MONDAY, Oct. 23, 2017 (HealthDay News) -- Teens who vape e-cigarettes with higher nicotine levels are more likely to start smoking conventional cigarettes soon after, new research shows.
"We know that teens who vape e-cigarettes are much more likely to become conventional cigarette smokers," said study lead researcher Adam Leventhal. "Our study suggests that the nicotine in e-cigarettes may be a key reason why teens who vape progress to more frequent smoking."
Leventhal directs the University of Southern California Health, Emotion and Addiction Laboratory at the Keck School of Medicine in Los Angeles.
E-cigarettes are sold with nicotine levels ranging from zero to more than 25 milligrams of nicotine per milliliter (mg/mL). In this study, a high-nicotine device was defined as having levels at or above 18 mg/mL.
Leventhal's team tracked outcomes for 181 grade-10 students from high schools in the Los Angeles area. All of the teens said they had used e-cigarettes within the past month, and they provided data on nicotine levels in the devices they used.
Six months later, those who used higher nicotine levels in their e-cigarettes were more likely to report use of both e-cigarettes and regular cigarettes within the past month. These teens also reported vaping and/or smoking more intensely.
While 43 percent of the students who'd used high-nicotine e-cigarettes said they were "frequent smokers" of traditional cigarettes six months later, that was true for only 10 percent of those who'd vaped using lower-nicotine devices, Leventhal's group found.
And teens who vaped using high-nicotine e-cigarettes smoked an average of 14 times as many "regular" cigarettes per day six months later compared to those who'd tried nicotine-free versions of the devices, the findings showed.
More kids are trying high-nicotine e-cigarettes nowadays, Leventhal noted.
"While previous research reported that most adolescents were using nicotine-free e-cigarettes, results from our survey and other soon-to-be published studies show that many more teens are vaping e-cigarettes with nicotine than we originally thought," he said in a university news release.
Two anti-smoking advocates weren't surprised by the findings.
"Vaping nicotine through e-cigarettes -- especially at higher concentrations -- is associated with continued vaping and with smoking traditional cigarettes," said Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in New York City.
Patricia Folan is a nurse who directs the Center for Tobacco Control at Northwell Health in Great Neck, N.Y. She said that this, and other research, "highlights the imperative for the U.S. Food and Drug Administration to regulate these devices, including the amount of nicotine in these products and proper labeling of their content."
Folan warned that "vaping has the potential to addict a new generation, which might not otherwise have experimented with traditional cigarettes, to nicotine. If these devices are not regulated and this trend goes unchecked, we will most likely see an increase in smoking rates among youth."
E-cigarettes are available in a wide variety of nicotine concentrations. Recently, the FDA was given regulatory power over e-cigarette solutions containing nicotine.
The study was published Oct. 23 in the journal JAMA Pediatrics.
The U.S. Food and Drug Administration has more on e-cigarettes and related devices.