Electronic Cigarettes: Common Questions and Answers


Electronic cigarettes (e-cigarettes) are popular devices designed to heat a liquid solution, often containing nicotine, that generates an inhaled aerosol, or vapor. e-Cigarettes have been marketed as healthier alternatives to traditional cigarettes. Thus, most adult users are current or former smokers who use e-cigarettes to reduce or quit cigarette smoking. Switching completely from cigarettes to e-cigarettes is associated with reduced toxicant exposure and reduced short-term respiratory symptoms; however, long-term health effects of e-cigarettes are unknown. Although a recent randomized trial suggests that e-cigarettes may promote smoking cessation, systematic reviews have had low certainty of evidence regarding cessation. e-Cigarettes pose several potential health risks, including exposure to heavy metals and toxicants, and nicotine poisoning. e-Cigarettes are also popular among youth, with rates of e-cigarette use surpassing those of cigarette use in this population. Youth e-cigarette use is associated with increased risk of subsequent cigarette and marijuana use. Screening for e-cigarette use in youth and adults, including pregnant women, in conjunction with screening for tobacco use, is advised. Education and interventions to prevent e-cigarette use should be provided to all youth. Youth should be counseled to stop using nicotine/tobacco products, including e-cigarettes. Although the impact of e-cigarette use in pregnancy is unknown, nicotine is a teratogen; thus, pregnant women should be counseled to abstain from using all nicotine/tobacco products.

What Is an e-Cigarette?

Electronic cigarettes (e-cigarettes) are battery-operated devices that heat a liquid solution to generate an aerosol that users inhale. The liquid solution in most e-cigarettes contains nicotine, the primary addictive agent in traditional cigarettes, and is available in a variety of flavors. Because e-cigarette aerosol is commonly called vapor, patients may refer to e-cigarette use as vaping. Currently, the most popular e-cigarette brand is Juul, which uses small, rectangular flavored cartridges that resemble a thumb drive. Most adults report using e-cigarettes to reduce or stop cigarette smoking.


Among U.S. youth, rates of e-cigarette use surpassed rates of traditional cigarette use in 2014. In 2017, one in five U.S. high school students reported using e-cigarettes in the previous year.

A recent meta-analysis indicated that among teens and young adults who have never smoked, the odds of smoking initiation are three to six times greater in those who have ever used e-cigarettes than in those who have never used e-cigarettes.

The U.S. Preventive Services Task Force concludes that the current evidence is insufficient to recommend e-cigarettes for tobacco cessation in adults, including pregnant women.

e-cigarette = electronic cigarette.

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Clinical recommendationEvidence ratingComments

Ask about e-cigarettes when screening for tobacco use in youth and adults, including pregnant women. Multiple terms should be used, including slang terms and brand names (especially Juul), to help identify all e-cigarette users.8,40,41


Computerized school-based surveys conducted at two high schools (n = 1,960)

e-Cigarettes, e-cigarette liquids, and all products containing nicotine should be kept out of reach of children. Adults should be counseled on safe storage practices and symptoms of nicotine poisoning.24,25


Case-series studies (review of 8,269 exposures registered in the National Poison Data System between January 2012 and April 2017); review of 26 case reports

Women should be counseled and assisted with quitting all nicotine/tobacco products, including e-cigarettes, during pregnancy.29


Narrative review of 326 human and animal studies

e-Cigarettes are not recommended for youth. Youth should be counseled to stop all nicotine/tobacco products, including e-cigarettes.4,30


Consensus guidelines (surgeon general's report and policy statement of the American Academy of Pediatrics)

Smokers should be counseled to quit using evidence-based smoking cessation guidelines, including behavioral counseling and/or U.S. Food and Drug Administration–approved smoking cessation products.12,37,39,40


Two systematic reviews/meta-analyses with a small number of studies and low certainty of evidence; one recent positive randomized controlled trial

If evidence-based smoking cessation methods are ineffective or the patient does not comply with them, e-cigarettes may be discussed for smoking cessation

The Authors

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MICHAEL D. KLEIN, MD, FAAFP, is a clinical assistant professor in the Department of Family Medicine at the Warren Alpert Medical School of Brown University, Providence, R.I., and a physician shareholder at Compass Medical, Easton, Mass....

NATASHA A. SOKOL, ScD, is a postdoctoral fellow at the Center for Alcohol and Addiction Studies at the Brown University School of Public Health, Providence, R.I.

LAURA R. STROUD, PhD, is a professor in the Department of Psychiatry and Human Behavior at the Warren Alpert Medical School of Brown University and is a senior research scientist at the Centers for Behavioral and Preventive Medicine at The Miriam Hospital, Providence, R.I.

Address correspondence to Michael D. Klein, MD, FAAFP, Dept. of Family Medicine, 111 Brewster St., Pawtucket, RI 02860 (email: Michael_D_Klein@brown.edu). Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.


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1. Glasser AM, Collins L, Pearson JL, et al. Overview of electronic nicotine delivery systems: a systematic review. Am J Prev Med. 2017;52(2):e33–e66....

2. Collins L, Glasser AM, Abudayyeh H, et al. e-Cigarette marketing and communication: how e-cigarette companies market e-cigarettes and the public engages with e-cigarette information. Nicotine Tob Res. 2019;21(1):14–24.

3. Stratton KR, Kwan LY, Eaton DL. National Academies of Sciences, Engineering, and Medicine. Public Health Consequences of E-Cigarettes. National Academies Press; 2018.

4. U.S. Department of Health and Human Services. e-Cigarette use among youth and young adults. A report of the Surgeon General. 2016. Accessed May 12, 2019. https://bit.ly/2sKHv9P

5. Marynak KL, Gammon DG, Rogers T, et al. Sales of nicotine-containing electronic cigarette products: United States, 2015. Am J Public Health. 2017;107(5):702–705.

6. Singh T, Kennedy S, Marynak K, et al. Characteristics of electronic cigarette use among middle and high school students—United States, 2015. MMWR Morb Mortal Wkly Rep. 2016;65(50–51):1425–1429.

7. Zhu SH, Sun JY, Bonnevie E, et al. Four hundred and sixty brands of e-cigarettes and counting: implications for product regulation. Tob Control. 2014;23(suppl 3):iii3–iii9.

8. Morean ME, Camenga DR, Bold KW, et al. Querying about the use of specific e-cigarette devices may enhance accurate measurement of e-cigarette prevalence rates among high school students [published online November 5, 2018]. Nicotine Tob Res. Accessed May 9, 2019. https://bit.ly/2VOZ3wg

9. Tobacco21 Idaho. Stamping out jargon: understanding e-cigarettes, vaping and more. Accessed May 8, 2019. https://tobacco21idaho.org/understanding-jargon-e-cigarettes-vaping/

10. Tobacco free Rhode Island. e-Cigarette glossary of vaping terms. Accessed May 8, 2019. http://tobaccofree-ri.org/Training-EcigGlossary.pdf

11. Bao W, Xu G, Lu J, et al. Changes in electronic cigarette use among adults in the United States, 2014–2016. JAMA. 2018;319(19):2039–2041.

12. El Dib R, Suzumura EA, Akl EA, et al. Electronic nicotine delivery systems and/or electronic non-nicotine delivery systems for tobacco smoking cessation or reduction: a systematic review and meta-analysis. BMJ Open. 2017;7(2):e012680.

13. Verplaetse TL, Moore KE, Pittman BP, et al. Intersection of e-cigarette use and gender on transitions in cigarette smoking status: findings across waves 1 and 2 of the Population Assessment of Tobacco and Health (PATH) study [published online September 19, 2018]. Nicotine Tob Res. Accessed May 9, 2019. https://bit.ly/2GiMXF3

14. Stanton CA, Bansal-Travers M, Johnson AL, et al. Longitudinal e-cigarette and cigarette use among US youth in the PATH study (2013–2015) [published online January 25, 2019]. J Natl Cancer Inst. Accessed May 9, 2019. https://bit.ly/2IoJw37

15. Johnston LD, O'Malley PM, Miech RA, et al. Monitoring the Future. National survey results on drug use: 1975–2015. 2015 overview. Key findings on adolescent drug use. Accessed May 9, 2019. https://bit.ly/2GnoHCw

16. Cullen KA, Ambrose BK, Gentzke AS, et al. Notes from the field: use of electronic cigarettes and any tobacco product among middle and high school students—United States, 2011–2018. MMWR Morb Mortal Wkly Rep. 2018;67(45):1276–1277.

17. Barrington-Trimis JL, Leventhal AM. Adolescents' use of “pod mod” e-cigarettes—urgent concerns. N Engl J Med. 2018;379(12):1099–1102.

18. Hammond D, Wackowski OA, Reid JL, et al.; International Tobacco Control Policy Evaluation Project Team. Use of Juul e-cigarettes among youth in the United States [published online October 27, 2018]. Nicotine Tob Res. Accessed May 9, 2019. https://bit.ly/2GuF40z

19. Goniewicz ML, Gawron M, Smith DM, et al. Exposure to nicotine and selected toxicants in cigarette smokers who switched to electronic cigarettes: a longitudinal within-subjects observational study. Nicotine Tob Res. 2017;19(2):160–167.

20. Cibella F, Campagna D, Caponnetto P, et al. Lung function and respiratory symptoms in a randomized smoking cessation trial of electronic cigarettes. Clin Sci (Lond). 2016;130(21):1929–1937.

21. Polosa R, Morjaria JB, Caponnetto P, et al. Evidence for harm reduction in COPD smokers who switch to electronic cigarettes. Respir Res. 2016;17(1):166.

22. Peace MR, Baird TR, Smith N, et al. Concentration of nicotine and glycols in 27 electronic cigarette formulations. J Anal Toxicol. 2016;40(6):403–407.

23. Goniewicz ML, Knysak J, Gawron M, et al. Levels of selected carcinogens and toxicants in vapour from electronic cigarettes. Tob Control. 2014;23(2):133–139.

24. Govindarajan P, Spiller HA, Casavant MJ, et al. e-Cigarette and liquid nicotine exposures among young children. Pediatrics. 2018;141(5):e20173361.

25. Patterson SB, Beckett AR, Lintner A, et al. A novel classification system for injuries after electronic cigarette explosions. J Burn Care Res. 2017;38(1):e95–e100.

26. Liu B, Xu G, Rong S, et al. National estimates of e-cigarette use among pregnant and nonpregnant women of reproductive age in the United States, 2014-2017 [published online April 29, 2019.] JAMA Pediatr. Accessed July 14, 2019. https://jamanetwork.com/journals/jamapediatrics/fullarticle/2732142

27. Drake P, Driscoll AK, Mathews TJ. Cigarette smoking during pregnancy: United States, 2016. NCHS Data Brief. 2018 Feb;(305):1–8.

28. McCubbin A, Fallin-Bennett A, Barnett J, et al. Perceptions and use of electronic cigarettes in pregnancy. Health Educ Res. 2017;32(1):22–32.

29. England LJ, Aagaard K, Bloch M, et al. Developmental toxicity of nicotine: a transdisciplinary synthesis and implications for emerging tobacco products. Neurosci Biobehav Rev. 2017;72:176–189.

30. Jenssen BP, Walley SC; Section on Tobacco Control. e-Cigarettes and similar devices. Pediatrics. 2019;143(2):e20183652.

31. Soneji S, Barrington-Trimis JL, Wills TA, et al. Association between initial use of e-cigarettes and subsequent cigarette smoking among adolescents and young adults. JAMA Pediatr. 2017;171(8):788–797.

32. Dai H, Catley D, Richter KP, et al. Electronic cigarettes and future marijuana use. Pediatrics. 2018;141(5):e20173787.

33. Hoffman AC, Salgado RV, Dresler C, et al. Flavour preferences in youth versus adults: a review. Tob Control. 2016;25(suppl 2):ii32–ii39.

34. Siqueira LM; Committee on Substance Use and Prevention. Nicotine and tobacco as substances of abuse in children and adolescents. Pediatrics. 2017;139(1):e20163436.

35. Wang TW, Marynak KL, Agaku IT, et al. Secondhand exposure to electronic cigarette aerosol among US youths. JAMA Pediatr. 2017;171(5):490–492.

36. Bayly JE, Bernat D, Porter L, et al. Secondhand exposure to aerosols from electronic nicotine delivery systems and asthma exacerbations among youth with asthma. Chest. 2019;155(1):88–93.

37. Hartmann-Boyce J, McRobbie H, Bullen C, et al. Electronic cigarettes for smoking cessation. Cochrane Database Syst Rev. 2016;(9):CD010216.

38. Halpern SD, Harhay MO, Saulsgiver K, et al. A pragmatic trial of e-cigarettes, incentives, and drugs for smoking cessation. N Engl J Med. 2018;378(24):2302–2310.

39. Hajek P, Phillips-Waller A, Przulj D, et al. A randomized trial of e-cigarettes versus nicotine-replacement therapy. N Engl J Med. 2019;380(7):629–637.

40. U.S. Preventive Services Task Force. Tobacco smoking cessation in adults, including pregnant women. Accessed May 9, 2019. https://bit.ly/2e1fcer

41. Pbert L, Farber H, Horn K, et al.; American Academy of Pediatrics, Julius B. Richmond Center of Excellence Tobacco Consortium. State-of-the-art office-based interventions to eliminate youth tobacco use: the past decade. Pediatrics. 2015;135(4):734–747.



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