SMOKING rates may be on the decline, but the use of e-cigarettes – those little devices that often contain nicotine and flavored vapor – is rapidly growing. Particularly among teens and younger adults, the popularity is skyrocketing. But are they safer than traditional cigarettes? And what about for those with asthma, whose sensitive airways cannot tolerate even secondhand cigarette smoke? Are they any better off with or around e-cigarettes? Allergic Living turns to the experts in the quest for answers.
What are e-cigarettes?
An e-cigarette is a small battery-operated device that produces an aerosol, or vapor, that is inhaled. The user inserts a cartridge of a liquid mixture, typically propylene glycol or vegetable glycerin, flavoring and often nicotine, into the device. When heated and then cooled, the liquid becomes an aerosol.
Who’s using them?
Statistics show that a rapidly growing number of users are taking up “vaping.” According to the U.S. Food and Drug Administration (FDA), more than three million middle and high school students were current users of e-cigarettes as of 2015. That’s up from an estimated 2.4 million in 2014. As well, 16 percent of high school students and 5.3 percent of middle schoolers were users of e-cigarettes in 2015, “making e-cigarettes the most commonly used tobacco product among youth for the second consecutive year,” says the FDA.
According to a 2016 review of e-cigarette use, published in the New England Journal of Medicine (NEJM), about 1.8 percent of American adults in 2010 reported having used an e-cigarette “at some time.” By 2013, that figure jumped to 13 percent. The paper estimated that global sales of e-cigarettes would have hit $10 billion in 2017.
Who’s regulating them?
In the summer of 2016, a “deeming rule” came into effect in the U.S., amending the federal Tobacco Control Act to bring a number of products, including e-cigarettes, under the FDA’s regulatory authority.
The changes, which are being phased in over a number of stages, include prohibiting the sale of e-cigarettes to minors, requiring warning labels (much like cigarettes now carry) and calling for manufacturers to register with the FDA. The changes still allow for state and civic governments to enact their own laws governing e-cigarettes, including where they can and cannot be used.
But extensions have been granted to some key parts of the new guidelines, including the provision that e-cigarette manufacturers submit formal product applications to the FDA. The applications will allow the FDA, for the first time, to evaluate the ingredients, safety, product design and potential health risks of e-cigarettes.
Originally, the applications were to be required by November 2018. Then FDA commissioner Scott Gottlieb announced that deadline was being pushed ahead until August 2022. [Update: In March 2019, the FDA announced that industry compliance on e-cigarettes would be required by August 2021.]
Cessation aid or not?
While government moves slowly toward some regulatory control of e-cigarettes, research into their health safety is still in its infancy. Dr. Chitra Dinakar, allergist at the Stanford University School of Medicine and co-author of the NEJM e-cigarette review, breaks users into two categories when discussing vaping’s potential health impacts.
One group is smokers who may consider vaping as a way to cut down on the use of tobacco cigarettes or to quit entirely. The other is users who have never smoked, particularly adolescents and youths.
On whether an e-cigarette is an effective smoking cessation aid, the research is mixed. Observational studies seem to suggest that e-cigarettes may help smokers to reduce their use of tobacco cigarettes. However, in the “ideal study,” as Dinakar puts it, a randomized trial in which participants were given either nicotine patches, e-cigarettes with nicotine or e-cigarettes without nicotine, there was no statistically significant difference in the quitting rate among the three groups.
“What it showed, dishearteningly, was dual use of tobacco and e-cigarettes persisted at six months at moderately high levels,” says Dinakar, clinical chief of allergy and asthma and a professor of medicine at Stanford University in California. “One-third of the people continued to use both.”
Teens & e-cigarettes
Dinakar says there is cause for concern about the exploding popularity of e-cigarettes, particularly among young people, and what that means for their health and future tobacco use. Many physicians contend e-cigarettes could be a gateway to other tobacco products, but there is some dispute in the evidence to date.
In a study of more than 5,000 high school juniors and seniors, researchers in the University of Southern California’s department of preventative medicine found that e-cigarette users were six times more likely to start using regular cigarettes compared to those who had never used the devices. The link between e-cigarettes and subsequent use of tobacco cigarettes was “stronger” among those who said they had “no intention of smoking” when the study began.
But there’s a caveat. “It is possible in principle that e-cigarette use among never smoking adolescents is a marker for those who would have begun to smoke even if e-cigarettes were not available,” the study’s authors say. “The availability of e-cigarettes may have delayed the initiation of smoking among those who would have gone on to smoke anyway.”
The study notes that there are “several plausible mechanisms” through which e-cigarette use in adolescence may lead to tobacco use. The flavoring may desensitize teens to the effects of the nicotine, which they may also be growing addicted to; the device itself may appeal to youth who are always looking for the next technology to embrace; and vaping appears to be normalizing “smoking-like behavior” that had been marginalized in recent years.
But the gateway to tobacco argument is by no means settled. A review of e-cigarette research by scientists at the University of Victoria in British Columbia, Canada concluded that e-cigarette use does not, in fact, contribute to tobacco use later on.
The researchers note that four population surveys reveal that rates of tobacco use among youth declined as the use of vaping devices increased. Two other studies found that, in groups of adolescents who were legally able to purchase e-cigarettes, the rate of tobacco use was lower compared to groups who were barred from purchasing e-cigarettes. These researchers also wrote that because many youths use e-cigarettes that do not contain nicotine, the theory that they become addicted to the substance is dubious.
However, even that point’s contentious. In another review of e-cigarettes, published in 2015, Florida allergist Dr. Thomas Casale and colleagues wrote that some “nicotine-free” vaping products in fact do contain some of the addictive chemical, since some retailers “make their own formulations without regulation or oversight.”
“One of the biggest concerns I have with e-cigarettes is a result of all of the flavorings and additives that are done at the local vape shops without any information as to their safety,” Casale told Allergic Living. Dinakar, meantime, adds that the “adolescent brain is particularly vulnerable to nicotine.” She says studies have shown that it can “open the gateway that makes them prone to other high-risk behaviors.”
Are the devices safer?
Since there’s little research evaluating the potential impacts of the levels of nicotine and other chemicals in e-cigarettes, the jury is still out on the question of health safety. The University of Victoria researchers point out that e-cigarettes do not contain tar and don’t have about 61 of 79 known toxins found in regular cigarettes.
“What we do know is that combustible cigarettes contain many more harmful materials and chemicals than e-cigarettes,” Casale says. “However, that does not mean that e-cigarettes do not have adverse consequences.”
Indeed, the U.S. Surgeon General has concluded that aerosol from e-cigarettes contains not only potentially harmful chemicals, but chemicals that are known to be harmful, as well as small particles that can be inhaled into the lungs. In addition, chemicals used in the liquid that is heated to produce the vapor, such as propylene glycol, are approved for use as food additives and considered safe for human consumption. Yet, the safety has not been proven when these chemicals are heated to high temperatures and inhaled, as occurs with vaping.
“If you read the ingredients, many of them seem very innocent: menthol, eucalyptus, flavorings, propylene glycol and vegetable glycol,” Dinakar says. “The problem is that nobody thinks of the next step, which is actually heating it to a very high temperature. That changes their chemical nature.”
In the NEJM review, she and her co-author note that some liquid flavorings in e-cigarettes contain formaldehyde and acetaldehyde, known carcinogens. While the concentration of these and other compounds is significantly lower than in tobacco cigarettes, “this concentration is elevated when the voltage used to generate the aerosol is elevated.”
The review also notes that e-cigarette liquids include diacetyl or acetyl propionyl, which are approved for use in food, “but have been associated with respiratory disease when inhaled during manufacturing processes.”
As Casale and his colleagues wrote, “The greatest fear for the majority of health-care professionals is that [e-cigarettes] might pose unforeseen health problems either in the short term or long term. These harms stem from the toxic or carcinogenic constituents of the vapor, deleterious effects on lung function, or some unexpected consequence.”
E-cigarettes and asthma
Dinakar points out that asthmatics, who smoke have more symptoms, greater difficulty controlling their asthma and more asthma attacks compared to non-smokers, and switching to e-cigarettes has been linked to improvement in their conditions.
But there’s more to the story. Asthmatics are susceptible to all sorts of chemical irritants that can trigger inflammation in the airways. “Their airways are hyper-reactive and therefore inhalation of the high-temperature vapor could trigger bronchial spasms,” the expert says.
While there is no hard evidence about the impact of e-cigarettes on those with asthma, that will soon change. Casale has applied to the National Institutes of Health for a grant to study the acute and chronic effects of e-cigarettes versus combustible cigarettes in patients with asthma.
A challenge facing researchers is the wide range of e-cigarette products with a myriad array of liquid mixes, so there is seldom consistency in the vapor that’s produced. That lack of consistency will make it challenging to draw conclusions that can be applied broadly to the e-cigarette market.
When it comes to secondhand e-cigarette exposure, the University of Victoria researchers find it appears to pose a health risk. They say the vapor is less toxic than secondhand cigarette smoke, with no carbon monoxide or tar, but that vaping produces a “measurable absorption of nicotine by bystanders.”
While the risks from that secondhand vapor exposure have yet to be determined, with asthma, such effects are usually magnified when compared to the general public.
Clearing the air
Casale and Dinakar note that what research does exist suggests that e-cigarettes may be safer than tobacco cigarettes for smokers who intend to quit smoking. That said, there’s still no data on the implications of vaping for non-tobacco smokers or for smokers over the long-term.
Ultimately, scientists just don’t know what exposure to e-cigarette vapor does to either asthmatics or non-asthmatics, Casale says. But the allergist who’s seen asthma’s debilitating effects on lung function can say this with confidence: “The bottom line is that patients with asthma should not use either combustible or e-cigarettes.”