Electronic cigarettes and vaping products are subjecting adolescents and young adults who use them to severe lung injuries from nicotine exposure. Here’s how to counsel your young patients about the health risks of these devices.
Figure 1 - Reproduced with permission from JAMA Pediatrics. 2015;169(2):177-182.
The use of electronic cigarettes (e-cigarettes), known commonly as vaping, has increased significantly among the pediatric and adolescent population in the past several years. Currently, e-cigarettes are the most frequently used tobacco product by young persons.1 Of ongoing concern is a new study reporting that adolescents in the United States are initiating e-cigarette use at earlier ages. In 2014, 8.8% of lifetime e-cigarette users initiated use at age 14 years or younger, whereas in 2018 this number increased to 28.6%.2
On December 18, 2018, the US Surgeon General declared e-cigarette use among adolescents an “epidemic.” Although the most recent focus has been on the nationwide outbreak of severe lung injuries associated with the use of e-cigarette or vaping products, it is important to understand the historical context surrounding this public health issue facing the pediatric population.
Brief history of JUUL
Following widespread recognition of the dangers associated with cigarette smoking in the mid-20th century, the rate of conventional tobacco use declined significantly such that, in 2015, only 14% of the US population identified as smokers.3 This decline was attributed to several successful public health initiatives including a higher price of cigarettes, Tobacco 21 initiatives (which raised the minimum age to legally purchase tobacco products to 21 years), and increased antismoking education, all of which led to fewer young people starting to smoke.3 However, in 2006, e-cigarettes were developed and introduced as a safe alternative to combustible tobacco use as well as a tobacco cessation tool.
Following their introduction, e-cigarettes, commonly known as “vaping,” became increasingly popular among the adolescent and young adult population, even in those who had no prior combustible tobacco use.4 Cited reasons included the variety of flavors available that made nicotine more palatable, especially to those who did not previously use combustible tobacco; lower cost than traditional cigarettes; social acceptability among peers; widespread advertising; and the myth that e-cigarettes are less harmful than traditional cigarettes.
In 2016, as e-cigarette use was declining among teenagers, JUUL was introduced, leading to a resurgence in use among adolescents.5 Extrapolated data suggests that in 2019, an estimated 4.1 million high school students and 1.2 million middle school students used e-cigarettes, with an estimated 1.6 million students reporting “frequent use” and 970,000 reporting “daily use.”6 JUUL was unique in that its pod contained significantly more nicotine (either 3% or 5%, or one pod equivalent to 1 to 2 packs of conventional cigarettes) compared with the majority of e-cigarette brands (0% to 2.4%).7
The nicotine in JUUL is in a salt formulation that allows a high level of nicotine to be inhaled more easily with less irritation than the traditional base, with expedited absorption and crossing of the blood-brain barrier leading to an increased “high.”8 JUUL’s sleek design allowed it to be used covertly in public settings. Most concerning, however, is that approximately 63% of adolescent and young adult users reportedly did not know that JUUL always contains nicotine.8
Characteristics of e-cigarette devices and liquids
There are many different types and brands of e-cigarettes available but generally they all have the same components, including a battery, heating coil, atomizer (transforms the e-liquid to an aerosol), cartridge (contains e-liquid), and mouthpiece, and operate in a similar manner. E-liquids typically contain nicotine, flavorings, and a humectant.4 Each component of an e-cigarette has the potential to affect health outcomes independently but also interact to cause different effects.
Prior to the widespread distribution of e-cigarettes, there was very little research regarding the short- term and long-term health effects of use and a lack of quality control performed on marketed devices and liquids. Whereas the health effects of nicotine are well-documented, the effects of nicotine delivered as an aerosol as compared with a constituent in combustible smoke are not well understood.9 Additionally, although most flavorings have been thoroughly evaluated for safety when included in food and ingested, their effects when they enter the bloodstream through inhalation is less well studied. Similarly, there is very little known about the effects of inhaling aerosolized humectants such as propylene glycol and glycerol.
The heating coils and atomizer influence the properties of the aerosol and therefore can add additional health effects. For example, if the heating power is too high, it can create a negative sensation, known as a “dry hit,” in users that likely results from thermal decomposition of the humectants, causing the formation of byproducts such as toxic carbonyl compounds.10,11 In some devices, e-liquids come in direct contact with the heating coils, known as “dripping,” which can introduce metals and other components into the aerosol that is then inhaled by users.
The most recently developed devices, and those most commonly used by adolescents including the JUUL, bear no resemblance to traditional cigarettes or previous generations of e-cigarettes, and allow users to mix their own filler liquids. Of note, many e-liquids now contain tetrahydrocannabinol (THC) in addition to or instead of nicotine.
Specific health risks in the pediatric/adolescent population
The rise in e-cigarette use and vaping among adolescents is especially concerning given that many of the long-term hazards are relatively unknown, and despite the perception that e-cigarettes are less harmful than and a safer alternative to traditional combustible tobacco products, they are far from harmless. The negative health effects of nicotine are well documented in the literature and include an increased risk for cardiovascular disease, stroke, respiratory disease, and cancer, as well as significant potential for long-term addiction. Studies have shown that the adolescent brain in particular is uniquely susceptible to nicotine addiction,12 and animal studies have shown that nicotine exposure during adolescence has longstanding effects on the brain, leading to both immediate and persistent behavioral changes.
E-cigarette use leads to an increase in cough, impairs mucociliary clearance making individuals more susceptible to infection,13 and increases the rate of exacerbations in individuals with asthma.14,15 E-cigarette use has the potential to damage endothelial vessels, which increases the risk for cardiovascular disease. Furthermore, in vitro and in vivo studies have shown an association between e-cigarette use and oxidative stress, inflammation, and an impaired innate immune response, which leads to immune dysregulation and the potential for the development of malignancy.9
Especially important in the adolescent and young adult population is the potential for addiction. The Population Assessment of Tobacco and Health (PATH) Study is currently investigating the behavioral and adverse health impact of tobacco use by studying how and why individuals start using tobacco, switch products or modalities, quit using, and then potentially start using again, with a specific focus on the adolescent and young adult population.
E-cigarettes, and especially the JUUL given its high percentage of nicotine, have been shown to lead to and increase nicotine addiction in adolescents with even intermittent exposure resulting in increased smoking frequency, intensity, and/or duration, and serve as a gateway product to long-term combustible tobacco use16 or other inhalant drug use, especially THC and marijuana.17 The amount of nicotine contained in e-cigarettes, and subsequently found in the blood stream and brain of users, is highly variable and dependent on product characteristics (device and e-liquid), how the device is used, and user characteristics (experienced smoker versus naÃ¯ve smoker).9 Given this variability, it may be less than, equal to, or considerably more than that of traditional combustible cigarettes.
Additionally, the secondhand aerosol emitted from e-cigarettes is different from that of conventional cigarettes because it is directly inhaled from the device without the generation of sidestream smoke. Therefore, the aerosol emitted is almost 100% mainstream and has been shown to be comprised primarily of small liquid droplets versus the solid and semisolid material that makes up secondhand tobacco smoke.9
Studies have shown that concentrations of carbonyls, such as formaldehyde and acetaldehyde, are significantly higher (2 to 125 times) in exhaled e-cigarette breaths compared with background breaths.18 Additionally, airborne nicotine, measured as cotinine, was found to be higher in homes where individuals used e-cigarettes as compared with controls, and cotinine of nonsmokers exposed to e-cigarette users was higher than in those not exposed.19 This is of particular importance when considering pediatric patients who may not be using e-cigarettes themselves but may have significant exposure through parents and other caregivers.
Injuries from unintentional exposure to both e-cigarette solutions and e-cigarette devices have been reported in pediatric patients. E-cigarette liquid nicotine exposures, which occur primarily via ingestion, have increased by 1085% from 2012 to 2016.20 The high concentration of nicotine in some e-cigarette solutions can cause significant damage to children even in small volumes and has resulted in at least 1 death.
Most recently, vaping and e-cigarette use have been tied to multiple cases of acute respiratory distress syndrome, now termed e-cigarette/vaping acute lung injury (EVALI). As of December 2019, a total of 2409 patients had been hospitalized throughout the United States with 52 deaths reported.21 The median patient age was 24 years; 67% were male; and the largest number of weekly hospitalized cases occurred during the week of September 15, 2019, with a slow decrease in the number of cases since then. Overall, 80% of hospitalized patients with EVALI reported using THC-containing e-liquids. Vitamin E acetate, a cutting agent often added to THC vape cartridges in order to dilute the THC content and boost profit margins, has been isolated from the majority of samples tested, and further investigation is ongoing.21 Although the vast majority of these patients experienced improvement in their acute respiratory symptoms, currently there is not enough evidence to prognosticate about long-term outcomes and effects on lung function.
Given the risk of pediatric and adolescent vaping, particularly as a stepping-stone to combustible cigarette use, reversing the vaping epidemic in the form of prevention and education should be a priority for all health care professionals. The American Academy of Pediatrics (AAP) as well as the American Thoracic Society recommend that pediatric health care providers screen for e-cigarette use when screening patients for tobacco use and tobacco-smoke exposure.
For parents, caregivers, and adolescents who use tobacco, the AAP clinical practice policy recommends offering nicotine replacement therapy (NRT) and other tobacco-use treatment to address use and eliminate exposure. Most importantly, however, advocacy initiatives that were previously successful in lowering cigarette use can be employed to reduce vaping, such as raising the price of e-cigarettes; ensuring that no one aged younger than 21 years can buy e-cigarettes; better education on the dangers of vaping; eliminating advertising; and immediate regulation by the US Food and Drug Administration of all e-cigarette products.
Note from Dr. Lee
Electronic cigarettes in their marketed forms should not be simply viewed as a safe nicotine replacement delivery system. Additional concerns for being able to modify these devices to inhale other toxic substances has resulted in significant morbidity and mortality.
-Carlton Lee, PharmD, MPH, FASHP, FFPAG
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