The Grapevine

Teens Who Vape, Smoke Hookah More Likely To Try Marijuana Later: Study

High school students who used tobacco products when they were freshmen were more likely to try marijuana by the time they were in junior year, according to new findings.

The study titled "Adolescent E-Cigarette, Hookah, and Conventional Cigarette Use and Subsequent Marijuana Use" was published in the journal Pediatrics on Aug. 6.

The research team from the University of Pennsylvania and the University of Southern California recruited 2,668 students from ten high schools located in Los Angeles.

The teens answered questions related to their use of tobacco products and marijuana in two surveys — the first one took place in 2013 when they were in ninth grade and aged 14, while the second one took place in 2015 when they were in 11th grade and aged 16.

Students who used tobacco products like e-cigarettes or hookah during their freshman year were almost three times more likely to try marijuana by the time they were juniors, the researchers found. The association was found to be particularly strong with those who used hookah.

"These tobacco products may give an adolescent experience inhaling such that they are more willing to try other substances that also require inhaling hot smoke or vapor," said lead author Janet Audrain-McGovernan, an associate professor at Penn's Perelman School of Medicine.

Another point to consider was the airway of the respiratory system could get used to inhaling hot substances, easing any possible transition to inhaling marijuana smoke. 

Richard Miech, a professor at the University of Michigan who was not involved with the study, shed light on social factors which are known to strongly influence teenage behavior.

"Once you start vaping, I think you become known as the person who vapes, who's cool," he said. "You get invited to parties where people are going to smoke cigarettes and smoke marijuana because you vape already. So there's that social component."

However, causality was not yet established since the study was only an observational one. It is possible a separate factor which drove teens to try tobacco products may be the same one driving them to try marijuana. All the participants were recruited from Los Angeles high schools, which may lessen generalizability, according to the authors.

The strong association revealed in the study is, nevertheless, worth investigating further. Since adolescent brains are still developing, there is an increased risk of changes in the nervous system as well as a dependence on both nicotine and cannabis.

"If youth e-cigarette use follows the same pattern as cigarette smoking, widespread use could expose youth to social environments that encourage substance use, thereby accelerating youths' transitions to the use of other substances with more adverse health effects," the authors wrote.

Among other limitations, the study did not measure the frequency of marijuana use and did not consider characteristics such as e-cigarette flavorings. Earlier this year, experts called for a ban of flavors as they believed this would increase the appeal of the product among adolescents.