a b Hedman, L; Galanti, MR; Ryk, L; Gilljam, H; Adermark, L (13 October 2021). "Electronic cigarette use and smoking cessation in cohort studies and randomized trials: A systematic review and meta-analysis". Tobacco Prevention and Cessation. European Network for Smoking and Tobacco Prevention. 7 (62): 62. doi: 10.18332/tpc/142320. PMC 8508281. PMID 34712864. million vapers worldwide in 2021: the GSTHR estimate". Global State of Tobacco Harm Reduction . Retrieved 13 November 2022. Jimenez Ruiz, CA; Solano Reina, S; de Granda Orive, JI; Signes-Costa Minaya, J; de Higes Martinez, E; Riesco Miranda, JA; Altet Gómez, N; Lorza Blasco, JJ; Barrueco Ferrero, M; de Lucas Ramos, P (August 2014). "The electronic cigarette. Official statement of the Spanish Society of Pneumology and Thoracic Surgery (SEPAR) on the efficacy, safety and regulation of electronic cigarettes". Archivos de Bronconeumologia. 50 (8): 362–7. doi: 10.1016/j.arbres.2014.02.006. PMID 24684764. Vaping correlates with smoking among young people, even in those who would otherwise be unlikely to smoke. [88] Experimenting with vaping encourages young people to continue smoking. [89] A 2015 study found minors had little resistance to buying e-cigarettes online. [90] Teenagers may not admit to using e-cigarettes, but use, for instance, a hookah pen. [91] As a result, self-reporting may be lower in surveys. [91]

Another common chemical found in e-cigarettes is ketene. When it enters the lungs after inhaled, this chemical causes damage to the cellular structure of lung tissue causing the cells to not function at maximum capacity and not absorb gasses as readily. This can cause shortness of breath which can lead to other health conditions such as tachycardia and respiratory failure. E-cigarette users who use devices that contain nicotine are exposed to its potentially harmful effects. [92] a b Gibson, Laura A.; Creamer, MeLisa R.; Breland, Alison B.; Giachello, Aida Luz; Kaufman, Annette; Kong, Grace; Pechacek, Terry F.; Pepper, Jessica K.; Soule, Eric K.; Halpern-Felsher, Bonnie (2018). "Measuring perceptions related to e-cigarettes: Important principles and next steps to enhance study validity". Addictive Behaviors. 79: 219–225. doi: 10.1016/j.addbeh.2017.11.017. ISSN 0306-4603. PMC 5807230. PMID 29175027. a b Schraufnagel, Dean E.; Blasi, Francesco; Drummond, M. Bradley; Lam, David C. L.; Latif, Ehsan; Rosen, Mark J.; Sansores, Raul; Van Zyl-Smit, Richard (2014). "Electronic Cigarettes. A Position Statement of the Forum of International Respiratory Societies". American Journal of Respiratory and Critical Care Medicine. 190 (6): 611–618. doi: 10.1164/rccm.201407-1198PP. ISSN 1073-449X. PMID 25006874. S2CID 43763340.

E-Cigars in the UK

Thirión-Romero, Ireri; Pérez-Padilla, Rogelio; Zabert, Gustavo; Barrientos-Gutiérrez, Inti (2019). "Respiratory Impact of Electronic Cigarettes and Low-Risk Tobacco". Revista de investigación Clínica. 71 (1): 17–27. doi: 10.24875/RIC.18002616. ISSN 0034-8376. PMID 30810544. S2CID 73511138.

One of the challenges in studying e-cigarettes is that there are hundreds of brands and models of e-cigarettes sold that vary in the design and operation of the devices and composition of the liquid, and the technology continues to change. [160] E-cigarettes have not been subjected to the same type of efficacy testing as nicotine replacement products. [161] There are also social concerns - use of e-cigarettes may normalize tobacco use and prolong cigarette use for people who could have quit instead, or it could put extra pressure on smokers to stop cigarette smoking because e-cigarettes are a more socially acceptable alternative. [124] The evidence indicates smokers are more frequently able to completely quit smoking using tank devices compared to cigalikes, which may be due to their more efficient nicotine delivery. [162] Other devices to deliver inhaled nicotine have been developed. [397] They aim to mimic the ritual and behavioral aspects of traditional cigarettes. [397] A small number of studies have looked at whether using e-cigarettes reduces the number of cigarettes smokers consume. [147] E-cigarette use may decrease the number of cigarettes smoked, [148] but smoking just one to four cigarettes daily greatly increases the risk of cardiovascular disease compared to not smoking. [83] The extent to which decreasing cigarette smoking with vaping leads to quitting is unknown. [149] In 2022, after two years of review, the Food and Drug Administration (FDA) denied Juul's application to keep its tobacco and menthol flavored vaping products on the market. [341] Critics of this denial note that research published in Nicotine and Tobacco Research found that smokers who transitioned to Juuls in North America were significantly more likely to switch to vaping than those in the United Kingdom who only had access to lower-strength nicotine products. [342] This happens as the Biden Administration seeks to mandate low-nicotine cigarettes which, critics note, is not what makes cigarettes dangerous. [343] They also note that vaping does not contain many of the components that make smoking dangerous such as the combustion process and certain chemicals that are present in cigarettes that are not present in vape products.Pax Labs has developed vaporizers that heats the leaves of tobacco to deliver nicotine in a vapor. [408] [409] In June 2015, they introduced Juul a type of e-cigarette which delivers 10 times as much nicotine as other e-cigarettes, equivalent to an actual cigarette puff. [385] Juul was spun off from Pax Labs in June 2017 and is now available by the independent company Juul Labs. [410] The eTron 3T from Vapor Tobacco Manufacturing, launched in December 2014, [411] employs a patented, aqueous system whereby the tobacco is extracted into water. [412] The e-liquid contains organic tobacco, organic glycerin, and water. [411] The gateway hypothesis is the idea that using less harmful drugs can lead to more harmful ones. [59] Evidence shows that many users who begin by vaping will go on to also smoke traditional cigarettes. [60] [61] [62] [63] People with mental illnesses, who as a group are more susceptible to nicotine addiction, are at particularly high risk of dual use. [64] [65] The core concern is that smokers who could have quit entirely will develop an alternative nicotine addiction. [118] Dual use may be an increased risk to a smoker who continues to use even a minimal amount of traditional cigarettes, rather than quitting. [83] Because of the convenience of e-cigarettes, it may further increase the risk of addiction. [125] The promotion of vaping as a harm reduction aid is premature, [126] while a 2011 review found they appear to have the potential to lower tobacco-related death and disease. [118] Evidence to substantiate the potential of vaping to lower tobacco-related death and disease is unknown. [127] The health benefits of reducing cigarette use while vaping is unclear. [128] E-cigarettes could have an influential role in tobacco harm reduction. [124] The authors warned against the potential harm of excessive regulation and advised health professionals to consider advising smokers who are reluctant to quit by other methods to switch to e-cigarettes as a safer alternative to smoking. [129]

Since 2016 the US Food and Drug Administration (US FDA) regulated e-cigarettes under the classification of tobacco products and labeled them as electronic nicotine delivery systems. [191] A 2018 report commissioned by the US FDA decided to use the term e-cigarettes, indicating that for some use e-liquids containing no nicotine. [191] As of 2018 [update], 95% of e-cigarette devices were made in China, [30] mainly in Shenzhen. [372] [373] Chinese companies' market share of e-liquid is low. [374] In 2014, online and offline sales started to increase. [375] Since combustible cigarettes are relatively inexpensive in China a lower price may not be a large factor in marketing vaping products over there. [375] a b c d Siu, AL (22 September 2015). "Behavioral and Pharmacotherapy Interventions for Tobacco Smoking Cessation in Adults, Including Pregnant Women: U.S. Preventive Services Task Force Recommendation Statement". Annals of Internal Medicine. 163 (8): 622–634. doi: 10.7326/M15-2023. PMID 26389730. Long-term exposure to nicotine can also result in downregulation of glutamate transporter 1. [209] Long-term nicotine exposure upregulates cortical nicotinic receptors, but it also lowers the activity of the nicotinic receptors in the cortical vasodilation region. [210] These effects are not easily understood. [210] With constant use of nicotine, tolerance occurs at least partially as a result of the development of new nicotinic acetylcholine receptors in the brain. [206] The health risks of e-cigarettes are not known for certain, but the risk of serious adverse events is thought to be low, [94] [21] and e-cigarettes are likely safer than combusted tobacco products. [note 5] [89] [96] However, this does not mean that e-cigarettes are harmless. E-cigarette use is associated with increased risk of chronic obstructive pulmonary disease, asthma, [97] chronic bronchitis, and emphysema. Those who use e-cigarettes daily have higher risk than those who use them occasionally. [98] According to the National Academies of Sciences, Engineering, and Medicine, "Laboratory tests of e-cigarette ingredients, in vitro toxicological tests, and short-term human studies suggest that e-cigarettes are likely to be far less harmful than combustible tobacco cigarettes." [11] Randomized controlled trials provide "high-certainty" evidence e-cigarette containing nicotine are more effective than nicotine replacement therapy for discontinuing tobacco smoking, and moderate‐certainty evidence that they are more effective than e-cigarettes free of nicotine. [22] [note 6]

Electronic Cigar: What Are the Benefits?

a b Farsalinos KE; Spyrou A; Tsimopoulou K; Stefopoulos C; Romagna G; Voudris V (2014). "Nicotine absorption from electronic cigarette use: Comparison between first and new-generation devices". Scientific Reports. 4: 4133. Bibcode: 2014NatSR...4E4133F. doi: 10.1038/srep04133. PMC 3935206. PMID 24569565. Despite these earlier efforts, Hon Lik, a Chinese pharmacist and inventor, who worked as a research pharmacist for a company producing ginseng products, [259] is frequently credited with the invention of the modern e-cigarette. [242] Hon quit smoking after his father, also a heavy smoker, died of lung cancer. [259] In 2001, he thought of using a high frequency, piezoelectric ultrasound-emitting element to vaporize a pressurized jet of liquid containing nicotine. [260] This design creates a smoke-like vapor. [259] Hon said that using resistance heating obtained better results and the difficulty was to scale down the device to a small enough size. [260] Hon's invention was intended to be an alternative to smoking. [260] Hon Lik sees the e-cigarette as comparable to the "digital camera taking over from the analogue camera." [261] Ultimately, Hon Lik did not quit smoking. He is now a dual user, both smoking and vaping. [262] The Ruyan e-cigar was first launched in China in 2004. [263] The mixture used in vapor products such as e-cigarettes is called e-liquid. [33] E-liquid formulations vary widely. [27] [34] A typical e-liquid is composed of propylene glycol and glycerin (95%) and a combination of flavorings, nicotine, and other additives (5%). [35] [36] The flavorings may be natural, artificial, [34] or organic. [37] Over 80 harmful chemicals such as formaldehyde and metallic nanoparticles have been found in e-liquids at trace quantities. [38] There are many e-liquid manufacturers, [39] and more than 15,000 flavors. [40]