Health effects of electronic cigarette (e‑cigarette) use on organ systems and its implications for public health

The relationship between oxidative balance scores and chronic diarrhea and constipation: a population-based study

BACKGROUND

Oxidative stress is closely related to gut health. Exposures to oxidative stress in one's diet and lifestyle can be evaluated by the oxidative balance score (OBS). However, the relationship between OBS and intestinal habits is unknown. This study aimed to investigate the relationships between OBS and intestinal habits (chronic diarrhea and chronic constipation) and the underlying mechanisms involved.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2010, we included a total of 8065 participants. Twenty dietary and lifestyle factors were selected for the OBS calculates. Chronic constipation and chronic diarrhea were defined using the Bristol stool form scale (BSFS) types 1 and 2 and the BSFS 6 and 7, respectively. Multivariate logistic regression, subgroup analysis, and restricted cubic splines (RCS) analysis were used to evaluate the relationship between OBS and defecation habits. Finally, we used mediation analysis to explore the indirect effects of oxidative stress and inflammatory markers on these associations.

RESULTS

After adjusting for all the covariates, multivariate logistic regression analysis revealed that OBS was negatively correlated with diarrhea (OR = 0.57; 95%CI = 0.39-0.83; P = 0.008)and positively correlated with constipation (OR = 1.75; 95%CI = 1.19-2.25; P = 0.008). The RCS showed a nonlinear relationship between OBS and diarrhea (P for nonlinearity = 0.02) and a linear relationship between OBS and constipation (P for nonlinearity = 0.19). Mediation analysis showed that the C-reactive protein (CRP) concentration and white blood cell (WBC) count mediated the correlation between OBS and diarrhea by 6.28% and 6.53%, respectively (P < 0.05).

CONCLUSIONS

OBS is closely related to changes in patients' defecation habits. Oxidative stress and inflammation may play a role in the relationship between the two. This result emphasizes the importance of the public adjusting their lifestyle and dietary habits according to their own situation. However, further prospective studies are needed to analyze the relationship between oxidative stress and changes in defecation habits.

Social Network Analysis of e-Cigarette-Related Social Media Influencers on Twitter/X: Observational Study

BACKGROUND

An e-cigarette uses a battery to heat a liquid that generates an aerosol for consumers to inhale. e-Cigarette use (vaping) has been associated with respiratory disease, cardiovascular disease, and cognitive functions. Recently, vaping has become increasingly popular, especially among youth and young adults.

OBJECTIVE

The aim of this study was to understand the social networks of Twitter (now rebranded as X) influencers related to e-cigarettes through social network analysis.

METHODS

Through the Twitter streaming application programming interface, we identified 3,617,766 unique Twitter accounts posting e-cigarette-related tweets from May 3, 2021, to June 10, 2022. Among these, we identified 33 e-cigarette influencers. The followers of these influencers were grouped according to whether or not they post about e-cigarettes themselves; specifically, the former group was defined as having posted at least five e-cigarette-related tweets in the past year, whereas the latter group was defined as followers that had not posted any e-cigarette-related tweets in the past 3 years. We randomly sampled 100 user accounts among each group of e-cigarette influencer followers and created corresponding social networks for each e-cigarette influencer. We compared various network measures (eg, clustering coefficient) between the networks of the two follower groups.

RESULTS

Major topics from e-cigarette-related tweets posted by the 33 e-cigarette influencers included advocating against vaping policy (48.0%), vaping as a method to quit smoking (28.0%), and vaping product promotion (24.0%). The follower networks of these 33 influencers showed more connections for those who also post about e-cigarettes than for followers who do not post about e-cigarettes, with significantly higher clustering coefficients for the former group (0.398 vs 0.098; P=.005). Further, networks of followers who post about e-cigarettes exhibited substantially more incoming and outgoing connections than those of followers who do not post about e-cigarettes, with significantly higher in-degree (0.273 vs 0.084; P=.02), closeness (0.452 vs 0.137; P=.04), betweenness (0.036 vs 0.008; P=.001), and out-of-degree (0.097 vs 0.014; P=.02) centrality values. The followers who post about e-cigarettes also had a significantly (P<.001) higher number of followers (n=322) than that of followers who do not post about e-cigarettes (n=201). The number of tweets in the networks of followers who post about e-cigarettes was significantly higher than that in the networks of followers who do not post about e-cigarettes (93 vs 43; P<.001). Two major topics discussed in the networks of followers who post about e-cigarettes included promoting e-cigarette products or vaping activity (55.7%) and vaping being a help for smoking cessation and harm reduction (44.3%).

CONCLUSIONS

Followers of e-cigarette influencers who also post about e-cigarettes have more closely connected networks than those of followers who do not themselves post about e-cigarettes. These findings provide a potentially practical intervention approach for future antivaping campaigns.

Toxicological Aspects Associated with Consumption from Electronic Nicotine Delivery System (ENDS): Focus on Heavy Metals Exposure and Cancer Risk

Tobacco smoking remains one of the leading causes of premature death worldwide. Electronic Nicotine Delivery Systems (ENDSs) are proposed as a tool for smoking cessation. In the last few years, a growing number of different types of ENDSs were launched onto the market. Despite the manufacturing differences, ENDSs can be classified as "liquid e-cigarettes" (e-cigs) equipped with an atomizer that vaporizes a liquid composed of vegetable glycerin (VG), polypropylene glycol (PG), and nicotine, with the possible addition of flavorings; otherwise, the "heated tobacco products" (HTPs) heat tobacco sticks through contact with an electronic heating metal element. The presence of some metals in the heating systems, as well as in solder joints, involves the possibility that heavy metal ions can move from these components to the liquid, or they can be adsorbed into the tobacco stick from the heating blade in the case of HTPs. Recent evidence has indicated the presence of heavy metals in the refill liquids and in the mainstream such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb). The present review discusses the toxicological aspects associated with the exposition of heavy metals by consumption from ENDSs, focusing on metal carcinogenesis risk.

Associations between e-cigarette use and sleep health among adults in the United States, NHANES 2015-2018

OBJECTIVE

To examine the associations between e-cigarette use or dual (e-cigarette and combustible cigarette) use and short sleep duration and trouble sleeping among U.S. adults.

METHODS

We used 2015-2018 data from the National Health and Nutrition Examination Survey (NHANES) (n = 11,659). E-cigarette use and dual use were categorized as current, former, and never use. Short sleep duration was defined as sleep duration ≤6 h. Trouble sleeping was self-reported. Weighted logistic regression analyses were performed.

RESULTS

Among those with current e-cigarette use, 53.9 % were with current dual use and 23.8 % were with former dual use. Compared to never e-cigarette use, current e-cigarette use was associated with significantly higher odds of trouble sleeping (OR = 2.16, 95 % CI: 1.49-3.13), adjusting for potential confounders. Significant associations were also observed for former e-cigarette use versus never use with trouble sleeping (OR = 1.54, 95 % CI: 1.15-2.07) after full adjustment. Current cigarette use was associated with both short sleep duration (OR = 1.65, 95 % CI: 1.28-2.14) and trouble sleeping (OR = 1.36, 95 % CI: 1.03-1.79) after full adjustment. Additionally, the fully adjusted ORs for short sleep duration and trouble sleeping were 1.64 (95 % CI: 1.06-2.54) and 2.14 (95 % CI: 1.34-3.42) among those with current dual use, and 1.46 (95 % CI: 1.17-1.81) and 2.11 (95 % CI: 1.66-2.67) among those with former dual use, compared to those without dual use.

CONCLUSIONS

Current cigarette use or dual use is associated with significantly higher odds of short sleep duration and trouble sleeping. Moreover, former e-cigarette use or dual use is associated with increased odds of trouble sleeping.

Association between e-cigarette use and asthma among US adolescents: Youth Risk Behavior Surveillance System 2015-2019

BACKGROUND

Previous studies have suggested that e-cigarette use, which has increased rapidly among US adolescents, may cause respiratory distress. This cross-sectional study aimed to investigate the factors associated with e-cigarette use and the relationship between e-cigarette use and asthma among US adolescents.

METHODS

Data from the Youth Risk Behavior Surveillance System between 2015 and 2019 were analyzed, and multivariable logistic regression was used to identify demographic and behavioral factors associated with e-cigarette use. Stratified analyses were conducted to assess the relationship between e-cigarette use and asthma among adolescents by previous combustible product use.

RESULTS

This study found that Hispanic adolescents had lower odds of e-cigarette use than White adolescents in Texas, with factors such as age, substance use, and depression being associated with use. In the US, male gender, previous combustible and substance use, and depression were associated with higher odds of ever using e-cigarettes, while current use was associated with several factors including age and White race. E-cigarette use was significantly associated with asthma among adolescents who have never used combustible products in both Texas and the entire US after adjusting for covariates (OR 1.32, 95% CI 1.06-1.66 and OR 1.18, 95% CI 1.02-1.37, respectively).

CONCLUSION

The findings from this study can be used to inform public health strategies and policies aimed at reducing e-cigarette use and its associated health risks among adolescents.

Quick nic: novel smokeless nicotine products and pediatric trends

PURPOSE OF REVIEW

The development and marketing of smokeless nicotine products in recent years have become increasingly popular among adolescents. In addition to well known conventional inhaled nicotine products, noninhaled products, such as nicotine toothpicks, orbs, lozenges, strips, and more, have dangerously captivated a new youth audience. Although smokeless nicotine products may seem to be less threatening than conventional inhaled nicotine products, there are significant risks associated with the use of these products, including addiction and severe health issues. The purpose of this review is to provide up-to-date information about alternative nicotine products currently on the market that may appeal to youth, and the dangers of nicotine use for pediatric populations.

RECENT FINDINGS

Smokeless nicotine products appeal to minors with their varying flavors and discrete packaging. These products may lead to nicotine toxicity as well as severe health problems, such as cancer, issues with reproduction, and heart attacks. Nicotine is extremely dangerous for young children; in fact, using nicotine products before the age of 18 years can lead to addiction and is linked to an increased likelihood of experimenting with stronger nicotine products or illicit drugs. The development of inconspicuous nicotine packaging has led to increasing concerns for accidental nicotine exposure and overdose in youth.

SUMMARY

Greater knowledge regarding current nicotine products on the market, specifically smokeless nicotine products, will help clinicians be more aware of the dangers associated with these products. Clinicians will be better able to provide their patients and families with proper guidance to avoid nicotine addiction, further drug use, and detrimental health issues. Caregivers and medical professionals must recognize novel and inconspicuous nicotine products commonly used among youth, understand the signs of nicotine abuse and dependence, and take measures to address possible nicotine-related health risks.

The impact of e-cigarette exposure on different organ systems: A review of recent evidence and future perspectives

The use of electronic cigarettes (e-cigs) is rapidly increasing worldwide and is promoted as a smoking cessation tool. The impact of traditional cigs on human health has been well-defined in both animal and human studies. In contrast, little is known about the adverse effects of e-cigs exposure on human health. This review summarizes the impact of e-cigs exposure on different organ systems based on the rapidly expanding recent evidence from experimental and human studies. A number of growing studies have shown the adverse effects of e-cigs exposure on various organ systems. The summarized data in this review indicate that while e-cigs use causes less adverse effects on different organs compared to traditional cigs, its long-term exposure may lead to serious health effects. Data on short-term organ effects are limited and there is no sufficient evidence on long-term organ effects. Moreover, the adverse effects of secondhand and third hand e-cigs vapour exposure have not been thoroughly investigated in previous studies. Although some studies demonstrated e-cigs used as a smoking cessation tool, there is a lack of strong evidence to support it. While some researchers suggested e-cigs as a safer alternative to tobacco smoking, their long-term exposure health effects remain largely unknown. Therefore, more epidemiological and prospective studies including mechanistic studies are needed to address the potential adverse health effects of e-cigs to draw a firm conclusion about their safe use. A wide variation in e-cigs products and the lack of standardized testing methods are the major barriers to evaluating the existing data. Specific regulatory guidelines for both e-cigs components and the manufacturing process may be effective to protect consumer health.

An ecological momentary assessment study to examine covariates and effects of concurrent and simultaneous use of electronic cigarettes and marijuana among college students

INTRODUCTION

The prevalence of concurrent and simultaneous use of e-cigarette and marijuana among college students is high. Yet, the literature was mainly based on cross-sectional surveys with emphasis on the smoking route. This is the first ecological momentary assessment (EMA) study that examined the vaping route of nicotine-marijuana co-use and the associated short-term psychological effects.

METHODS

This study recruited 686 college student e-cigarette users to participate in an on-line survey and 7-day EMA. Frequent marijuana users (247) - using marijuana weekly or daily - were compared with infrequent/non-users (439) on academic performance, e-cigarette use patterns, and dependence and respiratory symptoms. EMA data from the frequent users were used to study the association between marijuana vaping and e-cigarette consumption and the short-term psychological effects of e-cigarette and marijuana use.

RESULTS

The results show that e-cigarette users who frequently used marijuana tended to have lower academic performance, be involved in higher-risk use patterns, and have higher levels of e-cigarette dependence, marijuana problems, and respiratory symptoms, compared to infrequent/non-users. Marijuana vaping was associated with a higher level of e-cigarette consumption. E-cigarette use and marijuana use were both associated with higher levels of positive affect, physiological sensation, and craving for e-cigarettes. While marijuana use was linked to a lower level of negative affect, e-cigarette use did not have a significant effect. Further, none of the interaction effects between e-cigarette and marijuana use on psychological states were significant.

CONCLUSIONS

The results showed additive effects of e-cigarette and marijuana use although the hypothesized synergistic effects were not supported.

Promotion of E-Cigarettes on TikTok and Regulatory Considerations

E-cigarettes are promoted extensively on TikTok and other social media platforms. Platform policies to restrict e-cigarette promotion seem insufficient and are poorly enforced. This paper aims to understand how e-cigarettes are being promoted on TikTok and provide insights into the effectiveness of current TikTok policies. Seven popular hashtag-based keywords were used to identify TikTok accounts and associated videos related to e-cigarettes. Posts were independently coded by two trained coders. Collectively, the 264 videos received 2,470,373 views, 166,462 likes and 3426 comments. The overwhelming majority of videos (97.7%) portrayed e-cigarettes positively, and these posts received 98.7% of the total views and 98.2% of the total likes. A total of 69 posts (26.1%) clearly violated TikTok's own content policy. The findings of the current study suggest that a variety of predominantly pro-vaping content is available on TikTok. Current policies and moderation processes appear to be insufficient in restricting the spread of pro-e-cigarette content on TikTok, putting predominantly young users at potential risk of e-cigarette use.

Perceptions of e-cigarettes among Australian adolescents, young adults, and adults

Increases in e-cigarette use are of concern to public health authorities given the harms associated with vaping. Understanding people's perceptions of the risks and benefits of e-cigarette use has the potential to assist with prevention efforts. However, research assessing the perceptions of Australian adolescents and any differences in perceptions between adolescents, young adults, and adults is limited. Additionally, research exploring perceptions of various types of e-cigarettes is lacking. To inform the development of prevention and intervention programs and policies, this study aimed to explore Australians' perceptions of the risks and benefits associated with e-cigarette use and whether perceptions differ by age and user status. A sample of 4,617 Australians aged 12 + years completed an online survey that assessed (i) smoking and e-cigarette user status, (ii) e-cigarette risk perceptions, (iii) beliefs about e-cigarettes as a smoking cessation tool, and (iv) positive e-cigarette outcome expectancies. Across all age groups, respondents perceived non-nicotine and flavoured e-cigarettes as less harmful than nicotine e-cigarettes. Significantly more adolescents and young adults than adults held positive outcome expectancies, and a substantial minority of non-users and never users in all age groups believed that using e-cigarettes confers social and mental health benefits. Given the potential benefits they perceived to be associated with e-cigarette use, a substantial proportion of adolescent and young adult never users may be vulnerable to initiation. These findings highlight the importance of (i) adequately communicating the risks associated with non-nicotine e-cigarette use and (ii) addressing misperceptions about use, especially among youth.

Addictive Potential of e-Cigarettes as Reported in e-Cigarette Online Forums: Netnographic Analysis of Subjective Experiences

BACKGROUND

While e-cigarettes usually contain nicotine, their addictive potential is not yet fully understood. We hypothesized that if e-cigarettes are addictive, users will experience typical symptoms of addiction.

OBJECTIVE

The aim of our study was to investigate whether and how e-cigarette users report signs of addiction.

METHODS

We identified 3 large German-language e-cigarette online forums via a systematic Google search. Based on a netnographic approach, we used deductive content analysis to investigate relevant posts in these forums. Netnography has the advantage of limiting the social desirability bias that prevails in face-to-face research, such as focus groups. The data were coded according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria for tobacco use disorder, adapted for e-cigarettes. The DSM-5 criteria were used to portray a broad spectrum of possible experiences of addiction.

RESULTS

Overall, 5337 threads in 3 forums were screened, and 451 threads containing relevant information were included in the analysis. Users reported experiences consistent with the DSM-5 criteria, such as craving e-cigarettes, excessive time spent vaping, and health issues related to e-cigarette use. However, our analysis also showed that users reported the absence of typical tobacco use disorder criteria, such as successful attempts to reduce the nicotine dosage. For most themes, reports of their absence were more frequent than of their presence. The absence of perceived addiction was mostly reported in contrast to prior tobacco smoking.

CONCLUSIONS

This is the first study to use a netnographic approach to explore unfiltered self-reports of experiences of e-cigarette addiction by users in online forums. As hypothesized, some but not all users reported subjective experiences that corresponded to the criteria of tobacco use disorder as defined by the DSM-5. Nevertheless, subjective reports also indicated that many e-cigarette users felt in control of their behavior, especially in contrast to their prior use of tobacco cigarettes. The finding that some e-cigarette users subjectively experience addiction highlights the need for effective cessation programs to support users who experience their e-cigarette use as burdensome. This research can guide the refinement of instruments to assess e-cigarette addiction and guide cessation programs.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s40359-021-00682-8.

The Influence of Mental Health and Respiratory Symptoms on the Association Between Chronic Lung Disease and E-Cigarette Use in Adults in the United States

BACKGROUND

Adults with chronic lung disease use electronic cigarettes (e-cigarette) at higher rates than those without chronic lung disease. Because e-cigarettes have now been shown to cause adverse pulmonary effects and impair immune responses, it is particularly important to identify the factors that contribute to e-cigarette use in individuals with chronic lung disease. We tested whether mental health explains the association between chronic lung disease and e-cigarette use, and whether the association between chronic lung disease and e-cigarette use is conditional on the presence of respiratory symptoms.

METHODS

Data were obtained from the 2018 Behavioral Risk Factor Surveillance System. Logistic regression was used to test the association between chronic lung disease status and e-cigarette use when controlling for demographic variables and comorbidities. Structural equation modeling was then used to evaluate (a) whether the number of bad mental health days in the past 30 days explained the association between chronic lung disease and e-cigarette use, and (b) if respiratory symptoms moderated the association between chronic lung disease and e-cigarette use.

RESULTS

The prevalence of lifetime and current e-cigarette use was significantly higher in those with than in those without chronic lung disease, as was the number of bad mental health days in the past 30 days. Mediation analysis indicated a statistically significant indirect effect of chronic lung disease on the likelihood of e-cigarette use (lifetime and current) through mental health. However, our analyses did not indicate a statistically significant interaction between chronic lung disease and respiratory symptoms in the likelihood of e-cigarette use.

CONCLUSIONS

The association between chronic lung disease and e-cigarette use may be due, in part, to poorer mental health among individuals with chronic lung disease. These findings provide preliminary evidence that improving the mental health of individuals with chronic lung disease could reduce e-cigarette use in this vulnerable population.

Effects of E-Cigarette Refill Liquid Flavorings with and without Nicotine on Human Retinal Pigment Epithelial Cells: A Preliminary Study

Smoking is an etiologic factor for age-related macular degeneration (AMD). Although cigarette smoke has been extensively researched for retinal pigment epithelial (RPE) cell degeneration, the potential for adverse effects on the retinal epithelium following exposure to flavored e-cigarette refill liquid has never been explored. In this preliminary study, we have examined the effects of 20 e-liquids (10 different flavored nicotine-free and 10 nicotine-rich e-liquids) used in e-cigarettes on the metabolic activity, membrane integrity, and mitochondrial membrane potential of RPE cells. Our results showed that of the flavors studied over the concentration range: 0.5, 1, and 2% v/v for a duration of 48 h, cinnamon was the most toxic and menthol was the second most toxic, while other flavors showed lesser or no cytotoxicity. The presence of nicotine augmented cytotoxicity for cinnamon, menthol, strawberry, vanilla, and banana while for other flavors there was no synergism. Together, our results demonstrate that exposure of RPE to flavored e-cigarette refill liquids caused significant cytotoxicity and may be a risk factor for the development of retinal pathogenesis, although further in-depth studies are necessary.

The Chemical Complexity of e-Cigarette Aerosols Compared With the Smoke From a Tobacco Burning Cigarette

Background: As e-cigarette popularity has increased, there is growing evidence to suggest that while they are highly likely to be considerably less harmful than cigarettes, their use is not free of risk to the user. There is therefore an ongoing need to characterise the chemical composition of e-cigarette aerosols, as a starting point in characterising risks associated with their use. This study examined the chemical complexity of aerosols generated by an e-cigarette containing one unflavored and three flavored e-liquids. A combination of targeted and untargeted chemical analysis approaches was used to examine the number of compounds comprising the aerosol. Contributions of e-liquid flavors to aerosol complexity were investigated, and the sources of other aerosol constituents sought. Emissions of 98 aerosol toxicants were quantified and compared to those in smoke from a reference tobacco cigarette generated under two different smoking regimes. Results: Combined untargeted and targeted aerosol analyses identified between 94 and 139 compounds in the flavored aerosols, compared with an estimated 72-79 in the unflavored aerosol. This is significantly less complex (by 1-2 orders of magnitude) than the reported composition of cigarette smoke. Combining both types of analysis identified 5-12 compounds over and above those found by untargeted analysis alone. Gravimetrically, 89-99% of the e-cigarette aerosol composition was composed of glycerol, propylene glycol, water and nicotine, and around 3% comprised other, more minor, constituents. Comparable data for the Ky3R4F reference tobacco cigarette pointed to 58-76% of cigarette smoke "tar" being composed of minor constituents. Levels of the targeted toxicants in the e-cigarette aerosols were significantly lower than those in cigarette smoke, with 68.5->99% reductions under ISO 3308 puffing conditions and 88.4->99% reductions under ISO 20778 (intense) conditions; reductions against the WHO TobReg 9 priority list were around 99%. Conclusion: These analyses showed that the e-cigarette aerosols contain fewer compounds and at significantly lower concentrations than cigarette smoke. The chemical diversity of an e-cigarette aerosol is strongly impacted by the choice of e-liquid ingredients.

Differences in electronic cigarette use among adolescents in Korea: A nationwide analysis

INTRODUCTION

The use of electronic cigarettes (e-cigarettes) has increased among adolescents. This study aimed to investigate the relationship between e-cigarette use and different sociodemographic factors among Korean adolescents.

METHODS

The study used the 2017 to 2019 Korea Youth Risk Behavior Web-based Survey (KYRBS) data. The study measured sociodemographic status based on living arrangement, economic status, and parental birthplace. We used a Chi-square test to investigate the general characteristics of the study population. We applied multiple logistic regression analysis to analyze the association between e-cigarette use and sociodemographic status. Model 1 included electronic cigarettes only as the outcome variable and model 2 included electronic cigarettes plus combustible cigarettes. The study expressed results as odds ratios (OR) and their 95% confidence interval (95% CI).

RESULTS

A total of 2.4% of adolescents used e-cigarettes only and 6.5% e-cigarettes and/or conventional cigarettes. In e-cigarettes users (model 1), compared to individuals living with their parents, those living with their relatives (OR 3.23, 95% CI 2.45-4.24) and in protective facilities (OR 4.36, 95% CI 2.98-6.39) were more likely to smoke. The "middle" showed lower odds than the "low" economic status group (OR 0.78, 95% CI 0.69-0.87). Adolescents with both parents born abroad (OR 2.92, 95% CI 1.78-4.82) also had a higher likelihood of smoking than those with both native Korean parents. The study found similar trends in model 2, which accounted for both electronic and combustible cigarettes.

CONCLUSION

E-cigarette use among adolescents was associated with living arrangement, economic status, and parental birthplace. E-cigarettes use among adolescents should be monitored, particularly in the vulnerable groups of adolescents that this study identified.

Machine Learning-Based Nicotine Addiction Prediction Models for Youth E-Cigarette and Waterpipe (Hookah) Users

Despite the harmful effect on health, e-cigarette and hookah smoking in youth in the U.S. has increased. Developing tailored e-cigarette and hookah cessation programs for youth is imperative. The aim of this study was to identify predictor variables such as social, mental, and environmental determinants that cause nicotine addiction in youth e-cigarette or hookah users and build nicotine addiction prediction models using machine learning algorithms. A total of 6511 participants were identified as ever having used e-cigarettes or hookah from the National Youth Tobacco Survey (2019) datasets. Prediction models were built by Random Forest with ReliefF and Least Absolute Shrinkage and Selection Operator (LASSO). ReliefF identified important predictor variables, and the Davies–Bouldin clustering evaluation index selected the optimal number of predictors for Random Forest. A total of 193 predictor variables were included in the final analysis. Performance of prediction models was measured by Root Mean Square Error (RMSE) and Confusion Matrix. The results suggested high performance of prediction. Identified predictor variables were aligned with previous research. The noble predictors found, such as ‘witnessed e-cigarette use in their household’ and ‘perception of their tobacco use’, could be used in public awareness or targeted e-cigarette and hookah youth education and for policymakers.

The Evolving E-cigarette: Comparative Chemical Analyses of E-cigarette Vapor and Cigarette Smoke

Background: E-cigarette designs, materials, and ingredients are continually evolving, with cotton wicks and diverse coil materials emerging as the popular components of atomisers. Another recent development is the use of nicotine salts in e-liquids to replicate the form of nicotine found in cigarette smoke, which may help cigarette smokers to transition to e-cigarettes. However, scientific understanding of the impact of such innovations on e-cigarette aerosol chemistry is limited.

Methods: To address these knowledge gaps, we have conducted a comparative study analyzing relevant toxicant emissions from five e-cigarettes varying in wick, atomiser coil, and benzoic acid content and two tobacco cigarettes, quantifying 97 aerosol constituents and 84 smoke compounds, respectively. Our focus was the potential for benzoic acid in e-liquids and cotton wicks to form aerosol toxicants through thermal degradation reactions, and the potential for nickel–iron alloy coils to catalyze degradation of aerosol formers. In addition, we analyzed e-cigarette emissions for 19 flavor compounds, thermal decomposition products, and e-liquid contaminants that the FDA has recently proposed adding to the established list of Harmful and Potentially Harmful Constituents (HPHCs) in tobacco products.

Results: Analyses for benzene and phenol showed no evidence of the thermal decomposition of benzoic acid in the e-cigarettes tested. Measurements of cotton decomposition products, such as carbonyls, hydrocarbons, aromatics, and PAHs, further indicated that cotton wicks can be used without thermal degradation in suitable e-cigarette designs. No evidence was found for enhanced thermal decomposition of propylene glycol or glycerol by the nickel–iron coil. Sixteen of the 19 FDA-proposed compounds were not detected in the e-cigarettes. Comparing toxicant emissions from e-cigarettes and tobacco cigarettes showed that levels of the nine WHO TobReg priority cigarette smoke toxicants were more than 99% lower in the aerosols from each of five e-cigarettes as compared with the commercial and reference cigarettes.

Conclusions: Despite continuing evolution in design, components and ingredients, e-cigarettes continue to offer significantly lower toxicant exposure alternatives to cigarette smoking.