Final Draft 8

Final Draft 8

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  E-cigarettes safer than thereal thing? Rebecca Ngo, Hugh McGrory, Charmaine E. Tan, Dr Cían J. Henry Supervisor: Dr Alison Dougall Introduction Cigarettes and other combusted tobacco products have been recognised as public health enemy number one for almost fifty years. Despite this, 6·3 million deaths were attributed to tobacco smoking worldwide in 2010. In Ireland, tobacco use is a principle cause of preventable morbidity and mortality. Every year, approximately 5,200 deaths are tobacco related. Despite being recognised as the leading cause of a plethora of systemic and oral (often fatal) diseases, the addictive qualities of nicotine still perpetuate tobacco use in approximately 20-30% of developed populations. Although highly addictive, the adverse effects of nicotine, isolated from combusted tobacco, are purported to be minimal and thus medicinal nicotine replacement therapy (NRT) has established itself as an aid to smoking cessation. Combined with behavioural therapy and other medication, it can double or triple an individual’s probability of sustained tobacco abstinence. A novel product the “Electronic Cigarette” (EC) has gained informal recognition as an efficient nicotine delivery system, and aid to smoking cessation. ECs, or more correctly “Electronic Nicotine Delivery Systems” (ENDS), lack a universal definition but are described in broad terms as devices that “deliver to the oral cavity, upper respiratory tract, and lungs a vapourised liquid usually containing nicotine and other chemicals”. As no combustion occurs (over 300 carcinogens are generated by tobacco combustion), the inhalation of nicotine through an EC is postulated to be a safer alternative to cigarette smoking. This poster explores the science validating this assertion by reviewing the relevant literature. Safety & Adverse Effects Is the devil unknown better than the devil known? With any nicotine delivery device, health and safety are primary public health considerations. However, evidence concerning the safety of ECs is mixed. In order to definitively assure their safety, hundreds of users followed for several years in longitudinal studies are necessary. Less challenging approaches include chemical and toxicological studies, and laboratory studies of the cytotoxicity, mutagenicity, genotoxicity and oxidative stress & inflammatory responses in human cell lines. These have shown: • Potentially harmful chemicals identified in vapour and liquid, however at several magnitudes less than cigarette smoke. • Harmful substances are found for the most part in trace amounts, comparable with levels in approved forms of NRT. • No adverse effects reported in short term clinical trials; some have even shown harm reversal after cessation of smoking. • Propylene glycol, the major constituent has been deemed safe as an additive to foods. However, the effects of sustained respiratory tract exposure remain unknown. • Flavourings appear to be cytotoxic to human cells in- vitro. • Case reports of serious medical adverse effects in association with EC use, but causation cannot be extrapolated from these studies. Regulation The regulation of ECs has been an increasingly divisive element among scientific experts in the field. Some argue they should be regulated as medicinal products to protect vulnerable members of society, with others stating over regulation will stifle innovation increasing the difficulty to bring products to the market, maintaining the monopoly of tobacco in the nicotine market. However, if thoughtfully regulated, ECs could act as NRT at a population scale. The table below presents the argument both for, and against strict regulation. General Consumer Product  ECs threaten to undermine progress made by Tobacco Free Legislation by renormalising smoking in public places which may negatively impact air quality, expanding the public health risk to those who are not directly engaging with the product.  Will allow heavy users to circumvent existing laws, thus perpetuating nicotine addiction and discouraging cessation.  May encourage dual use, increasing relapse into nicotine addiction among ex-smokers  Aggressive marketing and light regulation encourages nicotine addiction which acts as “gateway drug” to tobacco cigarettes.  Enable manufacturers to continually innovate the product - enhancing nicotine delivery & encouraging mass substitution to a safer product with subsequent health benefits across the entire smoking population.  Does not require a lengthy time to obtain general product safety legislation → does not delay potential for ECs to secure potential public health gains. Tobacco Product / Medicinal Device  Existing smoke free regulations will prevent users circumventing tobacco control legislation and will discourage dual use.  Help to mitigate against use among youths and non- smokers, preventing the potential increase in the burden of nicotine addiction in society.  Strict regulation and controlled access to product will reduce potential for relapse among ex-smokers.  Prevents minors from buying products & restricts the use of flavourings, preventing appeal to youth and non-smokers.  Tighter regulation as either a tobacco product or medicinal device will stifle innovation and restrict the appeal of the product.  Smaller independent companies swallowed up by big tobacco companies, who will encourage switching from ECs to their main product, traditional cigarettes.. Conclusion Based on the evidence we can conclude that the scientific community must balance the ethical considerations of sustaining, and possibly encouraging, nicotine addiction against denying addicts access to a potentially effective, yet much less hazardous alternative. Therefore, within a climate of inadequate regulation and paucity in the evidence of the product’s safety and efficacy for smoking cessation, the dental and medical profession cannot condone this product as first line treatment in the crusade for tobacco abstinence. However, as the alternative may be combusted tobacco for a number of recent ex-smokers who are highly resistant to conventional NRT, use should not be discouraged, as this may jeopardize the quit attempt. ECs may have an important role to play in the future (especially for patients who have failed initial therapy), provided their efficacy for cessation is validated by high quality clinical trials and their long term safety guaranteed. We must always bear in mind, NRT only retains its validity if it treats nicotine addiction rather than perpetuating it. Key References 1. McRobbie H, Bullen C, Hartmann-Boyce J, Hajek P. Electronic cigarettes for smoking cessation and reduction. Cochrane Database Syst Rev. 2014;12:CD010216. 2. Brown J, West R, Beard E, Michie S, Shahab L, McNeill A. Prevalence and characteristics of e-cigarette users in Great Britain: Findings from a general population survey of smokers. Addict Behav. 2014;39(6):1120-5. 3. Stead LF, Perera R, Bullen C, Mant D, Hartmann-Boyce J, Cahill K, et al. Nicotine replacement therapy for smoking cessation. Cochrane Database Syst Rev. 2012;11:Cd000146. 4. Bullen C, Howe C, Laugesen M, McRobbie H, Parag V, Williman J, et al. Electronic cigarettes for smoking cessation: a randomised controlled trial. Lancet. 2013;382(9905):1629-37. Efficacy for Smoking Cessation Conventional NRT fails to address the behavioural rituals associated with tobacco smoking. Additionally, when compared to smoking, the nicotine delivery is modest. Proponents of the EC argue that it addresses these major failings of conventional NRT, more closely emulating the actual experience of smoking and delivering rapid and high blood concentrations of nicotine to the user. The scientific data supporting these claims are, however, weak: • A systematic review of the best available evidence has concluded that there is data from two trials that ECs assist smokers in long-term tobacco abstinence compared with placebo ECs. However, the evidence they based this conclusion upon was graded as low according to conventional standards. • None of the randomised clinical trials published to date report cessation rates beyond what is seen in unassisted/low-assistance trials using conventional NRT. In determining the efficacy of therapies for smoking cessation, “the active drug is considered effective when it outperforms the placebo”. The use of non-nicotine ECs themselves as placebos in current trials is thus considered inadequate. • Population studies have concluded that EC use does correlate with reduced tobacco smoking. However, in terms of abstinence, EC use in the real world is associated with significantly lower odds of tobacco cessation. • We must be cautious of grey literature published on the efficacy, which includes uncontrolled surveys of self-selecting populations whereby unpaid evangelicals dedicated to the EC cause bias the conclusions of these studies. The bottom line remains, higher rates of cessation are associated with NRT use coupled with behavioural therapy. Although weak evidence does point to ECs as efficacious agents for cessation; clinicians are ethically obliged to promote smoking cessation using evidence based strategies. Figure 1: The continuum of risk in relation to nicotine products (adapted from Brown et. al 2014) Figure 2: Overview of the various types of Electronic Nicotine Delivery Systems (ENDS) KEY: Positives Negatives