For teens and young adults, e-cigarettes could be a gateway drug toward smoking traditional cigarettes, according to a new paper published by JAMA Pediatrics.
The study, which tracked the habits of nearly 700 young people over a year, revealed that young nonsmokers who showed no interest in smoking were more likely to take up the habit if they had used electronic cigarettes.
E-cigarettes heat a liquid filled with nicotine and other (often flavored) chemicals that can be inhaled as a vapor. They are generally considered to be less dangerous than traditional cigarettes, whose smoke generated by burning tobacco-based products is filled with cancer-causing chemicals.
As e-cigarette use, or vaping, has grown, experts have hotly debated whether it offers a net benefit or net harm to consumers, and whether e-cigarettes should be regulated as tobacco products are.
Some have pointed to a potential to help wean smokers off traditional cigarettes. Others have said that the devices, often marketed with child-friendly flavors, could introduce more young people to nicotine addiction that could later develop into a tobacco smoking habit.
To see whether there was a link, researchers from the University of Pittsburgh, Dartmouth University and the University of Oregon surveyed young people from around the U.S. who had never smoked traditional cigarettes and who were not susceptible to smoking at the time.
A person's susceptibility to smoking was evaluated by two questions: "If one of your friends offered you a cigarette, would you try it?" And, "Do you think you will smoke a cigarette sometime in the next year?"
Those surveyed could choose "definitely yes," "probably yes," "probably no" or "definitely no" — but if they chose anything other than "definitely no," they were not included in the study. This left the researchers with 694 nonsmoking participants with no stated desire to smoke traditional cigarettes.
A small number of these participants who had expressed zero interest in smoking cigarettes (16, to be exact) had previously used electronic cigarettes. The scientists then followed up with the participants a year later, to see whether they had progressed toward smoking traditional, combustible cigarettes.
The researchers found that 11 out of 16 of the e-cigarette users, or nearly 69%, had progressed toward smoking. Five had changed their answers from "definitely no," and six had smoked traditional cigarettes — despite their previous lack of interest.
Among the 678 participants who had not previously smoked e-cigarettes, 128 (or just under 19%) had progressed toward smoking — 63 no longer said "definitely no" to future cigarette smoking, and 65 had ended up smoking.
"These results raise concerns that the many adolescents and young adults who initiate nicotine use through e-cigarettes are at substantially increased risk for later use of cigarettes, even if they do not intend to smoke cigarettes in the future," the study authors wrote. "Thus, while e-cigarettes may potentially represent a product that can reduce harm for established cigarette smokers, they may simultaneously contribute to the development of a new population of cigarette smokers."
The researchers did, however, note that their sample of the teens and young adults who had used e-cigarettes was quite low, just 2.3% of the overall sample.
"It could be interpreted that this small number may not translate into substantial risk," they wrote. "However, data published in 2015 suggest that large numbers of youth are initiating e-cigarette use and that as many as half of these individuals do not smoke traditional combustible cigarettes."
A recent report from the Centers for Disease Control and Prevention found that rates of e-cigarette use among high schoolers jumped from 4.5% in 2013 to 13.4% in 2014 — tripling in just one year.
The U.S. Food and Drug Administration is examining whether to impose regulations on e-cigarettes.
"At a time when many claim to be uncertain about the harms and benefits of e-cigarettes and argue for more studies, these data provide strong longitudinal evidence that e-cigarette use leads to smoking, most likely owing to nicotine addiction," Jonathan D. Klein, associate executive director of the American Academy of Pediatrics, wrote in an editorial in JAMA Pediatrics accompanying the study. "We do not need more research on this question.... What we still need is the political will to act on the evidence and protect our youth."