Cigarettes on the cardiovascular system

Impact of Electronic Cigarettes on the Cardiovascular System
Hanan Qasim, BPharm; Zubair A. Karim, PhD; Jose O. Rivera, PharmD; Fadi T. Khasawneh, PhD; Fatima Z. Alshbool, PharmD, PhD
Tobacco smoking is a major public health threat for both
smokers and nonsmokers. There is accumulating evi-
dence demonstrating that smoking causes several human
diseases, including those affecting the cardiovascular system.
Indeed, tobacco smoking is responsible for up to 30% of heart
disease–related deaths in the United States each year.1
This
is the single most preventable risk factor related to the
development of cardiovascular disease, bringing about a trend
toward tobacco harm reduction that started years ago.2
As
tobacco usage declined over time in the United States,
industries introduced an alternative known as electronic
cigarettes (e-cigarettes) claiming they were a healthier
alternative to tobacco smoking.3
Since then, the number of e-cigarette users has increased
significantly because of the perception that they serve as a
healthy substitute to tobacco consumption with minimal or no
harm, a lack of usage regulations (although that has now
changed), and the appealing nature of these devices, among
other reasons.4
Consequently, e-cigarettes became the most
commonly used smoking products, especially among youth,
with more than a 9-fold increase in usage from 2011 to
2015.5
Based on these considerations, it is clear that there
are many unanswered questions regarding the overall safety,
efficacy of harm reduction, and the long-term health impact of
these devices.
Besides their potential negative health effects on users,
there is increasing evidence that e-cigarettes emit consider-
able levels of toxicants, such as nicotine, volatile organic
compounds, and carbonyls, in addition to releasing particulate
matter (PM).6,7
Thus, they possess a potential harm to
nonusers either through secondhand or thirdhand exposure.
This is especially the case in vulnerable populations, such as
children, elderly, pregnant females, and those with a history of
cardiovascular disease.8
Thus, it is critical to establish
e-cigarettes’ short- and long-term health effects on both
users and nonusers. In this review, we will discuss the current
state of literature regarding the potential negative cardiovas-
cular effects of direct/active and passive e-cigarette expo-
sure. Furthermore, we will review the possible impact of the
individual constituents of the e-cigarette on hemodynamics
and their contribution to the development of cardiovascular
disease. The notion that e-cigarettes may negatively impact
the cardiovascular system should uncover new avenues of
research focused on establishing and understanding the
safety of e-cigarette usage on human health.
E-Cigarettes
E-cigarettes, also known as vape pens, e-cigars, or vaping
devices, are electronic nicotine delivering systems, which
generate an aerosolized mixture containing flavored liquids
and nicotine that is inhaled by the user.9
The extensive
diversity of e-cigarettes arises from the various nicotine
concentrations present in e-liquids, miscellaneous volumes of
e-liquids per product, different carrier compounds, additives,
flavors, and battery voltage.9
Regardless of the exact design,
each e-cigarette device has a common functioning system,
which is composed of a rechargeable lithium battery,
vaporization chamber, and a cartridge (Figure 1). The lithium
battery functions as the powerhouse; it is connected to the
vaporization chamber that contains the atomizer9
(Figure 1).
In order to deliver nicotine to the lungs, the user inhales
through a mouthpiece, and the airflow triggers a sensor that
then switches on the atomizer.9–11
Finally, the atomizer
vaporizes liquid nicotine in a small cartridge (Figure 1) and
delivers it to the lungs.9
With regard to their design, there are 4 generations of
devices currently on the market.4
The first-generation e-
cigarettes are the “ciga-like” devices, which are utilized mainly
by new e-cigarette users; they are constructed of a cartomizer
(cartridge and an atomizer) with a low-voltage battery
(3.7 V).4,12–14
Second-generation e-cigarettes are primarily
used by more-experienced users and are bigger in size with a
refillable tank (unlike first-generation devices).4,13,14
Their
battery voltage is adjustable, allowing users to use low or high
voltage (3–6 V) during vaping.4,13,14
The third-generation
From the Department of Pharmaceutical Sciences, School of Pharmacy, The
University of Texas El Paso, El Paso, TX.
Correspondence to: Fatima Z. Alshbool, PharmD, PhD, 500 W University Dr,
El Paso, TX 79968. E-mail: fzalshbool@utep.edu
J Am Heart Assoc. 2017;6:e006353. DOI: 10.1161/JAHA.117.006353.
ª 2017 The Authors. Published on behalf of the American Heart Association,
Inc., by Wiley. This is an open access article under the terms of the Creative
Commons Attribution-NonCommercial License, which permits use,
distribution and reproduction in any medium, provided the original work is
properly cited and is not used for commercial purposes.
DOI: 10.1161/JAHA.117.006353 Journal of the American Heart Association 1
CONTEMPORARY REVIEW
byguestonSeptember26,2017http://jaha.ahajournals.org/Downloadedfrom

devices are also known as mods and have the largest size
batteries, with voltages up to 8 V.13
Finally, the fourth and
most recent generation includes Sub ohm tanks (devices
whose atomizer coils have a resistance of less than 1 ohm)
and temperature control devices, which allow for temperature
modulation during vaping. With these devices, the “vaper” can
inhale huge puff volumes, leading to extremely high e-liquid
consumption per puff.4
Taken together, there is diversity in e-cigarette designs,
which has an effect on the levels of ingredients being
delivered to the user and the environment (including
nonusers). This variability also complicates our ability to
assess the health consequences of e-cigarettes.
Prevalence of e-Cigarette Usage
Since their introduction in 2007, e-cigarettes have experienced
widespread success among smokers, nonsmokers, pregnant
females, and even youth. Their sales increased by 14-fold since
2008,15
contributing to scientists’ desire/necessity to evalu-
ate their safety, population patterns, and usage reasons.16
Usage patterns vary depending on consumers’ age group.4
In
adults, usage increased over the past decade to include 3.8% of
US adults, of which almost 16% are current cigarette smokers,
whereas 22% are former smokers.17
Importantly, almost 3.2%
of individuals who never smoked before/na€ıve have tried
e-cigarettes, reflecting exposure to harmful chemicals for
“neoteric” purposes.17,18
In fact, adults primarily use
e-cigarettes to discontinue smoking because they perceive
them to be: (1) a healthier choice, which can reduce nicotine
cravings, and (2) less harmful to nonusers in their proximity.4,19
As for seniors, it appears that e-cigarettes are used to stop
smoking or to bypass smoke-free policies.20,21
Usage of e-cigarettes among the youth is mainly linked to
their curiosity and the “appealing” flavored nature of
e-liquids.19
It is alarming that this group has the highest
increase in usage18
; 5.3% of all users are middle school
students, and 16% are high school students. This is a 9- and
10-fold increase, respectively, since 2011.18
Because the brain
is only fully developed by the age of mid-twenties, youths’
exposure to nicotine may disrupt their brain development, and
hinder attention and learning, while elevating susceptibility for
addiction to nicotine or other drugs such as cocaine.22
Despite the known negative consequences of tobacco
smoking, many pregnant females continue to use e-cigarettes
based on their safety perception as compared with tobacco.23
Ironically, given that nicotine contributes to the negative
health consequences of smoking on newborns, e-cigarette
use will likely expose the fetus to nicotine, leading to adverse
effects, such as reduced cognitive deficits and perhaps even
sudden infant death syndrome.22,24,25
It is to be noted that aggressive marketing provoked a false
perception, albeit has yet to be confirmed, about the
effectiveness and safety of these devices, which further
emboldened their use.20
In light of the aggressive marketing
and the fact that e-cigarettes use is growing among all
populations, it is paramount to establish their safety profiles,
especially in vulnerable populations, and take measures to
ensure their protection.
Public Health and e-Cigarettes
The long-term health effects of e-cigarettes have not yet been
documented in humans; however, the short-term negative
effects have been suggested by several studies.8,9,26,27
These
studies focused mainly on the cytotoxic profile of e-cigarettes
Nicotine cartridge Atomizer Voltage controller
Rechargeable battery
LED indicator
Heating coilVaporizing chamber Microprocessor
Figure 1. Typical e-cigarette design. E-cigarettes are usually composed of nicotine cartridge (e-liquid container), vaporizing chamber, a heating
coil (heats e-liquid) followed by an atomizer (e-vapor generator), rechargeable battery and voltage controller (which will adjust the amount of
nicotine delivered during vaping), microcompressor, and LED indicator—not present in all types—to activate the battery and visually mimic the
conventional cigarette, respectively. LED indicates light-emitting diode.
E-Cigarettes and the Cardiovascular System Qasim et al
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and their effects on the respiratory tract,9,26,27
central
nervous system,9,10
immune system,28,29
and a few
others9,30,31
(Table 1).
As the primary system exposed to vapors from
e-cigarettes, most reported health effects have centered on
the pulmonary tract. Recent clinical and animal studies
showed that (active or passive) e-vapors/e-cigarettes may
cause irritation of both the upper and lower respiratory tract,
in addition to inducing bronchospasm and cough9,32–34
; the
latter effects may be attributed to a chain of inflammatory
reactions through oxidative stress.28
As for effects on other systems, e-cigarettes also reduce,
in mice, the efficiency of the immune system, as reflected by
the increased susceptibility to infection with influenza A and
Streptococcus pneumonia.29
As for the central nervous
system, e-cigarettes may alter brain functions, which affects
the mood, learning abilities, memory, and could even induce
drug dependence in both humans and animals.35–37
E-cigarettes may also directly damage neurons and cause
tremor and muscle spasms.9
Carcinogenicity, mostly manifested in the lungs, mouth,
and throat,30
is another important aspect of the e-cigarette’s
negative health profile; this may be linked to nitrosamines,
propylene-glycol (the major carrier in e-liquids), and even
some flavoring agents.9,31
In fact, one study indicated that
after being heated and vaporized, propylene glycol may
transform into propylene oxide, which is a class 2B carcino-
gen. Moreover, e-liquid exposure was found to exert a direct
cytotoxic effect on human embryonic stem cells and mouse
neural stem cells, highlighting a potential harm for pregnant
females.15,32
Other adverse effects include nausea, vomiting,
and contact dermatitis, as well as eye, mouth, and throat
irritation.9,31
It is noteworthy that the harm related to
e-cigarette usage reaches further beyond “beings” to include
fire hazards and explosions; issues the public tends to
underestimate.38,39
In summary, there is increasing evidence that short term
e-cigarette exposure exerts deleterious effects on multiple
biological systems, but the mechanism by which these effects
occur is presently unknown. While the long-term effects have
not yet been studied, one can predict that e-cigarettes will
likely cause more harm if used for extended periods, a notion
that also warrants investigation.
The Impact of e-Cigarettes on the
Cardiovascular System
Cardiovascular disease is the major cause of death among
smokers1
and is responsible for as much as 30% of heart
disease–related deaths in the United States each year.1
As
smokers considered safer alternatives to help them quit,
they started using e-cigarettes, in part, because they have
“lower” levels of harmful constituents.19
Nevertheless, this
notion should be reconciled in light of the high “sensitivity”
of the cardiovascular system and evidence of a nonlinear
dose-response relationship between tobacco exposure and
development of cardiovascular disease. Thus, even exposure
to low levels of harmful constituents could have a
pronounced effect, and, consequently, the reduction
of such materials in e-cigarettes does not assure a
proportional harm reduction.40
Conversely, exposure to
toxicants may not necessarily translate into a negative
health effect.
It is therefore paramount to evaluate e-cigarette’s short-
and long-term safety on the cardiovascular system, especially
given the limited studies in this area and/or their controver-
sial findings.28
Several studies suggest that e-cigarette use
acutely and negatively (increased) impacted vital signs, such
as heart rate41,42
and blood pressure.43,44
In this regard,
Andrea et al showed that heart rate acutely increased after
e-cigarettes use by smokers,41
which was also observed in a
separate study.42
Additionally, Yan et al found that
e-cigarettes elevated both diastolic blood pressure and heart
rate in smokers, but to a lesser extent when compared with
tobacco cigarettes.43
It was also found that endothelial cell dysfunction and
oxidative stress, which play important roles in the pathogenesis
of cardiovascular disease,45
are associated with e-cigarettes,
even a single use, but the effect was less pronounced compared
with cigarette smoking.46
On the other hand, relative to
cigarette smoking, e-cigarette use caused a comparable and
rapid increase in the number of circulating endothelial progen-
itor cells, which could be attributed to acute endothelial
dysfunction and/or vascular injury.47
Given that platelets are
key players in the development of cardiovascular disease—
especially thrombosis and atherosclerosis—a recent in vitro
study evaluated the effects of e-cigarettes on these cells.48
Table 1. Potential Effects of e-Cigarettes on Biological
Systems
System Effects of e-Cigarettes
Pulmonary
system
Upper and lower respiratory tract irritation9,26,27
Bronchitis, cough, and emphysema9,26,27
Immune
system
Inflammation induction28
Reduce immune efficiency29
Central
nervous
system
Behavioral changes9
Memory impairment (animal models)9,10
Tremor and muscle spasms10
Miscellaneous Ocular irritation9
Contact dermatitis and burns9,31
Nausea and vomiting9,31
Throat and mouth irritation30,31
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Consequently, e-cigarette vapor extracts were found to
enhance activation (aggregation and adhesion) of platelets
from healthy human volunteers.48
Alternatively, some studies have shown that short-term
exposure to e-cigarettes has no cardiovascular harm.49–51
These studies found that acute exposure to e-cigarettes had
no immediate effects on the coronary circulation, myocardial
function, and arterial stiffness.10,49,50
Another study
revealed no significant changes in smokers’ heart rate after
acute use of e-cigarettes.52
However, the discrepancy in
findings should be examined in the context of evidence
indicating that vaping topography (e-cigarette usage patterns
such as inhalation duration and the magnitude of inhaled
volume) and user’s experience are critical factors in
determining the health effects of e-cigarettes.39,53
The
discrepancy in the results, aside from the user’s experience
and vaping topography, which could be attributed to
differences in sample size, study groups (former smokers’
versus nonsmokers), exposure’s nature (acute versus pro-
longed), and wide variety of e-cigarette products, makes it
difficult to draw conclusions regarding the cardiovascular
health consequences of e-cigarettes. Of note, the long-term
effects of e-cigarettes have not been studied, nor has the
mechanism(s) by which they exert their effects on the
cardiovascular system.
Although some studies support and promote the idea that
e-cigarettes could be a safer alternative to tobacco, it is
important to consider (and address) the public safety of these
devices to nonusers who are in proximity and would be
subject to secondhand vaping/exposure.54
Furthermore, a
new threat, thirdhand vaping/exposure, has been discovered;
it arises from exposure to e-cigarette residues remaining on
surfaces in areas where vaping took place.55
Given that
secondhand and even thirdhand exposure to tobacco smoke
exerts toxicity, including the cardiovascular system,56
whether e-cigarettes are a source of secondhand or thirdhand
vapors was investigated. Subsequent studies provided sub-
stantial evidence that e-cigarettes are not an emission-free
device; instead, they negatively affect indoor air quality.
Specifically, e-cigarette vaping was found to release various
potentially noxious constituents.57,58
Although the indoor use of e-cigarettes was found to result
in lower levels of “secondhand and thirdhand” residues,
compared with tobacco smoke,59
these hazards are still a
health threat to those who are involuntarily exposed
(nonusers). The latter notion should be considered with
survey findings that e-cigarette users (unfortunately) do not
consider laws that prohibit tobacco smoking to apply to them
and hence vape in smoke-free areas.60
This is consistent with
another survey that showed a large proportion of middle and
high school students have been exposed to secondhand
vapes.61
Thus, research should be initiated to evaluate health
effects of secondhand and thirdhand vaping, which would, in
turn, inform (stricter) e-cigarette regulations.
The Impact of e-Cigarette Toxicants/
Constituents on the Cardiovascular System
There are limited studies on the health effects of e-cigarettes,
particularly on the cardiovascular system. Therefore, to gain a
better understanding of their possible/potential harm, we
sought to review the effects of constituents/toxicants known
to exist in e-cigarettes. In this regard, e-liquids and e-vapors are
a source of a large number of these chemicals,7,10,53,57,62–66
affecting several biological systems37,43,67–88
(Table 2). The
levels of some of these toxicants in e-cigarette aerosols are
claimed to be lower than in tobacco smoke. For instance,
several studies have shown that e-cigarette usage results in
lower volatile organic compounds levels compared with the
combustible cigarette.64,89,90
Notably, the levels of e-cigarette
chemicals appear to vary between studies, attributed to the
wide range of products on the market, different nicotine
concentrations, study designs, vaping techniques (puffing
topography), and users’ experiences.91
Nevertheless, most
studies do support the presence of carbonyl compounds,
nicotine, and particulate matter in e-cigarette liquids and/or
vapors,8,9
and those will be the focus of the discussion in the
following sections.
The Impact of Nicotine on the Cardiovascular
System
Nicotine, which is the major constituent in most smoking
products, is considered a strong alkaloid that can be absorbed
by various routes: oral mucosa, lungs, skin, or gut.93
After
absorption, nicotine is metabolized by the liver into cotinine
as one of the metabolites.94
Most e-liquids contain nicotine at
concentrations that vary between 0 and 36.6 mg/mL.95
Interestingly, it has been reported that several e-cigarette
brands inaccurately labeled nicotine concentration,96
and, in
fact, some of the “nicotine free” brands apparently contain
some.8
As expected, e-liquids with higher nicotine concen-
trations deliver more nicotine than those with lower concen-
trations.43,97
Nicotine delivery to the human body is affected by other
factors, such as the type of device used.39
Thus, studies on
first-generation e-cigarettes reported delivery of low concen-
trations of nicotine to the bloodstream,98
unlike newer-
generation devices (equipped with a high-capacity battery).13
To this end, Farsalinos et al showed a 35% to 72% increase in
nicotine delivery with newer generations of e-cigarettes,
relative to first-generation devices.13
Furthermore, although
studies have shown that conventional cigarettes result in
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quicker and 60% to 80% higher plasma nicotine levels,45,98,99
e-cigarettes vaping still could result in comparable levels,92
especially with experienced smokers who can adjust the
topography of vaping.53,62,100,101
However, e-cigarette users
take a longer time to reach such levels.53,92
Consistent with
its systemic uptake, comparable saliva and plasma levels
were reported for cotinine, which is considered one of the
major metabolites and a marker of nicotine, in both e-
cigarette users and conventional smokers.92,102,103
Collectively, these studies support the notion that e-cigarette
usage results in increased nicotine delivery to the human
body.
Table 2. Chemicals Emitted in e-Cigarette Vapors and Their Potential Health Effects
Chemical Detected Concentration Range Biological System Affected
Nicotine ND to 36.6 mg/mL10,62,63
Lung tumor promoter67
Addiction67
Gastrointestinal carcinogen67
Raises blood pressure and heart rate68
Reduce brain development in adolescents37
Cotinine ND* Reduce fertility and reproduction69
Aldehydes Acetaldehyde 0.11 to 2.94 lg/15 puffs53,64,65
Carcinogen70
Aggravation of alcohol-induced liver damage71
Acrolein 0.044 to 6.74 lg/15 puffs53,64,65
Ocular irritation72
Respiratory irritation72
Gastrointestinal irritation72
Formaldehyde 0.2 to 27.1 lg/15 puffs53,64,65
Carcinogen68
Bronchitis, pneumonia, and increase asthma risk in children73,74
Ocular, nasal, and throat irritant74
o-Methyl benzaldehyde ND to 7.1 lg/15 puffs7
Unknown
Acetone ND to 91.27
Gastric distress75
Weakness of extremities and headache75
Ocular irritation75
Volatile organic
compounds
Propylene glycol 0 to 82.875 mg/15 puffs7
Throat and airways irritation.76
Carcinogen68
Gastric distress68
Increase asthma risk in children68
Ocular irritation68
Glycerin 75 to 225 lg/15 puffs57
Lipoid pneumonia77
Ocular, dermal, and pulmonary irritant78
3-Methylbutyl-
3-methylbutanoate
1.5 to 16.5 lg/15 puffs57
Unknown
Toluene <0.63 lg/15 puffs64
CNS damage79
Renal damage80
Nitrosamines NNN 0.8 to 4.3 ng/e-cigarette64
Carcinogen87
NNK 1.1 to 28.3 ng/e-cigarette64
Carcinogen87
Metals Chromium ND to 0.0105 lg/15 puffs7,66
Pulmonary irritation and inflammation, nasal mucosa
atrophy and ulcerations81
Nasal mucosa atrophy, reduce fertility and reproduction82
Cadmium ND to 0.022 lg/15 puffs64,66
Increase risk of lung cancer83
Pulmonary and nasal irritation83
Lead 0.025 to 0.57 lg/15 puffs64,66
Hypertension induction83,84,88
Renal damage88
CNS damage84,88
Nickel 0.0075 to 0.29 lg/15 puffs64,66
Carcinogen43
CNS and pulmonary damage85
Renal and hepatic toxicity85
ND indicates not detected; CNS, central nervous system; NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; NNN, N-nitrosamines.
*Variable concentrations found in plasma after using e-cigarettes.92
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Studies with conventional cigarettes showed that nicotine
increased the risk of cardiovascular disease in smokers,
including the development of acute coronary disease,46
elevated blood pressure,104
and heart failure.105
As for
nicotine effects on thrombogenesis, it seems to be contro-
versial, with studies suggesting it to be elevated,106,107
reduced,108
or not affected109
; but this discrepancy could be
attributed to the dose of nicotine used,110
route of adminis-
tration,111
and the method used to measure platelet function.
Additionally, it was established that nicotine induces endothe-
lial dysfunction,112
angiogenesis,113
inflammation,114
and
lipogenesis, which may increase thrombosis risk. Conversely
and interestingly, nicotine delivered from nicotine replace-
ment therapy was not found to be associated with increased
cardiovascular diseases risk.104
This finding could be
attributed to the standardized dose-delivery system of
nicotine replacement therapy, in which the nicotine dose is
reduced over a short period of time.104
Thus, it seems that the
cardiovascular effects of nicotine depend on the dose
delivered and its distribution kinetics.115–117
Given that the
pharmacokinetics of nicotine delivery to human body by
e-vaping seems to be different from tobacco smoking, both in
the magnitude and the speed by which peak levels are
reached,118
it is essential to evaluate whether “e-vaped”
nicotine has an effect on cardiovascular system.
Unfortunately, studies on e-cigarette nicotine effects have
been limited, and controversial. A study by D’Ruiz et al
indicated an elevation in heart rate after using (different
brands of) e-cigarettes, which correlated with elevation in
plasma nicotine levels. This is consistent with findings that
both heart rate and plasma nicotine were elevated after
5 minutes of the first puff, and throughout 1 hour of the ad-lib
period in e-cigarette users.43
A separate study found no
changes in heart rate in e-cigarette users, and no increase in
nicotine plasma levels were observed.52
However, these “guilt
by association” studies do not provide a direct cause-and-
effect relationship between nicotine concentration and human
hemodynamics. This notion seems to be consistent with a
recent in vitro study by Rubenstein et al, which indicated that
the enhanced activity of human platelets upon exposure to
e-vapor extracts was independent of nicotine.48
It is clear that
further investigation is warranted to address and better
understand the short- and long-term effects of nicotine
delivered by e-cigarettes on the cardiovascular system.
Additional concerns related to e-cigarettes include nicotine
dependence and toxicity, given that the nicotine concentra-
tions found in plasma of e-cigarette smokers are high enough
to produce and maintain nicotine dependence, especially in
youth. This may explain why many adolescents shift to
tobacco smoking in their adulthood or cannot abandon vaping
easily.22
E-cigarettes may also present higher risks of nicotine
toxicity, especially for children, because some incidents of
ingesting e-liquids were reported.9,119
In fact, the number of
calls to poison centers for ingestion of e-liquids increased
from “one per month in September 2010 to 215 per month in
February 2014”.120
Thus, the Child Nicotine Poisoning
Prevention Act was initiated in January 2016; this required
e-cigarettes manufacturers to use child-resistant e-liquid
packaging.
Concerns also exist for passive exposure to nicotine
(nonusers); there is considerable evidence that e-vapors are a
source of nicotine contamination.103
Indeed, examination of
indoor air quality revealed a significant elevation of air nicotine
concentrations, which was commensurate with an increase in
nicotine levels in plasma and saliva of nonusers.90
In agreement
with these results, salivary concentrations of cotinine were
found to be elevated in nonusers living with e-cigarette
users.103,121
In addition to this, a detectable amount of nicotine
was found on the surfaces of e-cigarette users’ homes,
suggesting a potential risk for thirdhand exposure.55,59
Taken
together, these data advocate that e-cigarettes are a source of
secondhand and thirdhand exposure to nicotine, especially in
sensitive or vulnerable populations, regardless of whether its
levels from passive exposure to e-vapors are similar or lower
than those from tobacco smoke.
The Impact of Carbonyl Compounds on the
Cardiovascular System
In addition to nicotine, e-cigarettes emit other potentially
harmful constituents like carbonyls; this includes aldehydes,
such as formaldehyde, acetaldehyde, and acrolein,64,122
which result from thermal degradation of propylene glycol
and glycerol (most commonly used solvents in e-liquids123
).
As was the case with nicotine, newer generations of
e-cigarettes reportedly result in comparable carbonyls levels
relative to cigarettes (voltage dependent).122,124
In this
regard, whereas some studies showed that levels of aldehy-
des increased significantly under high voltage, or “dry-puff”
conditions,122,125
recent studies confirmed their presence
even under normal puffing conditions.126
Interestingly, levels
of the acrolein metabolite, 3-HPMA, were found to be elevated
in urine samples obtained from e-cigarette smokers when
compared with nonsmokers, confirming its systemic delivery
to the human body.127
On the other hand, levels of 3-HPMA
were reduced by 83% when tobacco smokers switched to e-
cigarettes and were similar to levels observed in those who
quit smoking.128
The presence of the aforementioned alde-
hydes represents a major health concern; in fact, formalde-
hyde was classified as a carcinogen and acetaldehyde as a
potential carcinogen by the International Agency for Research
on Cancer.129
Aside from their cytotoxic effects, animal studies suggest
that aldehydes exert various negative cardiovascular
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effects.130–132
Given the limited clinical studies evaluating the
effects of e-cigarette aldehydes on the human cardiovascular
system, we will rely on and extrapolate evidence from non-e-
cigarette sources. In this regard, animal studies revealed that
formaldehyde exposure altered the heart rate,132
by a
sympathetic nerve activity,132
and it also altered blood
pressure133
and cardiac contractility.131
Additionally, suba-
cute and chronic inhalation of formaldehyde was associated
with cardiac oxidative stress and, consequently, cardiac cell
damage.134
With regard to platelets, it was shown that total
platelet count significantly increased in mice exposed to
formaldehyde gas130
; this effect should be considered in the
context of the importance of platelets in hemostasis and their
role in thrombotic disorders. As for acetaldehyde, elevated
blood pressure and heart rate were reported in animals
following inhalation of variable doses, which could be
attributed to its sympathomimetic effect.135,136
It is notewor-
thy that formaldehyde and acetaldehyde concentrations used
in these studies are comparable to the levels generated by e-
cigarettes. Collectively, studies clearly suggest potential harm
from exposure to aldehydes, which could serve as a basis for
future and further studies focusing on the cardiovascular
consequences of their chronic exposure in real-life e-cigarette
settings.
Exposure from smoking and other sources to acrolein, the
other carbonyl, is associated with a wide range of cardiovas-
cular toxicity.137
Thus, inhalation of only 3 ppm of acrolein
caused an increase in systolic, diastolic, and mean arterial
blood pressure in an animal model.138
Furthermore, acrolein-
mediated autonomic imbalance caused an increase in the risk
of developing arrhythmia in rats.139
Additionally, it has been
suggested that acrolein can directly induce myocardial
dysfunction and cardiomyopathy.140
As for the mechanisms
of acrolein-induced cardiotoxicity, the following is some of
what has been proposed thus far: the formation of myocardial
protein-acrolein adduct, induction of oxidative stress signal-
ing, upregulation of proinflammatory cytokines, and inhibition
of cardioprotective signaling.140,141
In line with the negative effects on the vasculature,
acrolein can result in vascular injury by impairing vascular
repair capacity, as well as increasing the risk of thrombosis
and atherosclerosis, a possible result of endothelial
dysfunction, dyslipidemia, and platelet activation, among
others.142–144
Moreover, Sithu et al found that inhalation of
acrolein vapor, generated from either acrolein liquid or
tobacco smoke, results in a prothrombotic phenotype in
mice.145
Acute (5 ppm for 6 hours) or subchronic (1 ppm for
6 hours/day for 4 days) exposure to acrolein, regardless of
its source, induced platelet activation and aggregation.145
Additionally, an increase in acrolein-protein adduct in platelets
was observed, which suggests its systemic delivery and that it
exerts a direct effect on platelets.145
In support of this notion,
a human study revealed a correlation between levels of
acrolein metabolite (ie, 3-HPMA) and platelet-leukocyte
aggregates, in addition to increased risk of cardiovascular
diseases.146
The effects of acrolein on the cardiovascular
system are summarized in Figure 2.
Although acrolein sources were different in these studies,
to gain insight regarding their relevance and applicability to
e-cigarettes, we converted the concentrations emitted from
e-cigarettes to ppm, as reported by several studies, taking
into account puff volumes64,147–149
(Table 3). Thus, based on
the average of 120 puffs/day reported in the literature,101
our calculated levels of acrolein emitted by e-cigarette users
per day were found to vary between 0.00792 and 8.94 ppm/
day (Table 3). Because its harmful cardiovascular levels fall
within this range, acrolein emitted from e-cigarettes may
produce similar harm, which warrants investigation.
As mentioned before, an additional concern, that is often
forgotten or ignored, is that e-cigarettes can be a source of
secondhand or thirdhand exposure to aldehydes (and other
toxicants) for nonusers.150,151
Indeed, under human puffing
conditions, indoor air quality was found to be reduced,
attributed to aldehydes emission in e-cigarette vapors.57
Even
though detected levels were low, they may still pose a health
concern, especially in people with a history of cardiovascular
disease, as well as in children, casino/housekeeping workers,
and in pregnant women. Hence, the safety of exposure to low
levels of aldehydes for extended periods of time needs to be
examined in nonusers who live with e-cigarette users or work
in places where their use is allowed.
The Impact of PM on the Cardiovascular
System
Another health concern related to e-cigarette usage is the
generation of fine and ultrafine particles, known as PM, which
represents the solid and liquid particles suspended in the air.
PM2.5, which includes particles with a diameter of 2.5 lm or
less, will be the focus of this section because of their small
size; this enables them to easily penetrate airways and reach
circulation, thereby causing a potential hazard to the respi-
ratory and cardiovascular systems.152
Several studies evalu-
ated their presence in e-cigarette vapors and concluded that
significant levels of PM2.5 are indeed exhaled by e-cigarette
users.58
The number of particles and size distribution in
emitted PM in e-vapors were found to vary depending on the
e-liquid, nicotine concentration, and puffing topogra-
phy12,101,153
and seem to be comparable to those generated
from tobacco smoke.153,154
Several studies, conducted under controlled conditions
that almost resemble real-life settings, revealed a significant
increase in PM2.5 concentrations in rooms and/or experi-
mental chambers in which e-cigarettes were consumed by
CONTEMPORARYREVIEW

human subjects.57,65,90
This highlights e-cigarettes as a
source of PM2.5 secondhand exposures.57,65,90
In fact,
PM2.5 concentrations increased dramatically (125–330-folds)
in hotel rooms where e-cigarette use was allowed for 2 days,
compared with the same rooms before active vaping
occurred.155
Surprisingly, these concentrations of PM2.5
are higher than the reported values from tobacco smoking
in Hookah cafes and indoor bars.155
On the other hand, it
has been shown that the level of PM2.5 in houses of e-
cigarette users was 95% lower than those from homes of
conventional cigarette users.58
Collectively, these studies
provide evidence that e-cigarette users do indeed exhale
PM2.5, thus putting themselves as well as nonusers under
health risks.
Table 3. Acrolein Concentrations Emitted in e-Cigarette Vapors
Reference Puff Volume
Acrolein
Concentration/15 puffs*
Acrolein Concentration/d
(120 puffs)
Acrolein
Concentration ppm†
Acrolein Concentration
ppm/d (120 puffs)
Goniewicz et al64
70 mL 0.07 to 4.19 lg 0.564 to 33.516 lg 6.6910À5
to 0.0039 0.00792 to 0.468
Uchiyama et al147
55 mL 3.15 to 24 lg 25.2 to 192 lg 0.0038 to 0.029 0.456 to 3.48
Gillman et al148
55 mL 0.3 to 82.5 lg 2.4 to 660 lg 0.00036 to 0.1 0.0432 to 12
Flora et al149
55 mL 61.5 lg 492 lg 0.0745 8.94
*15 puffs=1 conventional cigarette.
†
ppm=lg/mL, to convert lg/puff to ppm, we divided the concentration (lg) by the volume of each puff (mL).
ppm ¼
concentration ðlgÞ
volume (mL)
Potential effects of inhaled
acrolein on the cardiovascular
system
Increase the risk of
thrombosis
Increase blood pressure
Induce myocardial
dysfunction and
cardiomyopathy
Impair vascular repair
capacity and induce vascular
injury
Increase the risk of cardiac
ventricular arrhythmia
Reduce cardiac contractility
Figure 2. Effects of acrolein on the cardiovascular system. Wide ranges of cardiovascular effects of acrolein inhalation from smoking and
ambient air pollution are reported in animal studies.138,139,142,146
CONTEMPORARYREVIEW

Epidemiological and clinical studies suggest a strong
association between human exposure to PM2.5 and the risk
of cardiovascular disease development. Specifically, these
studies showed that exposure to PM2.5 from ambient air
pollution and/or tobacco smoking is linked to hypertension,156
coronary artery disease,157
myocardial infarction,158,159
atherosclerosis,156
arrhythmia,160
as well as mortality relative
risk.161,162
Interestingly, risk of atherosclerosis was reported to
increase with long-term exposure to ambient air PM2.5, and to
be higher in elderly, female, and nonsmoker participants,163
underscoring the sensitivity of special populations. This notion
is consistent with reports that exposure of the elderly popula-
tion with a history of cardiovascular disease to PM2.5 for only
28 days was accompanied with higher resting cerebrovascular
resistance and increased mean arterial blood pressure.164
The physiomolecular mechanisms underlying the aforemen-
tioned effects are divided into a direct and indirect pathway, as
summarized in Figure 3.156
The direct pathway is mediated by
the delivery of PM2.5 into the bloodstream, thereby targeting
multiple organs.165,166
Thus, if ion channels and calcium
regulation are affected by PM2.5, it could lead to contractile
dysfunction and arrhythmia,165,167
whereas vascular dysfunc-
tion and thrombus formation can result from producing local
oxidative stress and inflammation.168–170
Regarding the indi-
rect pathway, PM2.5-induced cardiovascular toxicity is asso-
ciated with the development of inflammatory responses and
modulation of the autonomic nervous system.167
Thus, depo-
sition of PM2.5 on alveoli was found to trigger the release of a
host of proinflammatory mediators, vasoactive molecules, and
reactive oxygen species into the circulation. These will
subsequently affect vascular integrity and induce thromboge-
nesis.168,170
As for PM2.5 modulation of the autonomic
nervous system, it results in increased vasoconstriction and
change in heart rate variability, which will potentially enhance
the risk of developing arrhythmias and thrombosis.171
Importantly, it has been found that the dose-response
relationship between PM exposure and cardiovascular mor-
tality is also nonlinear,172
and that a consequential adverse
cardiovascular outcome can happen as a result of exposure to
low levels.172
Interestingly, it was suggested that PM2.5 is
responsible for more than 90% of the predicted harm caused
by thirdhand smoke pollutants.173
Although, clearly, PM2.5
from ambient air pollution and smoking exerts harmful effects
on the cardiovascular system, its mere presence—as a result
of e-cigarette use—does not mean that it will have an effect;
this issue should be investigated.
Effects of exposure to PM 2.5 on the
cardiovascular system
Indirect Pathway
Deposition of PM 2.5 in lungs
Direct Pathway
Direct entry of PM 2.5 into blood
stream
Induce oxidative stress
Increase intracellular calcium
Autonomic nervous system
(ANS)
Increase Reactive Oxygen Species
(ROS)
Trigger inflammatory pathways
(systemic and local)
Thrombosis
• Contractile dysfunction
• Cardiac arrhythmia
Change heart rate variability
• Arrhythmia
• Thrombosis
Figure 3. Effects of particulate matter (PM2.5) on the cardiovascular system. PM2.5 exposure from tobacco and environment/ambient
negatively affects the cardiovascular system either directly or indirectly. The direct pathway is mediated by the delivery of PM2.5 into the
bloodstream. The indirect pathway is attributed to deposition of PM2.5 in lungs and a modulation of autonomic nervous system. Oxidative stress
is triggered by both pathways and induces local and systemic inflammatory processes. PM2.5 indicates particulate matter less than 2.5 microns
in diameter.
CONTEMPORARYREVIEW

Studies have shown that e-cigarette PM2.5, even from a
single puff, undergoes cardiopulmonary delivery into the
systemic circulation,174
resulting in a signiﬁcant amount of
deposition in the respiratory tree.175
Furthermore, in vitro
experiments documented a venous absorption between 7%
and 18% of the total e-aerosol and arterial absorption through
the alveoli between 8% and 19%.174
Finally, a recent in vitro
study concluded that PM2.5 may be the primary constituent
that mediates e-cigarette-induced platelet activation and
aggregation.48
Based on these considerations, it is important
to examine the negative health effects of short- and long-term
(active and passive) exposure to e-cigarettes PM2.5.
Recent Regulatory Updates
Because of the growing evidence that e-cigarettes’ present
potential harm to public health, and the “skyrocketing” usage
among youth, the US Food and Drug Administration issued new
legislation (on August 8, 2016) that extended their regulations
to e-cigarettes. This is expected to protect public health,
minimize the risks associated with e-cigarettes and reduce
youth’s exposure to these devices. Under this expansion,
manufacturers will be required to report all ingredients and
undergo a premarket review to obtain permission to market
their products.176
Furthermore, selling of e-cigarettes to those
aged <18 years is now prohibited, as is selling any tobacco
products in vending machines (unless in an adult-only facil-
ity).176
Of note, the tobacco 21 movement, a regulation that
advocates for raising the minimum legal sale age for tobacco
products to 21, was followed during 2016 only in 2 states
(California and Hawaii). However, as of March 2017, the pattern
is expanding to include at least 220 localities across the United
States.177
Nonetheless, and unfortunately, e-cigarettes are still
available for purchase from online vendors, which would be the
ﬁrst alternative for youth. Thus, this aspect/“loophole” should
be covered/closed by state legislation or by stricter rules from
the US Food and Drug Administration.
The Public Health and Tobacco Policy Center report revealed
that even though 31 states have (state) restrictions and laws
addressing where e-cigarettes usage is allowed, only 10 of 31
prohibited their use wherever tobacco is prohibited effective
January 2017. The majority of the remaining states prohibit
vaping in schools, day care facilities, and a few on campuses.178
However, concerns remain regarding the use of e-cigarettes at
work and public places across the country, which results in
exposing nonusers to potentially harmful vapors.
Conclusion
Although much is known about smoking-induced cardiovas-
cular toxicity, little is known about that of e-cigarettes. This is
an issue that continues to be a subject of debate. Neverthe-
less, based on the current body of evidence, e-cigarettes are
not emission free (as some believe) and, in fact, they emit
various potentially harmful and toxic chemicals. Whether or
not the levels of these toxicants are lower than traditional
smoking remains controversial. In this connection, recent
studies showed that e-cigarettes-emitted chemicals reach
levels comparable to tobacco smoke, and those levels vary
depending on multiple factors, including types of devices, e-
liquid, vaping topography, and vaping experience.179
Given the
sensitivity of the cardiovascular system and its “smoke”
nonlinear dose-response/toxicity relationship, it is important
to evaluate the cardiovascular safety of e-cigarettes.
Although it was originally argued that e-cigarettes are
“harm free,” the present prevailing belief is that they are
“reduced harm” alternatives to conventional cigarettes. This
latter notion is still debatable and not supported by conclusive
evidence, especially considering the wide variation between
e-cigarette products. Even if that were the case, their harm
can still extend to innocent/bystander nonsmokers through
secondhand and thirdhand vaping, including children, preg-
nant women, casino/housekeeping workers, and people with
preexisting cardiovascular and other diseases.
The widespread and increasing usage of e-cigarettes in the
United States is concerning because of the lack of studies on
the long-term health effects of these devices on biological
systems. Therefore, future research should establish, under
real-life conditions, not only the long-term, but also the short-
term negative effects of e-cigarette usage, on both users
(active) and nonusers (passive), and provide mechanistic
insights regarding these effects. These should, in turn, guide
and shape policy for further evidence-based vaping control.
Ultimately, we hope to underscore the need for prevention of
exposure to various forms of vaping, especially in vulnerable
populations like children and youth.
Acknowledgments
The authors thank Julie A. Rivera, MA, of The University of Texas at El
Paso for proofreading and editing this manuscript. The authors also
acknowledge the support of the staff of the Smoke Free Initiative,
supported by a grant from Paso del Norte Health Foundation (to
J.O.R.).
Disclosures
None.
References
1. Centers for Disease Control and Prevention. CDC death report. 2014.
2. Yanbaeva DG, Dentener MA, Creutzberg EC, Wesseling G, Wouters EF.
Systemic effects of smoking. Chest. 2007;131:1557–1566.
3. Berg CJ, Barr DB, Stratton E, Escoffery C, Kegler M. Attitudes toward
e-cigarettes, reasons for initiating e-cigarette use, and changes in smoking
CONTEMPORARYREVIEW

behavior after initiation: a pilot longitudinal study of regular cigarette
smokers. Open J Prev Med. 2014;4:789–800.
4. Brandon TH, Goniewicz ML, Hanna NH, Hatsukami DK, Herbst RS, Hobin JA,
Ostroff JS, Shields PG, Toll BA, Tyne CA, Viswanath K, Warren GW. Electronic
nicotine delivery systems: a policy statement from the American Association
for Cancer Research and the American Society of Clinical Oncology. J Clin
Oncol. 2015;33:952–963.
5. Corey CG, Ambrose BK, Apelberg BJ, King BA. Flavored tobacco product use
among middle and high school students—United States, 2014. MMWR Morb
Mortal Wkly Rep. 2015;64:1066–1070.
6. Farsalinos KE, Gillman IG, Melvin MS, Paolantonio AR, Gardow WJ, Humphries
KE, Brown SE, Poulas K, Voudris V. Nicotine levels and presence of selected
tobacco-derived toxins in tobacco flavoured electronic cigarette refill liquids.
Int J Environ Res Public Health. 2015;12:3439–3452.
7. Cheng T. Chemical evaluation of electronic cigarettes. Tob Control. 2014;23
(Suppl 2):ii11–ii17.
8. Kaisar MA, Prasad S, Liles T, Cucullo L. A decade of e-cigarettes: limited
research & unresolved safety concerns. Toxicology. 2016;365:67–75.
9. Grana R, Benowitz N, Glantz SA. E-cigarettes: a scientific review. Circulation.
2014;129:1972–1986.
10. Farsalinos KE, Polosa R. Safety evaluation and risk assessment of electronic
cigarettes as tobacco cigarette substitutes: a systematic review. Ther Adv
Drug Saf. 2014;5:67–86.
11. Giroud C, de Cesare M, Berthet A, Varlet V, Concha-Lozano N, Favrat B.
E-cigarettes: a review of new trends in cannabis use. Int J Environ Res Public
Health. 2015;12:9988–10008.
12. Bhatnagar A, Whitsel LP, Ribisl KM, Bullen C, Chaloupka F, Piano MR,
Robertson RM, McAuley T, Goff D, Benowitz N; American Heart Association
Advocacy Coordinating Committee, Council on Cardiovascular and Stroke
Nursing, Council on Clinical Cardiology, and Council on Quality of Care and
Outcomes Research. Electronic cigarettes: a policy statement from the
American Heart Association. Circulation. 2014;130:1418–1436.
13. Farsalinos KE, Spyrou A, Tsimopoulou K, Stefopoulos C, Romagna G, Voudris
V. Nicotine absorption from electronic cigarette use: comparison between
first and new-generation devices. Sci Rep. 2014;4:4133.
14. Crotty Alexander LE, Vyas A, Schraufnagel DE, Malhotra A. Electronic
cigarettes: the new face of nicotine delivery and addiction. J Thorac Dis.
2015;7:E248–E251.
15. E-cigarette use among youth and young adults. A Report of the Surgeon
General. 2016.
16. Palazzolo DL. Electronic cigarettes and vaping: a new challenge in clinical
medicine and public health. A literature review. Front Public Health.
2013;1:56.
17. Schoenborn CA, Gindi RM. Electronic cigarette use among adults: United
States, 2014. NCHS Data Brief. 2015;217:1–8.
18. Centers for Disease Control and Prevention. Youth and tobacco use. 2015.
19. Patel D, Davis KC, Cox S, Bradfield B, King BA, Shafer P, Caraballo R, Bunnell
R. Reasons for current e-cigarette use among U.S. adults. Prev Med.
2016;93:14–20.
20. Cataldo JK, Petersen AB, Hunter M, Wang J, Sheon N. E-cigarette marketing
and older smokers: road to renormalization. Am J Health Behav.
2015;39:361–371.
21. Pearson JL, Richardson A, Niaura RS, Vallone DM, Abrams DB. E-cigarette
awareness, use, and harm perceptions in US adults. Am J Public Health.
2012;102:1758–1766.
22. US Department of Health and Human Services eneral ARotS. E-cigarette use
among youth and young adults: a report of the Surgeon General. 2016.
23. Baeza-Loya S, Viswanath H, Carter A, Molfese DL, Velasquez KM, Baldwin PR,
Thompson-Lake DG, Sharp C, Fowler JC, De La Garza R II, Salas R.
Perceptions about e-cigarette safety may lead to e-smoking during
pregnancy. Bull Menninger Clin. 2014;78:243–252.
24. Wickstrom R. Effects of nicotine during pregnancy: human and experimental
evidence. Curr Neuropharmacol. 2007;5:213–222.
25. Spindel ER, McEvoy CT. The role of nicotine in the effects of maternal
smoking during pregnancy on lung development and childhood respiratory
disease. Implications for dangers of e-cigarettes. Am J Respir Crit Care Med.
2016;193:486–494.
26. Scheffler S, Dieken H, Krischenowski O, Forster C, Branscheid D, Aufderheide
M. Evaluation of e-cigarette liquid vapor and mainstream cigarette smoke
after direct exposure of primary human bronchial epithelial cells. Int J Environ
Res Public Health. 2015;12:3915–3925.
27. Vardavas CI, Anagnostopoulos N, Kougias M, Evangelopoulou V, Connolly GN,
Behrakis PK. Short-term pulmonary effects of using an electronic cigarette:
impact on respiratory flow resistance, impedance, and exhaled nitric oxide.
Chest. 2012;141:1400–1406.
28. Lerner CA, Sundar IK, Yao H, Gerloff J, Ossip DJ, McIntosh S, Robinson R,
Rahman I. Vapors produced by electronic cigarettes and e-juices with
flavorings induce toxicity, oxidative stress, and inflammatory response in lung
epithelial cells and in mouse lung. PLoS One. 2015;10:e0116732.
29. Sussan TE, Gajghate S, Thimmulappa RK, Ma J, Kim JH, Sudini K, Consolini N,
Cormier SA, Lomnicki S, Hasan F, Pekosz A, Biswal S. Exposure to electronic
cigarettes impairs pulmonary anti-bacterial and anti-viral defenses in a mouse
model. PLoS One. 2015;10:e0116861.
30. Jensen RP, Luo W, Pankow JF, Strongin RM, Peyton DH. Hidden formaldehyde
in e-cigarette aerosols. N Engl J Med. 2015;372:392–394.
31. Hess CA, Olmedo P, Navas-Acien A, Goessler W, Cohen JE, Rule AM.
E-cigarettes as a source of toxic and potentially carcinogenic metals. Environ
Res. 2017;152:221–225.
32. Callahan-Lyon P. Electronic cigarettes: human health effects. Tob Control.
2014;23:ii36–ii40.
33. Hua M, Alfi M, Talbot P. Health-related effects reported by electronic
cigarette users in online forums. J Med Internet Res. 2013;15:e59.
34. Cho JH, Paik SY. Association between electronic cigarette use and asthma
among high school students in South Korea. PLoS One. 2016;11:e0151022.
35. Ponzoni L, Moretti M, Sala M, Fasoli F, Mucchietto V, Lucini V, Cannazza G,
Gallesi G, Castellana CN, Clementi F, Zoli M, Gotti C, Braida D. Different
physiological and behavioural effects of e-cigarette vapour and cigarette
smoke in mice. Eur Neuropsychopharmacol. 2015;25:1775–1786.
36. Yamada H, Bishnoi M, Keijzers KF, van Tuijl IA, Small E, Shah HP, Bauzo RM,
Kobeissy FH, Sabarinath SN, Derendorf H, Bruijnzeel AW. Preadolescent
tobacco smoke exposure leads to acute nicotine dependence but does not
affect the rewarding effects of nicotine or nicotine withdrawal in adulthood in
rats. Pharmacol Biochem Behav. 2010;95:401–409.
37. Dutra LM, Glantz SA. Electronic cigarettes and conventional cigarette use among
U.S. adolescents: a cross-sectional study. JAMA Pediatr. 2014;168:610–617.
38. Colaianni CA, Tapias LF, Cauley R, Sheridan R, Schulz JT, Goverman J. Injuries
caused by explosion of electronic cigarette devices. Eplasty. 2016;16:ic9.
39. Brown CJ, Cheng JM. Electronic cigarettes: product characterisation and
design considerations. Tob Control. 2014;23(suppl 2):ii4–ii10.
40. Bhatnagar A. Cardiovascular perspective of the promises and perils of
e-cigarettes. Circ Res. 2016;118:1872–1875.
41. Vansickel AR, Eissenberg T. Electronic Cigarettes: Effective Nicotine Delivery
After Acute Administration. Nicotine & Tobacco Research. 2013;15(1):267–
270. doi:10.1093/ntr/ntr316.
42. Nides MA, Leischow SJ, Bhatter M, Simmons M. Nicotine blood levels and
short-term smoking reduction with an electronic nicotine delivery system. Am
J Health Behav. 2014;38:265–274.
43. Yan XS, D’Ruiz C. Effects of using electronic cigarettes on nicotine delivery
and cardiovascular function in comparison with regular cigarettes. Regul
Toxicol Pharmacol. 2015;71:24–34.
44. Vlachopoulos C, Ioakeimidis N, Abdelrasoul M, Terentes-Printzios D, Geor-
gakopoulos C, Pietri P, Stefanadis C, Tousoulis D. Electronic cigarette
smoking increases aortic stiffness and blood pressure in young smokers. J
Am Coll Cardiol. 2016;67:2802–2803.
45. Higashi Y, Noma K, Yoshizumi M, Kihara Y. Endothelial function and oxidative
stress in cardiovascular diseases. Circ J. 2009;73:411–418.
46. Carnevale R, Sciarretta S, Violi F, Nocella C, Loffredo L, Perri L, Peruzzi M,
Marullo AG, De Falco E, Chimenti I, Valenti V, Biondi-Zoccai G, Frati G. Acute
impact of tobacco vs electronic cigarette smoking on oxidative stress and
vascular function. Chest. 2016;150:606–612.
47. Antoniewicz L, Bosson JA, Kuhl J, Abdel-Halim SM, Kiessling A, Mobarrez F,
Lundb€ack M. Electronic cigarettes increase endothelial progenitor cells in the
blood of healthy volunteers. Atherosclerosis. 2016;255:179–185.
48. Hom S, Chen L, Wang T, Ghebrehiwet B, Yin W, Rubenstein DA. Platelet
activation, adhesion, inflammation, and aggregation potential are altered in
the presence of electronic cigarette extracts of variable nicotine concentra-
tions. Platelets. 2016;27:694–702.
49. Szoltysek-Boldys I, Sobczak A, Zielinska-Danch W, Barton A, Koszowski B,
Kosmider L. Influence of inhaled nicotine source on arterial stiffness. Przegl
Lek. 2014;71:572–575.
50. Farsalinos KE, Tsiapras D, Kyrzopoulos S, Savvopoulou M, Voudris V. Acute
effects of using an electronic nicotine-delivery device (electronic cigarette)
on myocardial function: comparison with the effects of regular cigarettes.
BMC Cardiovasc Disord. 2014;14:78.
51. Farsalinos K, Tsiapras D, Kyrzopoulos S, Stefopoulos C, Spyrou A, Tsakalou
M, Avramidou E, Vasilopoulou D, Romagna G, Voudris V. Immediate effects of
CONTEMPORARYREVIEW

electronic cigarette use on coronary circulation and blood carboxyhe-
moglobin levels: comparison with cigarette smoking. Eur Heart J. 2013;34
(suppl_1):102. doi: 10.1093/eurheartj/eht307.102
52. Vansickel AR, Cobb CO, Weaver MF, Eissenberg TE. A clinical laboratory
model for evaluating the acute effects of electronic “cigarettes”: nicotine
delivery profile and cardiovascular and subjective effects. Cancer Epidemiol
Biomark Prev. 2010;19:1945–1953.
53. Vansickel AR, Eissenberg T. Electronic cigarettes: effective nicotine delivery
after acute administration. Nicotine Tob Res. 2013;15:267–270.
54. US Department of Health and Human Services. 14th report on carcinogens
(RoC). 2016.
55. Goniewicz ML, Lee L. Electronic cigarettes are a source of thirdhand
exposure to nicotine. Nicotine Tob Res. 2015;17:256–258.
56. Karim ZA, Alshbool FZ, Vemana HP, Adhami N, Dhall S, Espinosa EV, Martins-
Green M, Khasawneh FT. Third-hand smoke: impact on hemostasis and
thrombogenesis. J Cardiovasc Pharmacol. 2015;66:177–182.
57. Schripp T, Markewitz D, Uhde E, Salthammer T. Does e-cigarette consump-
tion cause passive vaping? Indoor Air. 2013;23:25–31.
58. Fernandez E, Ballbe M, Sureda X, Fu M, Salto E, Martinez-Sanchez JM.
Particulate matter from electronic cigarettes and conventional cigarettes: a
systematic review and observational study. Curr Environ Health Rep.
2015;2:423–429.
59. Bush D, Goniewicz ML. A pilot study on nicotine residues in houses of
electronic cigarette users, tobacco smokers, and non-users of nicotine-
containing products. Int J Drug Policy. 2015;26:609–611.
60. Shi Y, Cummins SE, Zhu SH. Use of electronic cigarettes in smoke-free
environments. Tob Control. 2017;26(e1):e19–e22.
61. Agaku IT, Singh T, Rolle I, Olalekan AY, King BA. Prevalence and determinants
of secondhand smoke exposure among middle and high school students.
Pediatrics. 2016;137:e20151985.
62. Schroeder MJ, Hoffman AC. Electronic cigarettes and nicotine clinical
pharmacology. Tob Control. 2014;23(suppl 2):ii30–ii35.
63. Goniewicz ML, Kuma T, Gawron M, Knysak J, Kosmider L. Nicotine levels in
electronic cigarettes. Nicotine Tob Res. 2013;15:158–166.
64. Goniewicz ML, Knysak J, Gawron M, Kosmider L, Sobczak A, Kurek J,
Prokopowicz A, Jablonska-Czapla M, Rosik-Dulewska C, Havel C, Jacob P III,
Benowitz N. Levels of selected carcinogens and toxicants in vapour from
electronic cigarettes. Tob Control. 2014;23:133–139.
65. Schober W, Szendrei K, Matzen W, Osiander-Fuchs H, Heitmann D, Schettgen
T, Jorres RA, Fromme H. Use of electronic cigarettes (e-cigarettes) impairs
indoor air quality and increases FeNO levels of e-cigarette consumers. Int J
Hyg Environ Health. 2014;217:628–637.
66. Williams M, Villarreal A, Bozhilov K, Lin S, Talbot P. Metal and silicate
particles including nanoparticles are present in electronic cigarette car-
tomizer fluid and aerosol. PLoS One. 2013;8:e57987.
67. Mishra A, Chaturvedi P, Datta S, Sinukumar S, Joshi P, Garg A. Harmful
effects of nicotine. Indian J Med Paediatr Oncol. 2015;36:24–31.
68. Schaller K, Ruppert L, Kahnert S, Bethke C, Nair U, P€otschke-Langer M.
Electronic cigarettes—an overview. Tobacco Prevention and Tobacco Control
German Cancer Research Center, Heidelberg. 2013;19.
69. Shaw JL, Oliver E, Lee KF, Entrican G, Jabbour HN, Critchley HO, Horne
AW. Cotinine exposure increases Fallopian tube PROKR1 expression via
nicotinic AChRalpha-7: a potential mechanism explaining the link
between smoking and tubal ectopic pregnancy. Am J Pathol. 2010;177:
2509–2515.
70. Xing YF, Xu YH, Shi MH, Lian YX. The impact of PM2.5 on the human
respiratory system. J Thorac Dis. 2016;8:E69–E74.
71. Lieber CS. Metabolic effects of acetaldehyde. Biochem Soc Trans.
1988;16:241–247.
72. Faroon O, Roney N, Taylor J, Ashizawa A, Lumpkin MH, Plewak DJ. Acrolein
health effects. Toxicol Ind Health. 2008;24:447–490.
73. Fischer MH. The toxic effects of formaldehyde and formalin. J Exp Med.
1905;6:487–518.
74. McGwin G, Lienert J, Kennedy JI. Formaldehyde exposure and asthma in
children: a systematic review. Environ Health Perspect. 2010;118:313–317.
75. National Research Council. Emergency and Continuous Exposure Limits for
Selected Airborne Contaminants: Volume 2. Washington, DC: The National
Academies Press; 1984.
76. Kienhuis AS, Soeteman-Hernandez LG, Bos PM, Cremers HW, Klerx WN,
Talhout R. Potential harmful health effects of inhaling nicotine-free shisha-
pen vapor: a chemical risk assessment of the main components propylene
glycol and glycerol. Tob Induc Dis. 2015;13:15.
77. Breland AB, Spindle T, Weaver M, Eissenberg T. Science and electronic
cigarettes: current data, future needs. J Addict Med. 2014;8:223–233.
78. Pisinger C, Dossing M. A systematic review of health effects of electronic
cigarettes. Prev Med. 2014;69:248–260.
79. Filley CM, Halliday W, Kleinschmidt-DeMasters BK. The effects of toluene on
the central nervous system. J Neuropathol Exp Neurol. 2004;63:1–12.
80. Tang HL, Chu KH, Cheuk A, Tsang WK, Chan HW, Tong KL. Renal tubular
acidosis and severe hypophosphataemia due to toluene inhalation. Hong
Kong Med J. 2005;11:50–53.
81. Wilbur S, Abadin H, Fay M, Yu D, Tencza B, Ingerman L, Klotzbach J, James S.
Toxicological Profile for Chromium. Atlanta, GA: Agency for Toxic Substances
and Disease Registry (US); 2012.
82. Elbetieha A, Al-Hamood MH. Long-term exposure of male and female mice to
trivalent and hexavalent chromium compounds: effect on fertility. Toxicology.
1997;116:39–47.
83. Faroon O, Ashizawa A, Wright S, Tucker P, Jenkins K, Ingerman L, Rudisill C.
Toxicological Profile for Cadmium. Atlanta, GA: Agency for Toxic Substances
and Disease Registry (US); 2012.
84. Flora G, Gupta D, Tiwari A. Toxicity of lead: a review with recent updates.
Interdiscip Toxicol. 2012;5:47–58.
85. Das KK, Das SN, Dhundasi SA. Nickel, its adverse health effects & oxidative
stress. Indian J Med Res. 2008;128:412–425.
86. National Toxicology P. NTP 11th report on carcinogens. Rep Carcinog.
2004;11:1–A32.
87. Alavanja M, Bartsch H, Allen N, Bhisey RA. Personal habits and indoor
combustions. Int Agency Res Cancer. 2012;100E:319–328.
88. Abadin H, Ashizawa A, Stevens YW, Llados F, Diamond G, Sage G, Citra M,
Quinones A, Bosch SJ, Swarts SG. Toxicological Profile for Lead. Atlanta, GA:
Agency for Toxic Substances and Disease Registry (US); 2007.
89. Marco E, Grimalt JO. A rapid method for the chromatographic analysis of
volatile organic compounds in exhaled breath of tobacco cigarette and
electronic cigarette smokers. J Chromatogr A. 2015;1410:51–59.
90. Czogala J, Goniewicz ML, Fidelus B, Zielinska-Danch W, Travers MJ, Sobczak
A. Secondhand exposure to vapors from electronic cigarettes. Nicotine Tob
Res. 2014;16:655–662.
91. Callahan-Lyon P. Electronic cigarettes: human health effects. Tob Control.
2014;23(suppl 2):ii36–ii40.
92. Marsot A, Simon N. Nicotine and cotinine levels with electronic cigarette: a
review. Int J Toxicol. 2016;35:179–185.
93. Langone JJ, Gjika HB, Van Vunakis H. Nicotine and its metabolites.
Radioimmunoassays for nicotine and cotinine. Biochemistry.
1973;12:5025–5030.
94. Sobkowiak R,Lesicki A. [Absorption, metabolism and excretion of nicotine in
humans]. Postepy Biochem. 2013;59:33–44.
95. Goniewicz ML, Gupta R, Lee YH, Reinhardt S, Kim S, Kim B, Kosmider L,
Sobczak A. Nicotine levels in electronic cigarette refill solutions: a
comparative analysis of products from the U.S., Korea, and Poland. Int J
Drug Policy. 2015;26:583–588.
96. Buettner-Schmidt K, Miller DR, Balasubramanian N. Electronic cigarette refill
liquids: child-resistant packaging, nicotine content, and sales to minors. J
Pediatr Nurs. 2016;31:373–379.
97. Ramôa CP, Hiler MM, Spindle TR, Lopez AA, Karaoghlanian N, Lipato T,
Breland AB, Shihadeh A, Eissenberg T. Electronic cigarette nicotine delivery
can exceed that of combustible cigarettes: a preliminary report. Tob Control.
2016;25:e6–e9.
98. Bullen C, McRobbie H, Thornley S, Glover M, Lin R, Laugesen M. Effect of an
electronic nicotine delivery device (e cigarette) on desire to smoke and
withdrawal, user preferences and nicotine delivery: randomised cross-over
trial. Tob Control. 2010;19:98–103.
99. Eissenberg T. Electronic nicotine delivery devices: ineffective nicotine
delivery and craving suppression after acute administration. Tob Control.
2010;19:87–88.
100. St Helen G, Havel C, Dempsey DA, Jacob P III, Benowitz NL. Nicotine delivery,
retention and pharmacokinetics from various electronic cigarettes. Addiction.
2016;111:535–544.
101. Robinson RJ, Hensel EC, Morabito PN, Roundtree KA. Electronic cigarette
topography in the natural environment. PLoS One. 2015;10:e0129296.
102. Etter JF. Levels of saliva cotinine in electronic cigarette users. Addiction.
2014;109:825–829.
103. Flouris AD, Chorti MS, Poulianiti KP, Jamurtas AZ, Kostikas K, Tzatzarakis MN,
Wallace Hayes A, Tsatsakis AM, Koutedakis Y. Acute impact of active and
CONTEMPORARYREVIEW

passive electronic cigarette smoking on serum cotinine and lung function.
Inhal Toxicol. 2013;25:91–101.
104. Centers for Disease Control and Prevention (US); National Center for
Chronic Disease Prevention and Health Promotion (US); Office on Smoking
and Health (US). How Tobacco Smoke Causes Disease: The Biology and
Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon
General. Atlanta, GA: Centers for Disease Control and Prevention (US);
2010.
105. Villarreal FJ, Hong D, Omens J. Nicotine-modified postinfarction left
ventricular remodeling. Am J Physiol. 1999;276:H1103–H1106.
106. Hioki H, Aoki N, Kawano K, Homori M, Hasumura Y, Yasumura T, Maki A,
Yoshino H, Yanagisawa A, Ishikawa K. Acute effects of cigarette smoking on
platelet-dependent thrombin generation. Eur Heart J. 2001;22:56–61.
107. Fahim MA, Nemmar A, Singh S, Hassan MY. Antioxidants alleviate nicotine-
induced platelet aggregation in cerebral arterioles of mice in vivo. Physiol
Res. 2011;60:695–700.
108. Girdhar G, Xu S, Bluestein D, Jesty J. Reduced-nicotine cigarettes increase
platelet activation in smokers in vivo: a dilemma in harm reduction. Nicotine
Tob Res. 2008;10:1737–1744.
109. Ljungberg LU, Persson K, Eriksson AC, Green H, Whiss PA. Effects of
nicotine, its metabolites and tobacco extracts on human platelet function
in vitro. Toxicol In Vitro. 2013;27:932–938.
110. Pfueller SL, Burns P, Mak K, Firkin BG. Effects of nicotine on platelet function.
Haemostasis. 1988;18:163–169.
111. Benowitz NL, Fitzgerald GA, Wilson M, Zhang Q. Nicotine effects on
eicosanoid formation and hemostatic function: comparison of transdermal
nicotine and cigarette smoking. J Am Coll Cardiol. 1993;22:1159–1167.
112. Messner B, Bernhard D. Smoking and cardiovascular disease: mechanisms of
endothelial dysfunction and early atherogenesis. Arterioscler Thromb Vasc
Biol. 2014;34:509–515.
113. Heeschen C, Jang JJ, Weis M, Pathak A, Kaji S, Hu RS, Tsao PS, Johnson FL,
Cooke JP. Nicotine stimulates angiogenesis and promotes tumor growth and
atherosclerosis. Nat Med. 2001;7:833–839.
114. Ambrose JA, Barua RS. The pathophysiology of cigarette smoking and
cardiovascular disease: an update. J Am Coll Cardiol. 2004;43:1731–1737.
115. Porchet HC, Benowitz NL, Sheiner LB, Copeland JR. Apparent tolerance to the
acute effect of nicotine results in part from distribution kinetics. J Clin Invest.
1987;80:1466–1471.
116. Benowitz NL, Gourlay SG. Cardiovascular toxicity of nicotine: implications for
nicotine replacement therapy. J Am Coll Cardiol. 1997;29:1422–1431.
117. Benowitz NL, Porchet H, Sheiner L, Jacob P III. Nicotine absorption and
cardiovascular effects with smokeless tobacco use: comparison with
cigarettes and nicotine gum. Clin Pharmacol Ther. 1988;44:23–28.
118. Benowitz NL, Hukkanen J, Jacob P III. Nicotine chemistry, metabolism,
kinetics and biomarkers. Handb Exp Pharmacol. 2009;192:29–60.
119. Payne JD, Michaels D, Orellana-Barrios M, Nugent K. Electronic cigarette
toxicity. J Prim Care Community Health. 2016;8:100–102.
120. CDC. New CDC study finds dramatic increase in e-cigarette-related calls to
poison centers. 2014.
121. Ballbe M, Martınez-Sanchez JM, Sureda X, Fu M, Perez-Ortu~no R, Pascual JA,
Salto E, Fernandez E. Cigarettes vs. e-cigarettes: passive exposure at home
measured by means of airborne marker and biomarkers. Environ Res.
2014;135:76–80.
122. Hutzler C, Paschke M, Kruschinski S, Henkler F, Hahn J, Luch A. Chemical
hazards present in liquids and vapors of electronic cigarettes. Arch Toxicol.
2014;88:1295–1308.
123. Wang P, Chen W, Liao J, Matsuo T, Ito K, Fowles J, Shusterman D, Mendell M,
Kumagai K. A device-independent evaluation of carbonyl emissions from
heated electronic cigarette solvents. PLoS One. 2017;12:e0169811.
124. Geiss O, Bianchi I, Barrero-Moreno J. Correlation of volatile carbonyl yields
emitted by e-cigarettes with the temperature of the heating coil and the
perceived sensorial quality of the generated vapours. Int J Hyg Environ Health.
2016;219:268–277.
125. Kosmider L, Sobczak A, Fik M, Knysak J, Zaciera M, Kurek J, Goniewicz
ML. Carbonyl compounds in electronic cigarette vapors: effects of nicotine
solvent and battery output voltage. Nicotine Tob Res. 2014;16:1319–
1326.
126. Bhatnagar A. E-cigarettes and cardiovascular disease risk: evaluation of
evidence, policy implications, and recommendations. Curr Cardiovasc Risk
Rep. 2016;10:24.
127. Hecht SS, Carmella SG, Kotandeniya D, Pillsbury ME, Chen M, Ransom BW,
Vogel RI, Thompson E, Murphy SE, Hatsukami DK. Evaluation of toxicant and
carcinogen metabolites in the urine of e-cigarette users versus cigarette
smokers. Nicotine Tob Res. 2015;17:704–709.
128. O’Connell G, Graff DW, D’Ruiz CD. Reductions in biomarkers of exposure
(BoE) to harmful or potentially harmful constituents (HPHCs) following partial
or complete substitution of cigarettes with electronic cigarettes in adult
smokers. Toxicol Mech Methods. 2016;26:443–454.
129. Humans IWGotEoCRt. Formaldehyde, 2-butoxyethanol and 1-tert-butoxypro-
pan-2-ol. IARC Monogr Eval Carcinog Risks Hum. 2006;88:1–478.
130. Zhang Y, Liu X, McHale C, Li R, Zhang L, Wu Y, Ye X, Yang X, Ding S. Bone
marrow injury induced via oxidative stress in mice by inhalation exposure to
formaldehyde. PLoS One. 2013;8:e74974.
131. Tani T, Horiguchi Y. Effects of formaldehyde on cardiac function. Jpn J
Pharmacol. 1990;52:563–572.
132. Tani T, Kogi K, Horiguchi Y. Inhibitory effects of formaldehyde inhalation on
the cardiovascular and respiratory systems in unanesthetized rabbits. Jpn J
Pharmacol. 1986;40:551–559.
133. Tani T, Satoh S, Horiguchi Y. The vasodilator action of formaldehyde in dogs.
Toxicol Appl Pharmacol. 1978;43:493–499.
134. Gulec M, Songur A, Sahin S, Ozen OA, Sarsilmaz M, Akyol O. Antioxidant
enzyme activities and lipid peroxidation products in heart tissue of subacute
and subchronic formaldehyde-exposed rats: a preliminary study. Toxicol Ind
Health. 2006;22:117–124.
135. Egle JL Jr. Effects of inhaled acetaldehyde and propionaldehyde on blood
pressure and heart rate. Toxicol Appl Pharmacol. 1972;23:131–135.
136. James TN, Bear ES. Cardiac effects of some simple aliphatic aldehydes. J
Pharmacol Exp Ther. 1968;163:300–308.
137. Henning RJ, Johnson GT, Coyle JP, Harbison RD. Acrolein can cause
cardiovascular disease: a review. Cardiovasc Toxicol. 2017;17:227–236.
138. Perez CM, Hazari MS, Ledbetter AD, Haykal-Coates N, Carll AP, Cascio WE,
Winsett DW, Costa DL, Farraj AK. Acrolein inhalation alters arterial blood
gases and triggers carotid body-mediated cardiovascular responses in
hypertensive rats. Inhalation Toxicol. 2015;27:54–63.
139. Hazari MS, Haykal-Coates N, Winsett DW, Krantz QT, King C, Costa DL, Farraj
AK. TRPA1 and sympathetic activation contribute to increased risk of
triggered cardiac arrhythmias in hypertensive rats exposed to diesel exhaust.
Environ Health Perspect. 2011;119:951–957.
140. Luo J, Hill BG, Gu Y, Cai J, Srivastava S, Bhatnagar A, Prabhu SD. Mechanisms
of acrolein-induced myocardial dysfunction: implications for environmental
and endogenous aldehyde exposure. Am J Physiol Heart Circ Physiol.
2007;293:H3673–H3684.
141. Wang GW, Guo Y, Vondriska TM, Zhang J, Zhang S, Tsai LL, Zong NC, Bolli R,
Bhatnagar A, Prabhu SD. Acrolein consumption exacerbates myocardial
ischemic injury and blocks nitric oxide-induced PKCepsilon signaling and
cardioprotection. J Mol Cell Cardiol. 2008;44:1016–1022.
142. Wheat LA, Haberzettl P, Hellmann J, Baba SP, Bertke M, Lee J, McCracken J,
O’Toole TE, Bhatnagar A, Conklin DJ. Acrolein inhalation prevents vascular
endothelial growth factor-induced mobilization of Flk-1+/Sca-1+ cells in
mice. Arterioscler Thromb Vasc Biol. 2011;31:1598–1606.
143. Srivastava S, Sithu SD, Vladykovskaya E, Haberzettl P, Hoetker DJ, Siddiqui
MA, Conklin DJ, D’Souza SE, Bhatnagar A. Oral exposure to acrolein
exacerbates atherosclerosis in apoE-null mice. Atherosclerosis.
2011;215:301–308.
144. Conklin DJ, Barski OA, Lesgards JF, Juvan P, Rezen T, Rozman D, Prough RA,
Vladykovskaya E, Liu S, Srivastava S, Bhatnagar A. Acrolein consumption
induces systemic dyslipidemia and lipoprotein modification. Toxicol Appl
Pharmacol. 2010;243:1–12.
145. Sithu SD, Srivastava S, Siddiqui MA, Vladykovskaya E, Riggs DW, Conklin DJ,
Haberzettl P, O’Toole TE, Bhatnagar A, D’Souza SE. Exposure to acrolein by
inhalation causes platelet activation. Toxicol Appl Pharmacol. 2010;248:100–
110.
146. DeJarnett N, Conklin DJ, Riggs DW, Myers JA, O’Toole TE, Hamzeh I, Wagner
S, Chugh A, Ramos KS, Srivastava S, Higdon D, Tollerud DJ, DeFilippis A,
Becher C, Wyatt B, McCracken J, Abplanalp W, Rai SN, Ciszewski T, Xie Z,
Yeager R, Prabhu SD, Bhatnagar A. Acrolein exposure is associated with
increased cardiovascular disease risk. J Am Heart Assoc. 2014;3:e000934.
DOI: 10.1161/JAHA.114.000934.
147. Uchiyama S, Senoo Y, Hayashida H, Inaba Y, Nakagome H, Kunugita N.
Determination of chemical compounds generated from second-generation e-
cigarettes using a sorbent cartridge followed by a two-step elution method.
Anal Sci. 2016;32:549–555.
148. Gillman IG, Kistler KA, Stewart EW, Paolantonio AR. Effect of variable power
levels on the yield of total aerosol mass and formation of aldehydes in e-
cigarette aerosols. Regul Toxicol Pharmacol. 2016;75:58–65.
CONTEMPORARYREVIEW

149. Flora JW, Meruva N, Huang CB, Wilkinson CT, Ballentine R, Smith DC, Werley
MS, McKinney WJ. Characterization of potential impurities and degradation
products in electronic cigarette formulations and aerosols. Regul Toxicol
Pharmacol. 2016;74:1–11.
150. Bahl V, Weng NJ, Schick SF, Sleiman M, Whitehead J, Ibarra A, Talbot P.
Cytotoxicity of thirdhand smoke and identification of acrolein as a volatile
thirdhand smoke chemical that inhibits cell proliferation. Toxicol Sci.
2016;150:234–246.
151. Zhang X, Pu J. E-cigarette use among US adolescents: secondhand smoke at
home matters. Int J Public Health. 2016;61:209–213.
152. Anderson JO, Thundiyil JG, Stolbach A. Clearing the air: a review of the effects
of particulate matter air pollution on human health. J Med Toxicol.
2012;8:166–175.
153. Fuoco FC, Buonanno G, Stabile L, Vigo P. Influential parameters on particle
concentration and size distribution in the mainstream of e-cigarettes. Environ
Pollut. 2014;184:523–529.
154. Ingebrethsen BJ, Cole SK, Alderman SL. Electronic cigarette aerosol
particle size distribution measurements. Inhal Toxicol. 2012;24:976–984.
155. Soule EK, Maloney SF, Spindle TR, Rudy AK, Hiler MM, Cobb CO. Electronic
cigarette use and indoor air quality in a natural setting. Tob Control.
2017;26:109–112.
156. Nelin TD, Joseph AM, Gorr MW, Wold LE. Direct and indirect effects of
particulate matter on the cardiovascular system. Toxicol Lett. 2012;208:293–
299.
157. Puett RC, Hart JE, Yanosky JD, Paciorek C, Schwartz J, Suh H, Speizer FE,
Laden F. Chronic fine and coarse particulate exposure, mortality, and
coronary heart disease in the Nurses’ Health Study. Environ Health Perspect.
2009;117:1697–1701.
158. Peters A, Dockery DW, Muller JE, Mittleman MA. Increased particulate air
pollution and the triggering of myocardial infarction. Circulation.
2001;103:2810–2815.
159. Sullivan J, Sheppard L, Schreuder A, Ishikawa N, Siscovick D, Kaufman J.
Relation between short-term fine-particulate matter exposure and onset of
myocardial infarction. Epidemiology. 2005;16:41–48.
160. Wang T, Lang GD, Moreno-Vinasco L, Huang Y, Goonewardena SN, Peng YJ,
Svensson EC, Natarajan V, Lang RM, Linares JD, Breysse PN, Geyh AS,
Samet JM, Lussier YA, Dudley S, Prabhakar NR, Garcia JG. Particulate
matter induces cardiac arrhythmias via dysregulation of carotid body
sensitivity and cardiac sodium channels. Am J Respir Cell Mol Biol.
2012;46:524–531.
161. Pope CA III, Dockery DW. Health effects of fine particulate air pollution: lines
that connect. J Air Waste Manag Assoc. 2006;56:709–742.
162. Kloog I, Coull BA, Zanobetti A, Koutrakis P, Schwartz JD. Acute and chronic
effects of particles on hospital admissions in New-England. PLoS One.
2012;7:e34664.
163. Kunzli N, Jerrett M, Mack WJ, Beckerman B, LaBree L, Gilliland F, Thomas D,
Peters J, Hodis HN. Ambient air pollution and atherosclerosis in Los Angeles.
Environ Health Perspect. 2005;113:201–206.
164. Wellenius GA, Boyle LD, Wilker EH, Sorond FA, Coull BA, Koutrakis P,
Mittleman MA, Lipsitz LA. Ambient fine particulate matter alters cerebral
hemodynamics in the elderly. Stroke. 2013;44:1532–1536.
165. Du Y, Xu X, Chu M, Guo Y, Wang J. Air particulate matter and cardiovascular
disease: the epidemiological, biomedical and clinical evidence. J Thorac Dis.
2016;8:E8–E19.
166. Nemmar A, Hoet PH, Vanquickenborne B, Dinsdale D, Thomeer M, Hoylaerts
MF, Vanbilloen H, Mortelmans L, Nemery B. Passage of inhaled particles into
the blood circulation in humans. Circulation. 2002;105:411–414.
167. Martinelli N, Olivieri O, Girelli D. Air particulate matter and cardiovascular
disease: a narrative review. Eur J Intern Med. 2013;24:295–302.
168. Steinvil A, Kordova-Biezuner L, Shapira I, Berliner S, Rogowski O. Short-term
exposure to air pollution and inflammation-sensitive biomarkers. Environ Res.
2008;106:51–61.
169. van Eeden SF, Tan WC, Suwa T, Mukae H, Terashima T, Fujii T, Qui D, Vincent
R, Hogg JC. Cytokines involved in the systemic inflammatory response
induced by exposure to particulate matter air pollutants (PM(10)). Am J Respir
Crit Care Med. 2001;164:826–830.
170. Gurgueira SA, Lawrence J, Coull B, Murthy GG, Gonzalez-Flecha B. Rapid
increases in the steady-state concentration of reactive oxygen species in the
lungs and heart after particulate air pollution inhalation. Environ Health
Perspect. 2002;110:749–755.
171. Magari SR, Schwartz J, Williams PL, Hauser R, Smith TJ, Christiani DC. The
association between personal measurements of environmental exposure to
particulates and heart rate variability. Epidemiology. 2002;13:305–310.
172. Pope CA III, Burnett RT, Krewski D, Jerrett M, Shi Y, Calle EE, Thun MJ.
Cardiovascular mortality and exposure to airborne fine particulate matter and
cigarette smoke: shape of the exposure-response relationship. Circulation.
2009;120:941–948.
173. Sleiman M, Logue JM, Luo W, Pankow JF, Gundel LA, Destaillats H.
Inhalable constituents of thirdhand tobacco smoke: chemical characteriza-
tion and health impact considerations. Environ Sci Technol. 2014;48:
13093–13101.
174. Zhang Y, Sumner W, Chen DR. In vitro particle size distributions in electronic
and conventional cigarette aerosols suggest comparable deposition patterns.
Nicotine Tob Res. 2013;15:501–508.
175. Manigrasso M, Buonanno G, Fuoco FC, Stabile L, Avino P. Aerosol deposition
doses in the human respiratory tree of electronic cigarette smokers. Environ
Pollut. 2015;196:257–267.
176. FDA. Vaporizers, e-cigarettes, and other electronic nicotine delivery systems
(ends). 2016.
177. Suner IJ, Espinosa-Heidmann DG, Marin-Castano ME, Hernandez EP, Pereira-
Simon S, Cousins SW. Nicotine increases size and severity of experimental
choroidal neovascularization. Invest Ophthalmol Vis Sci. 2004;45:311–317.
178. Tobacco Control Legal Consortium. U.S. E-cigarette regulation: a 50-state
review. 2015.
179. Sleiman M, Logue JM, Montesinos VN, Russell ML, Litter MI, Gundel LA,
Destaillats H. Emissions from electronic cigarettes: key parameters affecting
the release of harmful chemicals. Environ Sci Technol. 2016;50:9644–9651.
Key Words: cardiovascular disease • electronic cigarettes •
safety • smoke • tobacco use
CONTEMPORARYREVIEW

Hanan Qasim, Zubair A. Karim, Jose O. Rivera, Fadi T. Khasawneh and Fatima Z. Alshbool
Impact of Electronic Cigarettes on the Cardiovascular System
Online ISSN: 2047-9980
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