Current Trends in Vaping, Recent Legislation and Health Findings

Current Trends in Vaping, Recent Legislation and Health Findings

Figure 1. Sleek EC designs

The introduction of e-cigarettes (EC; vapes) into the United States occurred in 2007,1Rogér JM, Abayon M, Elad S, Kolokythas A. Oral trauma and tooth avulsion following explosion of e-cigarette. J Oral Maxillofac Surg 2016;74(6):1181-5. after which EC vehicles evolved into sleek designs and ‘pod mods’ with a prefilled or refillable pod or cartridge. (Figure 1) Advertising suggested that EC were safe, did not generate second-hand smoke, were less harmful than smoking tobacco, and performed well as smoking cessation aids.2Cobb CO, Hendricks PS, Eissenberg T. Electronic cigarettes and nicotine dependence: evolving products, evolving problems. BMC Med 2015;13:119. EC have also been advertised as ‘cool’, were available in a wide array of appealing flavors and heavily marketed to youth.3Birdsey J, Cornelius M, Jamal A et al. Tobacco product use among U.S. middle and high school students—National Youth Tobacco Survey, 2023. Morb Mortal Wkly Rep 2023;72:1173-82.^,4Gentzke AS, Wang TW, Cornelius M et al. Tobacco product use and associated factors among middle and high school students—National Youth Tobacco Survey, United States, 2021. Morb Mortal Wkly Rep Surveill Summ 2022;71(No. SS-5):1-29.^,5U.S. Food & Drug Administration. Vaporizers, E-Cigarettes, and other Electronic Nicotine Delivery Systems (ENDS). Available at: https://www.fda.gov/tobacco-products/products-ingredients-components/vaporizers-e-cigarettes-and-other-electronic-nicotine-delivery-systems-ends. By 2018, EC use was reported by 27.5% of twelfth-graders.

EC are battery-powered, contain a microprocessor and a sensor that causes the atomizer to rapidly heat the e-liquid in the EC cartridge (prefilled or refillable), thereby producing vapor/aerosol.5U.S. Food & Drug Administration. Vaporizers, E-Cigarettes, and other Electronic Nicotine Delivery Systems (ENDS). Available at: https://www.fda.gov/tobacco-products/products-ingredients-components/vaporizers-e-cigarettes-and-other-electronic-nicotine-delivery-systems-ends. Typically, the e-liquid contains water, nicotine at varying levels, glycerin or propylene glycol as a humectant that results in the aerosol mimicking cigarette smoke, flavorings, and tetrahydrocannabinol (THC) or cannabidiol (CBD). EC have also been found that contain methamphetamine, methadone or vitamins.6American Heart Association. Current evidence identifies health risks of e-cigarette use; long-term research needed. July 17, 2023. https://newsroom.heart.org/news/current-evidence-identifies-health-risks-of-e-cigarette-use-long-term-research-needed.

Since 2019, the public perception of EC has been changing, in part due to a lung disease outbreak and increasing information on the potential harms of EC. Furthermore, there is inadequate evidence to support EC in general for increased smoking cessation,7U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. and EC products are not approved by the U.S. Food & Drug Administration (FDA) as smoking cessation aids. Federal legislation, State regulations, and public health campaigns have collectively helped more recently to reduce access and EC use.

Current Trends

Figure 2. Flavor preferences for pre-filled and disposable EC

Trends show a gradual reversal of the rapid rise in EC use seen up until 2018.8Gentzke AS, Wang TW, Jamal A et al. Tobacco Product Use Among Middle and High School Students — United States, 2020. Morb Mortal Wkly Rep 2020;69(50):1881-8. https://www.cdc.gov/mmwr/volumes/69/wr/mm6950a1.htm?s_cid=mm6950a1_w. By 2019, 3.6 million students used EC in the prior 30-day period, including 19.6% of high school students and 4.7% of middle school students, compared to 27.5% and 10.5%, respectively, in 2018.8Gentzke AS, Wang TW, Jamal A et al. Tobacco Product Use Among Middle and High School Students — United States, 2020. Morb Mortal Wkly Rep 2020;69(50):1881-8. https://www.cdc.gov/mmwr/volumes/69/wr/mm6950a1.htm?s_cid=mm6950a1_w. Among 18- to 24-year-olds, 4.5% and 9.3% of individuals used EC in the same time periods.9Centers for Disease Control and Prevention. 50.6 Million U.S. Adults Currently Use Tobacco Products. Cigarettes remain most used tobacco product in 2019. November 2020. https://www.cdc.gov/media/releases/2020/p1119-millions-use-tobacco.html. Additionally, in 2020 it was reported that more than half of students using CE wanted to quit, and more than half had attempted to do so in the prior year.10Zhang L, Gentzke A, Trivers KF, VanFrank B. Tobacco cessation behaviors among U.S. middle and high school students, 2020. J Adolesc Health 2022;70(1):147-54. By 2023, 10% of students (2.8 million) used a ‘tobacco product’.11U.S. Food & Drug Administration. National Survey Shows Drop in E-Cigarette Use Among High School Students. November 2, 2023. https://www.fda.gov/news-events/press-announcements/national-survey-shows-drop-e-cigarette-use-among-high-school-students. The majority used EC, equating to 2.1 million (7.7%) of students overall.3Birdsey J, Cornelius M, Jamal A et al. Tobacco product use among U.S. middle and high school students—National Youth Tobacco Survey, 2023. Morb Mortal Wkly Rep 2023;72:1173-82. Vaping was more common among high school than middle school students, estimated at 1.56 million and 0.55 million students, respectively, and for high school students, this was 580,000 fewer individuals compared to 2022.11U.S. Food & Drug Administration. National Survey Shows Drop in E-Cigarette Use Among High School Students. November 2, 2023. https://www.fda.gov/news-events/press-announcements/national-survey-shows-drop-e-cigarette-use-among-high-school-students. The majority of students were using disposable EC in 20223Birdsey J, Cornelius M, Jamal A et al. Tobacco product use among U.S. middle and high school students—National Youth Tobacco Survey, 2023. Morb Mortal Wkly Rep 2023;72:1173-82. and flavored products, with preferred brands including Elf Bar, Esco Bars, Vuse, JUUL, and Mr. Fog (used by 56.7%, 21.6%, 20.7%, 16.5% and 13.6% of students who vaped, respectively).3Birdsey J, Cornelius M, Jamal A et al. Tobacco product use among U.S. middle and high school students—National Youth Tobacco Survey, 2023. Morb Mortal Wkly Rep 2023;72:1173-82.^,11U.S. Food & Drug Administration. National Survey Shows Drop in E-Cigarette Use Among High School Students. November 2, 2023. https://www.fda.gov/news-events/press-announcements/national-survey-shows-drop-e-cigarette-use-among-high-school-students. Among high school students, the most popular flavor in 2020 was fruit for both cartridge-based and disposable EC.12Wang TW, Neff LJ, Park-Lee E et al. E-cigarette Use Among Middle and High School Students — United States, 2020. Morb Mortal Wkly Rep 2020;69:1310-2. http://dx.doi.org/10.15585/mmwr.mm6937e1. (Figure 2)

Current and Recent Legislation

Numerous legislative actions have been taken since the Tobacco Control Act was modified to include ECs (plus hookahs, nicotine gels, pipe tobacco and certain dissolvables) and became effective on August 8, 2016.13U.S. Food & Drug Administration. Effective and Compliance Dates Applicable to Retailers, Manufacturers, Importers, and Distributors of Deemed Tobacco Products. https://www.fda.gov/tobacco-products/compliance-enforcement-training/effective-and-compliance-dates-applicable-retailers-manufacturers-importers-and-distributors-deemed. The FDA developed legislation that applies to retailers, distributors, importers, and manufacturers (who in this context the FDA defines as one that makes, modifies, mixes, manufactures, fabricates, assembles, processes, labels, repacks, relabels, or imports any tobacco product).14U.S. Food & Drug Administration. Manufacturing. https://www.fda.gov/tobacco-products/compliance-enforcement-training/manufacturing. In addition, free EC samples were banned as was selling products in vending machines (unless located where minors were never permitted). Later, a warning was required on packaging for nicotine-containing EC that stated that the EC contained nicotine and that nicotine is an addictive chemical. The FDA initially allowed a 2-year window to submit applications for pre-market authorization (PMA), which was later extended.

A new Federal law enacted in December 2019 prohibited the sale of all products falling under the Tobacco Control Act (including EC) to individuals under 21 years-of-age.15Centers for Disease Control and Prevention. State Tobacco Activities Tracking and Evaluation (STATE) System. https://www.cdc.gov/statesystem/factsheets/ecigarette/ECigarette.html. Subsequently, the FDA issued guidance on January 2, 2020 that restricted sales of all unauthorized flavored cartridge-based EC (i.e., EC with a sealed/unsealed cartridge or pod that holds e-liquid), with the exception of tobacco or menthol flavors.16U.S. Food & Drug Administration. FDA finalizes enforcement policy on unauthorized flavored cartridge-based e-cigarettes that appeal to children, including fruit and mint. FDA News Release, January 2, 2020. https://www.fda.gov/news-events/press-announcements/fda-finalizes-enforcement-policy-unauthorized-flavored-cartridge-based-e-cigarettes-appeal-children. The FDA also announced that, 30 days later, it would prioritize enforcement on groups that continued to market the restricted EC, targeted minors or likely promoted EC to them, or did not adequately prevent access by minors. Unintended consequences of the guidance included users switching from mint- to menthol-flavored EC, an increase in queries for disposable vapes, and a 1,000% increase in sales of flavored disposable EC (which were not included in the guidance).12Wang TW, Neff LJ, Park-Lee E et al. E-cigarette Use Among Middle and High School Students — United States, 2020. Morb Mortal Wkly Rep 2020;69:1310-2. http://dx.doi.org/10.15585/mmwr.mm6937e1.^,17Li D, Ossip DJ, Bansal-Travers M, Xie Z. Impact of the FDA flavour enforcement policy on flavoured electronic cigarette use behaviour changes. Tob Control 2022;31(Suppl 3):s176-83. doi: 10.1136/tc-2022-057492.^,18Boakye E, Dzaye O, Erhabor J et al. Impact of the Food and Drug Administration enforcement policy on flavored e-cigarettes on the online popularity of disposable e-cigarettes: analyses of Google search query data. BMC Public Health 2022;22(1):1937. (Figure 3) Furthermore, an increased number of vapers started concocting e-liquids containing nicotine, artificial flavorings and in some cases THC or CBD, using online recipes.19Gold J. More vapers are making their own juice, but not without risks. Kaiser Health News, Nov 13, 2019. https://www.nbcnews.com/health/vaping/more-vapers-are-making-their-own-juice-not-without-risks-n1081496.

By July 2020, the FDA had issued warning letters to several companies marketing e-liquids in packaging that appealed to youth or looked similar to foodstuff packaging.20U.S. Food & Drug Administration. Misleadingly Labeled E-Liquids that Appeal to Youth. Available at: https://www.fda.gov/tobacco-products/ctp-newsroom/misleadingly-labeled-e-liquids-appeal-youth. All vape shops were later incorporated into the Prevent All Cigarette Trafficking (“PACT”) Act and companies were prohibited from using the US Postal Service to deliver EC.21Farmer L. Small Businesses Scrambling To Figure Out New State Vaping Rules And Taxes. Forbes, April 28, 2021. https://www.forbes.com/sites/lizfarmer/2021/04/28/small-businesses-scrambling-to-figure-out-new-state-vaping-rules-and-taxes/#:~:text=It%20means%20that%20anyone%20who%20sells%2C%20transfers%2C%20or,collect%20excise%20and%2For%20sales%20tax%20in%20those%20states.^,22Vape Ban 2021: Home Delivery of Vaping Products in Jeopardy? February 18, 2021. Available at: https://www.vaporvanity.com/vape-ban/ Among other requirements, EC companies were now obliged to file registration with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and tobacco tax administrators in every State where they advertised/sold EC, and to adhere to States’ sales and excise tax regulations. (Table 1)

Pre-market authorization and legal violations

All manufacturers and importers of EC products that were not being marketed as of Feb. 15, 2007, or that were modified after that date, must submit a pre-market tobacco application to the FDA and obtain PMA for their products.23U.S. Food & Drug Administration FDA. Flowchart: Compliance and Enforcement Processes for Unauthorized Electronic Nicotine Delivery Systems (ENDS) Products. https://www.fda.gov/media/179783/download The submitting company must prove that their EC products “are appropriate for protection of public health.” By June 2024, the FDA had reviewed 26 million applications and, as of August 20, 2024, PMA had been given to 34 tobacco- and menthol-flavored e-cigarette products and devices.24Boes E. Advisory and Enforcement Actions Against Industry for Unauthorized Tobacco Products. Accessed 8/19/2024. https://cstoredecisions.com/2024/06/21/fda-authorizes-first-ever-menthol-flavored-e-cigarettes/#:~:text=The%20FDA%20has%20received%20applications%20for%20nearly%2027,products%20and%20devices%2C%20including%20the%20four%20authorized%20today. ^,25U.S. Food & Drug Administration. https://www.accessdata.fda.gov/scripts/searchtobacco/. A few submissions that resulted in a marketing denial order are still under further agency review as of that date.26U.S. Food & Drug Administration. Advisory and Enforcement Actions Against Industry for Unauthorized Tobacco Products. Accessed 8/19/2024. https://www.fda.gov/tobacco-products/compliance-enforcement-training/advisory-and-enforcement-actions-against-industry-unauthorized-tobacco-products. Readers can find an up-to-date list of authorized EC products going forward by visiting the Searchable Tobacco Products Database at: https://www.accessdata.fda.gov/scripts/searchtobacco/.

Manufacturers, importers and retailers are in violation if they market and/or sell EC products without PMA or are non-compliant with other applicable laws. Violators are subject to compliance enforcement actions (a few manufacturers with submissions under re-review and with stays are currently excepted).26U.S. Food & Drug Administration. Advisory and Enforcement Actions Against Industry for Unauthorized Tobacco Products. Accessed 8/19/2024. https://www.fda.gov/tobacco-products/compliance-enforcement-training/advisory-and-enforcement-actions-against-industry-unauthorized-tobacco-products. The first action is typically an FDA warning letter with the objective of obtaining voluntary compliance, and by July 2024 almost 700 had been issued to retailers alone. The FDA can take other actions for non-compliance, including civil money penalties (fines), injunctions, seizure and criminal prosecution.

Update on Health-related Concerns

Most EC contain nicotine, which impairs adolescent brain development, with negative effects on impulse control, learning and other capabilities.7U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html.^,27U.S. Department of Health and Human Services. E-cigarette Use Among Youth and Young Adults: A Report of the Surgeon General. Centers for Disease Control and Prevention; 2016. EC users report dependency.2Cobb CO, Hendricks PS, Eissenberg T. Electronic cigarettes and nicotine dependence: evolving products, evolving problems. BMC Med 2015;13:119.^,28National Center for Chronic Disease Prevention and Health Promotion (US) Office on Smoking and Health. E-Cigarette Use Among Youth and Young Adults: A Report of the Surgeon General [Internet]. Atlanta (GA): Centers for Disease Control and Prevention (US); 2016. Chapter 3, Health Effects of E-Cigarette Use Among U.S. Youth and Young Adults. https://www.ncbi.nlm.nih.gov/books/NBK538688/. Furthermore, nicotine exposure causes increases in heart rate by activating the sympathetic nervous system, and also causes increased blood pressure due to its vasoconstrictive effect.29Rose JJ, Krishnan-Sarin S, Exil VJ et al. Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association. Circulation 2023;148(8):703-728. doi: 10.1161/CIR.0000000000001160. In addition, long-term exposure to nicotine can encourage the development of heart failure. Nicotine-containing EC are also a concern for pregnant women since nicotine adversely affects fetal development.7U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html.

In a recent scientific statement report from the American Heart Association, a thorough review of EC and cardiopulmonary findings to date is provided.29Rose JJ, Krishnan-Sarin S, Exil VJ et al. Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association. Circulation 2023;148(8):703-728. doi: 10.1161/CIR.0000000000001160. In a separate review with adolescent EC users, reported effects on cardiac function from some large studies included increases in myocardial fibrosis and coronary vascular disease, and decreases in on-demand myocardial blood flow, nitric oxide production and endothelial function.30Wold LE, Tarran R, Crotty Alexander LE et al. Cardiopulmonary Consequences of Vaping in Adolescents: A Scientific Statement From the American Heart Association. Circ Res 2022;131(3):e70-e82. doi: 10.1161/RES.0000000000000544. Reported effects on vascular function included increased arterial stiffness and blood pressure. In addition, the Population Assessment of Tobacco and Health (PATH) study on pulmonary health began in 2013. Findings have included a greater likelihood among current and former EC users of developing chronic obstructive pulmonary disease, chronic bronchitis, emphysema or asthma within the following two years.6American Heart Association. Current evidence identifies health risks of e-cigarette use; long-term research needed. July 17, 2023. https://newsroom.heart.org/news/current-evidence-identifies-health-risks-of-e-cigarette-use-long-term-research-needed. The long-term adverse health effects of vaping are still not known, and need to be determined.29Rose JJ, Krishnan-Sarin S, Exil VJ et al. Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association. Circulation 2023;148(8):703-728. doi: 10.1161/CIR.0000000000001160.^,30Wold LE, Tarran R, Crotty Alexander LE et al. Cardiopulmonary Consequences of Vaping in Adolescents: A Scientific Statement From the American Heart Association. Circ Res 2022;131(3):e70-e82. doi: 10.1161/RES.0000000000000544. Among EC users, E-cigarette, or vaping, product use-associated lung injury (EVALI) emerged as an acute condition in 2019, causing severe bronchial inflammation and scarring.31Centers for Disease Control and Prevention. Smoking and Tobacco Use. Outbreak of Lung Injury Associated with the Use of E-Cigarette, or Vaping, Products, February 25, 2020. https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html. By mid-February 2020 almost 3,000 hospitalized cases had been reported, including 68 deaths, and were eventually attributed to vitamin E acetate, an additive in some THC-containing EC. Other reported adverse health events for EC include bronchiolitis, hypersensitivity pneumonitis, pneumonia and alveolar hemorrhage.32Landman ST, Dhaliwal I, Mackenzie CA et al. Life-threatening bronchiolitis related to electronic cigarette use in a Canadian youth CMAJ 2019;191(48):E1321-31. doi: 10.1503/cmaj.191402.

In a review with more than 35,000 subjects, the most frequently reported adverse events were intraoral or throat irritation, anxiety, depressed mood, nausea, and insomnia.33Liu X, Lu W, Liao S et al. Efficiency and adverse events of electronic cigarettes: A systematic review and meta-analysis (PRISMA-compliant article). Medicine (Baltimore) 2018;97(19):e0324. doi: 10.1097/MD.0000000000010324. Throat irritation, a dry cough, nausea and headache, are commonly reported by EC users.5U.S. Food & Drug Administration. Vaporizers, E-Cigarettes, and other Electronic Nicotine Delivery Systems (ENDS). Available at: https://www.fda.gov/tobacco-products/products-ingredients-components/vaporizers-e-cigarettes-and-other-electronic-nicotine-delivery-systems-ends.^,7U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. Propylene glycol, glycerol, and trace metals (fine and ultrafine particles) including lead and cadmium, are irritants and found in EC aerosol.7U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html.^,34Farsalinos KE, Voudris V, Poulas K. Are metals emitted from electronic cigarettes a reason for health concern? A risk-assessment analysis of currently available literature. Int J Environ Res Pub Health 2015;12(5):5215-32. Additionally, when propylene glycol in the e-liquid is heated it can produce propylene oxide, formaldehyde and acetaldehyde all of which are carcinogens.35Harrell PT, Simmons VN, Correa JB et al. Electronic nicotine delivery systems (‘‘e-cigarettes’’): review of safety and smoking cessation efficacy. Otolaryngol Head Neck Surg 2014:1-13. Multiple free radicals can be present, and aldehydes such as vanillin are used as a flavoring agent. Diacetyl in e-liquid, which is used to provide a buttery flavor, is a further concern given its historical association with bronchiolitis obliterans in popcorn factory workers. Other ingredients have also demonstrated toxicity.

Second-hand smoke
There is now no doubt that secondhand exposure to nicotine and other substances in exhaled EC aerosol occurs. While this is of general concern given findings on these substances, it is a particular concern for pregnant women since nicotine adversely affects fetal development.7U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html.

Oral Health Considerations

Oral irritation is a frequent complaints among EC users.5U.S. Food & Drug Administration. Vaporizers, E-Cigarettes, and other Electronic Nicotine Delivery Systems (ENDS). Available at: https://www.fda.gov/tobacco-products/products-ingredients-components/vaporizers-e-cigarettes-and-other-electronic-nicotine-delivery-systems-ends.^,33Liu X, Lu W, Liao S et al. Efficiency and adverse events of electronic cigarettes: A systematic review and meta-analysis (PRISMA-compliant article). Medicine (Baltimore) 2018;97(19):e0324. doi: 10.1097/MD.0000000000010324. In one survey with more than 30,000 high school students, self-reported lingual and buccal mucosal oral pain was reported by more than half of all individuals.36Cho JH. The association between electronic-cigarette use and self-reported oral symptoms including cracked or broken teeth and tongue and/or inside-cheek pain among adolescents: A cross-sectional study. PLoS One 2017;12(7):e0180506. doi: 10.1371/journal.pone.0180506. Other potential oral adverse events include angular cheilitis and hairy tongue.37Bardellini E, Amadori F, Conti G, Majorana A. Oral mucosal lesions in electronic cigarettes consumers versus former smokers. Acta Odontol Scand 2018;76(3):226-8. EC use can result in changes to the oral microbiome, influencing the subgingival biofilm architecture, increasing levels of proinflammatory cytokines and decreasing levels of anti-inflammatory cytokines.38Ganesan SK, Dabdoub SM, Nagaraja HN et al et al. Adverse effects of electronic cigarettes on the disease-naive oral microbiome. Sci Adv 2020: EAAZ0108. https://advances.sciencemag.org/content/6/22/eaaz0108.^,39Xu F, Pushalkar S, Lin Z et al. Electronic cigarette use enriches periodontal pathogens. Mol Oral Microbiol 2022;37(2):63-76. doi: 10.1111/omi.12361. In a recent review of 99 articles, it was concluded that EC use increases the risk for periodontal disease and oral microbiome changes.40Yang I, Sandeep S, Rodriguez J. The oral health impact of electronic cigarette use: a systematic review. Crit Rev Toxicol 2020;50(2):97-127. Exposure to EC flavorings can cause oxidative stress, the release of inflammatory cytokines, and damage human periodontal ligament fibroblasts.41Sundar IK, Javed F, Romanos GE, Rahman I. E-cigarettes and flavorings induce inflammatory and pro-senescence responses in oral epithelial cells and periodontal fibroblasts. Oncotarget 2016;7(47):77196-204. doi: 10.18632/oncotarget.12857. In addition, EC use decreases antioxidants and thereby alters intraoral immune response.42Cichońska D, Kusiak A, Kochańska B et al. Influence of Electronic Cigarettes on Selected Physicochemical Properties of Saliva. Int J Environ Res Public Health 2022;19(6):3314. doi: 10.3390/ijerph19063314. Earlier research suggested that EC aerosol can induce an increased inflammatory response and cause DNA damage.43Yu V, Rahimy M, Korrapati A et al. Electronic cigarettes induce DNA strand breaks and cell death independently of nicotine in cell lines. Oral Oncol 2016;52:58-65. In a study with 72 subjects, oral epithelial DNA damage was observed in the POLB and HPRT genes in EC users, similar to the damage in tobacco smokers and significantly greater than for non-smokers.44Murphy S. What e-cigarette factors determine oral epithelial DNA damage in consumers? Evid Based Dent 2023;24(4):163-4. doi: 10.1038/s41432-023-00943-y. A dose-response relationship was found for the POLB gene.

In a recent review of 8 case-control studies, significant increases were found for plaque index and pocket depth in EC users than non-users, while bleeding on probing was lower in the vaping group (hypothesized to be due to the vasoconstrictive effect of nicotine).45Figueredo CA, Abdelhay N, Figueredo CM et al. The impact of vaping on periodontitis: A systematic review. Clin Exp Dent Res 2021;7(3):376-84. doi: 10.1002/cre2.360. It was concluded that there was insufficient evidence to determine the effect of EC on periodontal tissues. As noted by the researchers, only eight studies were available, four of which were at moderate risk of bias, and hookah use may have been a confounder. The long-term effects of EC on periodontal disease are not known.46Ebersole J, Samburova V, Son Y et al. Harmful chemicals emitted from electronic cigarettes and potential deleterious effects in the oral cavity. Tob Induc Dis 2020;18:41. doi: 10.18332/tid/116988. In vitro studies have shown that exposure to EC aerosol can increase Candida albicans pathogenicity,46Ebersole J, Samburova V, Son Y et al. Harmful chemicals emitted from electronic cigarettes and potential deleterious effects in the oral cavity. Tob Induc Dis 2020;18:41. doi: 10.18332/tid/116988.^,47Alanazi H, Semlali A, Chmielewski W, Rouabhia M. E-cigarettes increase Candida albicans growth and modulate its interaction with gingival epithelial cells. Int J Environ Res Public Health. 2019;16(2):294. and twice-daily 15-minute exposure to nicotine-containing e-cigarette vapor for 3 days can increase Streptococcus mutans pathogenicity.48Rouabhia M, Semlali A. Electronic cigarette vapor increases Streptococcus mutans growth, adhesion, biofilm formation, and expression of the biofilm-associated genes. Oral Dis 2021;27(3):639-47. In a cross-sectional study with more than 600 students, EC users had more early caries lesions (white spot lesions) and gingivitis compared to non-users.49Garcia BFS, Nascimento BB, Marques EF et al. The use of electronic cigarettes and other tobacco products among university students and their potential relationship with oral health: A cross-sectional study. J Am Dent Assoc 2024;155(8):647-56. doi: 10.1016/j.adaj.2024.04.012. Isolated cases of nicotinic stomatitis were also found for EC users.

Severe orofacial injury may result from spontaneous EC combustion, including burns, bone fractures, tooth fractures and subluxation, and facial injuries caused by burns and projectiles.50Harrison R, Hicklin D, Jr. Electronic cigarette explosions involving the oral cavity. J Am Dent Assoc 2016;147:891-6. ^,51Tran V, Mian M, Sreedharan S et al. Oral and Maxillofacial Injuries Associated With E-Cigarette Explosions: A Systematic Review and Management Guidelines Proposal. J Oral Maxillofac Surg 2023;81(5):583-92. doi: 10.1016/j.joms.2023.01.009. In one review, 32 spontaneous explosions of EC were reported.51Tran V, Mian M, Sreedharan S et al. Oral and Maxillofacial Injuries Associated With E-Cigarette Explosions: A Systematic Review and Management Guidelines Proposal. J Oral Maxillofac Surg 2023;81(5):583-92. doi: 10.1016/j.joms.2023.01.009. Treatments included dental extractions, grafts, fixation of fractures, and ocular surgery.

State Interventions

Individual states and territories have introduced laws, taxes and other requirements affecting EC commerce. The majority of States have passed legislation for a minimum legal sales age (MSLA) of 21 years for any tobacco product and/or require that brick-and-mortar EC retailers obtain a retail license, and EC taxes have also been introduced in many States.15Centers for Disease Control and Prevention. State Tobacco Activities Tracking and Evaluation (STATE) System. https://www.cdc.gov/statesystem/factsheets/ecigarette/ECigarette.html. (Figures 5,6) Additionally, of relevance to EC second-hand smoke, as of March 31, 2024, twenty-eight states and the District of Columbia have enacted comprehensive smokefree indoor air laws for bars, restaurants, and worksites (private and government) while twenty-two states have less comprehensive smokefree indoor air laws or have not yet put any legislation in place.52Centers for Disease Control and Prevention. State Tobacco Activities Tracking and Evaluation *STATE System. https://www.cdc.gov/statesystem/factsheets/sfia/SmokeFreeIndoorAir.html (Figure 7)

Conclusions

EC use has decreased amid changes in the perceptions of EC, federal and state legislation and public health campaigns. While more has been learned about the risks and potential adverse events associated with EC, much remains to be learned. Studies are still largely small, cross-sectional in nature, and the long-term adverse health effects of vaping are still not known. Researchers have recommended short-term clinical and laboratory studies since long-term results will take time to obtain and have called for long-term studies in EC users with and without pre-existing conditions. Currently, dental professionals can help educate youth and adults on the risks of vaping, potential adverse health events and other information that is already known. For individuals who are considering smoking cessation, other options can be recommended including smoking cessation groups and online tools.

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