Though e-cigarettes were first introduced into the market as a safer alternative to smoking, their popularity among youth has raised concerns of increased rates of smoking. But, a study published in October pushes back against this worry. Researchers found that high school seniors who currently smoke e-cigarettes would likely have smoked traditional cigarettes.
The study was conducted by Natasha Sokol, assistant professor of psychiatry and human behavior and research scientist at The Miriam Hospital Center for Behavioral and Preventive Medicine, and Justin Feldman, research fellow at the Harvard FXB Center for Health & Human Rights.
“This is a huge question in tobacco control: the idea being that e-cigarettes are an effective cessation tool (to help people move away from smoking cigarettes) but research has demonstrated that e-cigarettes are being used by youth who don’t use other tobacco products,” Sokol said. There’s concern in the public health community that the benefits of e-cigarettes as a cessation aid could be “negated by initiating youth into nicotine dependence,” she added.
This concern stems from the gateway theory — the idea that “if (people) get addicted to nicotine in e-cigarettes, ... they will switch from e-cigs to cigs,” said Professor of Behavioral and Social Sciences Jasjit Singh Ahluwalia, who has extensively researched tobacco use but was not part of the study. This theory is grounded in evidence, including findings from a 2015 study showing that “waterpipe smoking is harmful, addictive, can provide a gateway to cigarettes, as well as thwart cessation efforts.” Sokol’s and Feldman’s study tested this concept with e-cigarettes.
“What was really important for me to understand was whether the availability of e-cigarettes was not just initiating youth into nicotine dependence (but specifically youth) who wouldn’t have otherwise used a nicotine or tobacco product,” Sokol said. “If these kids are kids who otherwise would have used cigarettes, I’m not so sure that I share the level of concern over them using it in the first place.”
One challenge the researchers faced was designing the methods for their epidemiological research. The ideal way to conduct the experiment would be to “compare (patterns of smoking in) places where vaping became available to those where it was not yet available,” Feldman said. But, “vaping basically became available everywhere at once around 2014.”
As a result, Sokol and Feldman used data from a large sample of high schools from the Monitoring the Future 12th grade data set between 2009 and 2018 in the United States. Using this information, the researchers determined “whether youth who used e-cigarettes in 2014 to 2018 would have likely been smokers in the period preceding e-cigarette availability,” according to their study.
Using data from 2009 to 2014, before vaping became widely available, the researchers projected the expected number of smokers in 2014 to 2018. They generated a score for each individual in this study based on how likely they would have been to smoke using demographic factors.
“With that score, you can forecast in the future … what proportion of the 12th grade population would smoke every year if the trajectory continued,” Feldman said.
Then they compared this to data from 2014 to 2018, when vaping was available. They found a decrease of about two percent in the number of 12th graders who were actually smokers when vapes were available as compared to the projected number without vapes, Feldman said.
Still, while Ahluwalia acknowledged that the evidence is promising, he said it may not be enough to conclude that e-cigarette availability does not lead to cigarette smoking. The researchers’ usage of repeated cross-sectional studies to reach their conclusions on teen smoking patterns introduced “confounders and biases,” Ahluwalia said. He ranked different types of studies’ ability to show causality in descending order as randomized trials, prospective cohort studies and repeated cross-sectional studies. “So, in the hierarchy of studies, this (study) is going to have limitations with regards to the strength of concluding your findings are causally related,” he said.
In a scenario in which e-cigarettes would have never been made available, “what we see is that youth smoking rates would not have been declining as quickly” as they have with the introduction of e-cigarettes, Sokol said. “I don’t think it’s worth the concern over youth smoking initiation potentially mitigating the public health benefits of e-cigarettes as a cessation aid,” she added. This concern is “overblown.”