1. E-cigarettes
safer than the real 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