Levels of selected carcinogens and toxicants in vapour from electronic cigarettes

Impact of nicotine-free and nicotine-rich flavored electronic cigarette refill liquids on primary human melanocyte function

In this study, five popular EC liquid flavors-strawberry, banana, vanilla, tobacco, and menthol-were examined on human melanocyte functions. Each flavored e-liquid (in 80/20 PG/VG vehicle) was tested without or with 18 mg/mL nicotine. The effects of PG/VG and nicotine-containing vehicles were also evaluated. Results revealed that nicotine-free and nicotine-containing e-liquids had comparable cytotoxicity, with menthol> > banana> tobacco> vanilla> strawberry. This cytotoxicity was unrelated to either nicotine or the vehicle. PG/VG (1 and 2 %) increased melanin production without influencing cellular tyrosinase activity. The flavored e-liquids did not further affect melanin production, suggesting that the vehicle's effect, not the flavor, was responsible for the increased melanin production. Interestingly, nicotine at 2 % in the vehicle restored the stimulated melanin production to the control. Flavors suppressed cellular tyrosinase activity, with vanilla and banana flavors robustly inhibiting it. Vanilla and banana e-liquids also enhanced reactive oxygen species (ROS) production, which did not originate from the vehicle or nicotine-containing vehicle. Banana e-liquid with nicotine lowered ROS generation compared to nicotine-free banana e-liquid. Common flavors in e-liquids can cause cytotoxicity and influence melanogenesis even without nicotine, indicating that the use of ECs may not completely avoid the harmful effects of cigarette smoking. Further studies are warranted to investigate e-liquid aerosol effects on melanocytes.

Secondhand Exposure to Simulated Cannabis Vaping Aerosols

Emissions from cannabis vaping degrade indoor air quality and expose non-users to secondhand pollutants. We investigated how the vaping mixture composition affects indoor aerosol characteristics and exposures. Simulated cannabis vaping aerosol was produced by flash evaporation in a 20 m3 chamber of mixtures containing terpenoids, cannabinoids, cannabis extract constituents, and the adulterant vitamin E acetate (VEA). Aerosol time- and size-resolved concentrations (8 nm-2.5 μm at 1 Hz) were measured, and a dosimetry model was used to evaluate the intake of secondhand aerosols. The results showed peak particle number (PN) concentrations between 0.7 × 106 and 13 × 106 cm-3 and peak mass concentration (PM1.0) between 65 and 1191 μg m-3 at t = 5 min after emission. Concentrations decreased to 21-57% of peak PN and 33-69% of peak PM1.0 at t = 60 min. The PM1.0 yield was 0.06 for a terpenoid-only mixture, 0.22-0.36 for tetrahydrocannabinol (THC)-terpenoid mixtures, and >1 for mixtures containing high concentrations of cannabidiol (CBD) or VEA. For intake deposition, the highest aerosol fraction was deposited in the pulmonary region, followed by the tracheobronchial and head regions. Deposition increased in the presence of THC, CBD, or VEA, with aerosols <100 nm contributing the majority of particles deposited in all regions.

Investigation of some metal levels in people using electronic cigarettes and IQOS

OBJECTIVES

There has been a sharp increase in the use of e-cigarettes and heated tobacco products (HTPs) in the last decade. Related to the increase in the use, serious public health debates have been caused by the safety and risks of these products. Particularly due to the exposure to a lot of toxic substances, including heavy metals, there has been an increasing concern over their health effects. Heavy metals such as lead, arsenic, mercury, and cadmium are environmental pollutants poising significant health risks. These metals have a disposition to accumulate in the human body over time. Even at lower levels of exposure, they might lead to multiple organ damage and adverse health effects, including neurotoxicity, nephrotoxicity, and being carcinogenicity.

This study tests the idea that using electronic cigarettes (e-cigarettes) and IQOS devices raises the levels of metals in urine and that the amount of increase depends on which product is used. The study aims to look at the levels of lead, cadmium, nickel, zinc, and selenium in the urine of cigarette smokers, e-cigarette users, IQOS users, and nonsmokers; to check for significant differences in metal levels between these groups (with a significance level set at p < 0.05); to compare the metal levels found with safety limits; and to explore if there's a link between the metal levels in urine and the type of product used (cigarettes, IQOS, or e-cigarettes).

METHOD

This study aimed to compare the trace element, heavy element, and nicotine exposures of individuals who smoke (n = 39), use e-cigarettes (n = 28), use IQOS (n = 20), and do not use tobacco or tobacco products (n = 30) while living in Ankara, Türkiye. In order to evaluate the element levels of the participants, the levels of lead, cadmium, nickel, zinc, and selenium metals in their urine were determined using inductively coupled plasma mass spectrometry (ICP-MS), and nicotine exposures were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

The measurement showed that lead levels were higher in IQOS users (8.51 ng/g creatinine) and smokers (3.67 ng/g creatinine) compared to e-cigarette users (1.38 ng/g creatinine), and this difference was statistically significant (p < 0.05). In addition, a statistically significant difference was found between the cotinine level and lead level of the smoking and IQOS groups (p ˂ 0.05). No statistically significant difference was found between the groups in terms of cadmium level (p > 0.008). Nickel level was found to be higher in e-cigarette (3.43 ng/g creatinine) and IQOS (3.84 ng/g creatinine) users than in the smoking group (0.99 ng/g creatinine). In terms of nickel, a statistically significant difference was found between the e-cigarette and IQOS groups and both the smoking and control groups (p ˂ 0.05). No statistically significant difference was found between the selenium level and both the groups and the cotinine level (p > 0.008). Zinc levels were higher in IQOS users (596.13 ng/g creatinine) than in e-cigarette users (298.40 ng/g creatinine) and cigarette users (217.59 ng/g creatinine). No statistically significant difference was found between the cotinine levels of e-cigarette, IQOS, and cigarette users (p > 0.05).

CONCLUSION

This study investigated metal exposure profiles by comparing urinary metal concentrations across different groups of tobacco product users (cigarette smokers, IQOS users, and e-cigarette users). The findings revealed that lead and cadmium levels were significantly higher in cigarette smokers compared to nonsmokers. In contrast, elevated nickel concentrations were notably observed among IQOS and e-cigarette users. Variations in zinc and selenium levels appeared to be more attributable to physiological or external factors rather than product use. Overall, the results suggest that both conventional and novel tobacco products may pose potential toxicological risks related to metal exposure among users. However, the observed metal concentrations generally fell below established regulatory thresholds.

Beyond the puff: health consequences of vaping

Electronic nicotine delivery systems (ENDS) arrived on the U.S. market in 2007 and rapidly grew in popularity as a harm reduction tool for traditional cigarette users. While initially marketed as a healthier alternative to combustible cigarettes, the unique mixture of chemical constituents in ENDS products and their emissions have led to rising concern about their safety and the long-term health implications. Given the lack of long-term, epidemiological research on the health effects of these products, recent research has sought to understand the impacts on cellular components and gain understanding of acute effects to inform potential chronic health implications. Studies have demonstrated the deleterious effects the use of ENDS has on the oral cavity, respiratory, and cardiovascular systems. ENDS use has been linked to gingival inflammation and alterations in the oral microbiome contributing to periodontal disease. Further, the presence of heavy metals and other constituents in ENDS emissions contribute to aberrant oxidative stress and inflammation within the lung, contributing to alterations in functional lung capacity and respiratory symptoms in ENDS users. In addition, harmful components of ENDS emissions make their way to the circulatory system, leading to detrimental impacts in cardiovascular functioning such as a rise in blood pressure, impaired vascular functioning, and increased heart rate, all of which are known to underscore long-term cardiovascular ailments. This review will provide an in-depth discussion of the current literature available on the consequences of ENDS use on the oral cavity, respiratory, and cardiovascular systems as well as provide insight into long-term implications that may result.

The association of modifiable and socio-demographic factors with first transitions from smoking to exclusive e-cigarette use, dual use or no nicotine use: Findings from the Avon Longitudinal Study of Parents and Children United Kingdom birth cohort

BACKGROUND AND AIMS

E-cigarettes can aid smoking cessation and reduce carcinogen exposure. Understanding differences in characteristics between young adults who quit smoking, with or without e-cigarettes, or dual use can help tailor interventions. The aim of this study was to describe first transitions from smoking and explore substance use, sociodemographic, and health characteristic associations with the probability of each possible first transition from smoking.

DESIGN AND SETTING

Longitudinal birth cohort data from the Avon Longitudinal Study of Parents and Children (ALSPAC), conducted in the United Kingdom.

PARTICIPANTS

A total of 858 participants were included who reported tobacco smoking in the past month at age 21 during a questionnaire collected in 2013.

MEASUREMENTS

The first reported non-exclusive smoking event following smoking, observed approximately annually between ages 22 and 30, was categorized as either no nicotine use, exclusive e-cigarette use, or dual use. Discrete-time subdistribution hazard models were used to examine associations between different covariates, including substance use, sociodemographic, and health characteristics, with the probability of each first transition from smoking. Analyses were adjusted for early-life confounders and weighted to mitigate bias.

FINDINGS

Among participants, 52% stopped nicotine use, 27% reported dual use, and 9% used e-cigarettes exclusively. Smoking weekly or more (Subdistribution Hazard Ratio [SHR] = 0.28, 95% Confidence Interval [CI] = 0.22-0.35), having many friends who smoke (SHR = 0.64, 95% CI = 0.50-0.81), and lower education (SHR = 0.68, 95% CI = 0.52-0.90) reduced the likelihood of no nicotine use and increased dual use (frequent smoking SHR = 3.00, 95% CI = 1.96-4.59; peer smoking SHR = 1.55, 95% CI = 1.07-2.24; education SHR = 1.72, 95% CI = 1.03-2.90). Cannabis use (SHR = 0.67, 95% CI = 0.49-0.92), drug use (SHR = 0.77, 95% CI = 0.59-0.99), less exercise (SHR = 0.71, 95% CI = 0.53-0.95), and early parenthood (SHR = 0.46, 95% CI = 0.27-0.79) reduced no nicotine use. Higher BMI (SHR = 1.58, 95% CI = 1.08-2.31) increased dual use.

CONCLUSIONS

In the United Kingdom, young adults who smoke frequently, have more smoking peers, have lower education, engage in drug use, exercise less, or become parents early appear to be less likely to stop nicotine use than other young adults who smoke. Frequent smoking, peer smoking, lower education, and higher body mass index also appear to be associated with increased dual use of cigarettes and e-cigarettes.

A review of analytical techniques for the determination of e-liquid and electronic cigarette aerosol composition

Since the introduction of electronic cigarettes (ECs) to the global market, the composition of e-liquids has been a controversial topic. While some consider ECs to be an effective tool for quitting smoking, their primary criticism lies in the uncertain and varied composition of e-liquids. Manufacturers create the desired formulations by mixing different ratios of humectants, flavorings, nicotine, cannabinoids, and cooling agents. However, the health effects of inhaling these compounds are still not well understood. Regular analytical control of e-liquids and aerosols is crucial to gain valuable insights into e-liquid composition, generating new compounds during aerosolization, and the potential impact on human health. This work presents an overview of the analytical techniques used for the qualitative and quantitative determination of e-liquid and aerosol compounds, including a description of the methods used for aerosol collection. Gas and liquid chromatography are the most used analytical techniques for compound determination, followed by nuclear magnetic resonance spectroscopy. Additionally, inductively coupled plasma-mass spectrometry and inductively coupled plasma-optical emission spectroscopy are the most frequently used analytical techniques for elemental determination in e-liquids and their aerosols.

Biomarkers of Toxicant Exposure among Youth in Canada, England, and the United States Who Vape and/or Smoke Tobacco or Do Neither

BACKGROUND

Few studies examine biomarkers of exposure to vaping and tobacco products among youth. We compared biomarkers for toxicants between youth who vape, smoke, "dual-use", or neither.

METHODS

Participants ages 16 to 19 years in Canada, England, and the United States completed surveys and self-collected urine samples between September 2019 and January 2022 (N = 364). Urine was tested for metabolites of tobacco-specific nitrosamine NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone) and six volatile organic compounds. Regression models examined differences in biomarker concentrations by past-week tobacco smoking and vaping, adjusting for creatinine, age, sex, country, and cannabis use.

RESULTS

Compared with no vaping/smoking, exclusive vaping was associated with similar exposure to acrolein and acrylonitrile but higher exposure to toluene (P = 0.04) and acrylamide (P = 0.034, only in sensitivity analysis using past 24-hour measure). Compared with dual use or exclusive smoking, exclusive vaping was associated with lower exposure to NNK, acrolein, acrylamide, and acrylonitrile (P ≤ 0.01) but higher toluene exposure than dual use (P = 0.012). Exposure was similar for dual-use and exclusive smoking. Benzene and xylene biomarkers were detected in <5% and not compared. Among those smoking, NNK exposure was higher in the United States (geometric mean = 25.4 pg/mg creatinine) versus Canada (16.1 pg/mg; P = 0.006) and England (14.1 pg/mg; P = 0.018).

CONCLUSIONS

Youth exclusively vaping had similar exposure as no vaping/smoking except for two volatile organic compounds and lower exposure than smoking or dual use except toluene. Higher NNK levels among US youth who smoke likely reflect differences in tobacco blend.

IMPACT

Findings are generally consistent with literature indicating lower toxicant exposure from vaping versus smoking but elevated exposure versus no use for some.

Assessing the Italian version of the respiratory symptom experience scale (IT-RSES) in smokers and former smokers: a validation study

BACKGROUND

Smoking causes respiratory symptoms, and research suggests these improve with cessation or switching to less harmful nicotine products. The Respiratory Symptom Experience Scale (RSES) was developed and validated for the purpose of assessing these such symptoms online in an English-speaking American sample. This study aimed to develop and validate an Italian version, the IT-RSES, administered via telephone interview, and, further, to use it to assess symptoms in smokers who had switched to e-cigarettes or to heated tobacco products (HTPs).

METHODS

After translation into Italian, the IT-RSES was administered by phone interview to 750 Italian participants in 5 tobacco use groups (150 each never-smokers, former smokers not using alternative products, HTP users, e-cigarette users, and continuing smokers) who also reported any history of diagnoses with relevant medical conditions. Psychometric analyses examined scale factor structure, reliability, and convergent validity. Analyses controlling for age and for years smoking compared symptoms across tobacco use groups.

RESULTS

Factor analyses confirmed the IT-RSES' unidimensionality (factor one accounting for 74.2% of the variance; all factor loadings > 0.80). Internal-consistency reliability was high ( Cronbach's alpha = 0.91). IT-RSES scores correlated significantly with years of smoking (r = 0.51, p < 0.0001), and were higher in individuals with respiratory conditions (2.02 vs. 1.36, SE = 0.05, significant by THSD). Discriminant validity was demonstrated by higher scores in smokers compared to never-smokers, even among those without respiratory conditions. After adjustment for years of smoking, former smokers, HTP users and e-cigarette users had lower scores than smokers (m = 2.17 vs. 1.49, SE = 0.06, p < 0.05, THSD; 1.63 vs. 2.16, SE = 0.06, THSD) and did not significantly differ from each other.

CONCLUSIONS

The results support the reliability and validity of the IT-RSES, suggesting its utility for assessing respiratory symptoms in smokers, and former smoker who stopped smoking and were using e-cigarettes or HTPs. The scores of former smokers are similar to those not using these products, and lower than smokers', suggests that HTPs and e-cigarettes do not add materially to respiratory symptoms when smokers stop smoking.

Quantification of 16 Metals in Fluids and Aerosols From Ultrasonic Pod-Style Cigarettes and Comparison to Electronic Cigarettes

BACKGROUND

Electronic cigarette (e-cigarette) fluids and aerosols contain metals, which can be detrimental to human health. Recently marketed ultrasonic cigarettes (u-cigarettes) claim to be less harmful than e-cigarettes, which use heating coils.

OBJECTIVES

We quantified chemical elements/metals in multiple flavors of SURGE u-cigarettes, JUUL e-cigarettes, and "Other Brands" of pod-style e-cigarettes.

METHODS

Elements/metals were identified in atomizers of SURGE using a scanning electron microscope and energy-dispersive X-ray spectrometer. Quantitation of elements/metals in fluids and aerosols from SURGE, JUUL, and "Other Brands" was performed using inductively coupled plasma optical emission spectroscopy.

RESULTS

U-cigarettes contained a sonicator, unlike e-cigarettes, which had heated coils. Sixteen elements were identified in at least one fluid or aerosol sample. Generally, u-cigarette fluids and aerosols had more elements/metals at higher concentrations than aerosols from fourth-generation e-cigarettes. Element concentrations generally increased in fluids after vaping. All products, including SURGE, had silicon in their fluids and aerosols. Nickel, which was present in low concentrations in all fluids except KWIT Stick (up to 66,050 μ g / mL ), transferred to the aerosols with low efficiency. SURGE, but not e-cigarettes, also had copper and zinc in their fluids, but little transferred to their aerosols. SURGE fluids and aerosols, unlike e-cigarettes, had relatively high concentrations of arsenic and selenium. Arsenic and selenium, which are on the US Food and Drug Administration list of "Harmful and Potentially Harmful Constituents," likely came from poor quality solvents used to produce the e-fluids in SURGE pods and possibly from the sonicator, which heats during use.

DISCUSSION

SURGE u-cigarettes produce aerosols with metals equivalent to heated coil-style e-cigarettes and had high levels of arsenic and selenium, which are a health concern. Regulations limiting arsenic and selenium in these products are needed, and routine surveillance to identify rogue products, such as KWIT Stick, which have abnormally high levels of nickel or other metals, could protect human health. https://doi.org/10.1289/EHP15648.

Stability of Flavoring Chemicals in e-Cigarette Liquids: A Naturalistic Product Aging Study over 24 months

Flavoring chemicals commonly used in many consumer products, including pharmaceuticals, foods, and beverages, deteriorate over time. Flavoring chemicals are also common additives in e-cigarette liquid formulations, but their stability in vaping products has not been evaluated. Since e-cigarette liquids are exposed to varying environmental conditions during storage and use, we assessed the stabilities of 20 flavoring chemicals commonly used in vaping products, including benzaldehyde (cherry flavor), menthol (cooling flavor), and vanillin (vanilla flavor). We prepared reference e-cigarette liquids (reference solutions) containing individual flavorings and a mixed liquid with combined flavorings in a 55:45 (v/v) propylene glycol to vegetable glycerin solution. We also purchased 14 commercial e-cigarette liquids. Liquids were stored over 24 months in different temperatures (room and cold) and light exposure conditions (ambient light and dark). Gas chromatography/mass spectrometry techniques were used to measure the concentration of each flavoring chemical at the baseline and after 1, 3, 6, 12, and 24 months. We used a nontargeted approach to identify potential degradation byproducts. Using an air-liquid interface with bronchial epithelial cells and the Neutral Red assay, we also compared the cytotoxicity of selected reference solutions vaped at the baseline and after storage over 24 months. The flavorings in reference solutions stored at ambient temperature and exposed to light were the least stable. Reducing exposure to light and storing reference solutions in cold temperatures delayed the degradation of some flavorings. Tentatively identified byproducts of flavoring degradation found in unstable reference solutions suggested oxidation, hydrolysis, and condensation reactions with solvents. Despite substantial changes in the chemical composition, no significant cytotoxicity differences were detected between fresh and aged reference solutions. Our findings suggest that storing vaping products in dark places and at cold temperatures improves the stability of flavorings in e-cigarette liquids.

Electronic Cigarette-Derived Metals: Exposure and Health Risks in Vapers

Despite the popularity of electronic cigarettes (e-cigs) among adolescent and youth never-smokers and adult smokers seeking a less harmful substitute for tobacco cigarettes, the long-term health impact of vaping is largely unknown. Biochemical, molecular, and toxicological analyses of biospecimens from e-cig users as well as assays in relevant in vitro models and in silico studies can identify chemical constituents of e-cig emissions that may contribute to the disease-causing potential of vaping. E-cig aerosol contains a wide range of toxic and carcinogenic compounds, of which metals are of particular concern. This is due to the known or suspected role of various metals in the pathogenesis of numerous diseases. Many metals and metalloids (herein referred to as "metals") have been detected in e-cig liquid (e-liquid) and aerosol and/or in cells, tissues, biofluids, or other specimens from e-cig users. Metals can contaminate the ingredients of e-liquid or corrode from the internal components of the e-cig device. Metals may also be directly aerosolized from the surface of the heating element or other parts of the device. Inhalation of e-cig metal emissions in habitual vapers and nonusers through secondary exposure may increase the body burden of toxic and carcinogenic chemicals. This review summarizes the state of research on e-cig-derived metals and their contributions to the estimated health risks of vaping. Highlighting the chemical composition of e-cig liquid and aerosol, it focuses on the metal contents of the inhaled aerosol and the health risks associated with this exposure. Emphasis is placed on adolescents and youth who are vulnerable populations and bear a disproportionate burden of risk and harm from tobacco products. The gaps in knowledge, methodological challenges, and opportunities ahead are discussed. The importance of translating research findings into actionable information that can be used for the regulation of the manufacturing of tobacco products is underscored.

Vaping and Smoking Cessation

BACKGROUND

Electronic cigarettes (e-cigarettes) or vaping address a significant unmet need for traditional smokers who are endeavoring to quit this practice.

OBJECTIVES

We conducted an extensive PubMed search to review the studies involving e-cigarettes as an ostensibly healthier alternative to cigarette smoking and an approach to smoking cessation.

RESULTS

E-cigarettes are potentially carcinogenic, may confer severe cardiopulmonary symptoms and are inconclusively effective at occasioning smoking cessation; hence, consumers should be circumspect when considering this inhalation practice, especially vulnerable populations (e.g., teenagers and young adults) who may exhibit a greater proclivity to adopting this lifestyle choice.

CONCLUSIONS

Since the smoking cessation results are equivocal and the long-term safety and addictive nature of nicotine-containing e-cigarettes remain concerning, the use of e-cigarettes should be inadvisable until proven otherwise.

Prevalence, Knowledge, Attitudes, and Perceptions About E-Cigarette Smoking Among Students in the Dental Fields in Jordan

Introduction: Tobacco use is common in Jordan, with electronic cigarettes (e-cigarettes) becoming more prevalent, especially among the youth. Despite this trend, very few studies have been conducted on e-cigarette use among dental students, who should be more informed about the consequences of e-cigarette use on oral health. This study aimed at assessing the prevalence, knowledge, attitude, and perception of e-cigarette smoking among Jordanian dental students with respect to its effects on oral health. Methods: The study utilized a cross-sectional survey method and used a convenient sampling approach. The study included 645 students from Dentistry Schools in Jordan. Results: The most popular smoking type among participants was waterpipe. A total of 16% of students reported smoking e-cigarettes. The majority of e-cigarette users reported initiation of smoking at 17-18 years of age. Most users thought that e-cigarettes are less harmful compared to regular cigarettes, while 87% of them acknowledged the addictive nature of the product. Students demonstrated good awareness of the deleterious effects of e-cigarettes on oral health, and two-thirds of them expressed concern about its effects on general health. Conclusions: The prevalence of e-cigarette smoking among dental students in Jordan is high and necessitates health education programs to increase awareness of the associated health risks among young adults, specifically in educational settings.

Cross-sectional study on smoking types and stroke risk: development of a predictive model for identifying stroke risk

Background

Stroke, a major global health concern, is responsible for high mortality and long-term disabilities. With the aging population and increasing prevalence of risk factors, its incidence is on the rise. Existing risk assessment tools have limitations, and there is a pressing need for more accurate and personalized stroke risk prediction models. Smoking, a significant modifiable risk factor, has not been comprehensively examined in current models regarding different smoking types.

Methods

Data were sourced from the 2015-2018 National Health and Nutrition Examination Survey (NHANES) and the 2020-2021 Behavioral Risk Factor Surveillance System (BRFSS). Tobacco use (including combustible cigarettes and e-cigarettes) and stroke history were obtained through questionnaires. Participants were divided into four subgroups: non-smokers, exclusive combustible cigarette users, exclusive e-cigarette users, and dual users. Covariates such as age, sex, race, education, and health conditions were also collected. Multivariate logistic regression was used to analyze the relationship between smoking and stroke. Four machine-learning models (XGBoost, logistic regression, Random Forest, and Gaussian Naive Bayes) were evaluated using the area under the receiver-operating characteristic curve (AUC), and Shapley's additive interpretation method was applied for feature importance ranking and model interpretation.

Results

A total of 273,028 individuals were included in the study. Exclusive combustible cigarette users had an elevated stroke risk (β: 1.36, 95% CI: 1.26-1.47, P < 0.0001). Among the four machine-learning models, the XGBoost model showed the best discriminative ability with an AUC of 0.794 (95% CI = 0.787-0.802).

Conclusion

This study reveals a significant association between smoking types and stroke risk. An XGBoost-based stroke prediction model was established, which has the potential to improve the accuracy of stroke risk assessment and contribute to personalized interventions for stroke prevention, thus alleviating the healthcare burden related to stroke.

Menthol, a consumer product additive, adversely affects human embryonic stem cells via activation of TRPM8 and TRPA1 channels

Many electronic cigarettes (ECs) contain high concentrations of menthol. The effect of menthol on human embryos in pregnant women who vape is not well understood. Human embryonic stem cells (hESCs) (an epiblast model) were used to test the hypothesis that 6.4-640 nM and 19.2-192 µM menthol, which activates TRP (transient-receptor-potential) channels, alters calcium homeostasis in embryos and adversely affects processes that are critical to gastrulation. Micromolar concentrations of menthol inhibited mitochondrial reductase activity in hESCs, an effect that was blocked by TRPA1 and TRPM8 inhibitors. Pulsatile exposure to menthol elevated intracellular calcium primarily by activating TRPA1 channels at nanomolar concentrations and TRPM8 channels at µM concentrations. nM menthol significantly inhibited colony growth by activating TRPA1 channels, while both TRPA1 and TRPM8 were activated by µM menthol. Inhibition of colony growth was attributed to cell death induced by menthol activation of TRPA1 and TRPM8 channels. nM menthol altered colony phenotype by increasing the major/minor axis ratio via TRPA1 and TRPM8 channels. Both nM and µM menthol induced alterations in hESC colony motility, an effect that was blocked only by the TRPM8 inhibitor. The menthol-induced increase in intracellular calcium adversely influenced growth, death, and migration, processes that are critical in gastrulation. Menthol concentrations that reach embryos in women who vape are high enough to activate TRPA1 and TRPM8 channels and perturbed calcium homeostasis. Pregnant women who vape likely expose their embryos to menthol concentrations that are harmful. These data could help prevent birth defects or embryo/fetal death.

Associations between vaping during pregnancy and perinatal outcomes: A systematic review and meta-analysis

Despite numerous studies linking prenatal vaping to adverse perinatal outcomes, a systematic assessment for critical comparison remains absent. To investigate these associations, we conducted a systematic search of studies assessing perinatal outcomes in mothers and/or neonates exposed to vaping during pregnancy compared to those in women without prenatal vaping exposure through MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Library, PROSPERO, and Google Scholar until July 5, 2024. We performed inverse-variance random-effects meta-analyses for maternal and neonatal outcomes of 23 studies with a total of 924,376 participants with 7552 reporting vaping-only use during pregnancy. Prenatal vaping was associated with 53 % higher odds of an adverse maternal outcome (OR: 1.53; 95 % CI: 1.27-1.85; I2 = 80 %), particularly with decreased breastfeeding (OR: 0.53; 95 % CI: 0.38-0.72; I2 = 45 %) and reduced prevalence of adequate prenatal care (OR: 0.69; 95 % CI: 0.56-0.86; I2 = 82 %). Prenatal vaping was also associated with a similarly 53 % higher odds of an adverse neonatal outcome (OR: 1.53; 95 % CI: 1.34-1.76; I2 = 45 %), such as low birth weight (OR: 1.56; 95 % CI: 1.28-1.93; I2: 15 %), preterm birth (OR: 1.49; 955 CI: 1.27-1.76; I2: 0 %), and small for gestational age (OR: 1.48; 955 CI: 1.16-1.89; I2: 70 %). This is the first comprehensive systematic review and meta-analysis demonstrating vaping during pregnancy as a risk factor for increased odds of both maternal and neonatal outcomes and underscores the urgency to address awareness and regulations of vaping and its potential harms to both humans and the environment. REGISTRATION: PROSPERO CRD42023446266.

Packaging of disposable vaping products and e-liquids in England, Canada and the United States: A content analysis

BACKGROUND AND AIMS

Vaping product packaging is varied and often features bright colours and novel designs, particularly among recently marketed disposable vapes. This study provides an overview of attributes found on the packaging of popular disposable vapes and e-liquid bottles in England, Canada and the United States (US) and assesses compliance with local packaging regulations.

DESIGN

Content analysis.

SETTING

Brick-and-mortar and online shops in England (London), Canada (Ontario) and the US (New Hampshire and South Carolina).

CASES

108 vaping products (including packaging) from 76 brands in a range of flavours and nicotine levels. Specifically, 48 disposable vapes (15 from England, 16 from Canada, 17 from the US) and 60 e-liquid bottles (20 per country).

MEASUREMENTS

Textual and graphic branding and marketing elements, independently coded by two researchers and checked by a third.

FINDINGS

Compliance with local packaging regulations varied across countries. Health warnings were present on the packaging of all but one nicotine-containing product, although 33% of disposables and 17% of e-liquids featuring the warning did not adhere to formatting requirements. Leaflets were seldom included with e-liquid bottles, even in England (45%) where mandatory, and omitted elsewhere. Labelling of nicotine type and batch numbers was inconsistent. Vaping product packaging featured claims relating to sensory perceptions (41%), most often flavours, and some (32%) featured youth-appealing content. Common graphic elements included stylised brand fonts (80%), brand logos (54%), product representations on the external packaging (47%) and abstract graphic elements (64%). Colours on packaging, disposable vapes and e-liquid bottles were associated with product flavour.

CONCLUSIONS

In England, Canada and the United States, popular disposable vapes and e-liquid bottles appear to have varying compliance with local packaging regulations and inconsistent labelling of nicotine and product characteristics. The use of colourful designs, evocative descriptors and appealing graphics to promote flavours underscores the need for comprehensive packaging regulations and enforcement.

Composition of e-cigarette aerosols: A review and risk assessment of selected compounds

The potential harms and benefits of e-cigarettes, or electronic nicotine delivery systems (ENDS), have received significant attention from public health and regulatory communities. Such products may provide a reduced risk means of nicotine delivery for combustible cigarette smokers while being inappropriately appealing to nicotine naive youth. Numerous authors have examined the chemical complexity of aerosols from various open- and closed-system ENDS. This body of literature is reviewed here, with the risks of ENDS aerosol exposure among users evaluated with a margin of exposure (MoE) approach for two non-carcinogens (methylglyoxal, butyraldehyde) and a cancer risk analysis for the carcinogen N-nitrosonornicotine (NNN). We identified 96 relevant papers, including 17, 13, and 5 reporting data for methylglyoxal, butyraldehyde, and NNN, respectively. Using low-end (minimum aerosol concentration, low ENDS use) and high-end (maximum aerosol concentration, high ENDS use) assumptions, estimated doses for methylglyoxal (1.78 × 10-3-135 μg/kg-bw/day) and butyraldehyde (1.9 × 10-4-66.54 μg/kg-bw/day) corresponded to MoEs of 227-17,200,000 and 271-280,000,000, respectively, using identified points of departure (PoDs). Doses of 9.90 × 10-6-1.99 × 10-4 μg/kg-bw/day NNN corresponded to 1.4-28 surplus cancers per 100,000 ENDS users, relative to a NNN-attributable surplus of 7440 per 100,000 cigarette smokers. It was concluded that methylglyoxal and butyraldehyde in ENDS aerosols, while not innocuous, did not present a significant risk of irritant effects among ENDS users. The carcinogenic risks of NNN in ENDS aerosols were reduced, but not eliminated, relative to concentrations reported in combustible cigarette smoke.

Sample preparation methods for elemental analysis in electronic cigarette aerosols: a critical review

In the last decade, e-cigarettes have been marketed as a less harmful alternative to classical tobacco smoking and are currently being used by millions of people. An e-cigarette consists of an e-liquid and a heating device, generating an aerosol that the user can inhale. Recently, several studies have shown that metals and metalloids, including As, Cd, and Pb, known carcinogens, were present in these aerosols. To ensure the accuracy of dose-toxicity estimations, it is essential to have access to reliable and reproducible methods for estimating the dose in question. Although more standardization methodologies were introduced in the analysis of metal(loid)s from aerosols, a huge divergence in sample preparation can be found in the literature. This work aimed to provide an overview of the sample preparation methods used to quantify these metal(loid)s. Therefore, a literature search was conducted in September 2024, that followed the PRISMA guidelines. Among the 48 articles selected, a wide variability in sample preparation was observed, specifically variations in aerosol generation characteristics and collection techniques. Despite the widespread use of methods as filters and impingers, many studies failed to validate critical steps such as aerosol recovery, blank corrections, and the extent of matrix effects. In addition, poor inorganic methodological practices were often applied, such as excessive use of glass materials for aerosol collection or other sample preparation steps. Therefore, further standardization of methodologies is urgently needed to improve the reliability of metal quantification in e-cigarette aerosols, which could potentially enhance regulatory frameworks and facilitate the routine analysis of e-cigarette emissions.

Impact of E-Cigarettes on Fetal and Neonatal Lung Development: The Influence of Oxidative Stress and Inflammation

Electronic cigarettes (e-cigs) recently increased their popularity as "safer" alternatives to traditional tobacco smoking, including among pregnant women. However, the effect of e-cig exposure on fetal and neonatal developing lungs remains poorly investigated. In this review, we analysed the impact of e-cig aerosol components (e.g., nicotine, solvents, and flavouring agents) on respiratory system development. We particularly emphasized the role of e-cig-related oxidative stress and inflammation on lung impairment. Nicotine contained in e-cigs can impair lung development at anatomical and molecular levels. Solvents and flavours induce inflammation and oxidative stress and contribute to compromising neonatal lung function. Studies suggest that prenatal e-cig aerosol exposure may increase the risk of future development of respiratory diseases in offspring, such as asthma and chronic obstructive pulmonary disease (COPD). Preventive strategies, such as smoking cessation programs and antioxidant supplementation, may be essential for safeguarding respiratory health. There is an urgent need to explore the safety profile and potential risks of e-cigs, especially considering the limited studies in humans. This review highlights the necessity of regulating e-cig use during pregnancy and promoting awareness of its potential consequences on fetal and neonatal development.

Evaluation and Comparison of Capillary Morphology Among Combusted Tobacco, Heated Tobacco and E-Cigarette Users

The habit of smoking in its various forms represents a significant public health concern due to its wide range of pathological effects, included the oral cavity. In recent years, alternatives to traditional cigarettes, such as heated tobacco products and electronic cigarettes, have gained popularity and are often marketed as potentially less harmful options. This study seeks to evaluate and compare the morphometric characteristics of oral mucosal capillaries in individuals who consume combusted tobacco, heated tobacco, vaporized liquid, and non-smokers. Using videocapillaroscopy, we assessed both parametric and non-parametric data from 60 patients, divided into four groups according to their smoking habits. The analysis revealed significant differences in capillary morphology among the groups. Users of combusted tobacco exhibited pronounced reductions in capillary diameter, alongside increased tortuosity and the presence of microaneurysms. These alterations are indicative of chronic inflammation and vasoconstriction, likely driven by exposure to nicotine and the high temperatures associated with combustion. Conversely, users of heated tobacco and vaporized liquid exhibited comparatively fewer vascular abnormalities, although angiogenic effects attributable to nicotine were still observable. These findings suggest that alternative tobacco products may have a comparatively lesser impact on the oral microcirculation when compared to traditional smoking. However, the potential long-term effects of these products remain unclear. Further longitudinal research is required to fully understand the risks associated with prolonged use of heated tobacco and electronic cigarettes.

Perception of Health Risks of Electronic Cigarette Use Among College Students: Examining the Roles of Sex, Field of Study, Vaping Device Type, and Their Associations

Electronic cigarettes are marketed as a safer alternative to regular (combustible) cigarettes, based on the claim that there is no tobacco burning and fewer toxic chemicals in their vapor. However, recent evidence challenges the notion that e-cigarette aerosols are benign. Heating of compounds in e-liquids to high temperatures can lead to the release of toxic compounds in e-cigarette aerosols. However, users and the public may not be aware of these unique harms, impacting their perception of harm from using e-cigarettes. This research explored the perceptions of harm of e-cigarettes compared to regular cigarettes among 418 college students, aged 18-34, by employing a Qualtrics based smartphone survey. The findings revealed a vaping prevalence of 16.7% among our study population, indicating e-cigarette use among college aged young adults is at concerning levels. Perceptions of harm varied significantly by vaping status, sex, and field of study. Non-e-cigarette users and female students were less likely to perceive e-cigarettes as less harmful than regular cigarettes. Among e-cigarette users (vapers), male vapers and users of pod-type devices, such as JUUL and disposables, were more inclined to view e-cigarettes as less harmful. Among vapers, students in non-health-related fields were significantly more likely to perceive e-cigarettes as less harmful than regular cigarettes, underscoring the impact of educational background on health risk awareness. In conclusion, this study provides crucial insights into the varied perceptions of e-cigarettes among young adults. The results emphasize the need for targeted public health interventions and educational efforts to address this growing public health concern.

E-cigarette: a safe tool or a risk factor for oral cancer? A systematic review

Background

Electronic cigarettes (e-cigarettes) are considered relatively safe, thus tobacco and nicotine delivery products have become popular in the last few years. However, the safety of long-term use of these products on oral health is still questionable. E-cigarettes may have potential risks to oral health that can be demonstrated as cellular damage, genetic instability, and mucosal lesions. This review aims to observe the role of e-cigarettes as a risk factor for oral cancer development.

Material and Methods

This systematic review was conducted following the PRISMA guidelines to provide reliable data on the role of electronic cigarettes as a risk factor for oral cancer development. The research was performed on Pubmed and Scopus by three reviewers from the Oral Pathology Department (Sapienza University of Rome) in May 2024. The search terms included: "e-cigarette", "oral cancer", and "risk factor" where 32 articles from PubMed and 75 from Scopus were collected. A total of 12 studies met the eligibility criteria: 6 clinical studies and 6 in vitro. All the included studies were subjected to quality assessment and data extraction processes. The risk of bias assessment of in vitro studies revealed low or unknown risk. None of the studies had any industrial sponsoring and almost all the papers (90%) had the same methods, 64% measured the cell vitality. The qualitative analysis was done for all the included clinical studies using the RoB assessment tool (MINORS). The range of the total RoB score in the comparative studies was between 12 and 23.

Results

The clinical studies involved a total of 413 participants were also included. Most studies did not specify the age and gender of participants and patients were divided into three main groups based on specific criteria: non-smokers, smokers, and e-cigarette users. These studies highlighted cases of mucosal lesions and genetic instability associated with e-cigarette use.

Conclusions

However, the limited long-term data and conflicting results emphasize the need for a larger number of studies, such as randomized controlled trials and cohort studies, to acquire more data about the safety and risks associated with e-cigarettes. Key words:E-cigarettes, squamous cell carcinoma, oral oncology, smoking.

Understanding Potential Mechanisms of Vaping Prevention Messages: A Mediation Analysis of the Real Cost Campaign Advertisements

The U.S. Food and Drug Administration (FDA) developed a public education campaign, The Real Cost, that reduced youth susceptibility to tobacco product use. We sought to identify the mechanisms that may underlie the impact of The Real Cost ads on susceptibility to vaping to inform youth tobacco prevention campaigns. Our online randomized controlled trial (clinicaltrials.gov, identifier NCT04836455) examined a large sample of U.S. adolescents (n = 1,348) who had multiple exposures to Real Cost ads or control videos over a 3-week period in 2021. To examine potential mediating pathways between The Real Cost ads and susceptibility to vaping, we examined theory-based psychosocial and message-related variables. The largest impact of The Real Cost ads on susceptibility was via more negative attitudes toward vaping (βa*βb = -0.16; 95% confidence interval [CI] = [-0.25, -0.06]). Other mediation paths were via improved health harm risk beliefs (βa*βb = -0.08; 95% CI = [-0.13, -0.04]), addiction risk beliefs (βa*βb = -0.04; 95% CI = [-0.06, -0.01]), injunctive norms against vaping (βa*βb = -0.05; 95% CI = [-0.09, -0.02]), negative affect (βa*βb = -0.05; 95% CI = [-0.08, -0.02]), and cognitive elaboration (βa*βb = -0.03; 95% CI = [-0.05, -0.003]). Our findings suggest that ads that target negative attitudes may decrease susceptibility to vaping among youth. Our findings also introduce normative pressure as a novel factor that may be important for vaping prevention messages.

E-Cigarette effects on oral health: A molecular perspective

Electronic cigarettes (e-cigarettes) have emerged as a potential alternative to traditional smoking and may aid in tobacco harm reduction and smoking cessation. E-cigarette use has notably increased, especially among young non-tobacco users, raising concerns due to the unknown long-term health effects. The oral cavity is the first and one of the most crucial anatomical sites for the deposition of e-cigarette aerosols. E-cigarette aerosols contain nicotine, flavors, volatile organic compounds, heavy metals, carcinogens, and other hazardous substances. These aerosols impact the oral cavity, disrupting host-microbial interactions and triggering gingivitis and systemic diseases. Furthermore, oral inflammation and periodontitis can be caused by proinflammatory cytokines induced by e-cigarette aerosols. The toxic components of e-cigarette aerosols increase the cellular reactive oxygen species (ROS) levels, reduce antioxidant capacity, increase DNA damage, and disrupt repair processes, which may further contribute to harmful effects on oral epithelum, leading to inflammatory and pre-malignant oral epithelial lesions. In this review, we analyze the toxicological properties of compounds in e-cigarette aerosols, exploring their cytotoxic, genotoxic, and inflammatory effects on oral health and delving into the underlying molecular mechanisms. Further research is essential to understand the impact of e-cigarettes on oral health and make informed regulatory decisions based on reliable scientific evidence.

The use of the model organism Caenorhabditis elegans in the investigation of the adverse effects of electronic cigarettes

The use of tobacco products is one of the most preventable risk factors for mortality from a variety of diseases, including cardiovascular, infectious, respiratory, and neoplastic conditions. The use of electronic cigarettes (ECIGs), also known as electronic nicotine delivery devices, has increased significantly in recent years. Nicotine, propylene glycol, and / or glycerine, water, alcohol, flavorings, and other substances are among the many chemicals found in ECIGs that are vaporized and inhaled. A review of the existing literature shows that research dedicated to ECIGs is a rapidly developing and growing field of study. The rationale for the use of ECIGs is that they represent a safer alternative to traditional tobacco products. However, vaping safety profiles are still under development, as this is a relatively recent phenomenon. Various model organisms can be employed to examine the cellular processes that may be altered by exposure to the electronic liquids utilized for vaping. For example, the translucent multicellular eukaryote Caenorhabditis elegans is widely used as a model organism to explain a broad range of biological processes, including aging, stress response, development, and many others. Due to its short lifespan and easy use, C. elegans is an ideal model organism for studying chronic exposure to drugs and environmental toxicology. This review presents a summary of the most recent findings on the impact of electronic cigarettes on the physiological health of this nematode. Preliminary observations made in C. elegans can provide insight into the consequences of exposure to fundamental cellular physiology, which can then be used for future research in humans and mammalian models.

A systematic review on risk factors and reasons for e-cigarette use in adolescents

INTRODUCTION

The aim was to establish EC use risk and protective factors, the reasons for use, associations with tobacco and other substance use, and use for smoking cessation.

METHODS

A systematic review following PRISMA guidelines was registered in PROSPERO (CRD42024532771). Searches in Web of Science and PubMed/MEDLINE (March-April 2024) used terms like 'electronic cigarette' and 'adolescents' with a PICO framework. Inclusion criteria covered studies on adolescents aged 10-19 years, published in English or Spanish (2018-2024). Three reviewers independently screened studies, achieving 96% inter-rater reliability. Data extraction followed standardized tables, and methodological quality was assessed using MMAT and GRADE tools, ensuring a robust evaluation of evidence on adolescent electronic cigarette use.

RESULTS

From 895 studies, 50 met the inclusion criteria. The strongest risk factors for adolescent EC use include social acceptance and use within peer or family circles (13 studies), male gender (10 studies), low risk perception (6 studies), younger age (3 studies), and greater financial resources (3 studies). Motives for use include low perceived risk and appealing flavors, supported by both longitudinal and cross-sectional studies. EC use is significantly associated with smoking initiation (7 studies), cannabis consumption (8 studies), and alcohol use (4 studies). Evidence on the effectiveness of ECs as harm reduction or smoking cessation tools in adolescents remains inconclusive, with some cross-sectional studies supporting their utility and others finding contrary evidence. High-quality research indicates ECs are predominantly used alongside traditional cigarettes, with dual nicotine consumption patterns commonly observed.

CONCLUSIONS

Evidence on adolescent EC use identifies risk factors, motives, and links to substance use. However, its role in harm reduction and smoking cessation remains insufficient and controversial. High-quality research is needed, as most studies are low quality. Targeted prevention strategies addressing social influences, perceptions, and accessibility are crucial to reduce adolescent EC use.

Marketing claims on the websites of leading e-cigarette brands in England

INTRODUCTION

Exposure to electronic cigarette (EC) marketing is associated with EC use, particularly among youth. In England, the Tobacco and Related Products Regulations and Committee of Advertising Practice (CAP) regulate EC marketing to reduce appeal to youth; however, there are little published data on EC marketing claims used online. This study therefore provides an overview of marketing claims present on the websites of EC brands popular in England.

METHODS

From January to February 2022, a content analysis of 10 of England's most popular EC brand websites was conducted, including violation of CAP codes.

RESULTS

Of the 10 websites, all presented ECs as an alternative to smoking, 8 as a smoking cessation aid and 6 as less harmful than smoking. Four websites presented ECs as risk-free. All mentioned product quality, modernity, convenience, sensory experiences and vendor promotions. Nine featured claims about flavours, colours, customisability and nicotine salts. Seven featured claims concerning social benefits, personal identity, sustainability, secondhand smoke and nicotine strength. Six featured claims about fire safety. Some claimed ECs are cheaper than tobacco (n=5), cited health professionals (n=4) or featured collaborations with brands/icons (n=4). All were assessed by the research team to violate one or more CAP code(s) by featuring medicinal claims (n=8), contents which may appeal to non-smokers (n=7), associations with youth culture (n=6), depictions of youth using ECs (n=6) or media targeting youth (n=5).

CONCLUSION

Among 10 top EC brand websites in England, marketing elements that might appeal to youth were commonly identified and CAP code compliance was low.

[Safety of use of electronic cigarettes: A systematic review of bronchopulmonary, cardiovascular and cancer risks]

As the effects of electronic cigarettes (ECs) have rapidly become widely known, we propose to take stock of recent findings on the bronchopulmonary and cardiovascular adverse effects (AEs) and the risks of cancer occurrence entailed by EC use. METHOD: We carried out a search from 2018 to October 19, 2023 on PubMed, adopting the PRISMA guidelines (2020) with the following keywords in "Titles and abstracts": electronic cigarette, or e-cigarette, or ENDS, AND safety or toxicology or effect or health effect, using "Systematic Review" as a filter. The inclusion criteria were: systematic review of in vitro or in vivo studies in English or French dealing with the risks of ECs for the bronchopulmonary system, the cardiovascular system, or cancer occurrence. CONCLUSION: Twenty-eight systematic reviews on the adverse effects (AE) of electronic cigarettes (EC) in selected humans show that the toxic substances they generate can cause cancers and increase the risk of cardiac and pulmonary disorders. New studies on the potential dangerousness of EC use are essential and urgent.

Multi-Omics Assessment of Puff Volume-Mediated Salivary Biomarkers of Metal Exposure and Oxidative Injury Associated with Electronic Nicotine Delivery Systems

BACKGROUND

Since their inception, electronic nicotine delivery systems (ENDS) have gained increasing popularity, sparking a vaping epidemic among adolescents in the US and globally. Several ENDS safety concerns have emerged as device features and formats that contribute to heavy metal exposure and toxicity continue to evolve and outpace regulatory efforts.

OBJECTIVES

Our objective was to integrate ENDS emission profiles with salivary proteome and metabolome data to characterize exposure factors that may influence adverse vaping-mediated health outcomes.

METHODS

A total of 56 participants (38 exclusive ENDS users and 18 non-ENDS users) were recruited. A subset of 15 exclusive ENDS users completed puffing topography assessments to obtain individual vaping behavior patterns using each participant's ENDS device. Inductively coupled plasma mass spectrometry was used to determine the metal content of emissions (12 ENDS devices) generated using a programmable ENDS aerosol generation system and saliva (15 exclusive ENDS users and 5 non-ENDS users). Saliva samples from 10 exclusive ENDS users and 5 non-ENDS users were analyzed for proteomic, metabolomic, inflammatory, and oxidative stress/damage biomarkers.

RESULTS

A linear puff volume-dependent increase in particle emissions and heavy metals was observed in ENDS aerosols and saliva of exclusive ENDS users. Elevated puff volume-dependent levels of salivary cytokines, including tumor necrosis factor-alpha (TNFα ), interleukin-1 beta (IL-1β ), and IL-6, were observed alongside the oxidative damage indicators malondialdehyde (MDA), superoxide dismutase (SOD), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Proteome-metabolome network analysis showed a higher risk of potentially developing neurological and respiratory diseases in ENDS users compared with non-ENDS users. Integrated salivary proteome-metabolome-metallome network analysis further demonstrated that heavy metals were associated with proteomic and metabolomic perturbations, with notable alterations in inflammatory response, immune function, and disease-related pathways.

DISCUSSION

A significant correlation between heavy metals, cytokines, and oxidative stress markers reveals a potential role of vaping behavior in exposure to metals and changes in markers associated with DNA damage and inflammation. Our study demonstrates the importance of characterizing vaping behavior and puffing topography when examining the human health implications of ENDS use. https://doi.org/10.1289/EHP14321.

E-cigarettes and arterial health: A review of the link between vaping and atherosclerosis progression

Recent studies have suggested an evolving understanding of the association between vaping, specifically electronic cigarette (e-cigarette) use, and the progression of atherosclerosis, a significant contributor to cardiovascular disease. Despite the prevailing perception of vaping as a safer alternative to traditional tobacco smoking, accumulating evidence suggests that the aerosols emitted by e-cigarettes contain harmful constituents that may promote endothelial dysfunction, oxidative stress, inflammation, and dyslipidemia-key mechanisms implicated in atherosclerosis pathogenesis. While past research, including experimental studies and clinical investigations, has shed light on the potential cardiovascular risks associated with vaping, gaps in knowledge persist. Future research endeavors should focus on interpreting the long-term effects of vaping on atherosclerosis development and progression, exploring the impact of different e-cigarette formulations and user demographics, and identifying effective strategies for mitigating the cardiovascular consequences of vaping. By identifying and addressing these research gaps, we can enhance our understanding of the cardiovascular implications of vaping and inform evidence-based interventions and policies to safeguard public health.

The Impact of E-Cigarettes on Oral Health-A Narrative Review

Background/Objectives: Electronic cigarettes (e-cigarettes) are commonly used by former smokers as an alternative product to conventional cigarettes and also by young adults and adolescents to deliver nicotine. E-cigarettes are thought to be a less harmful and more socially acceptable alternative to tobacco smoking; however, their long-term effects on health, including oral health, are currently unknown. Methods: A literature search for relevant papers indexed in the literature from 2016 to 2023 was conducted using the PubMed, Scopus, and Google Scholar databases. In our paper, we included clinical trials and both in vivo and in vitro research concerning the impact of e-cigarettes on oral health. Results: E-cigarettes impact the oral cavity, which is directly exposed to inhaled chemicals present in e-cigarette aerosols. The use of e-cigarettes has been linked to teeth discoloration and dental caries, promoting the development of periodontal diseases and causing oral mucosa lesions, including oral cancer. E-cigarette aerosols might also negatively affect the oral microbiome by suppressing the growth of commensal bacteria and increasing the population of bacteria responsible for developing numerous oral disorders. E-cigarettes also impact saliva composition and its properties, including reducing saliva's antibacterial and antioxidant properties, which may subsequently lead to the promotion of oral diseases. Conclusions: The outcomes suggest that e-cigarette usage may cause the development of oral diseases, however further longitudinal studies of a larger and homogenous group of e-cigarette users are required.

E-cigarette flavoring chemicals and vehicles adversely impact the functions of pigmented human retinal ARPE-19 cells

Electronic cigarettes (ECs) have been shown to adversely impact the human eye's retinal pigment epithelium (RPE). Flavored e-liquids induced cytotoxicity in unpigmented human ARPE-19 cells independent of nicotine's presence in my previous study. In the current study, human ARPE-19 cells pigmented by sepia melanin were employed to examine the effects of four flavoring chemicals, vanillin, menthol, furanone, and cinnamaldehyde, and EC vehicles propylene glycol (PG)/vegetable glycerin (VG) ratios (0:100, 80:20, 100:0 % v/v), on metabolic activity, membrane integrity, oxidative stress, and wound healing capacity of these cells. Results demonstrate that cinnamaldehyde was the most cytotoxic flavoring, and all vehicles showed marked cytotoxicity at the highest concentration of 10 %. All four flavorings elicited a significant production of reactive oxygen species (ROS), while the three vehicles did not impact ROS levels. Vanillin significantly (p < 0.05) suppressed wound healing, while furanone and cinnamaldehyde had no effects, although menthol promoted wound healing at the lowest concentration. Moreover, the vehicles with two ratios of 0:100 PG/VG and 80:20 PG/VG suppressed wound healing. Together, these results suggest that vanillin and VG-containing vehicles exert the greatest adverse effects on ARPE-19 cells. These findings underscore the potential harm that exposure to ECs can cause to the human retina.

Variations in Adverse Events Typology Following E-Cigarette Use: The Role of Preexisting Medical Conditions

BACKGROUND

Electronic cigarettes (e-cigarettes) are often marketed as safer alternatives to traditional smoking, yet evidence suggests potential health risks, especially among vulnerable populations. This study examines the immediate adverse events following e-cigarette use in individuals with preexisting health conditions to better understand these risks.

METHODS

We conducted a STROBE-compliant observational study to identify specific preexisting medical conditions that may increase the risk of adverse events following e-cigarette use. A cross-sectional survey was deployed from January 3rd to March 3rd, 2023. A total of 4695 current and former e-cigarette users completed the survey. Logistic regression models were utilized to examine associations between 23 distinct preexisting conditions and 48 adverse events, adjusting for age, sex, race/ethnicity, education level, and income.

RESULTS

The analysis encompassed 4,421 respondents, demonstrating that individuals with solid organ transplants faced notably pronounced risks, with odds ratios indicating a seven-fold increase in mouth/tongue blisters (OR = 7.05), nearly five-fold for heart palpitations (OR = 4.92), and heartburn (OR = 4.79). Stem cell transplantation recipients also showed significantly heightened risks for similar adverse events, including mouth/tongue blisters (OR = 5.53) and heart palpitations (OR = 4.65). Metabolic diseases were linked to substantially increased odds of mouth/tongue blisters (OR = 5.63), hair loss (OR = 4.09), and migraine (OR = 3.50), highlighting a specific vulnerability to e-cigarette aerosol exposure among these groups.

CONCLUSION

The findings highlight the acute health risks associated with e-cigarette use in individuals with certain preexisting conditions. These results challenge the notion that e-cigarette use poses limited harm to human health and highlight the need for tailored public health strategies to protect vulnerable populations.

Quantification of Size-Binned Particulate Matter in Electronic Cigarette Aerosols Using Multi-Spectral Optical Sensing and Machine Learning

To monitor health risks associated with vaping, we introduce a multi-spectral optical sensor powered by machine learning for real-time characterization of electronic cigarette aerosols. The sensor can accurately measure the mass of particulate matter (PM) in specific particle size channels, providing essential information for estimating lung deposition of vaping aerosols. For the sensor's input, wavelength-specific optical attenuation signals are acquired for three separate wavelengths in the ultraviolet, red, and near-infrared range, and the inhalation pressure is collected from a pressure sensor. The sensor's outputs are PM mass in three size bins, specified as 100-300 nm, 300-600 nm, and 600-1000 nm. Reference measurements of electronic cigarette aerosols, obtained using a custom vaping machine and a scanning mobility particle sizer, provided the ground truth for size-binned PM mass. A lightweight two-layer feedforward neural network was trained using datasets acquired from a wide range of puffing conditions. The performance of the neural network was tested using unseen data collected using new combinations of puffing conditions. The model-predicted values matched closely with the ground truth, and the accuracy reached 81-87% for PM mass in three size bins. Given the sensor's straightforward optical configuration and the direct collection of signals from undiluted vaping aerosols, the achieved accuracy is notably significant and sufficiently reliable for point-of-interest sensing of vaping aerosols. To the best of our knowledge, this work represents the first instance where machine learning has been applied to directly characterize high-concentration undiluted electronic cigarette aerosols. Our sensor holds great promise in tracking electronic cigarette users' puff topography with quantification of size-binned PM mass, to support long-term personalized health and wellness.

A Review of the Toxicity of Ingredients in e-Cigarettes, Including Those Ingredients Having the FDA's "Generally Recognized as Safe (GRAS)" Regulatory Status for Use in Food

Some firms and marketers of electronic cigarettes (e-cigarettes; a type of electronic nicotine delivery system (ENDS)) and refill liquids (e-liquids) have made claims about the safety of ingredients used in their products based on the term "GRAS or Generally Recognized As Safe" (GRAS). However, GRAS is a provision within the definition of a food additive under section 201(s) (21 U.S.C. 321(s)) of the U.S. Federal Food Drug and Cosmetic Act (FD&C Act). Food additives and GRAS substances are by the FD&C Act definition intended for use in food, thus safety is based on oral consumption; the term GRAS cannot serve as an indicator of the toxicity of e-cigarette ingredients when aerosolized and inhaled (ie, vaped). There is no legal or scientific support for labeling e-cigarette product ingredients as "GRAS." This review discusses our concerns with the GRAS provision being applied to e-cigarette products and provides examples of chemical compounds that have been used as food ingredients but have been shown to lead to adverse health effects when inhaled. The review provides scientific insight into the toxicological evaluation of e-liquid ingredients and their aerosols to help determine the potential respiratory risks associated with their use in e-cigarettes.

Coverage of Indoor Smoking and Vaping Restrictions in the U.S., 1990-2021

INTRODUCTION

Secondhand smoke exposure increases the risk of premature death and disease in children and non-smoking adults. As a result, many U.S. states and local jurisdictions have enacted comprehensive indoor smoking restrictions (ISR). Indoor vaping restrictions (IVR) have also been adopted to protect against exposure to secondhand e-cigarette aerosol. This study aimed to quantify state and national U.S. coverage of policies restricting indoor cigarette and e-cigarette use over time.

METHODS

Data from the American Nonsmokers Rights' Foundation on U.S. ISR from 1990 to 2021 and IVR from 2006 to 2021 were analyzed. Combining these data with 2015 U.S. Census population estimates, the percentage of state and national residents covered by partial and comprehensive restrictions in bars, restaurants, and workplaces, were calculated (analysis in 2023-2024) over time.

RESULTS

Between 1990 and 2021, national coverage of comprehensive ISR increased for bars (0% to 67.3%), restaurants (0%-78.2%), and workplaces (0%-77.5%). Partial ISR coverage decreased for bars (14.8%-13.9%), restaurants (40.2%-15.4%) and workplaces (40.2%-22.5%). From 2006 to 2021, comprehensive IVR coverage increased for bars (0%-43.5%), restaurants (0%-51.5%), and workplaces (0%-53.2%). Despite these increases in coverage, by the end of 2021, <50% of the population was protected by comprehensive ISR for bars, restaurants, and workplaces in 19, 12, and 14 states, respectively.

DISCUSSION

The percentage of the U.S. population protected by ISR and IVR has increased over time. However, gaps in coverage remain, which may contribute to disparities in tobacco-related disease and death.

Nicotine interacts with DNA lesions induced by alpha radiation which may contribute to erroneous repair in human lung epithelial cells

PURPOSE

Epidemiological studies show that radon and cigarette smoke interact in inducing lung cancer, but the contribution of nicotine in response to alpha radiation emitted by radon is not well understood.

MATERIALS AND METHODS

Bronchial epithelial BEAS-2B cells were either pre-treated with 2 µM nicotine during 16 h, exposed to radiation, or the combination. DNA damage, cellular and chromosomal alterations, oxidative stress as well as inflammatory responses were assessed to investigate the role of nicotine in modulating responses.

RESULTS

Less γH2AX foci were detected at 1 h after alpha radiation exposure (1-2 Gy) in the combination group versus alpha radiation alone, whereas nicotine alone had no effect. Comet assay showed less DNA breaks already just after combined exposure, supported by reduced p-ATM, p-DNA-PK, p-p53 and RAD51 at 1 h, compared to alpha radiation alone. Yet the frequency of translocations was higher in the combination group at 27 h after irradiation. Although nicotine did not alter G2 arrest at 24 h, it assisted in cell cycle progression at 48 h post radiation. A slightly faster recovery was indicated in the combination group based on cell viability kinetics and viable cell counts, and significantly using colony formation assay. Pan-histone acetyl transferase inhibition using PU139 blocked the reduction in p-p53 and γH2AX activation, suggesting a role for nicotine-induced histone acetylation in enabling rapid DNA repair. Nicotine had a modest effect on reactive oxygen species induction, but tended to increase alpha particle-induced pro-inflammatory IL-6 and IL-1β (4 Gy). Interestingly, nicotine did not alter gamma radiation-induced γH2AX foci.

CONCLUSIONS

This study provides evidence that nicotine modulates alpha-radiation response by causing a faster but more error-prone repair, as well as rapid recovery, which may allow expansion of cells with genomic instabilities. These results hold implications for estimating radiation risk among nicotine users.

Are People More Likely to Vape or Smoke Indoors? A Population Survey of Adults in England

BACKGROUND

Increasingly, people smoke cigarettes outdoors and avoid exposing bystanders to harm. People may not have the same motivation to vape outdoors since e-cigarettes, unlike cigarettes, do not create side stream emissions and exhaled aerosol contains fewer toxicants than secondhand smoke. This study aims to estimate the prevalence and correlates of vaping and smoking indoors among adults in England.

AIMS AND METHODS

Data came from the Health Survey for England 2019, a cross-sectional household survey. Adults who vape or smoke (N = 1530) were asked whether they had vaped or smoked indoors inside the home, car, or other places within the past 7 days. Logistic regression was used to estimate prevalence and key correlates of indoor use, including age, sex, presence of adults/children in home, housing tenure, and nicotine dependence.

RESULTS

People who exclusively vaped were much more likely to use their product indoors than those who exclusively smoked (87.0% vs. 52.0%; odds ratio [OR] = 6.16, 95% confidence interval [CI] = 4.09 to 9.28). Similarly, people who dual used had higher odds of vaping than smoking indoors (62.1% vs. 44.3%; OR = 3.76, 95% CI = 2.06 to 6.84). The preference for vaping over smoking indoors was found across different locations, including at home and in cars. Those who were older, highly dependent on nicotine, and lived alone were most prone to use any product indoors. While housing tenure was not strongly associated with vaping indoors, those living in social housing were much more likely to smoke indoors than homeowners.

CONCLUSIONS

Adults in England are much more likely to vape than smoke indoors. Age, nicotine dependence, and living alone are strongly associated with both behaviors.

IMPLICATIONS

Our results show that people have a strong preference for vaping over smoking indoors, including in the home. Given the high prevalence of vaping indoors, policy makers, landlords, and businesses must weigh up the ethics, benefits, and harms of extending smoke-free laws to include e-cigarettes.

The Impact of Heat-Not-Burn, E-Cigarettes, and Cigarettes on Small Airway Function

Introduction

E-cigarettes and heated tobacco products (HTPs) are gaining worldwide significance. The tobacco industry is promoting these products as healthier alternatives to conventional cigarettes.

Methods

In this four-arm crossover study, we examined the acute effects of cigarette smoking, vaping IQOS, or vaping e-cigarettes (with or without nicotine) on hemodynamics, arterial stiffness, and small airways. Twenty subjects (10 male, 10 female), all occasional smokers, completed each study arm. There was at least a 48 h washout period before each test day. Arterial stiffness and peripheral and central hemodynamics were assessed using Mobil-O-Graph™ (I.E.M., Germany), whereas tremoFlo® c-100 (Thoracic Medical Systems Inc) was used to evaluate the effects on the small airways and resistance.

Results

Cigarettes, IQOS, e-cigarettes containing nicotine, and nicotine-free e-cigarettes had similar effects on peripheral and central hemodynamics as well as on arterial stiffness. We observed a significant increase in all parameters. However, only nicotine-containing products lead to increased bronchial obstruction, higher reactance, and a higher tidal volume.

Conclusion

Therefore, we concluded that cigarettes, IQOS, and e-cigarettes have similar effects on hemodynamics. No differences were observed between the nicotine-containing and nicotine-free e-cigarettes. All nicotine-containing products also influence small airways. These findings suggest that e-cigarettes and HTPs are not healthier alternatives than conventional cigarettes.

Epidemiology, Diagnostics, and Therapy of Oral Cancer-Update Review

Oral cavity and lip cancers are the 16th most common cancer in the world. It is widely known that a lack of public knowledge about precancerous lesions, oral cancer symptoms, and risk factors leads to diagnostic delay and therefore a lower survival rate. Risk factors, which include drinking alcohol, smoking, HPV infection, a pro-inflammatory factor-rich diet, and poor oral hygiene, must be known and avoided by the general population. Regular clinical oral examinations should be enriched in an oral cancer search protocol for the most common symptoms, which are summarized in this review. Moreover, new diagnostic methods, some of which are already available (vital tissue staining, optical imaging, oral cytology, salivary biomarkers, artificial intelligence, colposcopy, and spectroscopy), and newly researched techniques increase the likelihood of stopping the pathological process at a precancerous stage. Well-established oral cancer treatments (surgery, radiotherapy, chemotherapy, and immunotherapy) are continuously being developed using novel technologies, increasing their success rate. Additionally, new techniques are being researched. This review presents a novel glance at oral cancer-its current classification and epidemiology-and will provide new insights into the development of new diagnostic methods and therapies.

Urinary anatalline and nicotelline cut-points to distinguish between exclusive and dual use of tobacco products

OBJECTIVE

This study measured anatalline and nicotelline, two minor tobacco alkaloids, to discriminate between exclusive smokeless tobacco (SLT) use, exclusive electronic nicotine delivery systems (ENDS) use, exclusive cigarette use, dual SLT and cigarette use, and dual ENDS and cigarette use.

METHODS

N = 664 urine samples from participants in the Population Assessment of Tobacco and Health Study were analyzed for anatalline and nicotelline. Geometric means and 95% confidence intervals were calculated for biomarker levels and their ratios. Non-parametric Receiver Operating Characteristic analyses were used to determine optimal cut-points of natural log-transformed biomarker ratios for distinguishing between tobacco use groups.

RESULTS

The anatalline/nicotelline ratio distinguished exclusive cigarette from exclusive SLT use (threshold = 18.1, sensitivity = 89.3%, specificity = 86.4%, AUC = 0.90), and exclusive SLT from exclusive ENDS use (threshold = 12.8, sensitivity = 96.4%, specificity = 76.3%, AUC = 0.90) very well, but had reduced sensitivity and specificity when distinguishing exclusive cigarette from exclusive ENDS or any dual use with cigarettes.

CONCLUSIONS

This research fills a gap in understanding the public health consequences of SLT and ENDS use by providing objective measures that can signal use of these products alone or in combination with cigarettes.

The role of puff volume in vaping emissions, inhalation risks, and metabolic perturbations: a pilot study

Secondhand vaping exposure is an emerging public health concern that remains understudied. In this study, saliva and exhaled emissions from ENDS users (secondhand) and non-ENDS users (baseline) were collected, firsthand emissions were generated using an automated ENDS aerosol generation system programmed to simulate puffing topography profiles collected from ENDS users. Particulate concentrations and sizes along with volatile organic compounds were characterized. We revealed puffing topography metrics as potential mediators of firsthand and secondhand particle and chemical exposures, as well as metabolic and respiratory health outcomes. Particle deposition modeling revealed that while secondhand emissions displayed smaller deposited mass, total and pulmonary particle deposition fractions were higher than firsthand deposition levels, possibly due to smaller secondhand emission particle diameters. Lastly, untargeted metabolomic profiling of salivary biomarkers of lung injury due to firsthand ENDS exposures revealed potential early indicators of respiratory distress that may also be relevant in bystanders exposed to secondhand vaping scenarios. By leveraging system toxicology, we identified 10 metabolites, including leukotriene D4, that could potentially serve as biomarkers for ENDS use, exposure estimation, and the prediction of vaping-related disease. This study highlights characterization of vaping behavior is an important exposure component in advancing our understanding of potential health effects in ENDS users and bystanders.

The use of electronic cigarettes and other tobacco products among university students and their potential relationship with oral health: A cross-sectional study

BACKGROUND

The aim of this study was to evaluate oral alterations among university students and explore possible associations with tobacco consumption in its various forms.

METHODS

A cross-sectional study was conducted in 2 phases: the first phase involved administering an electronic questionnaire to participants determine the prevalence of tobacco use and the second phase involved a physical examination of the participants. The participants were grouped on the basis of their reported habits and compared using statistical analysis (P < .05).

RESULTS

Of the 620 participants, 57.1% reported using tobacco in some form, with 47.4% reporting electronic cigarette (e-cigarette) use. In the clinical phase, comparing the presence of oral changes in tobacco users vs nonusers, e-cigarette users had a higher proportion of white-spot caries lesions (P = .041) and gingivitis (P = .012). When e-cigarette use was combined with other forms of tobacco use, additional oral changes were more prevalent, including coated tongue and nicotinic stomatitis (P < .05).

CONCLUSIONS

The use of alternative forms of tobacco consumption is common among university students, with e-cigarette use being the most prevalent form, and may lead to detrimental effects on the oral cavity, such as caries and gingivitis, particularly when used in conjunction with other tobacco products.

PRACTICAL IMPLICATIONS

The use of tobacco in alternative forms, such as e-cigarettes, can affect oral health directly or indirectly. Dentists should be familiar with the characteristics of this population and the potential oral repercussions associated with tobacco use to address the impact on health and raise awareness of the associated risks.

Co-existing ambient fine particulate matter exacerbated electronic cigarette toxicity on human respiratory cells

Respiratory co-exposure to ambient PM2.5 and electronic cigarettes (e-cigarettes) frequently occurs in public. However, the combined effects on human respiratory health have not been well documented. To discuss potential co-effects and possible biological mechanisms, A549/THP-1 co-cultures and BEAS-2B cells were exposed to unvapedtobacco or mint-flavored e-liquids (0-7.2% v/v), e-cigarette aerosol extract (ECE, 0-50% v/v), PM2.5 (60 μg/mL), or PM2.5 + ECE for 24 h. Cell viability assessments on e-liquids, ECE, PM2.5 + ECE showed that the mint flavor exhibited higher cytotoxicity compared to the tobacco flavor in both A549/THP-1 and BEAS-2B. However, the influence of flavors on ROS levels and mRNA expression of inflammatory markers (IL-6, TNF-α, IL-8, IL-1β) after ECE exposure demonstrated inconsistency in the two cell models. PM2.5 + ECE treatment notably elevated ROS production and inflammation responses compared to ECE alone exposure. Only co-exposure induced a significant increase in nuclear transcription factor-κB p65 (NF-κB p65) and NOD-like receptor 3 (NLRP3) protein expression regardless of flavors. Our results indicate that PM2.5-treated cells exacerbate the adverse effects induced by ECE in both A549/THP-1 and BEAS-2B cells. Flavors in unvaped e-liquids affect cytotoxicity, oxidative stress and inflammation response, but these effects vary depending on the vaping process and the specific cell line.

Knowledge, attitude, and practice of e-cigarette use among undergraduate students: A comparative study between China and Indonesia

INTRODUCTION

The health risks associated with e-cigarettes are currently the focus of tobacco control efforts and public health initiatives. Given that China and Indonesia have the highest rates of adult smoking worldwide, it is imperative to gain a comprehensive understanding of e-cigarette prevalence among college students in these two nations.

METHODS

From May to June 2023, a cross-sectional study was employed to conduct an online questionnaire survey among college students in three universities located in Kunming (China) and Jakarta (Indonesia), respectively. The chi-squared test was utilized to compare the rates/ratios, while binary logistic regression analysis was applied to examine the factors influencing e-cigarette knowledge, attitude, and practice.

RESULTS

A total of 1327 individuals were included in the investigation. The proportion of Indonesian students (75.6%) with a high level of e-cigarette knowledge was lower than that observed among Chinese students (87.4%) (χ2=29.7, p<0.001). Additionally, the prevalence of e-cigarette use among Indonesian students (9.4%) was higher compared to their Chinese counterparts (3.0%) (χ2=22.32, p<0.001). Binary logistic regression analysis revealed that age, place of residence, studies, gender, and e-cigarette use by friends and family, significantly influenced knowledge levels and attitudes toward e-cigarettes in both countries (p<0.05).

CONCLUSIONS

Despite the positive knowledge, attitudes, and practices towards e-cigarettes among undergraduate students in both countries, a notable knowledge gap exists concerning the harmful effects of e-cigarettes. Chinese students had better e-cigarette knowledge and demonstrated lower usage rates, suggesting that heightened awareness plays a favorable role in preventing e-cigarette use. Furthermore, it becomes imperative for policymakers and health educators to focus on specific factors, such as the influence of close friends and family members, as well as the area of residence.

Harmful and Potentially Harmful Constituents in E-Liquids and Aerosols from Electronic Nicotine Delivery Systems (ENDS)

In 2012, the U.S. Food & Drug Administration (FDA) published an established list of 93 harmful and potentially harmful constituents (HPHCs) targeting four tobacco product types (cigarettes, cigarette tobacco, roll-your-own tobacco, smokeless tobacco). In 2016, the FDA finalized the deeming rule to regulate electronic nicotine delivery systems (ENDS). However, knowledge gaps exist regarding whether certain HPHCs are present in ENDS e-liquids and aerosols. We identified and addressed these gaps by conducting literature searches and then experimentally quantifying HPHCs in the e-liquid and aerosol of 37 ENDS brands based on gaps in the literature. The literature searches identified 66 e-liquid HPHCs and 68 aerosol HPHCs that have limited to no information regarding the quantifiability of these constituents. A contracted ISO 17025 accredited laboratory performed the HPHC quantifications. The availability of validated analytical methods in the contracted laboratory determined the HPHCs included in the study scope (63/66 for e-liquids, 64/68 for aerosols). Combining the results from the quantifications and literature searches, 36 (39%) and 34 (37%) HPHCs were found quantifiable (≥limit of quantification [LOQ]) in ENDS e-liquids and aerosols, respectively, with 25 HPHCs being quantifiable in both matrices. Quantifiability results imply potential HPHC transfers between matrices, leaching from components, or formations from aerosol generation. The study results can inform the scientific basis for manufacturers and regulators regarding regulatory requirements for HPHC reporting. The HPHC quantities can also inform evaluations of the public health impact of ENDS and public communications regarding ENDS health risks.

Electronic Cigarettes and Tobacco Product Cessation: A Survey of Healthcare Providers' Opinions on Safety and Recommendation

Background: This study aimed to: (1) assess healthcare providers' opinions on e-cigarette safety and compare them across professions; (2) evaluate providers' recommendations for e-cigarettes as a tobacco product cessation tool and identify any associations with their safety perceptions. Methods: A self-administered questionnaire was completed by 760 healthcare professionals (January-March 2020). The survey included eight opinions on e-cigarette safety with five Likert-scale answers and a question on recommending them for tobacco product cessation. Results: Among 760 healthcare providers (173 physicians/dentists, 69 pharmacists, and 518 nurses), only 20% reported prior experience with tobacco product cessation counseling. Providers expressed uncertainty regarding e-cigarette safety (mean ± SD: 2.5 ± 0.7 on a 5-point Likert scale), with no significant differences between professions (p = 0.836). Similarly, e-cigarette recommendations for tobacco product cessation remained low across professions (13%, 85/637), with no significant differences found (p = 0.072). The recommendation of e-cigarettes for tobacco cessation is associated with perceived safety, lower respiratory irritation, lower coughing, a lower risk of cancer, and a lower risk for secondhand smokers when compared to traditional cigarettes (p < 0.05). Conclusions: Most healthcare providers were unsure about the safety of e-cigarettes; about 13% of providers suggested using them for tobacco product cessation, with safety perceptions influencing recommendations.

Effect of conventional cigarette smoking and recent heated tobacco products on CAD/CAM restorative materials

OBJECTIVE

To determine the effects of conventional cigarette smoking (CS) and recent heated tobacco products (HTPs) on the surface roughness and color stability of different indirect restorative materials.

MATERIALS AND METHODS

One hundred disc-shaped samples were constructed of three different restorative CAD/CAM materials: lithium disilicate glass-ceramic (IPS e.max CAD; Ivoclar Vivadent, Liechtenstein), zirconia (BruxZir® Zirconia, Glidewell, USA) and polyetheretherketone (BioHPP® bredent GmbH, Germany). Of the IPS e.max CAD and the Bruxzir samples, 20 samples were glazed, and 20 samples were polished, while the BioHPP samples were all polished according to the manufacturer's instructions. Fifty samples were subjected to conventional cigarette smoking (LM, Philip Morris International Inc., Egypt) (Groups: IPS e.max CAD_Glazed exposed to CS (LD_G_Cig), IPS e.max CAD_Polished exposed to CS (LD_P_Cig), Bruxzir_Glazed exposed to CS (Zr_G_Cig), Bruxzir _Polished exposed to CS (Zr_P_Cig) and BioHPP exposed to CS (PEEK_Cig) and fifty samples were exposed to heated tobacco product smoking (Heets, Russet selection, Philip Morris International Inc., Italy) (Groups: IPS e.max CAD_Glazed exposed to HTP (LD_G_HTP), IPS e.max CAD_Polished exposed to HTP (LD_P_HTP), Bruxzir_Glazed exposed to HTP (Zr_G_HTP), Bruxzir CAD_Polished exposed to HTP (Zr_P_HTP) and BioHPP exposed to HTP (PEEK_HTP).. Six hundred cigarettes/heets representing 30 days of medium smoking behavior (20 cigarettes/day) were used. Before and after exposure to smoke, the surface roughness of all the samples was measured using JITAI8101 surface roughness tester (Beijing Jitai Tech Detection Device Co., Ltd, China, and the color parameters were assessed using VITA Easyshade Advance 4.01 (VITA shade, VITA made, VITA). The data were analyzed using One-way ANOVA, paired sample t-test and independent sample t-test. The significance level was set at α < 0.05. The surface topography was evaluated by scanning electron microscopy (SEM) and analyzed using energy-dispersive X-ray (EDX) spectroscopy to determine changes in the surface chemical composition.

RESULTS

Both types of smoking caused significant increases in the surface roughness of all the samples. There was a significant difference in color change between CS and HTP for all materials with different surface finish (P < 0.01) and zirconia had the greatest effect on color change (P < 0.001). In contrast, polyetheretherketone (PEEK) "BioHPP" had the least effect (P < 0.001).

CONCLUSION

Exposure to different types of smoking induce changes in the surface topography and color of different esthetic restorative materials. Compared with HTP, conventional cigarette smoke has a greater effect on the surface roughness and color stability of esthetic restorative materials. The glazed surfaces showed less change in surface topography than did the polished surfaces. Zirconia showed better color stability when compared to polyetheretherketone (PEEK).