The potential dangers of long-term vaping have largely been hypothetical, but a new study out Monday provides the first real evidence that it can increase the risk of chronic lung disease in humans. And while the risk may be much higher for those who smoke traditional tobacco cigarettes, it’s amplified in people who both vape and smoke.
The study, published in the American Journal of Preventive Medicine, relies on data from an existing, government-led research project called the Population Assessment of Tobacco and Health, or PATH, Study. As part of the study, nearly 50,000 volunteers over the age of 12 were asked about their use of tobacco products—including e-cigarette nicotine products—and had their overall health recorded. They were then re-interviewed every or every other year, for three years.
The authors of the new study found that people who reported being former or current e-cigarette users at the beginning of the study were more likely to develop lung disease, including chronic obstructive pulmonary disease, chronic bronchitis, emphysema, or asthma, up to three years later than those who reported no e-cigarette use. Specifically, their odds of lung disease rose by about 30 percent, after accounting for other risk factors like their age or a co-existing cigarette habit.
“We concluded that e-cigarettes are harmful on their own, and the effects are independent of smoking conventional tobacco,” said study author Stanton Glantz, director of the Center for Tobacco Control Research and Education at the University of California San Francisco, in a statement released by the university.
This sort of research can only suggest a connection between vaping and chronic lung disease. But because the study kept track of people’s health and tobacco use over time, its conclusions provide firmer evidence of a direct cause-and-effect than other studies that only look at a snapshot of people’s health.
The study’s findings come amidst a continuing debate over the merits of vaping as a harm-reduction tool for people trying to quit smoking. They do support a familiar counter-argument made by vaping advocates and some doctors that e-cigarettes are much less harmful than their tobacco counterpart. Tobacco smokers were 260 percent more likely to develop lung disease during that same period, for instance, compared to people who didn’t smoke.
That said, it was actually dual users of both products that seemed to fare the worst. Their associated increased risk—330 percent—was higher than either group alone combined.
That’s all the more troubling, because most adults who take up vaping are dual users. And while many dual users say they vape as a way to eventually quit tobacco smoking, the evidence is mixed whether that happens with any major success. That could mean that vapers are placing themselves at greater risk than they think, even if they’re not buying tainted products made with THC and toxic additives.
“Switching from conventional cigarettes to e-cigarettes exclusively could reduce the risk of lung disease, but very few people do it,” Glantz said. “For most smokers, they simply add e-cigarettes and become dual users, significantly increasing their risk of developing lung disease above just smoking.”