Electronic cigarettes are becoming more popular, but how safe or how risky are they?
At this point, the bottom line about e-cigarettes is: "If you're a chronic smoker looking for a nicotine fix and trying to decide between smoking and vaping, most experts would agree there’s a compelling case that e-cigarettes are less harmful. But a nonsmoker, or an ex-smoker, should think twice before taking up the habit. Even if e-cigarettes are safer than regular cigarettes, that doesn't mean they're totally safe. At this point, we just don't know," Julia Belluz
reports for
Vox.
Belluz came to this conclusion after reading more than 60 studies, articles and reviews, and interviewing nine researchers and health experts about their work. In her research, she notes that "There are only two published randomized control trials — considered the gold standard of scientific evidence — on e-cigarettes (
this one and
this one)."
Belluz immediately points out that "the state of the science is crap" regarding the current research published about e-cigarettes. A
review, published in the
American Journal of Preventive Medicine in 2014, looked at 76 of the best available studies on e-cigarettes, more politely concurred: "Due to many methodological problems, severe conflicts of interest, the relatively few and often small studies, the inconsistencies and contradictions in results, and the lack of long-term follow-up no firm conclusions can be drawn on the safety of [e-cigarettes]."
"The literature is very poor," Martin Dossing, one of the review's authors told Belluz. "The most worrying aspect of e-cigarettes is that we do not know the long-term health consequences of daily use. Will e-cigarette users come up with unsuspected diseases such as cancers in 10 or 20 years from the start of use 10 years ago? Substances known to be carcinogenic to man have been found in a few brands of e-cigarettes."
There are about 500 e-cigarette brands and more than 7,000 flavors on the market, and they work in different ways, delivering varying amounts of nicotine, toxins, and carcinogens. In addition, the technology surrounding e-cigarettes is constantly evolving, making generalized research findings near impossible and discrediting much of the earlier research.
E-cigarettes are battery-powered devices that deliver nicotine through a vapor by heating a solution of propylene glycol or vegetable glycerin, flavoring and other additives. They are expected to surpass traditional cigarette sales in the U.S. by 2017, reaching $10 billion, Belluz reports.
"The major appeal of e-cigarettes is that they don’t contain tobacco and the exhaled vapor carries no harmful smoke, tar, or carbon monoxide. They also seem to have significantly fewer toxins and carcinogens than regular cigarettes," Belluz writes.
How dangerous are e-cigarettes?
"We don't actually know," Belluz reports.
"In general, the health effects of e-cigarettes have not been well studied, and the potential harm incurred by long-term use of these devices remains completely unknown,"
says the
American Heart Association in its e-cigarette policy statement.
Belluz writes that the science so far says that short-term exposure to e-cigarettes does not appear to carry serious and immediate health effects, but also notes that the research is still early and could change because studies thus far have only been conducted on dozens or hundreds of people, not tens of thousands.
The AHA points out: "The data on health effects to date, studied primarily in healthy people with short-term exposure, reveal little or no evidence of severe adverse events. Respiratory irritation and the bronchial constriction from a propylene glycol aerosol raise concerns about harm to people with asthma and chronic obstructive pulmonary disease, but one small study reports no harm but rather benefit when users quit smoking or smoke fewer cigarettes per day."
Other studies have looked at the toxicity of e-cigarette's aerosol and liquids and their potential long-term effects.
One
study of 12 brands of e-cigarettes found that their vapors were mostly composed of nicotine and nicotine solvent (propylene glycol or vegetable glycerin), Belluz reports. It also found the levels of toxicants and carcinogens in the e-cigarette vapor were "nine to 450 times less prevalent than in traditional cigarette smoke."
One of the leading researchers on this study, Maciej Goniewicz, of
Roswell Park Cancer Institute, told Belluz that while "propylene glycol and glycerin are generally considered safe substances, not a lot is known about the long-term effects of daily inhalation." Some evidence points to propylene glycol as a lung irritant when used to create fog in theaters.
Goniewicz also found "toxic substances and cancer-causing compounds, such as formaldehyde and acetaldehyde, in e-cigarettes," noting that these levels varied between products.
Other research, though not conclusive yet, involves studies that have shown that "cells exposed to e-cigarette vapor show genetic changes as cells exposed to conventional cigarette smoke, raising concerns that e-cigarettes could potentially lead to lung cancer," Bulluz reports.
Another area of research looks at the heating process used in e-cigarettes, which can change the composition of potentially harmful chemicals. "If the temperature goes too high, then there are more toxicants," Goniewicz told Belluz, also noting that the heating process varies widely among products. And yet another unknown, Belluz writes, is the effects of the flavors used in e-cigarettes on the body when they have been heated and inhaled long-term.
Are e-cigarettes safer than regular cigarettes?
"Most researchers cautiously lean toward 'yes' — despite the unknowns," Belluz writes.
"It’s probably fair to say that a long-term e-cigarette user is not going to die from tobacco-caused disease," Thomas Eissenberg, co-director of the
Center for the Study of Tobacco Products, told Belluz. "But it’s not clear whether they’ll die from an e-cigarette-caused disease and whether their rates of death will be less than, more than, or the same as the rates of death we see from tobacco-caused diseases."
Do e-cigarettes actually help people stop smoking?
"The evidence on quitting is still limited and has mixed results," Belluz writes.
"So far, two randomized studies (
here and
here) have looked into the question of quitting — and both found that e-cigarettes may indeed help smokers quit. Another lower-quality web-based survey came to the same conclusion," Belluz writes. But weaknesses in these trials make it hard for many to buy in to it.
Another systematic systematic
review by the
Cochrane Library isn't ready to make this claim, noting: "The small number of trials, low event rates and wide confidence intervals around the estimates mean that our confidence in the result is rated 'low.'"
Belluz reports that two observational studies have found that e-cigarettes do not help people stop smoking.
"A study published in
JAMA Internal Medicine in 2014 concluded: "E-cigarette use by smokers was not followed by greater quitting, or reduction in consumption one year later."
"Another 2015 study in the journal
Addiction found that daily use of e-cigarettes seemed to be associated with an increase in the rate of attempts to quit smoking and less smoking, though not increased rates of quitting."
Could e-cigarettes "re-normalize" smoking?
"This issue is of great concern to many, especially after years of anti-smoking campaigns and evidence that the rates of traditional cigarette smoking are falling," writes Bulluz.
"Those in favor of e-cigarettes say this renormalization is unlikely. They point to recent CDC data showing that the threefold increase in e-cigarette use among youth has been accompanied by a decline in the use of traditional cigarettes," she writes.
On the flip side, researchers against e-cigarettes note that the absolute use of nicotine products (such as hookah and cigars) has been trending up.
"Maybe you get a chronic smoker to quit," Judith Prochaska, a professor at Stanford's prevention research center, told Belluz. "But what about this next generation coming up who would not have picked up a combustible cigarette because it’s a dying behavior, but these devices are so trendy and they’re flavored and marketed to be really appealing to kids?"
In 2015, the
Centers for Disease Control and Prevention reported that the use of e-cigarette devices among middle school and high school students tripled between 2013 and 2014.That means about 13 percent of students now use them, more than the number who smoke conventional cigarettes.
Is nicotine, on its own, harmful?
Some say it is, and others say it's not.
Researchers who view e-cigarettes favorably argue that nicotine doesn't harm people, it is the tobacco and other chemicals in combustible cigarettes that does harm.
Staunch tobacco-control types argue that it is dangerous and addictive and should be avoidable.
"The truth likely lies somewhere in between," Belluz writes.
Belluz reports that one review stated, "Nicotine is the addictive chemical in tobacco smoke, but its involvement in smoking-related harm (outside pregnancy) is very small, if any, compared to cigarette smoking."
Another systematic review pointed out that nicotine can have a variety of potential health effects, from raising one's cardiovascular risk to causing birth defects in pregnant women.
Other research suggest nicotine may help treat Parkinson's disease to enhancing attention and focus, Bulluz writes.
Do these scientific debates matter for policy?
"Yes. Right now, regulators are trying to figure out how to deal with e-cigarettes," she writes.
The
Food and Drug Administration proposed a draft rule in April 2014 that will redefine e-cigarettes as "tobacco products." Once finalized and enacted in another few years, e-cigarettes will be FDA-regulated under the Tobacco Control Act.
Among other things, this would: ban e-cigarette sales to minors; require health warning labels on e-cigarettes, which would warn of the possibility of addiction; prohibit vending machine sales of e-cigarettes except in places that don't allow minors; require e-cigarette manufacturers to register a list of their products' ingredients;require an FDA review of marketing plans;require FDA approval of any claims about e-cigarettes' benefits, such as the claim that e-cigarettes can help people quit cigarettes; and ban free samples of e-cigarettes
The FDA's rules don't include some restrictions that health advocates called for: They don't halt online sales of e-cigarettes, prevent television and radio advertising, or ban the marketing of appealing flavors.
Advocates of more restrictions are greatly concerned about the advertising and appealing flavors that are targeted toward children. Vaping advocates are concerned that too much regulation is overkill and would decrease accessibility of a device that could save lives. Others are concerned that too much regulation will halt innovation of newer devices that could help reduce smoking.
"For now, researchers and industry representatives are either unlikely bedfellows in a harm-reduction game plan or at odds over the best way forward," Belluz writes.
