Teen Vaping Likely a 'Gateway' to Cigarette Use

Use of e-cigarettes (ECs) and other vaping products by teens may lead to an increase in use of regular cigarettes over time, new research suggests.

A survey study of more than 2000 young people not only showed significant associations between EC use and nicotine-cigarette use but also showed that more frequent use of ECs predicted more frequent use of cigarettes in the future.

Lead author Michael S. Dunbar, PhD, behavioral scientist at the RAND Corporation, Pittsburgh, Pennsylvania, told Medscape Medical News their findings that ECs could act as a gateway to use of regular cigarettes supports recent news from the US Food and Drug Administration (FDA).

The FDA has announced that, in order to stem the "epidemic" of harmful teen EC use, it would be targeting EC products that appear to be marketed specifically to this young age group, especially through the use of kid-friendly flavors.

"Unlike what you might find with adult smokers using e-cigarettes as a way to cut down on their smoking as a means of harm reduction, our data suggested the opposite for the youth we were looking at," Dunbar said.

"In this case, the teens who vaped and smoked tended to escalate their use of both products over time. We also didn't see that increases in vaping over time were offset by decreases in smoking," he said.

The findings were published online October 2 in Nicotine and Tobacco Research.

FDA "Taking Steps"

Some past studies have shown benefit for adults seeking to stop smoking who use ECs. Results from two US population-based surveys published online October 12 in Nicotine and Tobacco Research, which included almost 60,000 adult participants, showed that EC use was significantly associated with a higher rate of quit attempts and greater smoking cessation.

However, its researchers note that they are not advocating EC use for young people.

"I think their research and ours is not incompatible. There are some major differences between adults and youth," noted Dunbar.

According to the FDA, more than 2 million middle- and high-school students were current EC users in 2017; and more than 80% of young people "do not see great risk of harm" in its use.

On September 12, FDA commissioner Scott Gottlieb, MD, announced that the agency would be taking new steps to address this epidemic.

"I use the word epidemic with great care. e-Cigs have become an almost ubiquitous – and dangerous – trend among teens," said Gottlieb. "The disturbing and accelerating trajectory of use we're seeing in youth, and the resulting path to addiction, must end."

He added that the FDA "won't tolerate a whole generation of young people becoming addicted to nicotine as a trade-off for enabling adults to have unfettered access to these same products."

The FDA launched its Youth Tobacco Prevention Plan earlier this year and, in partnership with the Federal Trade Commission, targeted "misleadingly labelled or advertised e-liquids resembling kid-friendly foods like juice boxes, candy, and cookies," Gottlieb reported.

He also reported that the FDA had issued 12 warning letters to companies because of their advertising, had issued 56 warning letters and six civil monetary penalties to retailers of products from JUUL Labs, and sent more than 1100 warning letters to retailers who had sold ECs to minors. It also requested that makers of JUUL, Vuse, MartkTen, blu e-cigarettes, and Logic, the five top-selling brands of ECs, provide a plan for "mitigating youth sales" within 60 days.

"We're especially focused on the flavored e-cigarettes. And we're seriously considering a policy change that would lead to the immediate removal of these flavored products from the market," Gottlieb said.

In a press release last week, the FDA announced that it had sent letters to 21 EC companies, including manufacturers and importers, seeking information about whether 40 products are being "illegally marketed and outside the agency's current compliance policy."

In a press release of their own, JUUL Labs noted it was committed to preventing underage use and that it had released more than 50,000 pages of documents to the FDA. "We want to be part of the solution in preventing underage use," Kevin Burns, chief executive officer of JUUL Labs, said in the release.

Escalation Over Time

The current investigators note that past longitudinal studies have shown links between use of ECs and cigarettes among youth. However, these studies did not "distinguish within- from between-person effects, which complicates interpretation of findings," they write.

"Further, the role of shared risk factors, such as substance use and mental health, in explaining [these associations] remains unclear," they add.

"Recently there have been several studies showing that e-cigarette use in teens increases the likelihood they'll start using cigarettes in the future. It's sort of an initiation: from no use to any use," Dunbar said. "What we know less about at this stage is how patterns of vaping and smoking unfold over time in terms of escalations in use."

A total of 6509 adolescents from 16 middle schools in the Los Angeles, California, area were initially recruited in 2008 to take part in CHOICE, a substance use prevention program.

For the current analysis, the investigators assessed data for 2039 of the CHOICE participants between 2015 and 2017, "allowing us to model EC and cigarette use from ages 16 to 20." In this group, 20% were white, 45% Hispanic, 21% Asian, 2% black, 10% multiethnic, and 1% other. In addition, 56% were women (mean age, 19.3 years).

Between-person and within-person links between past-month frequency of use of ECs, cigarettes, and so-called "third variable" risk factors over time were assessed using autoregressive latent growth models with structured residuals (ALT-SR).

The third variable risk factors were use of alcohol, use of marijuana, and mental health symptoms.

EC and cigarette use, as well as alcohol and marijuana use, were examined using modified items from the Monitoring the Future survey; mental health was assessed using the five-item Mental Health Index.

Unsafe for Youth

The ARCL model results showed a significant "cross-lagged" association between use of ECs and cigarettes.

Greater use of ECs was associated with greater subsequent use of cigarettes (ß = .09) and vice versa (ß = .17). In addition, greater use of cigarettes was associated with greater use of alcohol (ß = .11) and vice versa (ß = .05) (for all associations, P < .05).

Greater use of ECs also predicted increased subsequent use of alcohol (B = .08, P < .05), but the reverse was not true.

In addition, greater use of ECs was associated with greater use of marijuana (ß = .11) and vice versa (ß = .03; both comparisons, P < .05). Although greater use of marijuana was associated with increased use of cigarettes (ß = .03, P < .05), greater use of cigarettes did not predict increased use of marijuana.

No significant associations were found between EC use and mental health.

Although within-person analyses did not show a significant association between shared risk factors and frequency of subsequent use of either ECs or cigarettes, this association was significant for both EC and cigarette use in the between-person analyses.

The overall results "add to a growing body of research suggesting that EC use among youth is prospectively associated with progression toward greater cigarette use," the investigators write.

"The shared risk factors examined here did not affect escalations in e-cigarette and cigarette use over time within individuals, but likely influence which youths use these products," they add.

Dunbar said the findings underline the importance of efforts by clinicians to prevent young patients from initiating nicotine and tobacco products in the first place.

"e-Cigarettes, while they may be a great tool to help adult smokers break away from combustible cigarettes, they're not safe for teens," he said.

"Our data speak to youth who use these products more frequently over time go on to increase their use of what we know to be more dangerous combustible products in the future," he added.

"Strong Evidence"

When asked to comment on the study, Scott McIntosh, PhD, associate professor in the Department of Public Health Sciences, University of Rochester Medical Center, New York, told Medscape Medical News the findings add "good evidence" about a strong association between use of ECs and regular cigarettes in adolescents and young adults.

"This was really strong evidence in a very vulnerable population, and we need these types of results reported," he said.

McIntosh, who was not involved in the research, is also the associate director of the Smoking Research Program at the University of Rochester and director of the Center for a Tobacco-Free Finger Lakes.

He noted that the research provides more evidence-based backing for the FDA going after vaping products that target young people.

"Most adolescents end up being dual users, so this gives us more of an evidence base as to why that is a problem. Even if they say the product is just a vapor, they end up being a dual user and increasing their use of regular cigarettes," he said.

Although he reiterated Dunbar's statement that adults and adolescents are very different regarding the use of these products, he questions the benefit of ECs in adults.

"Even in adults, there's been mixed results. There's evidence from some researchers that there's a harm reduction when people start using e-cigarettes instead of regular cigarettes. However, they often become dual users also," McIntosh said.

"The really important point here is that the definition of 'harm reduction' is still being explored," he added.

He reported that his university center just received a $19 million grant, along with Roswell Park Comprehensive Cancer Center in Buffalo, New York, to study flavorings in ECs, tobacco, and tobacco products in order to "get to the bottom of a lot of its harms."

Even if manufacturers aren't adding these flavors to attract adolescents, "they're doing it to attract new users. And I believe they are wanting to appeal to adolescents and young adults because of wanting replacement users for people who quit or die; and they want to get to them young," McIntosh said.

In addition, "our own research has shown that e-cigarettes have six times the amount of copper than regular cigarettes and more of an effect on oxidative stress in the body's cells. So that shows it's even more harmful than regular cigarettes, if you just compare those variables," he added.

"You can't say these products are 'safe,' and even saying 'safer' is relative. The vast majority of them have nicotine in them, and clearly carcinogens are found in e-cigarettes. So when it's said that the long-term effects haven't been studied, I would argue that those carcinogens and their effects have been studied for decades," McIntosh concluded.

The study was funded by grants from the National Institute of Alcohol Abuse and Alcoholism. The study authors and Dr McIntosh have reported no relevant financial relationships.

Nicotine Tob Res. Published online October 2, 2018. Abstract

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Cite this: Teen Vaping Likely a 'Gateway' to Cigarette Use - Medscape - Oct 18, 2018.