Comment on E-Cigarettes and Cardiovascular Risk: Beyond Science and Mysticism
The letter referring to our article[1] on the effect of electronic cigarettes (e-cigarette) on human health by Farsalinos
et al is both interesting and of value.[2] The authors basically argue against two issues that we discussed in our previous
narrative review, that is, the cardiovascular risk attributable to nicotine and the
effective toxicity of liquid nicotine present in e-cigarettes. Besides the fact that
the biological evidence available on e-cigarette smoking remains to date rather limited,
some aspects need to be highlighted.
As regard the effect of nicotine on cardiovascular risk, two of the articles used
by Farsalinos et al[2] in support of a lack of plausible connection are fairly dated, being respectively
published in 1996 and 1998.[3]
[4] A more recent meta-analysis on smokeless tobacco and risk of myocardial infarction
and stroke published by Boffetta and Straif in 2009 concluded that the relative risk
for ever use of smokeless tobacco products was 1.13 (95% confidence interval [95%
CI], 1.06–1.21) for myocardial infarction and 1.40 (95% CI, 1.28–1.54) for fatal stroke.[5] Also, at variance with what is stated in their correspondence,[2] data about the cardiovascular potential of nicotine are contradictory. Besides episodic
case reports of patients developing acute myocardial infarction while using nicotine
patches,[6]
[7] additional population studies described a high rate of cardiovascular complications
in patients using these sticking plasters.[8]
[9] Even from a biological perspective, the statement that nicotine has minimal effects
in initiating and propagating atherosclerosis is questionable, as recent studies have
shown that this compound binds to nicotinic acetylcholine receptors and accelerates
the atherogenic process.[10] Therefore, although we would agree that nicotine replacement therapies (NRTs) present
a lesser hazard than continuing to smoke because there exists unquestionable data
supporting that use of NRTs carries much lower risks than traditional tobacco smoking,
our leading concern relates to the potential health effects of these devices on adolescent
and nonsmokers.[11] After decades of effective work to reduce cigarette smoking, the widespread availability
of e-cigarettes raises the question of whether these devices are reintroducing a form
of smoking to many adolescents, who may respond positively to advertising claims that
e-cigarettes are safe.[12] Once accustomed to e-cigarettes use, they may then be subjected to adverse side
effects of these devices or, even worse, prompted to shift to traditional tobacco
smoking.
We also dispute the statement by the authors[2] that we have exaggerated the toxicity of liquid nicotine present in e-cigarettes.
The number of case reports regarding toxicity of nicotine-containing solutions is
constantly growing in the scientific literature.[13]
[14]
[15]
[16] Moreover, a recent study investigating the nicotine concentration of several nicotine-containing
solutions has concluded that these mixtures could be toxic or lethal if taken other
than as directed, even at potentially lower levels of nicotine than expected using
manufacturer specifications.[17]
[18]
In conclusion, although we respect the points of view raised by Farsalinos et al,[2] at this point in time it seems premature and potentially hazardous to conclude that
e-cigarette use and/or nicotine intake are unlikely to significantly elevate harm.
Major caution should be observed until the outcome of randomized, perspective studies
on e-cigarette use become available.
