Lion Shahab, Emma Beard, and Jamie Brown conducted the study using data from 78,265 adolescents in the American National Youth Tobacco Survey.
The authors write: “There is considerable debate about the impact of e-cigarettes on youth smoking. A contentious point is whether e-cigarettes act as a gateway and increase the likelihood of subsequent cigarette smoking. A large number of studies have shown that e-cigarette experimentation is longitudinally associated with uptake of cigarettes.”
But they continue to point out that there are two major problems with the previous work claiming to demonstrate the so-called gateway effect: “First, most studies have considered the impact of e-cigarettes on ever use of cigarettes—that is, initiation—but ignore their effect on continued use.”
They explain that this means the studies do not “allow for a more nuanced analysis of the impact of e-cigarette use on smoking trajectories and health implications, as only regular cigarette use will result in subsequent premature death and disability.”
Secondly, they point out: “a causal association between e-cigarette use and subsequent cigarette smoking cannot be tested directly; it would be unethical (and impractical) to conduct a randomised controlled trial allocating non-smoking adolescents to receive e-cigarettes or not to see whether this leads to uptake of smoking.”
The team concluded: “The NYTS showed a continuing decrease in both cigarette smoking prevalence and in the use of any tobacco product, despite a concurrent increase in e-cigarette use between 2014 to 2017. This suggests that any gateway effect of e-cigarettes, if present, must be small. Further, despite e-cigarettes being more commonly used than any other product from 2015 onwards, cigarettes remained the most prevalent initiation product in 2014 and 2015, followed by other combustibles.”
<1% of adolescents trying an e-cigarette first became established cigarette smokers
“The current cross-sectional matched control study estimated that around a quarter of e-cigarette initiators go on to try cigarettes subsequently. However, <1% of adolescents trying an e-cigarette first became established cigarette smokers, significantly fewer than in any other product category.”
“The current analysis suggests that the association of e-cigarette initiation with subsequent smoking is largely explained by shared vulnerability such that those who try an e-cigarette first would have gone on to smoke cigarettes anyway.”
News from: https://www.vapingpost.com/2020/08/01/us-minnesota-issues-alert-over-new-evali-cases/