An Update on Vaping

An Update on Vaping

Vaping first occurred in the United States 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. when electronic cigarettes (e-cigs; vapes; EC) were introduced. EC are battery-powered, contain a microprocessor and sensor that cause the atomizer to heat up the liquid in the EC cartridge – known as e-liquid – and then produce a vapor/aerosol.2U.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. (Figure 1) Typically, e-liquid contains water, flavorings, a choice of nicotine levels, tetrahydrocannabinol (THC) or cannabidiol (CBD), and glycerin or propylene glycol as a humectant that results in the aerosol produced mimicking cigarette smoke.3CDC. E-cigarette, or vaping, products visual dictionary. Available at: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/pdfs/ecigarette-or-vaping-products-visual-dictionary-508.pdf. Some EC self-activate when the user puffs on them, and the cartridge may be prefilled or refillable. Advertising previously suggested EC were safe, less harmful than traditional cigarettes, did not produce second-hand (environmental) smoke, and were good smoking cessation aids which is the main reason noted by adults for using EC.4Cobb CO, Hendricks PS, Eissenberg T. Electronic cigarettes and nicotine dependence: evolving products, evolving problems. BMC Med 2015;13:119.

There is inadequate evidence to support EC in general for increased smoking cessation, and available EC constantly change and vary greatly in their use.5U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. Available at: https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. While safer than traditional cigarettes, EC are not safe, do produce second-hand smoke and have been heavily marketed to youth. Furthermore, youth who vape have been found to be more likely to later smoke cigarettes than youth who have never vaped.6Berry KM, Fetterman JL, Benjamin EJ. Association of Electronic Cigarette Use With Subsequent Initiation of Tobacco Cigarettes in US Youths. JAMA Netw Open 2019;2(2):e187794. doi:10.1001/jamanetworkopen.2018.7794. In this article, we will examine recent declines in vaping, potential health concerns, EC adoption by youth and related legislation that has been enacted.

Recent Declines in Use

By 2018, 27.5% of twelfth-graders alone reported using EC. (Figure 2) Based on results from the 2019-2020 National Youth Tobacco Survey, EC use is now declining.7Gentzke AS, Wang TW, Jamal A, Park-Lee E, Ren C, Cullen KA, Neff L. Tobacco Product Use Among Middle and High School Students — United States, 2020. MMWR 2020;69(50):1881–8. Available at: https://www.cdc.gov/mmwr/volumes/69/wr/mm6950a1.htm?s_cid=mm6950a1_w. In 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 2019.8CDC. 50.6 Million U.S. Adults Currently Use Tobacco Products. Cigarettes remain most used tobacco product in 2019. November 2020. Available at: https://www.cdc.gov/media/releases/2020/p1119-millions-use-tobacco.html. (Figure 2) In the same year, 4.5% of adults and 9.3% of young adults 18 to 24 years-of-age used EC in 2019.8CDC. 50.6 Million U.S. Adults Currently Use Tobacco Products. Cigarettes remain most used tobacco product in 2019. November 2020. Available at: https://www.cdc.gov/media/releases/2020/p1119-millions-use-tobacco.html.

Factors contributing to declines in vaping are believed to include new laws restricting EC sales, the FDA policy on flavored EC, fear following the 2019 lung disease outbreak, other health-related concerns, the resulting negative publicity around EC, price increases and public health campaigns.9Associated Press. Big drop reported in vaping by U.S. teenagers. September 9, 2020. Available at: https://www.nbcnews.com/health/vaping/big-drop-reported-vaping-u-s-teenagers-n1239723.

Health-related Concerns

E-cigarette, or vaping, product use-associated lung injury (EVALI)
EVALI, first reported in August 2019, causes severe inflammation and scarring of the lungs.10CDC. Smoking and Tobacco Use. Outbreak of Lung Injury Associated with the Use of E-Cigarette, or Vaping, Products, February 25, 2020. Available at: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html. Symptoms included difficulty breathing, coughing, fever, fatigue, diarrhea and vomiting. In many cases mechanical ventilators were needed, while one 17-year-old underwent a double lung transplant.11Edwards E. Michigan teen needed new lungs because of vaping, November 12, 2019. Available at: https://www.nbcnews.com/health/vaping/michigan-teen-needed-new-lungs-because-vaping-n1080666. By February 18, 2020, 2,807 hospitalized cases had been reported, including 68 deaths.10CDC. Smoking and Tobacco Use. Outbreak of Lung Injury Associated with the Use of E-Cigarette, or Vaping, Products, February 25, 2020. Available at: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html. Most affected individuals were under 34 years-of-age. After an extensive investigation, it was concluded that vitamin E acetate, an additive in some THC-containing EC, was associated with EVALI. The majority of affected individuals reporting using EC from informal/bootleg sources. The decline in cases followed growing public awareness of the dangers of THC-containing EC, removal of vitamin E acetate from EC, and law enforcement.10CDC. Smoking and Tobacco Use. Outbreak of Lung Injury Associated with the Use of E-Cigarette, or Vaping, Products, February 25, 2020. Available at: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html.

Other Potential Lung Conditions
In one Canadian report, a 17-year-old male suffered from bronchiolitis and persistent air flow obstruction not relieved by bronchodilators.12Landman ST, Dhaliwal I, Mackenzie CA, Martinu T, Steele A, Bosma KJ. Life-threatening bronchiolitis related to electronic cigarette use in a Canadian youth CMAJ 2019;191(48):E1321-31. doi: 10.1503/cmaj.191402. The authors noted that hypersensitivity pneumonitis, several types of pneumonia and alveolar hemorrhage have also been reported as adverse reactions to EC. Research has demonstrated increased pathogen virulence and inflammation, e.g., for S. pneumoniae, in association with vaping, with greater pathogen adherence and risk for pneumonia.13McAlinden KD, Eapen MS, Lu W, Chia C, Haug G, Sohal SS. COVID-19 and vaping: risk for increased susceptibility to SARS-CoV-2 infection? Eur Respir J 2020;56:2001645. doi:10.1183/13993003.01645-2020.^,14Miyashita L, Suri R, Dearing E, Mudway I, Dove RE, Neill DR, et al. E-cigarette vapour enhances pneumococcal adherence to airway epithelial cells. Eur Respir J 2018;51:1701592. doi:10.1183/13993003.01592-2017. Concern has also been raised about diacetyl which provides a buttery flavor for some EC. Diacetyl was traditionally used to flavor popcorn and resulted in ‘popcorn worker’s lung’ in individuals working in these factories, causing bronchiolitis obliterans.

COVID-19

While not proven to increase the risk for or severity of COVID-19, it is known that EC can damage the lungs.15Galiatsatos P. Coronavirus: Smoking, Vaping, Wildfire Smoke and Air Pollution, November 10, 2020. John Hopkins Medicine. Available at: https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/coronavirus-smoking-vaping-wildfire-smoke-and-air-pollution. A national survey was conducted in May 2020 with more than 4,000 participants ages 13 to 24 years. It was found that, compared to a similar non-vaping cohort, teenagers and young adults who had ever used EC had a five-fold risk of experiencing symptoms including tiredness, cough, fever, difficulty breathing and of being diagnosed with COVID-19.16Stanford Medicine. Vaping linked to COVID-19 risk in teens and young adults. J Adolescent Health, Aug 11. 2020. Available at: https://med.stanford.edu/news/all-news/2020/08/vaping-linked-to-covid-19-risk-in-teens-and-young-adults.html#:~:text=Among%20the%20participants%20who%20were,be%20diagnosed%20with%20the%20disease . If they also smoked cigarettes, the risk level further increased. Nicotine causes increases in the expression of angiotensin-converting enzyme 2 (ACE-2) in human bronchial epithelial cells, and ACE-2 expression is upregulated in smokers’ small airway epithelium.17Russo P, Bonassi S, Giacconi R, Malavolta M, Tomino C, Maggi F. COVID-19 and smoking: is nicotine the hidden link? Eur Respir J 2020;55:2001116. doi:10.1183/13993003.01116-2020. ^,18Brake SJ, Barnsley K, Lu W, McAlinden KD, Eapen MS, Sohal SS. Smoking upregulates angiotensin-converting enzyme-2 receptor: a potential adhesion site for novel coronavirus SARS-CoV-2 (Covid-19). J Clin Med 2020;9:841. doi:10.3390/jcm9030841. In another study, exposure to nicotine resulted in increased expression of ACE-2 receptor materials.19Maggi F, Rosellini A, Spezia PG, Focosi D, Macera L, Lai M, et al. Nicotine Upregulates ACE2 Expression and Increases Competence for SARS-CoV-2 in human pneumocytes. ERJ Open Research 2021; doi:10.1183/23120541.00713-2020. These outcomes would provide for increased binding, entry and replication of SARS-CoV-2. More research is required, while it is believed that upregulation of ACE-2 would also occur with nicotine in EC.

Other Considerations
There may be a link between vaping and cardiovascular conditions, including endothelial dysfunction, with use of nicotine-containing and nicotine-free EC. In one preliminary study, effects included decreased blood flow and increased vascular resistance in smaller blood vessels during an episode of vaping.20Caporale A, Langham MC, Guo W, Johncola A, Chatterjee S, Wehrli FW. Acute Effects of Electronic Cigarette Aerosol Inhalation on Vascular Function Detected at Quantitative MRI. Radiology 2019;293:1,97-106. In another study with almost 500 participants, use of nicotine-containing EC negatively affected cholesterol levels.21Majid S, McGlasson KL, Fetterman JL, Keith RJ, Weisbrod RM, Palmisano JN, et al. Electronic Cigarette Use is Associated With Altered Lipid Profiles in the CITU Study. Circulation 2019;140:A14816. Available at: https://www.ahajournals.org/doi/10.1161/circ.140.suppl_1.14816. LDL cholesterol levels were higher than for nonsmokers, and healthy HDL levels were lower in dual smokers. There is no doubt that secondhand exposure to nicotine in EC occurs, a concern for pregnant women since it adversely affects fetal development.5U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. Available at: https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. Passive vaping also results in exposure to other substances present in exhaled EC aerosol.

Oral Health Considerations
Data on the long-term effects of EC on oral health is still limited, however short-term and laboratory findings are disturbing. In a recent study, the oral microbiome was assessed using subgingival biofilm samples from periodontally healthy EC users.22Ganesan SK, Dabdoub SM, Nagaraja HN, Scott ML, Pamulapayi S, Berman ML, et al. Adverse effects of electronic cigarettes on the disease-naive oral microbiome. Sci Adv 27 May 2020: EAAZ0108. Available at: https://advances.sciencemag.org/content/6/22/eaaz0108. It was found that EC use influenced biofilm architecture, increased the level of proinflammatory cytokines and decreased levels of anti-inflammatory cytokines. Exposure to EC flavorings causes oxidative stress, the release of inflammatory cytokines and damage to human periodontal ligament fibroblasts.23Sundar 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. Research also suggests that exposure to EC aerosol can induce an increased inflammatory response and cause DNA damage.24Yu V, Rahimy M, Korrapati A, Xuan Y, Zou AE, Krishnan AR, et al. Electronic cigarettes induce DNA strand breaks and cell death independently of nicotine in cell lines. Oral Oncol 2016;52:58-65. The long-term effect of EC on periodontal disease is not known.25Ebersole J, Samburova V, Son Y, Cappelli D, Demopoulos C, Capurro A, 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 an in vitro study, the pathogenicity of Candida albicans was increased by EC aerosol exposure and an increased risk for fungal infections has been found for EC users.25Ebersole J, Samburova V, Son Y, Cappelli D, Demopoulos C, Capurro A, 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.

When e-liquid is heated, propylene glycol can produce propylene oxide, formaldehyde and acetaldehyde all of which are carcinogens.26Harrell PT, Simmons VN, Correa JB, Padhya TA, Brandon TH. Electronic nicotine delivery systems (‘‘e-cigarettes’’): review of safety and smoking cessation efficacy. Otolaryngol Head Neck Surg 2014:1-13. Propylene glycol and glycerol are also irritants, as are trace metals (fine and ultrafine particles), aldehydes such as vanillin used as a flavoring agent, and multiple free radicals found in EC aerosol.5U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. Available at: https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. Trace metals found also include lead and cadmium.27Farsalinos 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. Oral and throat irritation, a dry cough, nausea and headache, are often associated with EC use.2U.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. ^,5U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. Available at: https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. In a review of 14 articles with more than 35,000 subjects, the pooled rate of adverse events was approximately 50% and those reported most frequently were mouth or throat irritation, anxiety, depressed mood, nausea, and insomnia.28Liu X, Lu W, Liao S, Deng Z, Zhang Z, Liu Y, Lu W. 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 addition, in one survey of high school students with more than 30,000 respondents, self-reported lingual and buccal mucosal oral pain was reported by more than half of all individuals.29Cho 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.

Influencers for EC Adoption by Youth

EC flavorings attractive to youth include fruity, candy and mint flavors. These in particular, along with curiosity and the belief that ECs were safer than cigarettes, and advertising and marketing enticed younger individuals to vape.2U.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. In addition, nicotine is highly addictive, with vapers reporting dependency on EC,4Cobb CO, Hendricks PS, Eissenberg T. Electronic cigarettes and nicotine dependence: evolving products, evolving problems. BMC Med 2015;13:119.^,5U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. Available at: https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html. and plasma nicotine levels similar to those of cigarette smokers have been found.30National 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. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538688/. Nicotine also impairs adolescent brain development.5U.S. Department of Health & Human Services. Surgeon General Releases First Report Focused on Smoking Cessation in 30 Years. Press release, January 23, 2020. Available at: https://www.hhs.gov/about/news/2020/01/23/surgeon-general-releases-first-report-focused-on-smoking-cessation-in-30-years.html.

EC vehicles also evolved from looking industrial or like regular cigarettes, to sleek designs and ‘pod mods’ which have a prefilled or refillable pod or cartridge. Compatible prefilled pod cartridges contain nicotine, THC, or CBD with or without flavoring.2U.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. The most popular ‘pod mod’ brand is JUUL, which has a USB design that to an observer is not obvious to be an EC. (Figure 3)

Updated Regulations and EC

On May 10, 2016, the Tobacco Control Act was modified to include ECs (plus hookahs, nicotine gels, pipe tobacco and certain dissolvables). It became effective on August 8, 2016, giving the FDA authority over EC.31U.S. Food & Drug Administration. Effective and Compliance Dates Applicable to Retailers, Manufacturers, Importers, and Distributors of Deemed Tobacco Products. Available at: https://www.fda.gov/tobacco-products/compliance-enforcement-training/effective-and-compliance-dates-applicable-retailers-manufacturers-importers-and-distributors-deemed. It is now legally required to include a specific warning statement for products containing nicotine: “WARNING: This product contains nicotine. Nicotine is an addictive chemical.” In addition, free samples and vending machine sales were prohibited, EC could only be sold to customers age 18 or older and a photo ID check was required for everyone under age 27 years.31U.S. Food & Drug Administration. Effective and Compliance Dates Applicable to Retailers, Manufacturers, Importers, and Distributors of Deemed Tobacco Products. Available at: https://www.fda.gov/tobacco-products/compliance-enforcement-training/effective-and-compliance-dates-applicable-retailers-manufacturers-importers-and-distributors-deemed. A series of regulations and enforcement actions have since been pursued, such as the requirement to list ingredients and enforcement for retailers, distributors and manufacturers that are non-compliant with FDA regulations.

On December 20, 2019, a new Federal law was enacted, prohibiting the sale of EC and all other tobacco products to individuals under age 21.32CDC. State Tobacco Activities Tracking and Evaluation (STATE) System. Available at: https://www.cdc.gov/statesystem/factsheets/ecigarette/ECigarette.html. All 50 States, Puerto Rico and US territories have enacted this ban.32CDC. State Tobacco Activities Tracking and Evaluation (STATE) System. Available at: https://www.cdc.gov/statesystem/factsheets/ecigarette/ECigarette.html. Then, in January 2020, the FDA announced a new policy for flavored EC. In practice, sales of all flavored EC that used cartridges and pods, with the exception of those with menthol and tobacco flavors, were prohibited from February 6, 2020 onwards. Enforcement actions were and will be taken against manufacturers if they market to those under age 21 and do not adequately prevent access by this age group.33U.S. Food & Drug Administration. FDA News Release. FDA finalizes enforcement policy on unauthorized flavored cartridge-based e-cigarettes that appeal to children, including fruit and mint. January 2, 2020. Available at: https://www.fda.gov/news-events/press-announcements/fda-finalizes-enforcement-policy-unauthorized-flavored-cartridge-based-e-cigarettes-appeal-children. As an example, in July 2020, the FDA issued warning letters to several companies marketing e-liquids in packaging that appeals to youth and was similar to foods.34U.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. Companies are now prohibited from using the US Postal Service to delivery EC.35Vape Ban 2021: Home Delivery of Vaping Products in Jeopardy? February 18, 20201. Available at: https://www.vaporvanity.com/vape-ban/ (Table 1)

Table 1. Legislation on EC

Manufacturers have had to apply for premarket authorization and must prove that they “are appropriate for protection of public health” for these to be legally allowed on the market. This is pending. A majority of States has passed legislation requiring EC retailers of over-the-counter stores to obtain a retail license and many have legislation banning vaping indoors in restaurants, bars and private worksites.32CDC. State Tobacco Activities Tracking and Evaluation (STATE) System. Available at: https://www.cdc.gov/statesystem/factsheets/ecigarette/ECigarette.html. EC taxes have also been introduced in some States, some based on the amount of e-liquid in prefilled cartridges and others as a percentage of cost for refillable cartridges.32CDC. State Tobacco Activities Tracking and Evaluation (STATE) System. Available at: https://www.cdc.gov/statesystem/factsheets/ecigarette/ECigarette.html. (Figure 4)

However, disposable flavored EC use has increased. In practice, these did not fall under the flavorings ban, and a continued trend towards highly concentrated, high-nicotine, fruity-flavored refillable EC has occurred.36Edwards E. Federal flavor ban goes into effect Thursday, but many flavored vape products will still be available. Feb 5, 2020. Available at: https://www.nbcnews.com/health/vaping/federal-flavor-ban-goes-effect-thursday-many-flavored-vape-products-n1130466. In addition, school students have been using flavored nicotine pouches and sucking on these during the day at school. Flavoring bans also resulted in an increased number of vapers concocting e-liquids containing nicotine, artificial flavorings and in some cases THC or CBD, using online recipes.37Gold J. More vapers are making their own juice, but not without risks. Kaiser Health News, Nov 13, 2019. Available at: https://www.nbcnews.com/health/vaping/more-vapers-are-making-their-own-juice-not-without-risks-n1081496.

Conclusions

Recent events and regulations have resulted in a decline in the use of EC among youth in particular, but also in adults. The regulations restrict the sale of EC, flavorings, where vaping may occur and, manufacturers, distributors and retailers. In addition, while EC do help some individuals quit smoking, results from studies are equivocal and there is insufficient evidence of EC efficacy. At the same time, there has been a shift in public perception of EC. While EC are considered safer than cigarettes, they are not safe. Public perception became more negative following the 2019 lung disease outbreak and other health-related concerns. Recent studies provide disturbing insights into their existing and potential effects. While the long-term effects of EC on systemic and oral health are as yet unknown, dental professionals can help educate youth and adults on existing information and the potential risks of vaping.

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