Gateway Evidence Evaluated

Electronic cigarettes and subsequent cigarette smoking in young people: A systematic review was produced by Rachna Begh, Monserrat Conde, Thomas Fanshawe, Dylan Kneale, Lion Shahab, Sufen Zhu, Michael Pesko, Jonathan Livingstone-Banks, Nicola Lindson, Nancy Rigotti, Kate Tudor, Dimitra Kale, Sarah Jackson, Karen Rees, and Jamie Hartmann-Boyce.

The team wanted to assess the evidence for a relationship between the use of e-cigarettes and subsequent smoking in young people. For the purposes of this investigation, they considered all people under 29 years old as “young people”. They also wanted to see if demographic characteristics had any part to play.

The research took the form of a systematic review following the methods used by Cochrane for obtaining data.

“Our primary outcome was the association between e-cigarette use, availability or both, and change in population rate of smoking in young people. The secondary outcomes were initiation, progression and cessation of smoking at individual level. We assessed certainty using Grading of Recommendations, Assessment, Development and Evaluations (GRADE),” the team wrote.

In total, they considered 126 studies. 

“For our primary outcome, there was very low certainty evidence (limited by risk of bias and inconsistency) suggesting that e-cigarette use and availability were inversely associated with smoking in young people (i.e. as e-cigarettes became more available and/or used more widely, youth smoking rates went down or, conversely, as e-cigarettes were restricted, youth smoking rates went up),” they stated.

“All secondary outcomes were judged to be very low certainty due to very serious risk of bias. Data consistently showed direct associations between vaping at baseline and smoking initiation (28 studies) and smoking progression (5 studies). The four studies contributing data on smoking cessation had mixed results, precluding drawing any conclusion on the direction of association. There was limited information to determine whether relationships varied by sociodemographic characteristics.”

The group believes that due to the absence of evidence, future research papers “are very likely to change our conclusions.”

The team concluded: “At a population level, the balance of evidence suggests that overall, youth vaping and smoking are inversely related—that is, as more young people vape, fewer smoke, and vice versa. However, this could vary by context and was not consistent across all studies. There is insufficient information to say if this varies based on socio-demographic characteristics of individuals.

“Data showed a clear association between vaping and subsequent smoking initiation and progression in individuals, that is, young people who vape are more likely to progress to smoking. However, it is unclear whether these patterns in individuals reflect a causal relationship. On balance, population-level data show smoking rates decline as vaping rates go up. Patterns in individuals may be driven by underlying factors, which are often not considered in analyses. Further research establishing causal relationships between vaping and later smoking in young people, at both individual and population-level, is needed.”

Dave Cross

Journalist at POTV

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Dave is a freelance writer; with articles on music, motorbikes, football, pop-science, vaping and tobacco harm reduction in Sounds, Melody Maker, UBG, AWoL, Bike, When Saturday Comes, Vape News Magazine, and syndicated across the Johnston Press group. He was published in an anthology of “Greatest Football Writing”, but still believes this was a mistake. Dave contributes sketches to comedy shows and used to co-host a radio sketch show. He’s worked with numerous start-ups to develop content for their websites.