High school students who vape—that is, use e-cigarettes—at the start of a school year are more likely to become heavy smokers by the end, compared to their peers who don’t vape, according to new research published in the Journal of the American Medical Association.
“It’s such an emerging public health issue,” says lead author Adam Leventhal, director of the Health, Emotion and Addiction Laboratory at the Keck School of Medicine of University of Southern California. “These teens aren’t just experimenting—a significant portion are progressing to more regular levels of smoking.”
Leventhal and his team looked at 10th grade students who were about 15 years old. “This age range is a really critical time when smoking either onsets or accelerates,” he says. Past research indicates that 37% of 10th graders have used e-cigarettes, and the new study, which surveyed more than 3,000 10th graders across Los Angeles public schools, found similar rates. The teens filled out questionnaires at the beginning of the school year and again at the end.
Teens who vaped frequently were about 10 times more likely to become regular smokers six months later, compared to teens who had never vaped. While 20% of these regular e-cig users transitioned into frequent smokers, less than 1% of kids who had never vaped smoked cigarettes at followup.
“The amount of vaping mattered,” says Leventhal. “The more you vaped at baseline, the more you smoked at the followup.”
Why, of course, is the bull’s-eye question e-cigarette researchers are trying to answer. While this study wasn’t designed to come to such a conclusion, Leventhal has some ideas. Vaping nicotine may sensitize young brains to the addictive effects of the drug, making the first time with a cigarette more pleasurable or familiar, he says. “Compare that to teens who had never vaped: when they start smoking, the nicotine might be unpleasant to them because they’re not used to it,” he says. Side effects like nausea and dizziness might make them less likely to continue.
But even e-cigs that do not contain nicotine could be dangerous for teens, who may grow fond of the ritual of inhaling a substance, “making them more inclined to experiment with other tobacco products,” Leventhal says.
Some research suggests that e-cigarettes may help a person stop smoking, but this study didn’t find such a pattern. When Leventhal looked more closely at teens who smoked at the start of the year, he found that by the end, e-cigarettes weren’t associated with either a reduction or increase in smoking.
Leventhal and his team are still following the same group of teens to see how their substance use and other health behaviors change and interact over time.
This research is just the latest in a string of studies on the effects of e-cigarettes in teens. “I’m aware of six separate studies now that show that teens who vape are more likely to start using a smokable tobacco product,” whether they're cigarettes or hookah or cigars, he says. “This pattern is associated with a high risk of health effects and progression to adult and chronic smoking.”