Do e-cigarettes help young people quit smoking combustible cigarettes?


E-cigarettes are becoming more and more popular among youth, and there is growing concern that the tobacco industry is targeting young people with marketing strategies that appeal specifically to youth including colorful packaging, a significant online presence, celebrity endorsements and more than 7000 flavors, most of which are fruit or confectionary-flavored.

New e-cigarette products targeting youth appear on the market regularly. For example, e-cigarettes designed to vape cannabis have become increasingly popular and are associated with lower perceived risk and increased use. Additional concerns include the limited evidence that e-cigarettes with or without nicotine help smokers quit, the presence of nicotine in e-cigarettes which could hinder cessation efforts and delay cessation, the impact of e-cigarette use on re-normalizing smoking, smoking re-uptake in former smokers, and growing evidence that e-cigarettes might be a gateway to cigarette smoking initiation in youth.

More recently, there has been widespread alarm about vaping-induced respiratory injuries in the US and Canada. A special announcement from the US Center for Disease Control (CDC) in October 2019 reported that most lung injury cases involved tetrahydrocannabinol (THC)-containing products and its recommendations included that: people should not vape products containing THC or modify e-liquids; using any type of e-cigarette is unsafe; nicotine is highly addictive and can harm the developing brain; and e-cigarettes should not be used by youth or young adults. In light of this report, it is critical to better describe who young e-cigarette users are, which e-liquids they use and the reasons for their choices. In addition, few studies assess all sources of nicotine used by e-cigarette users to determine whether poly-nicotine use relates to nicotine dependence or difficulty quitting.

The objectives of a recent NDIT study were to describe young adult e-cigarette users by: (i) type of e-liquids vaped in the past year (i.e., with nicotine, without nicotine, with cannabis); (ii) poly-nicotine use (i.e., concurrent use of multiple nicotine-containing substances); (iii) nicotine dependence symptoms; and (iv) attempts to quit
conventional cigarettes using e-cigarettes.

We found that, at age 30:

  • 20% of NDIT participants reported past-year e-cigarette use.

  • Overall, 55% of e-cigarette users had used cannabis- containing e-liquid in the past year (32% vaped cannabis e-liquids exclusively); 49% used nicotine-containing e-liquid (24% vaped nicotine e-liquids only); and 39% used e-liquids without nicotine (9% vaped e-liquids without nicotine exclusively).

  • 84% used other nicotine-containing products including combustible cigarettes (74%)

  • 62% reported nicotine dependence symptoms

  • 25% tried to quit combustible cigarettes using e-cigarettes in the past-year, but only 15% found them helpful.


We concluded that many young adults use e-cigarettes to vape cannabis, that few young adults use e-cigarettes for cessation and that most use other nicotine-containing products including combustible cigarettes.

Because the rising popularity of e-cigarettes threatens tobacco control achievements, monitoring trends in who
uses which e-liquids and the reasons for that choice is critical in terms of understanding the evolving e-cigarette market and developing programs and policy that minimize any negative impacts on health.

Early Predictors of Daily Cannabis Use in Young Adults

Cannabis is one of the most widely used psychoactive substances in North America, and young adults ages 18-24 have the highest prevalence of use. Daily cannabis use can lead to dependence, as well as numerous social, physical and mental health issues.

Using NDIT data, we identified early risk factors (at age 12) for daily cannabis use at age 20. At age 20, 44% of NDIT participants reported using cannabis in the past year, and 10% were using it daily. Our results demonstrated that the risk of daily cannabis use in young adults can be identified as early as Grade 7. Older age, male sex, higher levels of family and other stress, use of alcohol, cigarettes and other tobacco products, parent(s), sibling(s) and friend(s) smoking cigarettes, higher BMI, higher impulsivity and novelty-seeking, and lower self-esteem increased the odds of daily cannabis use.

Parental Cannabis Use Is Associated With Cannabis Use in Offspring

Cannabis use can have detrimental effects on the developing brain, especially if a person is exposed at a young age and if he/she uses cannabis often. With the new cannabis legislation in Canada, burning questions include will cannabis become normalized and will use increase? What about when parents  use cannabis? Are you more likely to use it as well?

Our team wanted to better understand the association between parent and offspring cannabis use. Using data from the NDIT study and another adolescent longitudinal cohort (the AdoQuest study), we studied whether parental cannabis use was associated with use in adolescent never users (data from AdoQuest) and with use in young adults (data from NDIT).

Our results showed that grade 6 never cannabis users were twice as likely to begin using cannabis during high school if at least one parent used cannabis.

Young adults with two parents who used cannabis were 7 times more likely to use cannabis; young adults with cannabis-using parents were more likely to start using cannabis earlier and to use it more frequently.

A Tool to Identify Adolescents at Risk of Cigarette Smoking Initiation

There is growing evidence that nicotine dependence manifests soon after first puff and once these symptoms appear, it is very hard to quit. Pediatricians and family doctors are important sources of preventive counseling. However, they do not have valid tools to accurately identify adolescents at risk of smoking initiation, and they do not always have the time  to provide preventive counseling.

The NDIT team recently developed a prognostic tool to help physicians (and others) identify adolescents who have a high likelihood of beginning to smoke in the next year.

To build our tool, we used machine learning algorithms to select the best predictors from among more than 50 variables.

The best prediction tool included 12 items: age, four worry or stress-related items, one depression-related item, two self-esteem items and four alcohol or tobacco-related variables. Each question is answered by “yes” or “no” and the answers are analyzed to provide a score that describes the risk that the individual will begin smoking in the next year.

What is the next step? To validate this short tool in busy clinical practices and schools!

To hear Dr Marie-Pierre Sylvestre describe this NDIT project, please visit the Pediatrics journal website where the article is featured. You can view it here: http://pediatrics.aappublications.org/content/142/5/e20173701

Also view the tool online: http://biostatistique.epizy.com/pkgs/1YearRisk/1YearRisk.html