared with other flavors and higher association of the Fruit flavors with Cardiovascular than other flavors.ConclusionsThis study identified different potential associations between e-liquid flavors and the reporting of health symptoms using social media data. The results of this study provide valuable information for further investigation of the health effects associated with different e-liquid flavors.

Rapid identification of nicotine in electronic cigarette liquids based on surface-enhanced Raman scattering.

Nicotine-containing electronic cigarette liquid (e-liquid) is prohibited in many countries, creating requirements for rapid detection approaches for on-site inspection or screening for large amounts of samples. Here, we demonstrate a simple way to identify nicotine using surface-enhanced Raman scattering (SERS) with substrates made of silver nanoparticle arrays imbedded in anodic aluminum oxide nanochannels (Ag/AAO). Compared with the reported colloidal nanoparticle-based SERS, that required serial dilutions to enable colloid aggregation in the viscous e-liquid, a small amount of undiluted e-liquid sample can be directly added onto our solid-phase Ag/AAO substrate without any pre-treatment. The sensitivity of our SERS measurements is 2–3 orders of magnitude higher than that required for identification of nicotine in e-liquid, which is typically around 1000–18,000 ppm. Using such nanoparticle array-based SERS, we have tested 22 commercially available e-liquid products, using the corresponding gas chromatography-mass spectrometry (GC–MS) reports as the reference. The SERS measurements were done within one hour and successfully identified 20 samples. Only 2 samples showed SERS interference from ingredients that were not suitable for SERS analysis.

Conversion of Cannabidiol (CBD) into Psychotropic Cannabinoids Including Tetrahydrocannabinol (THC): A Controversy in the Scientific Literature.

Cannabidiol (CBD) is a naturally occurring, non-psychotropic cannabinoid of the hemp plant Cannabis sativa L. and has been known to induce several physiological and pharmacological effects. While CBD is approved as a medicinal product subject to prescription, it is also widely sold over the counter (OTC) in the form of food supplements, cosmetics and electronic cigarette liquids. However, regulatory difficulties arise from its origin being a narcotic plant or its status as an unapproved novel food ingredient. Regarding the consumer safety of these OTC products, the question whether or not CBD might be degraded into psychotropic cannabinoids, most prominently tetrahydrocannabinol (THC), under in vivo conditions initiated an ongoing scientific debate. This feature review aims to summarize the current knowledge of CBD degradation processes, specifically the results of in vitro and in vivo studies. Additionally, the literature on psychotropic effects of cannabinoids was carefully studied with a focus on the degradants and metabolites of CBD, but data were found to be sparse. While the literature is contradictory, most studies suggest that CBD is not converted to psychotropic THC under in vivo conditions. Nevertheless, it is certain that CBD degrades to psychotropic products in acidic environments. Hence, the storage stability of commercial formulations requires more attention in the future.

E-cigarette Product Characteristics and Subsequent Frequency of Cigarette Smoking.

There is a dearth of evidence regarding the association of use of electronic cigarettes (e-cigarettes) with certain product characteristics and adolescent and young adult risk of unhealthy tobacco use patterns (eg, frequency of combustible cigarette smoking), which is needed to inform the regulation of e-cigarettes. Data were collected via an online survey of participants in the Southern California Children's Health Study from 2015 to 2016 (baseline) and 2016 to 2017 (follow-up) (N = 1312). We evaluated the association of binary categories of 3 nonmutually exclusive characteristics of the e-cigarette used most frequently with the number of cigarettes smoked in the past 30 days at 1-year follow-up. Product characteristics included device (vape pen and/or modifiable electronic cigarette [mod]), use of nicotine in electronic liquid (e-liquid; yes or no), and use for dripping (directly dripping e-liquid onto the device; yes or no). Relative to never e-cigarette users, past-30-day e-cigarette use was associated with greater frequency of past-30-day cigarette smoking at follow-up. Among baseline past-30-day e-cigarette users, participants who used mods (versus vape pens) smoked >6 times as many cigarettes at follow-up (mean: 20.8 vs 1.3 cigarettes; rate ratio = 6.33; 95% confidence interval: 1.64-24.5) after adjustment for sociodemographic characteristics, baseline frequency of cigarette smoking, and number of days of e-cigarette use. After adjustment for device, neither nicotine e-liquid nor dripping were associated with frequency of cigarette smoking. Baseline mod users (versus vape pen users) smoked more cigarettes in the past 30 days at follow-up. Regulation of e-cigarette device type warrants consideration as a strategy to reduce cigarette smoking among adolescents and young adults who vape.

Electronic cigarette use among Italian smokers: patterns, settings, and adverse events.

Information is scanty on the patterns and settings of electronic cigarette use and on its possible adverse events. To fill the knowledge gap on these issues, we conducted a survey among ever-smokers attending smoking cessation services (SCS) in Italy. In 2016-2018, we enrolled 395 ever-smokers aged ⩾18 years who were current or former electronic cigarette users in 12 SCS from northern, central, and southern Italy. In all, 12.4% of ever smokers were regular, 9.4% occasional, and 78.2% past users of electronic cigarettes. Of all users, 93.8% consumed electronic cigarettes with nicotine, 95.9% used refillable devices, and 76.6% purchased electronic cigarette devices or liquids in vape shops. The mean duration of use was 3.7 months and the mean number of puffs per day was 86. Among users, 71.5% used electronic cigarettes in at least 1 smoke-free indoor environment, 53.7% in workplaces, 49.5% in restaurants and bars, 33.5% in train/metro stations or airports, and 18.4% in public transports. The use of electronic cigarettes in smoke-free environments significantly decreased with age and increased with duration of use and nicotine dependence. In our sample, 47.1% reported at least 1 adverse event attributable to electronic cigarette use: 19.5% dry cough, 12.0% dry mouth, 7.6% throat or mouth irritation, and 6.8% sore throat. In Italy, most conventional cigarette smokers use electronic cigarettes where smoking conventional cigarettes is prohibited. About half of users reported 1 or more symptoms attributable to electronic cigarettes, despite the relatively short duration of use.

Flavor-specific enhancement of electronic cigarette liquid consumption and preference in mice

BackgroundThe use of electronic cigarettes has increased over the past decade. To determine how the abuse liability of electronic cigarette liquids (e-liquids) differs from nicotine alone, and to determine the impact of flavor, we compared nicotine-containing fruit- and tobacco-flavored e-liquids, and their nicotine-free versions, to nicotine alone in mouse models of oral consumption, reward and aversion. MethodsAdult male C57BL/6 J mice voluntarily consumed oral nicotine, equivalent nicotine concentrations of fruit- and tobacco-flavored e-liquid, and equivalent dilutions of the nicotine-free versions in 2-bottle choice tests. Conditioned place preference and place aversion were assessed with peripherally administered e-liquids or nicotine. Serum nicotine and cotinine levels were measured after subcutaneous injections of e-liquid or nicotine. ResultsMice showed higher consumption and preference for the fruit-flavored e-liquid compared with nicotine alone. This increase was not due to the flavor itself as consumption of the nicotine-free fruit-flavored e-liquid was not elevated until the highest concentration tested. The increased consumption and preference were not observed with the tobacco-flavored e-liquid. The conditioned place preference, place aversion and nicotine pharmacokinetics of the fruit-flavored e-liquid were not significantly different from nicotine alone. ConclusionsOur data suggest that fruit, but not tobacco flavor, increased the oral consumption of e-liquid compared with nicotine alone. Moreover, this enhancement was not due to increased consumption of the flavor itself, altered rewarding or aversive properties after peripheral administration, or altered pharmacokinetics. This flavor-specific enhancement suggests that some flavors may lead to higher nicotine intake and increased use of e-liquids compared with nicotine alone.

E-Cigarette Quality Control: Impurity and Nicotine Level Analysis in Electronic Cigarette Refill Liquids.

This work targets mainly the quality control of electronic cigarette liquids. It relies on an analytical control of a “32-product” sample made of several types of e-cigarette liquids taken from various supermarkets and tobacconist's offices in Morocco. All along this study, we made sure to check both the conformity of the nicotine level indicated in the packaging of each product and the existence of any other components inside the product, especially toxic or unknown impurities. The method used for this study is known under the name of high-performance liquid chromatography. For statistical analysis, we used Student's t-test for a single sample in order to analyze the relative differences between nicotine quantity reported in the product and the one measured during our experiment. Finally, we used linear regression test to determine the relationship between the nicotine level accuracy on the packaging and the level of toxic impurities in the products. The differences between the nicotine concentrations reported in the packages and the measured ones varied from −100% to +3.3%. The study showed that 31% of analyzed products have an accurate indication of the level of nicotine on the packaging. However, 47% of the studied products showed more than 20% difference between measure and packaging indication. In all analyzed samples, the level of impurities altered from 0 to 32.6%. Furthermore, the level of the nicotine breakdown products did not exceed 2% of the nicotine content in pretty much all of the samples. The actual nicotine content of electronic cigarette refill liquids is not always as precise as what is stated on the packaging; in addition to the level of impurities detected in several brands and that exceeds the European Pharmacopoeia standards, some may even present a risk of causing toxicological damage.

The analysis of commercially available natural products recommended for use in electronic cigarettes.

Natural plant products have been used to promote health, prevent sickness, and treat various ailments. These products often consist of leaves, flowers, bark, roots, seeds, and/or other parts of the plant. Many of the pharmacologically active constituents of these products are known, but the pharmacology of these constituents may not be fully elucidated. Natural plant-based products are also available in various forms other than the raw plant material. A wide array of commercial products such as capsules, powders, extracts, and electronic cigarette (e-cigarette) electronic liquids (e-liquids) are readily available and can be purchased from various outlets, both store-based retailers and online. Newer e-cigarettes are often advertised as "heat not burn" and are used for "vaping" various forms of extracts including "waxes" and "dabs" and raw plant material. A single manufacturer was found online selling "24 different herbs" in powders, extracts, or e-liquids. These were advertised as "legal in the USA" and each product listed multiple effects. Eight e-liquids, six extracts (resins), and four powders from eight different "herbs," namely African dream, areca nut, blue lotus, damiana, kra thum na, kra thum kok, klip dagga, and wild lettuce, were purchased. An advertisement for these products stated, "Most people use the leaves, powder or resin in vaporizers." Direct analysis in real time AccuTOF™ mass spectrometry (DART-MS) was used to identify the psychoactive components in the natural products. The psychoactive compounds that were identified in only two of the eight e-liquids, three of the five resins, and three of the four powders were arecaidine, arecoline, coumarin, entadamide, mitragynine, 7-hydroxymitragynine, and nuciferine. Psychoactive and potentially harmful substances were present in the powders and resins of the natural products. The newer types of e-cigarettes made for consuming natural products may increase their abuse potential.

Superconducting at 298.2 K in lanthanum hydrides

We observed critical transitional phases of electronic liquids driven by an initial electric field inside LaH10±x (-1⩽x⩽2) under high pressure forcings near room-temperature regime after we adopted the verified theory of absolute reactions to find the almost-zero normalized resistance states. The enhanced superconducting critical temperatures (considering almost zero-resistance states; increased to around 298.2 K) for LaH10±x (x∼0) which are related to the nearly frictionless transport of many condensed electrons might be directly relevant to the dynamical transition at room-temperature regime after selecting specific activation energies and activation volumes.

Room-temperature transitional transport in LaH10

We observed critical dynamical transitional phases of electronic liquids driven by an initial electric field inside LaH10±x (-1⩽x⩽2) under high pressure forcings near room-temperature regime after we adopted the verified theory of absolute reactions to locate the almost-zero normalized resistance states. The enhanced critical temperatures (considering almost zero-resistance states; increased to around 298.2 K) for LaH10±x (x~0) which are related to the nearly frictionless transport of many condensed electrons might be directly relevant to the dynamical transition at room-temperature regime in after selecting specific activation energies and activation volumes.

Cancer and Non-Cancer Risk Concerns from Metals in Electronic Cigarette Liquids and Aerosols

We evaluated metal concentrations in e-liquids and e-aerosols from eight studies and estimated the range of corresponding cancer and non-cancer risks. Chromium and nickel were the leading contributors to cancer risk, with minor contributions from cadmium, lead, and arsenic. The increased cancer risks, assuming exposure to 2 mL/day, ranged from 5.7 to 30,000 additional cancers in a million e-cigarette users. The average cancer risk was 3 in 1000. Cancer risks in the mid to upper end of these ranges exceed acceptable levels. The hazard quotient (HQ) approach was used to evaluate non-cancer risks. Hazard quotients exceeding 1.0 indicate the possibility for non-cancer adverse health effects. Estimated exposures at the maximum reported concentrations of nickel, chromium, and manganese resulted in HQ values of 161, 1.1, and 1.0, respectively, with additional contributions from lead. The average concentration of nickel resulted in an HQ value of 14. We conclude from these studies that exposure to metals in e-cigarette liquids and aerosols may pose a significant cancer and non-cancer health risk at the mid and upper end of the reported ranges. The device design and heating elements appear to be the main source of metals in e-aerosols. The large range of metals within and across e-cigarette brands indicate the need for improvements in product design, enforced product safety regulations and manufacturing quality control. Implementation of such measures could reduce metal exposure in e-cigarette users.

Lung histomorphological alterations in rats exposed to cigarette smoke and electronic cigarette vapour.

Electronic cigarettes are becoming increasingly common as a form of nicotine usage, known as vaping. Numerous studies have demonstrated that using electronic cigarettes may lead to nicotine dependence and has a potentially harmful impact on health. The present study compared the impact of electronic and conventional cigarettes on lung tissue. The experiment included 30 male Wistar rats. The animals were divided into three groups: Group A was exposed to electronic cigarette liquid vapour; group B to conventional smoke; and group C constituted the control group without exposition to the nicotine. In both experimental groups numerous alterations were observed, including a collapse of parenchyma, hyperhagia, hyperplasia of type II of pneumocytes, collagen deposition and an increased number of macrophages within thickened alveolar septa. Additionally, an initial elastolysis was observed. The elastic fibers were disrupted, sparse, irregular and thickened, whereas the numbers of α-SMA positive myofibroblasts and blood vessels were highest in the group exposed to conventional cigarette smoke. In conclusion, the usage of the electronic cigarettes leads to milder pathological alterations compared with traditional cigarette smoking. Nevertheless, the histopathological damage caused by vaping may lead to the development of alterations in the lung tissue which consequently hinder gas exchange.

Comparison between in vitro toxicities of tobacco- and menthol-flavored electronic cigarette liquids on human middle ear epithelial cells

Since electronic-cigarettes (e-cigarettes) are considered less toxic than conventional tobacco smoking, the use of e-cigarettes has increased, and the market for e-cigarette liquids (e-liquids) is continuously increasing. However, many studies showed that e-cigarettes may cause various harmful effects in lung, oral and heart. In this study, we investigated the effects of e-liquids on otitis media (OM) using human middle ear epithelial cells (HMEECs). Menthol-flavored e-liquid induced significant cell death in HMEECs (IC50: 1.45 ± 0.14%) and tobacco-flavored e-liquid led to increase in inflammatory cytokine levels and higher mucin production. Flavored e-liquids decreased the mRNA levels of genes encoding epithelial sodium channels (ENaCs) in HMEECs. Apoptosis and autophagy reactions were induced by exposure of HMEECs to menthol- and tobacco-flavored e-liquids. Tobacco-flavored e-liquids caused a greater increase in the levels of autophagosome marker, LC3-II, compared to menthol-flavored e-liquids, which was followed by cell death. These results demonstrate that flavored e-liquids cause cytotoxicity via apoptosis, autophagy, inflammatory response, and mucin production in HMEECs. The flavors present in e-liquids might be a risk factor for the development of otitis media.

Voltammetric determination of nicotine in electronic cigarette liquids using a boron-doped diamond electrode (BDDE)

A simple, sensitive and rapid method of nicotine determination using Boron Doped Diamond Electrode (BDDE) and Differential Pulse Voltammetry (DPV) in electronic cigarette liquids was described. To the best of our knowledge, this is the first presentation of voltammetric method for the determination of nicotine in this type of complex samples. In presented conditions, nicotine undergoes irreversible two-electron oxidation controlled by diffusion process. Optimal measurement parameters were achieved using solution of 25% ammonia in 0.1 mol/L ammonium chloride at pH 7.5 as supporting electrolyte. The calibration graph was linear from 0.03–0.40 mg/L of nicotine, the detection limit was 0.01 mg/L with the correlation coefficient of 0.9950. Sample preparation requires only dilution of the liquid.The effective application of the described simply measurement procedure significantly extends the use of the BDD electrode as an electrochemical sensor. It enables the electrochemical detection of nicotine in samples with a complex chemical composition like liquids for e-cigarettes, which is important in the case of a limited and controlled nicotine concentration in these products.

Functional characterization of flavorings in electronic cigarette refill liquids by nuclear magnetic resonance spectroscopy

The chemical content of electronic cigarette liquids (e-liquids) was determined by NMR spectroscopy.

The flavoring and not the nicotine content is a decisive factor for the effects of refill liquids of electronic cigarette on the redox status of endothelial cells

Electronic cigarettes are constantly gaining ground as they are considered less harmful than conventional cigarettes, and there is also the perception that they may serve as a potential smoking cessation tool. Although the acute effects of electronic cigarette use have been extensively studied, the long-term potential adverse effects on human health remain largely unknown. It has been well-established that oxidative stress is involved in the development of various pathological conditions. So far, most studies on e-cigarettes concern the effects on the respiratory system while fewer have focused on the vascular system. In the present study, we attempted to reveal the effects of electronic cigarette refill liquids on the redox state of human endothelial cells (EA.hy926 cell line). For this purpose, the cytotoxic effect of three e-liquids with different flavors (tobacco, vanilla, apple/mint) and nicotine concentrations (0, 6, 12, 18 mg/ml) were initially examined for their impact on cell viability of EA.hy926 cells. Then, five redox biomarkers [reduced form of glutathione (GSH), reactive oxygen species (ROS), total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS) and protein carbonyls (CARBS)] were measured. The results showed a disturbance in the redox balance in favor of free radicals in tobacco flavored e-liquids while vanilla flavored e-liquids exhibited a more complex profile depending on the nicotine content. The most interesting finding of the present study concerns the apple/mint flavored e-liquids that seemed to activate the cellular antioxidant defense and, thus, to protect the cells from the adverse effects of free radicals. Conclusively, it appears that the flavorings and not the nicotine content play a key role in the oxidative stress-induced toxicity of the e-liquids.

Effects of electronic cigarette liquid on monolayer and 3D tissue-engineered models of human gingival mucosa.

Background There is limited data available on potential biological effects of E-cigarettes on human oral tissues. The aim of this study was to evaluate the effects of E-cigarette liquid on the proliferation of normal and cancerous monolayer and 3D models of human oral mucosa and oral wound healing after short-term and medium-term exposure. Methods Normal human oral fibroblasts (NOF), immortalized OKF6-TERET-2 human oral keratinocytes, and cancerous TR146 keratinocyte monolayer cultures and 3D tissue engineered oral mucosal models were exposed to different concentrations (0.1%, 1%, 5% and 10%) of E-cigarette liquid (12 mg/ml nicotine) for 1 hour daily for three days and for 7 days. Tissue viability was monitored using the PrestoBlue assay. Wounds were also produced in the middle surface of the monolayer systems vertically using a disposable cell scraper. The alterations in the cell morphology and wound healing were visualized using light microscopy and histological examination.Results Statistical analysis showed medium-term exposure of TR146 keratinocytes to 5% and 10% E-liquid concentrations significantly increased the viability of the cancer cells compared to the negative control. Short-term exposure of NOFs to 10% E-liquid significantly reduced the cell viability, whereas medium-term exposure to all E-liquid concentrations significantly reduced the NOF cells’ viability. OKF6 cells exhibited significantly lower viability following short-term and mediumterm exposure to all E-cigarette concentrations compared to the negative control. 3D oral mucosal model containing normal oral fibroblasts and keratinocytes showed significant reduction in tissue viability after exposure to 10% E-liquid, whereas medium-term exposure resulted in significantly lower viability in 5% and 10% concentration groups compared to the negative control. There was a statistically significant difference in wound healing times of both NOF and OKF6 cells after exposure to 1%, 5% and 10% E-cigarette liquid.Conclusion Medium-term exposure to high concentrations of the E-cigarette liquid had cytotoxic effects on normal human oral fibroblasts and OKF6 keratinocytes, but a stimulatory cumulative effect on the growth of cancerous TR146 keratinocyte cells as assessed by the PrestoBlue assay and histological evaluation of 3D oral mucosal models. In addition, E-liquid exposure prolonged the wound healing of NOF and OKF6 oral mucosa cells.

Characterization of Nicotine Salts in 23 Electronic Cigarette Refill Liquids.

Many electronic cigarette manufacturers have begun offering liquids containing "nicotine salts," which are formed when an acid is mixed in a solution with free-base nicotine. Type of salt could play a significant role in the abuse liability of electronic cigarette liquids. As a first step to understanding nicotine salts, this study sought to identify the types of acids present in 23 commercially available electronic cigarette liquids. Twenty-three electronic cigarette liquids advertised as containing nicotine salts were purchased for analysis. These liquids were tested for the presence of 11 different organic acids that were deemed likely to be used in a nicotine salt formulation. Liquids were analyzed using a combination of liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry methods, then compared to authentic acid standards for identification. Six of the 11 possible acids were identified in the liquids, from most to least common: lactic, benzoic, levulinic, salicyclic, malic, and tartaric acid. Acid(s) could not be identified in one of the liquids. Though most liquids contained only one type, three of the liquids contained multiple acids. These data demonstrate that several types of salts/acids are currently being used in electronic cigarette liquids. The type and concentration of salt(s) used in these liquids may differentially alter sensations in the throat and upper airway, and overall pharmacology of the aerosols by altering liquid pH and from flavor and sensory characteristics of the acids themselves. This study demonstrates that at least six different types of acids are being used to create the nicotine salts in electronic cigarette liquids, with the acids lactic, benzoic, and levulinic being the most frequently identified. Identification of these acids can serve as the foundation for future research to determine if type of nicotine salt alters pharmacological and toxicological effects of electronic cigarettes.

Cinnamon-flavored electronic cigarette liquids and aerosols induce oxidative stress in human osteoblast-like MG-63 cells

As noncombustible nicotine delivery devices, electronic cigarettes (e-cigarettes) are the most popular tobacco product among youth. The widespread popularity of e-cigarettes combined with possible health consequences suggest a need to further research health hazards associated with e-cigarette use. Since conventional tobacco use is a risk factor for osteoporosis, this study investigates the impact of nicotine-free, cinnamon-flavored e-cigarette liquid (e-liquid) on bone-forming osteoblasts compared to flavorless e-liquid. Human tumor-derived osteoblast-like MG-63 cells were exposed for 24 h or 48 h to 0.0.4 %, 0.04 %, 0.4 % or 1 % of unvaped e-liquid or 0.0025 %, 0.025 %, 0.25 %, 1 % or 2.5 % of aerosol condensate in addition to a culture medium only control. Changes in cell viability were assessed by MTT assay, and the expression of a key bone protein, collagen type I, was analyzed by immunofluorescence. Production of reactive oxygen species (ROS) was detected by fluorometry to assess oxidative stress. Cell viability decreased in a dose-dependent manner, and ROS production increased, which was most pronounced with cinnamon-flavored e-liquids. There were no detectable changes in collagen type I protein following exposure to any of the aerosol condensates. This study demonstrates osteoblast-like cells are sensitive to both e-liquids and aerosol condensates and suggests the cytotoxicity of cinnamon-flavored e-liquids might be associated with oxidative stress rather than changes in collagen type I protein expression. This in vitro study provides insight into the potential impacts of e-cigarette use on bone cells.

Assessing the Appeal of Instagram Electronic Cigarette Refill Liquid Promotions and Warnings Among Young Adults: Mixed Methods Focus Group Study.

BackgroundWhile marketing for electronic cigarette refill liquids (e-liquids) is widespread on Instagram, little is known about the post elements that create appeal among young adult Instagram users. Further information is needed to help shape regulatory strategies appropriate for social media.ObjectiveThis study examined young adult Instagram user perceptions of actual e-liquid marketing posts and US Food and Drug Administration (FDA)–mandated nicotine addiction warning statements on Instagram.MethodsA series of 12 focus groups (n=69) were held with non–tobacco users, vapers, smokers, and dual users in Wisconsin between September and December 2018. Participants discussed the elements of posts that they found appealing or unappealing, in addition to completing a survey about each post and e-liquid. Focus group transcripts were analyzed by smoking status using a framework analysis approach.ResultsAlthough willingness to try e-liquids was highest among nicotine users, focus group discussions indicated that Instagram posts promoting e-liquids held appeal for individuals across smoking statuses. The primary elements that created appeal were the perceived trustworthiness of the Instagram account, attractive design and flavor visuals, and promotion of flavors and nicotine levels that met personal preferences. Post appeal was reduced by references to vaping subcultures, indicators that the post creator did not take nicotine addiction seriously, and FDA-mandated nicotine warning statements. Non–tobacco users were particularly drawn to posts featuring nicotine-free e-liquids with attractive visual designs and flavors known from foods.ConclusionsYoung adults consider a broad range of elements in assessing the appeal of e-liquid marketing on Instagram, with minor but notable distinctions by smoking status. Non–tobacco users are uniquely drawn to nicotine-free e-liquids and are more deterred by the FDA’s mandated nicotine addiction warning statements than those from other smoking statuses. This suggests that it may be possible to tailor policy interventions in a manner that helps to reduce novel uptake of vaping without significantly diminishing its potential harm-reduction benefits.