Adolescents who use e-cigarettes are more likely to progress to smoking cigarettes, and are likely to continue using both products at once instead of substituting one for the other, according to research published in Nicotine & Tobacco Research.

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“Our work provides more evidence that young people who use e-cigarettes progress to smoking cigarettes in the future,” Michael S. Dunbar, PhD, a behavioral scientist at the RAND Corp. stated in a press release. “This study also suggests that teens don’t substitute vaping products for cigarettes. Instead, they go on to use both products more frequently as they get older.”

Dr. Dunbar and his colleagues followed 2,039 adolescents aged 16-20 years who were originally enrolled in a Los Angeles–based substance use prevention program in sixth and seventh grade (2008) and completed annual Web-based surveys during 2015-2017 on their use of e-cigarettes (EC), cigarettes, alcohol, and marijuana. They also answered questions about their mental health with questions about anxiety and depression. The researchers used two models to measures associations between different factors.

The first model showed an association between EC and cigarette use. Then other factors, such as alcohol use, were introduced. Alcohol use was associated with increased cigarette use, and cigarette use was associated with increased use of alcohol. When introducing marijuana as a factor, associations remained between cigarette use and EC use, with higher EC use associated with greater marijuana use and vice versa. Greater cigarette use, however, was not predictive of later marijuana use. There was no association between EC use and mental health, but more cigarette use was associated with poorer mental health.

Under the second model, there was a moderate to strong association between EC use and cigarette use, and participants with greater EC use and greater cigarette use also reported higher alcohol use. There also was a significant between-person association with higher EC use, cigarette use, and marijuana use. There was a small negative association between mental health and cigarette use, but not with mental health and EC use,the researchers said.

“For young people, using these products may actually lead to more harm in the long run,” Dr. Dunbar said in the press release. “This highlights the importance of taking steps to prevent youth from vaping in the first place. One way to do this could be to limit e-cigarette and other tobacco advertising in kid-accessible spaces.”

This study was funded by grants from the National Institute of Alcohol Abuse and Alcoholism. The authors reported no relevant conflicts of interest.

SOURCE: Dunbar MS et al. Nicotine Tob Res. 2018 Oct 3. doi: 10.1093/ntr/nty179.