Public statements from the U.S. Centers for Disease Control and Prevention (CDC) takean alarmist view of e-cigarettes, portraying them as a menace to the youth of America, who supposedly will start smoking again in droves once they try vaping and get hooked on nicotine. But the CDC’s data tell a different story.
Last week the CDC released the latest results from its National Youth Risk Behavior Survey (NYRBS), which is conducted every two years. The 2015 numbers show that cigarette smoking continues to fall among teenagers even as more and more of them experiment with vaping. But as usual, the CDC chose to accentuate the negative.
“Current cigarette smoking is at an all-time low, which is great news,” CDC Director Tom Frieden conceded. “However, it’s troubling to see that students are engaging in new risk behaviors, such as using e-cigarettes. We must continue to invest in programs that help reduce all forms of tobacco use, including e-cigarettes, among youth.”
You see what he did there? Frieden, as is his wont, called vaping “tobacco use,” even though e-cigarettes do not contain tobacco. In fact, data from the Monitoring the Future Study indicate that the e-cigarette liquids used by teenagers typically do not even contain nicotine. Even when teenagers use e-cigarettes to inhale nicotine, they face far smaller health risks than smokers do—a crucial point that the CDC recklessly and routinely obfuscates by implying that the rising popularity of vaping wipes out any public health benefit from the ongoing decline in smoking.
That decline has been dramatic. According to the NYRBS, the share of high school students who reported smoking cigarettes during the previous month fell from more than 36% in 1997 to less than 11% in 2015—a 70% drop. Other surveys, including Monitoring the Future and the CDC’s National Youth Tobacco Survey, show a similar downward trend, even as interest in e-cigarettes has increased dramatically.
The CDC has been raising the alarm about rising adolescent e-cigarette experimentation since 2012, based on answers to survey questions added in 2011. Yet the NYRBS shows that past-month cigarette smoking fell from 18.1% in 2011 to 10.8% in 2015. The CDC’s own numbers belie the notion that vaping is renewing interest in smoking.
A study published this week in the journal Pediatrics purports to show that vaping is nevertheless renewing interest in smoking. But that is not what the study actually shows.
Jessica Barrington-Trimis, a postdoctoral research associate at the University of Southern California, and her eight collaborators started with the Children’s Health Study, which has been following more than 5,000 kids in Southern California since 2002. The researchers focused on 213 subjects who in 2014, when they were juniors or seniors in high school, reported that they had never smoked. Barrington-Trimis et al. got 146 of those teenagers to complete new questionnaires an average of 16 months later. They found that teenagers who had reported trying e-cigarettes in 2014 were six times as likely as those who hadn’t to report in the follow-up survey that they had tried conventional cigarettes.
The researchers conclude that “e-cigarette use in never-smoking youth may increase risk of subsequent initiation of cigarettes and other combustible products during the transition to adulthood when the purchase of tobacco products becomes legal.” Then again, it may not. While Barrington-Trimis et al. found a strong association between vaping and smoking, it does not necessarily follow that the former causes the latter. It may simply be that the sort of teenagers who are inclined to try vaping are also inclined to try smoking, and that they try the former first because it smells and tastes better and causes less discomfort. Even if e-cigarettes did not exist, those same teenagers might have eventually tried smoking anyway.
Furthermore, as University of Boston public health researcher Michael Siegel points out, the researchers do not say how many of the subjects were using e-cigarettes regularly at baseline or had become regular smokers at follow-up:
Baseline e-cigarette use was defined as ever having taken even one puff of an e-cigarette. And smoking initiation was similarly defined as ever having taken even one puff of a cigarette. So the study did not document that even one subject in the study was ever a regular vaper. It is entirely possible (and in fact likely) that the majority of these kids had experimented with e-cigarettes, failed to become vapers, and then turned to regular cigarettes. In fact, it’s entirely possible that had these kids been able to stick with vaping, they would never have become smokers.
In addition, the study counted anyone who had even puffed a cigarette as being a smoker. So theoretically, a subject could have had a single puff of an e-cigarette and hated it, and then had a single puff of a cigarette and hated it, and they would be considered someone who initiated smoking because of first becoming addicted to vaping.
This study does not come close to confirming the hypothesis that teenagers who otherwise never would have smoked get addicted to nicotine by vaping and ultimately progress to conventional cigarettes. It does not show that any of the teenagers vaped enough to get hooked on nicotine (or even that the e-liquid they used contained nicotine). It does not show that teenagers who tried vaping and subsequently tried smoking liked either of them, let alone that they developed a long-lasting, life-threatening tobacco habit. Most crucially, it does not show that the availability of e-cigarettes had any impact on teenagers’ subsequent decisions to try the real thing.
“It is possible in principle that e-cigarette use among never smoking adolescents is a marker for those who would have begun to smoke even if e-cigarettes were not available,” Barrington-Trimis et al. concede. “In these adolescents, the availability of e-cigarettes use may have delayed the initiation of smoking among those who would have gone on to smoke anyway.” But they suggest that alternative explanation is implausible, given that “the risk of smoking associated with e-cigarette use was even higher among participants who reported no intention to smoke at initial assessment than among the group of adolescents who indicated they were likely to begin smoking.”
Then again, vaping may simply be a weaker signal of future tobacco use for those who already admit they are interested in smoking. Among teenagers who say they have no interest in smoking, interest in vaping helps differentiate those who will nevertheless try tobacco cigarettes from those who won’t. But among teenagers who say they probably will smoke one day, the fact that they have already tried vaping does not add as much information.
Putting aside the limitations of this particular study, the fact remains that vaping and smoking trends among teenagers have been moving in opposite directions for years. If e-cigarettes were priming adolescents to smoke, you would expect to see more of them smoking, or at least a diminution in the downward trend that began in the late 1990s. Instead the downward trend accelerated during the same period when interest in e-cigarettes took off. Perhaps the CDC’s professional worrywarts should consider the possibility that e-cigarettes are displacing the conventional kind, a development they should be celebrating instead of bemoaning.