For years, a public health debate has been smoldering over the merits of vaping up an electronic cigarette: the pen-shaped, battery-powered devices that deliver heated liquid nicotine (or cannabis) to your lungs without the need to light a stick of tobacco.
Pro-vapers claim—with a decent amount of evidence—that e-cigarettes are much safer than their tobacco-filled counterparts, making them a practically harmless way for smokers to cut back on their nicotine habit and eventually quit entirely. Critics have shot back that we've only just scratched the surface of knowing what vaping can do to the body, both immediately after a flavored puff and years down the road. And some aren't so sure e-cigarettes are helping smokers wean themselves off nicotine; in the case of young kids who try out vaping, they might even be grooming some into future smokers.
A small, new study published Friday in the American Journal of Respiratory and Critical Care Medicine isn't going to settle that debate, but it does seem to provide the anti-vaping side some ammo: it suggests that e-cigs trigger potentially harmful immune responses in the lungs.
For their study, University of North Carolina researchers looked at three groups: current smokers, non-smokers, and e-cigarette users. Specifically they looked at these people's sputum—the globs of spit and mucus we hack out whenever we cough—in order to check out immune system biomarkers in their lungs. As expected, they found increased levels of proteins associated with cigarette smoke exposure in the smokers, including markers of oxidative stress associated with lung disease. But they found increases in some of these immune markers in vapers, too.
Not only that, but the vapers's lungs also had higher levels of unique immune proteins; increases that weren't seen in either smokers and nonsmokers. These proteins, while essential for fighting off germs, can increase the risk of lung disorders like chronic obstructive pulmonary disease (COPD) if left constantly elevated.
"Our data presents the first, to our knowledge, in-vivo evidence from actual users that e-cigarettes may cause significant harm that produce[s] a unique innate response in the human airways," lead author Mehmet Kesimer, a pathologist at the University of North Carolina, tells Tonic. "Our findings, however, do not mean that e-cigarettes are worse than regular cigarettes or vice versa."
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As Kesimer sees it, it's not a question of whether e-cigarettes are safer than cigarettes, but whether they're safe at all. On that point, his team believes the findings are pretty worrying. "Our data shows that e-cigarettes have a signature of possible harm in the lung that is partially similar to cigarette smoke and partially unique from it," he says.
And while he's well-aware of the evidence suggesting otherwise, like a recent study which found e-cigarette users have much lower levels of carcinogens and toxins in their urine and saliva than smokers, he notes that a lot of it is often circumstantial. "Airway samples," meanwhile, "can be directly informative about the lungs' health and status of the harm of inhaled agents," he explains.
Louis DePalo, a pulmonologist at Mount Sinai hospital in New York, is less wary of e-cigarettes as a way to get people to stop smoking. But he's similarly skeptical about vaping's touted harmlessness. "We assume that because cigarettes are so bad for you, anything that [isn't] cigarettes must be great," he tells Tonic. "And I think the value of this study is that we can say, 'Look, there might be deleterious effects here not too dissimilar from smoking.'"
Still, DePalo worries about the promise of e-cigarettes as a solution to quit nicotine altogether. Unlike a nicotine patch or gum, e-cigarettes are great-tasting and appealing. So while smokers may tell themselves they can slowly ease away from nicotine completely by vaping, they might be more likely to simply trade one addiction for another. And if e-cigarettes aren't as healthy as their manufacturers say they are, we might not know for a long time. Many e-cigs are made by the same tobacco companies who insisted for decades that cigarettes weren't as bad as the science said.
"These studies are very reminiscent of the early tobacco days. And again, we have the same companies that gave us tobacco now giving us e-cigarettes. It doesn't pass the smell test," DePalo says. "It'd obviously be better if it wasn't tobacco companies pushing this."
The study, like all research, comes with its caveats. Leaving aside the small sample size (each group had 15 or fewer volunteers), all but three e-cigarette users had been former smokers. This makes it possible, if unlikely, according to the researchers, that the results may be less damning for e-cigarettes. Ideally, Kesimer says, future research needs to compare smokers with people who've only ever vaped. For better or worse, that's becoming more much common, especially among young teens (the teen vaping rate did however fall in 2016, after years of a steady increase).
The findings also have little to say about whether vaping could lead to lung cancer. Theoretically, the sort of chronic lung inflammation that Keismer's team suggests could happen with vaping could be a risk factor for cancer, but we'd need long-term research to know for sure.
"I think the takeaway should be: Cigarettes are bad. And e-cigarettes may be a tool in the triple approach to smoking cessation, which is really education, nicotine replacement, and counseling," DePalo says. "But research and regulation is required. [E-cigs] might save lives, might drive down lung cancer and COPD rates, but we need to understand it a little bit better before we adopt it as national policy."
Though the FDA was geared to begin regulating e-cigarettes as aggressively as it does tobacco products, the Trump administration's new FDA chief Scott Gottlieb unfortunately delayed the process in July, saying the agency now needs until 2022 to figure out how to regulate them.
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