Electronic Cigarettes: Potential Risks and Benefits

Release Date: July 1, 2014

Expiration Date: July 31, 2016

FACULTY:

Michelle Lamb, PharmD, CDE, BC-ACP
Clinical Assistant Professor
University of Oklahoma College of Pharmacy
Tulsa, Oklahoma

FACULTY DISCLOSURE STATEMENTS:

Dr. Lamb has no actual or potential conflict of interest in relation to this activity.

Postgraduate Healthcare Education, LLC does not view the existence of relationships as an implication of bias or that the value of the material is decreased. The content of the activity was planned to be balanced, objective, and scientifically rigorous. Occasionally, authors may express opinions that represent their own viewpoint. Conclusions drawn by participants should be derived from objective analysis of scientific data.

ACCREDITATION STATEMENT:

Pharmacy
acpePostgraduate Healthcare Education, LLC is accredited by the Accreditation Council for Pharmacy Education as a provider of continuing pharmacy education.
UAN: 0430-0000-14-028-H01-P
Credits: 2.0 hours (0.20 ceu)
Type of Activity: Knowledge

FEE INFORMATION:

Payment of $6.50 required for exam to be graded.

TARGET AUDIENCE:

This accredited activity is targeted to pharmacists. Estimated time to complete this activity is 120 minutes.

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DISCLAIMER:

Participants have an implied responsibility to use the newly acquired information to enhance patient outcomes and their own professional development. The information presented in this activity is not meant to serve as a guideline for patient management. Any procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this activity should not be used by clinicians without evaluation of their patients' conditions and possible contraindications or dangers in use, review of any applicable manufacturer's product information, and comparison with recommendations of other authorities.

GOAL:

To provide pharmacists with an overview of the characteristics of and risks associated with use of electronic cigarettes (e-cigarettes) as well as a discussion on the potential role of this device in smoking cessation and proposed considerations for future research.

OBJECTIVES:

After completing this activity, the participant should be able to:

  1. Recall components of one-, two-, and three-piece e-cigarette designs.
  2. Describe proposed FDA regulation of e-cigarettes and accessories.
  3. List potential health risks associated with the use of e-cigarettes.
  4. Discuss results of studies investigating the role of e-cigarettes in smoking cessation.
  5. Identify the role of the pharmacist in public education regarding risks and the role of e-cigarettes.

ABSTRACT: As the popularity of the electronic cigarette (e-cigarette) has grown since its introduction in 2007, so has the controversy related to this new nicotine-delivery device. Manufacturers have stated that the aerosols and vapor in e-cigarettes are "tar free" and lack carcinogens associated with traditional cigarettes, but the e-cigarette's true safety profile and potential role as a smoking cessation tool are yet to be determined. A study by the FDA found potentially harmful chemicals in some tested products, including diethylene glycol and tobacco-specific nitrosamines, as well as the presence of nicotine in products advertised as nicotine-free. It is anticipated that additional studies on safety and efficacy of these devices will provide pharmacists definitive information on how to counsel patients about using such products and their potential role in smoking cessation.

Despite the current controversy and novelty associated with electronic cigarettes (e-cigarettes), the concept of water vapor as a vehicle for nicotine delivery to the lungs is not new. Use of a hookah (also known as a water pipe) is a practice that has been embraced for hundreds of years and has also seen a dramatic increase in popularity, with a surge in hookah bars and cafes, often located near colleges and universities.1 E-cigarettes were first produced and patented in China in 2004 by a Beijing-based company, Ruyan Group (Holdings) Ltd, and were introduced to the U.S. market in 2007.2

Interest in e-cigarettes has surged, as evidenced by Google labeling electronic cigarettes as a "breakout term," meaning a phrase that has experienced a change in growth of greater than 5,000%. Another study found that Internet searches for e-cigarettes surpassed the number of searches for nicotine replacement therapy or varenicline (Chantix).3

How E-cigarettes Work

Most e-cigarettes resemble an ordinary cigarette, but some are designed to look like cigars, pipes, or even pens or computer memory sticks.4 The user clicks a button on the e-cigarette, activating a microcircuit and releasing a puff of vaporized nicotine.2, 5 The lit end of the e-cigarette may illuminate an orange or blue tip that simulates a traditional cigarette despite the lack of a combustion reaction.5 The similarity to smoking a traditional cigarette may provide a coping mechanism through the "hand-to-mouth" action,6 replicating some of the behavioral aspects of smoking. Some products even emit an aroma that is similar to tobacco.7 In comparison to conventional cigarettes, e-cigarettes are harder, colder, and heavier and require stronger suction.6

The battery found within the canister heats up the fluid-filled cartridge. Each cartridge contains flavoring agents, propylene glycol, glycerin, water, and other chemicals, although the exact combination of components varies by manufacturer and distributor.8 There are multiple variations of the device including a one-piece disposable unit, a two-piece design with rechargeable battery and nicotine cartridge with atomizer, and a three-piece design with rechargeable battery, an atomizer, and a replaceable nicotine cartridge. The cartridge of the three-piece design can be refilled with solution called "liquid," "e-liquid," or "juice," available in a variety of nicotine strengths and in flavors such as mint, strawberry, and orange. (Please see FIGURE 1 for additional detail.) Refill cartridges are usually provided with the three-piece device. Users remove the cartridge of the three-piece unit and add three to five drops of the liquid onto the atomizer in a practice known as dripping.9

New users may go through a learning curve when first starting to use e-cigarettes due to the complexity of the device. For example, components are not fully interchangeable, mismatched components can block airflow, and new users must become practiced in how to activate the atomizer to heat the liquid prior to inhalation using a manual switch or a "priming puff" before inhalation.9

The act of using e-cigarettes is also called vaping, because the user inhales vapor, not smoke. Other terms for this nicotine delivery device include personal vaporizers, PVs, or "vapes."2 The World Health Organization has termed these devices electronic nicotine delivery systems (ENDS).10 The vapor produced is a visible mist but does not contain flame or smoke.2 The mist from e-cigarettes is inhaled into the lung and allows for rapid absorption of nicotine into the blood, relieving craving and withdrawal symptoms associated with cessation of cigarette smoking.11 TABLE 1 describes other vocabulary and terminology associated with e-cigarettes.9

Manufacturer Information

Although unable to claim benefit for the e-cigarette as a smoking cessation aid without FDA approval, manufacturers of these devices advertise that the aerosols and vapor are "tar-free" and lack carcinogens associated with traditional cigarettes. Most of the growth in e-cigarette popularity may be attributed to Internet marketing, but the presence of e-cigarettes at U.S. shopping mall kiosks has been observed.12 (TABLE 2 lists some of the available brands.) Sample language from a one-piece (disposable) e-cigarette package insert reads as follows2:

PACKAGE INFORMATION 4.5% NICOTINE BY VOLUME.
WARNING: Products are not smoking cessation devices and have not been tested as such. The U.S. FDA has not approved products for any use and they are not intended to diagnose, cure, mitigate, treat, or prevent disorder, diseases, or physical or mental conditions. Products contain nicotine, a chemical known to the State of California to cause birth defects or other reproductive harm. Nicotine is very addictive and habit forming and is very toxic by inhalation, in contact with the skin, or if swallowed. Ingestion of the non-vaporized concentrated ingredients in the cartridge can be poisonous. Physical effects of nicotine may induce increased heart rate and accelerated blood pressure. If the cartridge is swallowed, seek medical assistance immediately. Products are intended for use by adults of legal smoking age (18 or older in California) and not by children, women who are pregnant or breastfeeding, or persons with or at high risk of heart disease, high blood pressure, diabetes, or taking medication for depression or asthma. Products may not be sold to minors. Identification of all persons under 16 will be required before purchase. Keep out of reach of children. Results may vary depending on usage.

PACKAGE INSERT
From its size, feel, and look to its amazing taste, it gives you everything you love about the smoking experience. So go ahead and give it a try. To begin take a long slow puff on the cigarette—no lighting or charging required. The tip will light up each time you puff. Each cigarette lasts up to 2 packs but may vary depending on usage. You'll know it's time for a new one when the red light blinks on and off.
2

Regulation

Historically, tobacco products (such as traditional cigarettes) have gone largely unregulated. For example, the FDA attempted to regulate cigarettes in 1996 under jurisdiction of the Food, Drug, and Cosmetic Act of 1938 (FDCA), but the courts found that the FDA did not have legal jurisdiction. However, on June 9, 2009, President Barack Obama signed the Family Smoking Prevention and Control Act granting the FDA authority to regulate tobacco products.7 The FDA classified the e-cigarette as a drug-delivery device in 2009 and stated that e-cigarettes would be regulated under the FDCA. The devices were banned for import at that time, but the ban was challenged and overturned on the premise that the devices were not actually marketed for a therapeutic purpose (i.e., smoking cessation) and thus could not be regulated as a drug-delivery device.2

The FDA has issued a proposed rule that would extend the agency's authority to cover additional types of tobacco products, such as e-cigarettes, cigars, pipe tobacco, certain dissolvables that are not "smokeless tobacco," nicotine gels, and water pipe tobacco.13-15 Public comments on the proposed rule will be accepted for 75 days beginning April 25, 2014 (comment period now extended to August 8, 2014), followed by possible changes and a 2-year window for manufacturers to apply to the FDA for product approval. The proposed regulation will also require manufacturers to register their products with the FDA, including full disclosure of ingredients, manufacturer processes, and scientific data. At this time, expensive "premium cigars" as well as e-cigarette liquid without nicotine will not be included under these regulations.13-15

The FDA has banned candy-flavored tobacco products, including e-cigarettes.5 All flavors are banned for conventional cigarettes, with the exception of menthol.13 Eventual FDA regulation will require the agency to review e-cigarette product design, function, formulation, labeling, and promotion (e.g., Internet statements), as well as information used to describe the intended use of the product (e.g., patents).7 Some countries have banned e-cigarettes outright due to safety concerns and unapproved regulatory status (e.g., Australia, Brazil, Canada, Panama). On a local level, some states (e.g., New Jersey, New York) have tried to prohibit sales or not allow the use of e-cigarettes in public according to existing smoking bans.5

Reasons for Use

Users state several reasons for smoking e-cigarettes: to quit smoking, to reduce the number of cigarettes consumed, to relieve withdrawal symptoms (e.g., due to workplace restrictions), and to continue to have the "smoking experience" with perceived fewer health risks.6 Users may also cite cleaner and fresher breath, absence of odors in clothing and hair, significantly lower cost than traditional cigarettes, and the ability to use the device in settings where traditional cigarettes are not allowed.6,10 Ingestion of nicotine (regardless of delivery device) is also associated with euphoric and sedative effects and beneficial effects on attention, concentration, and mood. Users have also identified positive effects on the respiratory system after switching from traditional to e-cigarettes such as breathing better and coughing less, as well as restored sense of taste and smell.9,11 Users may also perceive the e-cigarette as less bothersome to nonsmokers and may use it to avoid having to go outside.2,16 Users may prefer smoking cessation strategies that involve e-cigarettes (or nicotine replacement) over pharmacologic approaches because these products do not require an office visit with a medical professional.

Reasons for dissatisfaction with e-cigarettes include complaints that early models had leaky cartridges, insufficient amounts of vapor or nicotine, poor battery life, and not enough volume of visible vapor.6 Other negative aspects stated by users are that e-cigarettes are too big or heavy and too often friends or colleagues ask to have use of the device explained to them.11

Public health concerns related to e-cigarettes include their possible use as a "starter" product for nonusers of tobacco and the unknown abuse potential of the product. A study evaluating the abuse liability assessment of e-cigarettes examined the nicotine-delivery profile as well as subjective and cardiovascular effects of an e-cigarette after six 10-puff bouts with the device.3 An additional outcome included the relative reinforcing efficacy of e-cigarettes utilizing a multiple-choice procedure. This study found that although the e-cigarettes delivered significant amounts of nicotine and reduced cigarette cravings, the devices appeared to have lower potential for abuse than traditional tobacco cigarettes.3

E-cigarettes look like traditional cigarettes, so their expanded use may increase the social acceptability of smoking in general.4 Concern also exists that these devices may prove especially popular with younger users due to the novelty of the delivery device, easy accessibility, and variety of flavorings.17

Patterns of Use

Utilization of e-cigarettes among middle and high school students is increasing. A report released in September 2013 summarizing data from the 2011 and 2012 National Youth Tobacco survey (NYTS) found the following results: "Ever" e-cigarette use among middle school students increased from 1.4% to 2.7%, and current e-cigarette use increased from 0.3% to 0.7%. Similar patterns were seen among high school students, with "ever" e-cigarette use increasing from 4.7% to 10.0% and current e-cigarette use increasing from 1.5% to 2.8%.18

As experimentation and use are expected to continue to rise, these statistics are of unique concern due to the potential negative impact of nicotine in the adolescent brain and the absence of strategies to prevent marketing, sales, and use among youth.18 A focus group study aimed at exploring young adults' favorable perception of e-cigarettes looked at general perceptions of new tobacco products and e-cigarettes.19 This study of young adults between 18 and 26 years of age found that participants believed e-cigarettes to be accessible and convenient, with the advantage that the user did not need a lighter or have to spit. Participants also described e-cigarettes as "high tech" and suitable for younger and new generations of smokers and said that these devices were "definitely a lot healthier than cigarettes because you don't get all of the additives." Other findings from this study include statements from young adults that they believed users would "just keep smoking cigarettes, but try all this new stuff too" and that nonsmokers would start with e-cigarettes "because [I am] not smoking [with these products]."19

Role in Smoking Cessation

Although the role of e-cigarettes has not been determined, the devastating impact of tobacco smoking is a global pandemic, resulting in nearly 6 million tobacco-related deaths per year, making it the most important cause of preventable mortality in the world.6 It is important for the clinician and pharmacist to recall that other proven effective smoking cessation interventions exist. Nicotine replacement therapy (NRT) can double the quit rate of patients who want to stop using cigarettes, but even with the use of these medications, quit rates remain low. The relapse rate of smokers within the first 6 months is approximately 93% for users of NRT.20 This may be in part because NRT in patch or other oral formulation addresses the withdrawal symptoms associated with cessation but does not address the behavioral aspects ingrained with the addiction (e.g., socialization associated with smoking breaks, hand-to-mouth motion).

A qualitative study by Barbeau et al found multiple themes that help explain the appeal of e-cigarettes over NRT as a smoking cessation tool.20

Biobehavioral feedback: Users felt that the e-cigarette more closely mimicked smoking a real cigarette in terms of the inhalation experience, sensation of smoke against the throat, and alignment with smoking "routine," i.e., coffee breaks.

Social benefits: Users of e-cigarettes may find solidarity in a "vaping community" with the ability to ask questions and find support from other users. Social aspects may also include vaping clubs or discussion groups.

Hobby elements: Users may perceive vaping as more of a hobby or experience than as a means to quit nicotine. For example, participants in the study stated enjoyment related to mixing and matching different e-cigarette parts or blending "juice" flavors and bases.

Personal identity: Participants in this study also felt a connection to other "vapers." Former smokers who had lost that sense of identity stated they can now have a group with whom they can discuss flavors and types of e-cigarettes rather than brands of cigarettes, both online and in person.20

A New Zealand study published in the Lancet in September 2013 compared e-cigarettes to traditional NRT.21 The study took place over a 22-month period and randomized 657 smokers who desired to quit conventional cigarettes into one of three groups: nicotine e-cigarettes, nicotine patches, or placebo e-cigarettes. The study found the verified abstinence rates to be 7.3% (21 of 289) of participants in the nicotine e-cigarette group, 5.8% (17 of 295) in the patch group, and 4.1% (3 of 73) in the placebo group. Despite promising results, this trial was insufficiently powered to conclude whether e-cigarettes were superior to patches, and there were no significant differences in adverse effects found in the nicotine e-cigarette group compared to the nicotine patch group.21 More research will be needed to determine if experimenters will convert to regular or daily use.

Prescription nicotine inhalers (e.g., Nicotrol Inhaler, Nicorette Inhaler) have been approved by the FDA for use as a smoking cessation aid since 1997. However, these devices, which consist of a cartridge that contains nicotine and a mouthpiece, are not widely used. A study by Steinburg et al found that in comparison to nicotine inhalers, e-cigarettes provided more satisfaction and higher perceived benefit.22

Safety Concerns

An analysis by the FDA's Center for Drug Evaluation and Research (CDER) sampled two of the leading brands of e-cigarettes and found that of 18 samples tested, one contained diethylene glycol (an ingredient found in antifreeze) and that half of the samples contained tobacco-specific nitrosamines, a human carcinogen.2 In addition, the FDA has found that "light" e-cigarettes (labeled as nicotine-free) may still contain nicotine. Other potentially harmful ingredients in e-cigarettes may include irritants, genotoxins, and animal carcinogens.18

Fine particulate matter (PM) appears to be lower in e-cigarettes than traditional cigarettes. A study of fine and ultrafine PM emissions found higher particulate counts in traditional cigarette smoke versus e-cigarette vapors (PM10 = 922 vs. 52 mcg/m3 and PM1 = 80 vs. 14 mcg/m3).17

The aforementioned study by the CDER also found that nicotine per puff ranged from 26.8 to 43.2 mcg nicotine/100 mL, and independent studies have shown that the advertised amount of nicotine content may be inaccurate.2 The presence or absence of nicotine in these products is important since nicotine is a highly addictive substance associated with accelerated coronary artery disease, acute cardiac ischemic events, and hypertension. Additional adverse health effects associated with nicotine include stroke, poor wound healing, peptic ulcer disease, and esophageal reflux.7 In addition, nicotine reduces sensitivity to insulin and may worsen diabetes as well as contribute to endothelial dysfunction.6

Much is still unknown about the effect of e-cigarettes on lung function. A "puff," or the act of drawing air from the e-cigarette, requires more force than from a traditional cigarette, creating a nonuniform dosing pattern, which may be harmful to the user's health. One study on the safety of e-cigarettes noted an association between increased puffing time with e-cigarettes and dizziness brought about by hyperventilation.6 In addition, a research study examining the effects of e-cigarettes found participants in the e-cigarette group showing higher respiratory load, oxidative stress, and peripheral airway-flow resistance than users in the control group.2

A study by Vardavas et al recruited healthy smokers without chronic lung disease to evaluate the effects of e-cigarette vapors on airway mechanics.23 Subjects inhaled vapors of a commercially available e-cigarette for 5 minutes. Results found that compared to control subjects inhaling vaporless control cigarettes, subjects in the e-cigarette group experienced significant increase in airway resistance and significant decreases in fraction of exhaled nitric oxide (FENO). No significant effects were found on FEV1 (forced expiratory volume in 1 second), FVC (forced vital capacity), or the FEV1/FVC ratio. The pattern of these results is similar to those expected shortly after inhalation of tobacco smoke.10

Other safety concerns include explosion of the e-cigarette and contaminated and/or toxic liquids.2 One study analyzing the cartomizer (combined atomizer and cartridge) contents and aerosols found the presence of metal and silicate particulates, demonstrating the need for improved quality control in e-cigarette design and manufacture.24 Most of the discussion about safety of these devices is related to nicotine and carcinogenic components, but McCauley and colleagues published a case report of lipoid pneumonia in an e-cigarette user thought to be related to recurrent exposure to the glycerin-based flavoring oils found in e-cigarette vapor.25 In this case, the patient's symptoms improved upon avoidance of the use of e-cigarettes. Repeated inhalation of propylene glycol is also associated with throat irritation, but animal studies have shown no deleterious effects with long-term vapor exposure.16

In response to these concerns, some manufacturers have begun using combinations of distilled water and glycerin instead of propylene glycol.16 It can also be noted that propylene glycol and glycerin are the same chemicals used in fog machines of the entertainment industry (e.g., on movie sets or at concerts).26

Another area of uncertainty regarding the safety of e-cigarettes is secondhand exposure and the impact on indoor air quality. A series of studies comparing the pollutant concentrations between e-cigarettes and tobacco smoke samples found that, as expected, tobacco smoke contained pollutants including volatile organic compounds (VOCs), carbonyls, polyaromatic hydrocarbons (PAHs), nicotine, tobacco-specific nitrosamines (TSNA), and glycols at levels considered of harm to human health, but that e-cigarettes produced very small exposures compared to traditional cigarettes, indicating no apparent risk to human health. However, it should be noted that this study was funded, in part, by the National Vapers Club, an organization focused on educating people about e-cigarettes.27

Children playing with e-cigarette devices is another safety concern. A child may be exposed to nicotine from the device or refill bottles, which could be ingested or absorbed transdermally, leading to a fatal overdose.5 E-cigarettes should be disposed of in the same manner as other products containing ion batteries (i.e., at a battery recycling center), and charging batteries should not be left unattended.28

Research Agenda

At this time, there is a paucity of credible, peer-reviewed, scientific evidence to support the use of e-cigarettes as a smoking cessation tool. A research agenda devoted to characterization of these devices should set as first priority the true safety profile of e-cigarettes, including the effects of long-term use. If these products are determined to be safe, research priorities may then shift to their efficacy as smoking cessation tools in well-designed studies. Studies should be structured so that they biochemically evaluate e-cigarettes and establish whether the nicotine delivery occurs through the mucosa of the oral cavity or via the lung. This differentiation will help determine pulmonary nicotine levels and assist with assessment of abuse liability of the e-cigarette.2

The lack of standardization and quality control among the more than 250 brands remains a concern.4 National surveys on the topic of tobacco use should include questions about the use of e-cigarettes.5 Additional studies are also needed to assess the abuse potential and product appeal of e-cigarettes among nonsmokers as well as the effect of thirdhand smoke exposure (unintentional intake of smoke on clothes, furniture, or other indoor surfaces in the absence of a device user).3

The ideal study design is still to be determined, but Bullen et al proposed the following protocol for studies used to assess the effect of e-cigarettes versus nicotine patches for smoking cessation: a parallel, three-arm, randomized trial with a stratified randomization of e-cigarettes with nicotine cartridges, e-cigarettes with placebo cartridges (i.e., no nicotine), and nicotine patches.29 In this study design, patients would receive behavioral support from a telephone "quit line" (ideally with the same intensity of support that is currently available for users who are trying to stop smoking), and abstinence would be biochemically verified using exhaled carbon monoxide. It is also unknown if any risks that are found may be ameliorated by changes in engineering of the product.29

Even with a strong study design, in the absence of regulations e-cigarette manufacturers reserve the right to change product designs at will; thus, any research on current products may not be applicable because the technology changes rapidly, thus causing research results to quickly become obsolete.11 Additional trials are also needed to characterize potential adverse effects for patients who use both conventional and e-cigarettes (i.e., practice "dual use").

Pharmacists' Role

Pharmacists may be approached by smokers who want to use e-cigarettes for smoking cessation instead of proven-effective treatments. Pharmacists are in a unique role to advise patients that there are approved products for smoking cessation including nicotine replacement therapy (e.g., patches, gum, lozenges) and the prescription drug varenicline, as well as to provide contact information for smoking support programs and hotlines (e.g., 1-800-QUIT-NOW). Pharmacists should caution potential e-cigarette users that without FDA regulation, the marketing of these products may, at a minimum, be misleading or in the worst case scenario, completely untrue. Pharmacists should remind patients of the adverse health effects associated with the use of any nicotine product, including e-cigarettes, and that as with other medications and products that are not FDA-approved, the safety of these devices should not be assumed.

REFERENCES

  1. Chan A, Murin S. Up in smoke: the fallacy of the harmless hookah. Chest. 2011;139(4):737-738.
  2. Rankin KV. E-cigarettes: what's known, what's unknown. Tex Dent J. 2013:130(5):446-452.
  3. Vansickel AR, Weaver MF, Eissenberg T. Clinical laboratory assessment of the abuse liability of an electronic cigarette. Addiction. 2012;107:1493-1500.
  4. Sugerman DT. E-cigarettes. JAMA. 2014;311(2):212.
  5. Yamin CK, Bitton A, Bates DW. E-cigarettes: a rapidly growing Internet phenomenon. Ann Intern Med. 2010;153:607-609.
  6. Caponnetto P, Campagna D, Papale G, et al. The emerging phenomenon of electronic cigarettes. Expert Rev Respir Med. 2012;6(1):63-74.
  7. Wollscheid KA, Kremzner ME. Electronic cigarettes: safety concerns and regulatory issues. Am J Health Syst Pharm. 2009;66:1740-1742.
  8. Reed JL, Gervais AA, Reid RD. Five things to know about electronic cigarettes. CMAJ. 2013:185(16):1427.
  9. McQueen A, Tower S, Sumner W. Interviews with "vapers": implications for future research with electronic cigarettes. Nicotine Tob Res. 2011;13(9):860-867.
  10. Avdalovic MV, Murin S. Electronic cigarettes: no such thing as a free lunch...or puff. Chest. 2012;141(6):1371-1372.
  11. Etter JF. Electronic cigarettes: a survey of users. BMC Public Health. 2010;10(231):1-7.
  12. Noel JK, Rees VW, Connolly GN. Electronic cigarettes: a new ‘tobacco' industry? Tob Control. 2011;20:81.
  13. Phend C. FDA to ban e-cigarette sales to minors. MedPage Today. April 24, 2014. www.medpagetoday.com/Pulmonology/Smoking/45417. Accessed May 1, 2014.
  14. FDA. Extending authorities to additional tobacco products. June 20, 2014. ww.fda.gov/TobaccoProducts/Labeling/ucm388395.htm. Accessed June 23, 2014.
  15. FDA. Deeming tobacco products to be subject to the Federal Food, Drug, and Cosmetic Act, as amended by the Family Smoking Prevention and Tobacco Control Act; regulations on the sale and distribution of tobacco products and required warning statements for tobacco products. Proposed rule. April 25, 2014. www.regulations.gov/#!documentDetail;D=FDA-2014-N-0189-0001. Accessed June 23, 2014.
  16. Wagener TL, Siegel M, Borrelli B. Electronic cigarettes: achieving a balanced perspective. Addiction. 2012;107:1545-1548.
  17. Pellegrino RM, Tinghino B, Mangiaracina G, et al. Electronic cigarettes: an evaluation of exposure to chemicals and fine particular matter (PM). Ann Ig. 2012;24(4):279-288.
  18. Corey C, Wang B, Johnson SE; CDC. Notes from the field: electronic cigarette use among middle and high school students—United States, 2011-2012. MMWR Morb Mortal Wkly Rep. 2013;62(35):729-230.
  19. Choi K, Fabian L, Mottey N, et al. Young adults' favorable perceptions of snus, dissolvable tobacco products, and electronic cigarettes: findings from a focus group study. Am J Public Health. 2012;102(11):2088-2093.
  20. Barbeau AM, Burda J, Siegel M. Perceived efficacy of e-cigarettes versus nicotine replacement therapy among successful e-cigarette users: a qualitative approach. Addict Sci Clin Pract. 2013;8(5):1-7.
  21. Bullen C, Howe C, Laugesen M. Electronic cigarettes for smoking cessation: a randomised controlled trial. Lancet. 2013;382(9905):1629-1637.
  22. Steinberg MB, Zimmermann MH, Delnevo CD, et al. E-cigarette versus nicotine inhaler: comparing the perceptions and experiences of inhaled nicotine devices. J Gen Intern Med. 2014 May 15 [Epub ahead of print].
  23. Vardavas CI, Anagnostopoulos N, Kougias M, et al. Short-term pulmonary effects of using an electronic cigarette: impact on respiratory flow resistance, impedance, and exhaled nitric oxide. Chest. 2012;141(6):1400-1406.
  24. Williams M, Villarreal A, Bozhilov K, et al. Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol. PLoS One. 2013;8(3):1-11.
  25. McCauley L, Markin C, Hosmer D. An unexpected consequence of electronic cigarette use. Chest. 2012;141(4):1110-1113.
  26. Bertholon JF, Becquemin MH, Annesi-Maesano I, et al. Electronic cigarettes: a short review. Respiration. 2013;86:433-438.
  27. McAuley TR, Hopke P, Zhao J, et al. Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality. Inhal Toxicol. 2012;24:850-857.
  28. Volcano Fine Electronic Cigarettes. E-cigarette battery storage & care guideline. http://support.volcanoecigs.com/hc/en-us/articles/201066427-e-Cigarette-Battery-Storage-Care-Guideline. Accessed June 23, 2014.
  29. Bullen C, Williman J, Howe C, et al. Study protocol for a randomised controlled trial of electronic cigarettes versus nicotine patch for smoking cessation. BMC Public Health. 2013;13(210):1-8.

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