According to a new study from the University of Michigan, teenagers and young adults in the United States who use e-cigarettes are much more likely to start smoking cigarettes or using cannabis or other drugs.

Most studies on vaping focus on adolescents (12-17) in short time windows of about two years. Less is known about vaping in young adults (18-25) or the risk of starting to use other substances such as cigarettes, marijuana, or other drugs. To do this, researchers looked at data from 12- to 25-year-olds over an eight-year period. They found that those who vaped were more likely to start smoking cigarettes, using marijuana, or other drugs during the study period.

We found that this risk persists over time and poses a risk to both adolescents and young adults. The risk of initiating cannabis use was the same regardless of whether someone used e-cigarettes or other tobacco products.”

Rebecca Evans-Polce, study author, research assistant professor, UM School of Nursing

Results for 12 to 17 year olds during the study period:

• Those who used e-cigarettes and other tobacco products were 54 times more likely to start smoking, eight times more likely to start using marijuana, and three times more likely to start using other drugs.
• Those who used only e-cigarettes were 22 times more likely to start smoking, seven times more likely to start using marijuana, and three times more likely to start using other drugs.

For 18 to 25 year olds during the study period:

• Those who used e-cigarettes and other tobacco products were 22 times more likely to start smoking, nine times more likely to start using marijuana, and three times more likely to start using other drugs.
• Those who used only e-cigarettes were eleven times more likely to start smoking, six times more likely to start using marijuana, and twice as likely to start using other drugs.

The high risk for both age groups of starting smoking after vaping or using other tobacco products is alarming, Evans-Polce said.

“The really high likelihood of starting smoking is important regardless of what type of nicotine or tobacco products you’re using,” she said. “I think it really shows that if you can prevent initiation into vaping and other tobacco products, you’re going to go a long way in preventing initiation into smoking in the long term as well.”

According to the Substance Abuse and Mental Health Services Administration, 39 percent of teens report having vaped by 12th grade, and 14 percent of young adults report having vaped in the past month.

Other data suggest that people start smoking cigarettes later in life. Historically, people start smoking before they reach their 20s, so the finding that vaping puts young adults at higher risk for cigarette smoking is important when thinking about ways to discourage people from smoking cigarettes, Evans-Polce said.

The results also showed that the association between nicotine or tobacco use and the onset of marijuana use increased over time. While marijuana use became more common among adolescents and young adults over the course of the eight-year study, the risk appeared to increase most dramatically for those who vaped and used other tobacco products.

Overall, the findings suggest that strategies need to be developed to prevent young adults from starting vaping, and not just focus on teens, Evans-Polce said. Preventing vaping could also lead to fewer teens and young adults starting cigarettes, marijuana and other drugs.

The study appears in the journal Drug and Alcohol Dependence.