Nicotine is highly addictive.[9][10][11] Users become physically and psychologically dependent.[12] Scientists do not know how harmful e-cigarettes are over the long-term[13][14] because it is hard to separate the effects of vaping from the effects of smoking when so many people both vape and smoke.[note 4][15] E-cigarettes have not been used widely enough or for long enough to be sure.[16][17][18]
Vaping is likely far less harmful than smoking, but still harmful.[19][20][21] E-cigarette vapor contains far fewer toxins than cigarette smoke, and at much lower concentrations. The vapor contains traces of harmful substances not found in cigarette smoke.[21] E-cigarettes containing nicotine are more effective than nicotine replacement therapy (NRT) for smoking cessation.[22][23] However, e-cigarettes have not been subject to the same rigorous testing that most nicotine replacement therapy products have,[24] and health warnings may encourage a smoker to quit vaping.[25]
^Miyasato, K. (March 2013). "[Psychiatric and psychological features of nicotine dependence]". Nihon Rinsho. Japanese Journal of Clinical Medicine (in Japanese). 71 (3): 477–481. PMID23631239.
^Walley, Susan C.; Wilson, Karen M.; Winickoff, Jonathan P.; Groner, Judith (1 June 2019). "A Public Health Crisis: Electronic Cigarettes, Vape, and JUUL". Pediatrics. 143 (6): e20182741. doi:10.1542/peds.2018-2741. PMID31122947. S2CID163165584. Because e-cigarettes have only been marketed for ~10 years... scientific data are limited and will continue to emerge. Because e-cigarette solutions and emissions have been shown to contain nicotine and many of the same harmful toxicants and carcinogens as cigarettes, it is reasonable to assume that there is the potential for similar health effects for e-cigarette use, particularly with emerging data of tobacco toxicant exposure found among e-cigarette users.
^Gotts, Jeffrey E; Jordt, Sven-Eric; McConnell, Rob; Tarran, Robert (30 September 2019). "What are the respiratory effects of e-cigarettes?". BMJ. 366: l5275. doi:10.1136/bmj.l5275. PMC7850161. PMID31570493. We reiterate that, to date, no long term vaping toxicological/safety studies have been done in humans; without these data, saying with certainty that e-cigarettes are safer than combustible cigarettes is impossible.
^Bals, Robert; Boyd, Jeanette; Esposito, Susanna; Foronjy, Robert; Hiemstra, Pieter; Jiménez-Ruiz, Carlos A.; Katsaounou, Paraskevi; Lindberg, Anne; Metz, Carlos; Schober, Wolfgang; Spira, Avrum; Blasi, Francesco (February 2019). "Electronic cigarettes: a task force report from the European Respiratory Society". European Respiratory Journal. 53 (2): 1801151. doi:10.1183/13993003.01151-2018. ISSN0903-1936. PMID30464018. S2CID53711734. The long-term effects of ECIG use are unknown, and there is therefore no evidence that ECIGs are safer than tobacco in the long term. Based on current knowledge, negative health effects cannot be ruled out.
^ abBalfour, David J. K.; Benowitz, Neal L.; Colby, Suzanne M.; Hatsukami, Dorothy K.; Lando, Harry A.; Leischow, Scott J.; Lerman, Caryn; Mermelstein, Robin J.; Niaura, Raymond; Perkins, Kenneth A.; Pomerleau, Ovide F.; Rigotti, Nancy A.; Swan, Gary E.; Warner, Kenneth E.; West, Robert (September 2021). "Balancing Consideration of the Risks and Benefits of E-Cigarettes". American Journal of Public Health. 111 (9): 1661–1672. doi:10.2105/AJPH.2021.306416. PMC8589069. PMID34410826. Among potentially toxic substances common to both products, cigarette smoke generally contains substantially larger quantities than e-cigarette aerosol. However, e-cigarette aerosol contains some substances not found in cigarette smoke."
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