Journal Club-Electronic Cigarettes and Vaping as a Harm Reduction Alternative: Really?

Abstract

In the last few months I have seen 2 patients who presented with significant respiratory symptoms, (cough, shortness of breath and chest pain) that they temporally associated with use of electronic cigarettes (e-cigarettes). They were relatively new to e-cigarette use: one was a former cigarette smoker and the other was a never smoker but had a history of asthma. The severity of their symptoms had abated but they still had residual symptoms and were worried about the long-term consequences. When I went to review the literature regarding the latest data on the long-term health risks of using e-cigarettes, I noted an explosion of information being published in just the past few years. It is clear there is a great deal of controversy and concern about the introduction of these products into the marketplace without sufficient information about potential health risks nor adequate regulation over their indications, contents, and the technology used to generate their aerosol. Currently there are regular advertisements for e-cigarettes promoting them as viable and safe alternatives to cigarette smoking. One of the key initial promotions for these devices was as a smoking cessation tool despite an absence of any large double-blinded, randomized placebo-controlled trials to prove any superior efficacy to conventional smoking cessation strategies (such as nicotine replacement, bupropion hydrochloride, or the nicotine receptor partial agonists such as varenicline and counseling). More recently however, since their entry into the marketplace in the United States in 2006, manufacturers, many users, and some tobacco control experts, advocate e-cigarettes as a viable long-term harm reduction alternative to cigarette smoking without any long-term safety data. E-cigarettes have become a multi-billion-dollar industry (U.S. $ 11.3 billion in 2018) and projections suggest that their sales will surpass combustible cigarettes by 2023.1 There are few regulations concerning access to these devices and there is high utilization by teenagers and reports of use by middle school children.2 The question has been raised of whether these companies are specifically targeting this population with flavors such as “bubble gum.” There is also data to suggest that rather than reducing the risk of teenagers smoking cigarettes, use of e-cigarettes may act as a gateway to young people transitioning to smoking tobacco cigarettes. Recent studies show that adolescents and young adult e-cigarette users are at a 3 times greater risk of starting cigarette smoking compared to those who had never used e-cigarettes.3-8 (See abstracts below). The essential design of e-cigarettes includes an atomizer that uses an electrical current, generated by a battery, to heat a metal coil which aerosolizes the e-liquid conducted from a reservoir to the coil via a wick, typically made of cotton or silica. The user presses a button on the device, inhales and a plume of droplets carry the aerosol to the oropharynx and respiratory tree. E-cigarettes have evolved from cigarette look-alikes to new industrial-looking devices that afford greater control with regard to the delivery, content and nature of aerosolization as well as heat of the e-liquid. The typical constituents in most e-liquids are vegetable glycerin, propylene glycol, nicotine, water, alcohol, flavoring agents and a variety of other substances. Some e-liquids actually do not have nicotine in them but still contain various flavoring agents. The assumption has been that the elimination of tobacco tar, smoke particulate and various chemical additives and their combustible by-products renders the e- cigarettes to be a safer alternative. While this may very well be true, it is important to appreciate that the various components of the e-cigarette are not benign and can potentially pose significant health risks and there is no regulation over the content and access to these devices. Recent studies have outlined potential toxic effects from nicotine (see below) including increased airway hyper-reactivity, inflammation, reduction of host defenses and possible cardiovascular effects.9-14 While nicotine is not considered a carcinogen, there are studies to suggest it may potentiate cancer.15,16 There have also been recent studies suggesting that chronic obstructive pulmonary disease (COPD) patients may be more susceptible to potential harmful effects of e-cigarettes.17,18 There are reports of fatalities in children as young as 5 in which the e-liquids were ingested.19 The nicotine content of the e-liquid cartridges continues to be increased and there is 1 brand that offers a single e-liquid cartridge that contains the equivalent nicotine (47 mg) of 20 cigarettes (1 pack).20 Nicotine is highly addictive and with the increased stimulation of the central nervous system there is evidence not only that use of these e-cigarettes leads to some never cigarette smokerstransitioning to use of tobacco cigarettes (so called “gateway”)3,21,22 but also to the use of illicit drugs such as cannabinoids.14,23 Furthermore, studies of quality control have shown that there are inconsistencies between actual nicotine concentrations and those indicated on labeling.1,12,20,24-28 There are reported to be over 8000 flavoring agents now used in e-cigarettes. Aromatic aldehyde compounds such as cinnamon flavor, (cinnamon aldehyde), almond flavor, (benzaldehyde), and vanilla flavors (vanilla and ethyl vanilla), as well as formaldehyde, have potential toxic effects when inhaled.2,20,28-30 There are reports that some of these flavoring agents have already been associated with bronchiolitis, alveolitis and acute lung injury.1,31-33Diacetyl flavoring has been reported as a cause for bronchiolitis in microwave popcorn manufacturing workers.34,35 Despite the knowledge of this association between diacetyl and lung injury, a recent study identified its presence in 110 out of 159 tested “sweet” e- liquids.36,37 The e-cigarette metal coils have been reported to contain variable amounts of chromium, manganese, nickel, lead, copper, silver, zinc, and tin and the wicks can be made of silica.38,39 There are concerns that the higher heat settings that some devices offer can lead to the evolution of nanoparticles of these various metals38 (see article abstract below)and acrolein15 (a known carcinogen) from the various additives in the e-liquids. There also have been several reports of these devices exploding and causing major injuries.40 Hence, while e-cigarettes may indeed help some individuals to transition from the use of tobacco smoking to nicotine vaping, there is growing evidence that the ingredients, including nicotine itself, may have significant adverse health consequences. Yet there is very little information about the consequences of long-term use of these devices and they remain largely unregulated in terms of content, labeling and access. The first paper reviewed in this Journal Club is from the European Respiratory Society (ERS) Tobacco Control Committee Statement regarding e-cigarettes. The Taskforce cautions that tobacco harm reduction strategies that endorse the use of alternative nicotine delivery products for smoking cessation have not been proven to be as or more effective than traditional smoking cessation strategies and have been based upon incorrect assumptions and unfounded or undocumented claims.13 The ERS Statement emphasizes that there is lack of proof supporting claims that nicotine delivery devices such as e-cigarettes and “heated not burned” tobacco products (which eliminates combustible particulates and other components that evolve from the high heat of the actual burning of tobacco cigarettes) are efficacious in helping people to quit smoking permanently and in fact there is growing evidence that they are actually harmful to health. The Taskforce urges policymakers and public health bodies to reevaluate smoking cessation programs that involve the use of e-cigarettes and heated tobacco products and states that the Taskforce cannot recommend this approach as an effective population-based strategy. At the most recent American Thoracic Society International Conference in Dallas, Texas in May of this year, there were numerous posters and lectures on e-cigarettes and a large scientific symposium entitled, “Addicting a New Generation: JUULing, Vaping, Heat Not Burn, Flavorings and the Evidence for Why We Should Be Very Concerned.” Many of the topics outlined above were covered and the organizers emphasized the critical need for further research in several different areas. In this Journal Club we review the ERS task force report and some of the most recent studies looking at e-cigarettes as a method of harm reduction in smoking cessation, the potential that these new devices may actually have significant health effects, the likelihood of e-cigarettes leading to never tobacco smokers becoming tobacco smokers and concerns regarding the urgent need for research studies that can lead to informed and appropriate subsequent policy and regulation of these products. Note: Abstracts are presented in their original, published format and have not been edited to match JCOPDF style.