Electronic Nicotine Delivery Systems

• Secondhand aerosol: emissions from electronic nicotine delivery systems (ENDS) that are discharged into the surrounding environment with ENDS use, both directly from the ENDS and exhaled from the lungs of the user.

• Thirdhand aerosol: ENDS emissions that remain on surfaces and in dust after ENDS use, which can be reemitted into the gas phase or react with oxidants in the environment to yield secondary pollutants.

• ENDS alternate names: electronic cigarettes, e-cigarettes, e-cigs, electronic cigars, e-cigars, electronic hookah, e-hookah, hookah sticks, personal vaporizers, mechanical mods, vape pens, and vaping devices.

ENDS, including electronic cigarettes (e-cigarettes), are handheld devices that produce an aerosol from a solution typically containing nicotine, flavoring chemicals, and carrier solvents such as propylene glycol and vegetable glycerin (glycerol) for inhalation by the user. Wide variability exists in ENDS terminology, product design, and engineering. For the purposes of the current policy statement, the term ENDS encompasses devices that are typically battery operated and produce emissions for inhalation. Alternate names for these products include electronic cigarettes, e-cigarettes, e-cigs, electronic cigars, electronic hookah, e-hookah, hookah sticks, personal vaporizers, mechanical mods, vape pens, and vaping devices.

Although commonly referred to as a vapor, the emission from ENDS is most accurately referred to as an aerosol, which is a suspension of fine particles in a gas.¹ Despite variations in terminology, ENDS products generally have several common components that include a flow sensor, aerosol generator, battery, and solution storage area.² When a user draws a breath (or “vapes”) from the device, a flow sensor detects the change in pressure and activates the aerosol generator. The generator draws the solution from the storage area and heats and/or mechanically disperses the solution, creating an aerosol. This aerosol is inhaled by the user, who then exhales it. Nonusers can be exposed to the emissions both from the aerosol that is exhaled as well as from the aerosol that is generated from the device. Some ENDS products have a light-emitting diode that simulates the lit end of a conventional cigarette.

There are more than 460 different brands of ENDS, which vary considerably in price, quality, and design.^3,4 ENDS can be purchased in various retail outlets, including vendors that sell tobacco, “vape” shops, mall kiosks, gas stations, convenience stores, grocery stores, and pharmacies, as well as through Internet vendors. ENDS can be disposable or reusable; the reusable ENDS products have a rechargeable battery.⁴ The ENDS solution storage containers also vary widely, ranging from prefilled cartridges to tank-style, large refillable cartridges.^4,5 Although many of the early “first-generation” ENDS were designed to resemble conventional cigarettes, newer ENDS models largely do not and may resemble other common objects such as a pen or flashlight.

ENDS use has increased dramatically among youth. The National Youth Tobacco Survey (NYTS) began surveying ENDS use in 2011, asking questions only about e-cigarettes. Ever use (defined by the NYTS as having ever tried an e-cigarette) among middle school students increased from 1.4% in 2011 to 3% in 2013.^6,7 Current use (defined by the NYTS as use of an e-cigarette at least 1 day in the past 30 days) among middle school students was 0.6% in 2011 and increased to 3.9% in 2014, a 650% increase.^7,8 Among high school students, ever use increased from 4.7% in 2011 to 11.9% in 2013, and current use increased from 1.5% in 2011 to 13.4% in 2014, an 890% increase.^6,–9 Other surveys of high school students have found higher current use at 17% to 18%, with ever use as high as 29%.^10,11 The 2014 NYTS and Monitoring the Future survey both documented for the first time that more teenagers used e-cigarettes in the past 30 days than any other tobacco products, including conventional cigarettes.^8,11 ENDS use has been documented as highest among male subjects, non-Hispanic white youth, and Hispanic youth.^8,12 

A 2013 survey of high school students found that e-cigarette-only users had fewer social and behavioral risk factors than conventional cigarette users, raising concern that ENDS are attracting youth who may not otherwise have used tobacco products.¹⁰ In addition, high levels of dual use of ENDS and conventional cigarettes have been noted in both adults^13,14 and youth.^6,9,10,12,15 Among youth, self-reported e-cigarette use was also associated with higher odds of ever or current conventional cigarette smoking.¹⁵ Compared with nonusers, youth who used e-cigarettes perceived them as healthier than cigarettes¹⁰; however, youth using e-cigarettes were less likely to achieve abstinence from conventional cigarettes.¹⁵ 

Youth exposure to ENDS secondhand and thirdhand aerosol has also potentially increased with the increase in adult ENDS use. The percentage of e-cigarette ever use in adults rose from 3.3% in 2010 to 8.5% in 2013, and current use increased from 1% in 2010 to 2.6% in 2013.¹³ Adult conventional cigarette smokers exhibited the largest growth in ever use of ENDS, increasing from 9.8% in 2010 to 36.5% in 2013.

The increasing awareness, sales, and use of ENDS is being fueled by the marketing and promotion of ENDS in the media, including television, movies, video games, social media, the Internet, radio and print media, billboards, and point-of-sale advertising, as well as by celebrity role models. Advertisements and promotional efforts in broadcast media have been shown to promote youth initiation and progression of tobacco use.¹⁶ ENDS companies have marketed their products with claims of being “healthier” and “safer” than conventional cigarettes; these claims have not been scientifically validated.^3,17 There are also unsubstantiated claims that ENDS can be used to “smoke anywhere” and both explicit and implicit claims that ENDS are smoking cessation aids (currently unapproved by the US Food and Drug Administration [FDA]).

Among all media outlets, ENDS advertising expenditures increased from $6.4 million in 2011 to $18.3 million in 2012, with the majority spent on magazine and television advertisements.¹⁸ Although tobacco advertisements on television have been legally banned since 1971 because of the Public Health Cigarette Smoking Act, there are no current regulations in place limiting ENDS advertisements.¹⁹ Although the current generation of children and adolescents had not previously been exposed to tobacco advertisements on television, youth exposure to television advertisements for ENDS increased by 256% from 2011 to 2013.²⁰ In 2013, 80% of US youth aged 12 to 17 years were exposed to an average of 13 ENDS advertisements over the 1-year period. Driven in part by the significant increase in marketing and promotion, ENDS sales represented a billion-dollar industry in 2013, with some forecasters predicting they will eventually surpass sales for conventional cigarettes.²¹ 

The solutions used in ENDS products (often referred to as e-liquid or e-juice) can be purchased in prepackaged cartridges or by volume to fill a refillable cartridge. ENDS solutions are also available through Internet vendors, in stores, and places where ENDS products are sold. In addition to concentrated nicotine, components of the ENDS solutions generally include flavoring chemicals and carrier solvents, such as propylene glycol and glycerol.¹ Currently, there are no federal quality standards to ensure the accuracy of ENDS solution constituents as advertised or labeled. The refillable cartridges allow the user to deliver other psychoactive substances, including marijuana.⁴ 

In addition to nicotine, numerous toxicants and carcinogens harmful to human health have been found in ENDS solutions, including aldehydes, tobacco-specific nitrosamines, metals, tobacco alkaloids, and polycyclic aromatic hydrocarbons.^1,22,23 These quantitative and qualitative studies illustrate that there are additional components in ENDS solutions that are unknown to users.

Nicotine is the major psychoactive component of an ENDS solution.¹ In a study of 35 ENDS cartridges and refill solutions, there were substantial discrepancies (as much as 89%) between the label and the actual nicotine content.²⁴ The reported nicotine concentration in ENDS solutions ranges from 0 to 36 mg/mL with cartridges that vary in size.^5,17 In comparison, a single conventional cigarette contains from 10 to 30 mg of nicotine, although the absorbed nicotine yield for a user is far less, from 0.05 to 3 mg per cigarette.^25,26 The user's actual nicotine exposure is affected by many factors, including the delivery system, nicotine pharmacokinetics, and individual consumption behavior.^27,28 

More than 7760 unique flavors of ENDS solutions are advertised, the majority of which are confectionary in nature and appealing to children.^3,29 Popular options include fruit, candy, and dessert flavors such as “Belgian waffle” and chocolate.^3,17 The most commonly offered flavors are tobacco and menthol, which are offered by 93% and 92%, respectively, of ENDS brands.³ Because cigarettes with candy and fruit flavoring encourage youth experimentation, regular use, and addiction,³⁰ flavorings (other than menthol) have been banned in conventional cigarettes since the Family Smoking Prevention and Tobacco Control Act of 2009. Although the flavoring chemicals used in ENDS solutions have been cited as “food grade” and “generally recognized as safe,” under FDA guidelines, this certification relates only to ingestion, not inhalation.²⁹ A study of ENDS solutions found that many of the flavoring chemicals contain aldehydes (known respiratory irritants) in sufficient concentrations to be of toxicological concern.²⁹ 

The carrier solvents propylene glycol and vegetable glycerin (glycerol) are used in ENDS solutions to produce an aerosol that, when heated, simulates conventional cigarette smoke.¹ Although these carrier solvents are used in other settings, insufficient data exist on the health effects of repeated long-term inhalation and exposure to these solvents.³¹ 

The aerosol generated by ENDS is inhaled and then exhaled by the user, and some of the generated aerosol may be directly discharged into the surrounding environment. This aerosol, also referred to as secondhand aerosol or secondhand vapor, can be inhaled by bystanders in a manner similar to secondhand cigarette smoke. Although ENDS advertisers often claim the secondhand aerosol is “harmless water vapor,” these claims are false: known harmful toxicants and carcinogens have been found in ENDS emissions.⁴ These include polycyclic aromatic hydrocarbons³² as well as nicotine, volatile organic compounds, ultrafine particles, and particulate matter.^32,–34 Metal and silicate particles, some of which occur at higher levels than in conventional cigarettes, have also been detected in ENDS aerosol.^35,36 

Thirdhand aerosol, as with thirdhand smoke, is the residual aerosol that remains on surfaces and in dust after ENDS use; this residual may react with oxidants in the environment to yield secondary pollutants or be reemitted into the gas phase.³⁷ Because nicotine on surfaces has been shown to be increased after ENDS use,³⁸ thirdhand aerosol is another potentially harmful unintentional source of nicotine exposure for youth. ENDS use exposes nonusers, including at-risk populations such as children and pregnant women, to nicotine and other harmful toxicants from secondhand and thirdhand aerosol.

In laboratory studies, neonatal mice exposed to the aerosol from a nicotine-containing ENDS solution had detectable levels of plasma cotinine, a metabolite of nicotine.³⁹ The mice exposed to the ENDS solution containing nicotine had decreased weight gain and impaired postnatal lung growth compared with mice exposed to room air. ENDS solutions have also been shown to be cytotoxic to human embryonic stem cells.⁴⁰ These studies raise concern for harm from in utero exposure and neonatal exposure to nicotine-containing ENDS solution.

Nicotine is highly addictive and is the primary psychoactive component causing addiction in tobacco products.²⁵ Nicotine has neurotoxic effects on the developing brain.^41,42 In early adolescence, development of executive function and neurocognitive processes in the brain has not fully matured. Adolescents are more likely to engage in experimentation with substances such as cigarettes, and they are also physiologically more vulnerable to addiction.⁴³ Particularly in adolescence, nicotine also has an effect on the brain as a “gateway” drug for cocaine and other illicit drugs.⁴⁴ 

Nicotine is derived from the tobacco plant and, in addition to being highly addictive, is toxic to humans.²⁵ Nicotine is well absorbed from the respiratory tract, mucosal surfaces, skin, and intestines; thus, nicotine exposure can occur from inhaling, ingesting, or coming in physical contact with a nicotine-containing ENDS solution.^25,45 Although symptoms of acute nicotine toxicity are generally mild and resolve within 12 hours with no treatment, large exposures can be fatal.⁴⁶ Symptoms of acute nicotine toxicity are similar to those in a nicotine-naive user and include fine tremor, nausea, tachycardia, and elevated blood pressure.²⁵ Severe poisonings generally have a biphasic reaction. Early symptoms occur within the first hour of exposure and are characterized by cholinergic excess (increased salivation, vomiting, and diaphoresis); other signs may include cardiac dysrhythmias, seizures, and muscle fasciculations. Late symptoms of severe nicotine poisoning occur between 0.5 and 4 hours and include hypotension, bradycardia, lethargy, and respiratory failure secondary to neuromuscular blockade.

Severe nicotine toxicity in children has been reported with nicotine doses as low as 2 mg.²⁵ ENDS solutions have been advertised to contain as much as 36 mg/mL of nicotine (3.6%).¹⁷ The oral lethal dose of nicotine by body weight that is estimated to kill 50% of adults is projected at between 0.8 and 13 mg/kg.^25,46 Using the mid-range estimate (6 mg/kg) of a lethal dose of nicotine, an ingestion of the contents of 2 mL (<0.5 teaspoon) of an ENDS concentrated nicotine solution could be fatal to the average 12-kg, 20-month-old child. There is significant risk of pediatric morbidity and mortality with the current unregulated packaging and volume of nicotine concentrations available in ENDS solutions.

There has been an increase in unintentional exposures and poisonings from ENDS in the United States, including inhalations, eye and skin exposures, and ingestions. Calls to poison control centers for ENDS exposures increased from 1 exposure call per month in September 2010 to 215 calls in February 2014.⁴⁵ The majority of ENDS exposures were among children 0 to 5 years of age, and 57.8% of ENDS exposures produced adverse health effects, most commonly vomiting, nausea, and eye irritation.^45,47 As of publication date, there has been 1 reported child death in the United States from ingestion of a nicotine-containing ENDS solution.⁴⁸ There has also been 1 adult death in the United States from an intentional injection of a nicotine-containing ENDS solution.⁴⁷ In addition, the lithium-ion batteries used in ENDS have reportedly caused explosions and fires, most commonly while the battery is charging. The US Fire Administration has cautioned that, because of the shape and construction of ENDS, battery failure may be more likely to result in an explosion that is propelled like a “flaming rocket.”⁴⁹ 

ENDS products have been promoted by some manufacturers, either explicitly or implicitly, as a smoking cessation aid, although they are not approved by the FDA as a smoking cessation product.^3,17 There have been limited studies on its use as a medical device. As of publication date, 1 randomized controlled clinical trial has compared nicotine-containing ENDS, nicotine-replacement therapy (21-mg nicotine patches), and placebo (no nicotine) ENDS.⁵⁰ Six-month cessation rates were low overall, and no statistically significant difference was found among the 3 groups. Notable limitations to the study included inadequate behavioral support for all groups and poor participant adherence with study treatments, which was particularly low in the nicotine patch group. Because these results are from a single study, they should be interpreted with caution, considering the low overall tobacco cessation rates in all 3 study groups. An earlier meta-analysis of tobacco dependence treatments (which did not include ENDS) found that the nicotine patch was effective for the treatment of tobacco dependence, with cessation rates of 23% with the nicotine patch alone.⁵¹ Other population-based studies have found no association between ENDS use and successful cessation of conventional cigarette use.^4,52 Overall, there is insufficient evidence to recommend the use of ENDS for smoking cessation.

Although federal regulations ban the sale of conventional cigarettes to youth aged <18 years, there are no current federal age restrictions for purchasing ENDS or ENDS products. The American Academy of Pediatrics (AAP) recommends 21 years as the minimum age of purchase for all tobacco products.⁵³ In April 2014, the FDA issued a draft regulation that would extend the agency’s tobacco authority to cover the sale and distribution of ENDS and other tobacco products similar to conventional cigarettes. Final action on this regulation is pending. Federal regulations on the content, labeling, and packaging of ENDS and ENDS solutions also do not exist as of publication date. Federal legislation is pending that would give the Consumer Product Safety Commission the authority to require child-resistant packaging on liquid nicotine containers sold to consumers. Some states have already enacted legislation mandating child-resistant packaging for ENDS solutions.

The majority of states have enacted laws prohibiting ENDS sales to minors, and a few states have enacted comprehensive laws that prohibit ENDS use in private worksites, restaurants, and bars.⁵⁴ Updated information on state ENDS laws is available by contacting the AAP Division of State Government Affairs at [email protected]. There is no current federal regulation of Internet ENDS sales. No federal laws prevent ENDS and ENDS solutions from being purchased by anyone over the Internet, regardless of age.

• a. Screen children and adolescents, parents, and caregivers for ENDS use.

Screening for ENDS use and exposure should be incorporated into the screening for tobacco use. Opportunities to screen include health supervision visits and visits for diseases that may be caused or exacerbated by tobacco smoke exposure, including ENDS secondhand or thirdhand aerosol. Because ENDS products vary widely and are referred to by many names, ask about use of these products by using specific names (eg, electronic cigarettes, e-cigarettes, e-cigs, electronic cigars, electronic hookah, e-hookah, hookah sticks, personal vaporizers, mechanical mods, vape pens, vaping devices). For more information (including an ENDS fact sheet), please refer to the AAP Julius B. Richmond Center of Excellence ENDS Web page (http://www2.aap.org/richmondcenter/ENDS.html).

• b. Counsel children and adolescents about the harms of ENDS and the importance of remaining a nonuser of ENDS and all nicotine-containing products.

As part of tobacco use prevention counseling, pediatricians should include prevention counseling about the known hazards of ENDS and the importance of not initiating use of any nicotine-containing product. Personally relevant messages may include the severity and rapid development of nicotine addiction and health effects from ENDS use, lack of regulation of ENDS products and solutions, and the contaminants in the products.

No current evidence supports the efficacy or safety of ENDS as a tobacco dependence treatment product. Tobacco-dependent parents, caregivers, and adolescents should be offered behavioral counseling and support and should be educated on, offered, and/or referred to evidence-based, FDA-approved, tobacco dependence treatment medications as appropriate for the individual’s severity of tobacco dependence and readiness to quit.⁵¹ 

For further information on tobacco cessation counseling and resources for adults and youth, please refer to the following:

• Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke⁵⁵ 

• Treating Tobacco Use and Dependence (http://www.ahrq.gov/professionals/clinicians-providers/guidelines-recommendations/tobacco/index.html)

• Clinical Effort Against Secondhand Smoke Exposure (http://www2.massgeneral.org/ceasetobacco/)

• American College of Chest Physicians Tobacco Dependence Treatment ToolKit (http://tobaccodependence.chestnet.org/)

• a. Counsel parents and caregivers that ENDS and ENDS solutions should be stored in child-resistant packaging and out of the reach of children.

Although some states have enacted legislation mandating child-resistant packaging, no current federal regulations exist for child-resistant packaging for ENDS and ENDS solutions. Although counseling should be targeted to prevention of ENDS use, if there are household users of ENDS, pediatricians should counsel parents and caregivers about child-resistant packaging, handling, and storage.

• b. Counsel parents and caregivers about strategies to reduce exposure to ENDS aerosol, such as instituting bans on ENDS use in the home and car.

The best protection from exposure to ENDS aerosol is for parents and caregivers to not use ENDS. If that is not possible, pediatricians should recommend ENDS-free policies for their home and car.

Although most exposures will not require treatment, medical management of severe acute nicotine ingestion is largely symptomatic and supportive. If an exposure occurs or there is concern for exposure, the American Association of Poison Control Centers (1-800-222-1222) should be contacted.

• a. Ban the sale to and use of ENDS for children and youth younger than 21 years.

Banning the sale of ENDS to youth younger than 21 years will decrease youth access and the potential for nicotine addiction. The AAP recommends 21 years as the minimum legal age of purchase for all tobacco products.

• b. Ban Internet sales of ENDS and ENDS solutions.

Prohibition of Internet sales can help regulate the ability to restrict the sale of ENDS to youth. Internet sales of ENDS and ENDS solutions can easily be accessed by minors and used to evade local tobacco control regulations and taxes.

• Ban all flavors in ENDS.

Because flavors have been shown to promote tobacco product use among youth,³⁰ flavoring chemicals, including menthol, should be banned in all ENDS products and solutions. Flavoring chemicals attractive to youth also have the potential to increase risk of ingestion of the ENDS solution by young children.

ENDS advertisements in media, including television, radio and print, billboards, signage, Internet, and point-of-sale (advertisements located where ENDS are sold), promote a positive image of ENDS and encourage youth purchase and use of ENDS. Any promotional activities that can be accessed by children and/or adolescents should be considered advertising to youth.

Tobacco advertisements and promotional efforts in media promote youth tobacco initiation and progression of smoking. Movies, television shows, and video games that depict ENDS or ENDS use should be rated a minimum of R, TV-MA, or Mature, respectively.

• a. Protect youth and other nonusers from secondhand and thirdhand aerosol exposure.

Because ENDS secondhand and thirdhand aerosol contains nicotine and other harmful toxicants, ENDS use should be prohibited in all public spaces. ENDS use should also be prohibited in all locations where children and youth are cared for, learn, work, and play, including workplaces, restaurants, health care facilities, child care settings, schools, dormitories, entertainment venues, parks, athletic facilities, shopping malls, restaurants, and leisure facilities. School and college campuses should prohibit the sale and use of ENDS. Prohibitions of ENDS should be included as part of tobacco-free and smoke-free laws and policies.

• b. Protect children from unintentional nicotine exposure and poisonings.

  • i. The size of ENDS concentrated nicotine solution prefilled cartridges and containers should be limited to amounts that would not be lethal to a young child if ingested.

  • ii. ENDS solutions containing nicotine should be dispensed in child-resistant packaging.

  • iii. Child-resistant caps and other packaging technologies should be used to reduce the risk of exposure to children, including those that restrict the rate and amount of flow of liquid nicotine from a container.⁵⁶ 

• c. Tax ENDS at the same rate as conventional cigarettes.

Smokers, particularly youth, are very price-sensitive⁵⁷; therefore, ENDS and ENDS solutions should be taxed at a rate sufficient to discourage their use among youth and at a level not less than state and federal taxes on conventional cigarettes.

• d. Apply funds for public health initiatives to protect youth and to study the health effects of ENDS on users and nonusers.

Research demonstrating the adverse health effects of conventional cigarette use and exposure took decades, while millions of youth and adults died of tobacco-related diseases. It is critical that the funding and development of research on ENDS, ranging from basic science of exposure to effects on public health and youth initiation, progress as quickly as the increase in youth ENDS use. Research funding should also focus on public health initiatives, including outcomes evaluations.

ENDS use is rapidly increasing among youth and, according to the most recent data, ENDS are the most common tobacco product used among youth. ENDS use has the potential to addict youth to nicotine. There are potential health harms to nonusers of ENDS because of its toxicants, including nicotine, carcinogens, and metal particles found in the secondhand and thirdhand aerosol. There has been an increase in unintentional exposures of children with acute nicotine poisoning from a concentrated nicotine–containing ENDS solution, with at least 1 child death from unintentional ingestion of an ENDS solution.

The increasing use of ENDS among youth threatens 5 decades of public health gains in successfully deglamorizing, restricting, and decreasing the use of tobacco products. Health claims of ENDS as smoking cessation aids are currently unsupported by scientific evidence. There is a crucial need for effective local, state, and federal regulation to protect children and youth from ENDS use and exposure to ENDS secondhand and thirdhand aerosol and concentrated nicotine solution.

Susan C. Walley, MD, FAAP

Brian P. Jenssen, MD, FAAP

Ruth A. Etzel, MD, PhD, FAAP, Co-chairperson

Karen M. Wilson, MD, MPH, FAAP, Co-chairperson

Sophie J. Balk, MD, FAAP

Harold J. Farber, MD, MSPH, FAAP

Judith A. Groner, MD, FAAP

John E. Moore, MD, FAAP

Janet Brishke, MPH

AAP

American Academy of Pediatrics

e-cigarettes

electronic cigarettes

ENDS

electronic nicotine delivery systems

FDA

US Food and Drug Administration

NYTS

National Youth Tobacco Survey