March 22, 2022

expert reaction to research letter about US adolescents attempting to quit smoking or vaping

A research letter published in JAMA looks at failed attempts among US adolescents to quit cigarettes and e-cigarettes.

Prof Lion Shahab, Professor of Health Psychology and Co-Director of the UCL Tobacco and Alcohol Research Group, said:

“Unfortunately this study is seriously flawed and tells us very little. It does not provide any good evidence that e-cigarettes make quitting smoking harder. In fact, there is far better population-level evidence to show that smoking rates in youth in the US has plummeted to unprecedented low levels in recent years, despite increasing e-cigarette use.

“While this short report purports to show that unsuccessful nicotine/tobacco product quit attempts in 2020 in US youth are higher than in the previous 13 years, it is difficult to interpret this finding meaningfully for several reasons.

“First, the analysis compares apples with pears as data up to 2020 only included quit attempt rates of cigarettes and in 2020 also included e-cigarette quit attempts. If comparing like with like, the rate of unsuccessful cigarette use quit attempts is higher in 2020 compared with 2019 only. In fact, the successful cigarette quit attempt rate did not differ in 2020 from any year between 2011 and 2018, and more adolescents successfully quit smoking cigarettes in 2020 than in any year from 1997 to 2010.

“Second, the analysis conducted did not account for any underlying trends or other population-level influences (such as increasing the age of sale of cigarettes to 21), which would have affected changes in successful quit attempts across the time series considered. Without adjustment for these factors, a purely descriptive presentation of data is misleading.

“Most importantly, the year this analysis focuses on, 2020, was the year that the Covid-19 pandemic hit the US. This not only clearly had general environment, social and psychological corollaries affecting quit attempts, but it also affected the way this survey was conducted. Data collection stopped earlier in 2020 than it would normally do, resulting in a much smaller and likely quite different sample from previous years, making a direct comparison clearly problematic. This issue is further compounded by the fact that in 2019 (the year a difference was found in cigarette quit attempt success compared with 2020) methodology had also changed from previous years, with data collecting switching over from a pen and paper to electronic capture method.

“Taking all these problems together, it is unclear what to conclude from these results, especially given that the latest nationally representative results in the US show that use prevalence of the most harmful tobacco product – combustible cigarettes – by US youth was at the lowest rate ever, recorded in 2021 at 1.5%!  The implications of this paper – that e-cigarettes prevent smoking cessation – are contradicted not only by US population data but also by numerous high-quality randomised controlled trials, showing clear efficacy of e-cigarettes in helping smokers to quit cigarettes. E-cigarettes have a clear role to play as part of a comprehensive smoking cessation strategy to achieve a smokefree goal.”

Prof John Britton, Emeritus Professor of Epidemiology, University of Nottingham, said: 

“This paper demonstrates that users of nicotine, an addictive drug, find it difficult to stop using it. However the relevance of the study to actually quitting either smoking or e-cigarette use is unclear. We know that most people who quit smoking make several attempts before they succeed, so an increase in the proportion of smokers or vapers who attempt to quit but are unsuccessful, which at first sight is a bad thing, may simply reflect an increase in the proportion who even trying, which is a good thing.”

Prof Martin Jarvis, Emeritus Professor of Health Psychology at University College London, said:

“The Monitoring the Future (MTF) survey has documented a remarkable decline in cigarette smoking in US high school students over the past two decades, with ‘current users’ going from 28% in 1997 to 4% in 2020.  Plummeting cigarette use has been accompanied in recent years by a surge in vaping of e-cigarettes, and published analyses find strong evidence this may have contributed to an acceleration in the decline of cigarette use¹.  Counter to this evidence of a public health benefit from youth vaping, this new study, based on data from the same MTF survey, suggests that e-cigarettes may have hindered the decline in youth nicotine addiction.  

“The study reports that, among ever-users of cigarettes or e-cigarettes in 2020, the prevalence of unsuccessful attempts by adolescents to quit their smoking or vaping habit was higher than in each of the previous 13 years; leading the authors to conclude that the contribution of e-cigarettes to those unsuccessful quit attempts among adolescents is substantial.

“There are several weaknesses in the analysis.  They define ‘user’ as someone who has ever tried smoking/vaping (compared with past 30 day use in other analyses).  They have a loose and unanchored definition of a ‘quit attempt’.  There is no consideration of current cigarette smoking status, reflecting whether past attempts to quit may have succeeded.  They assume that cigarettes and e-cigarettes deliver similar levels of nicotine with similar addiction potential (in fact, in addition to greatly reduced toxicity, there is good evidence that vapers who have never smoked are much less dependent).

“This brief research letter does not add usefully to our understanding of the public health impact of adolescent nicotine vaping.  It provides some information on quit attempts that failed but does not compare these with quit attempts that worked, so it’s not that clear what we learn from this. On the numbers that really matter, we see US adolescent smoking rates falling very rapidly to historically low levels.”

¹ Sokol NA, Feldman JM. High school seniors who used e-cigarettes may have otherwise been cigarette smokers: Evidence from Monitoring the Future (United States, 2009–2018).  Nicotine & Tobacco Research, 2021, 1958–1961 doi:10.1093/ntr/ntab102

‘Failed Attempts to Quit Combustible Cigarettes and e-Cigarettes Among US Adolescents’ by Richard Miech et al. was published in JAMA at 3pm UK Time on Tuesday 22 March 2022.

Declared interests

Prof John Britton: “I don’t have any conflicts.”

Prof Lion Shahab: “none.”

None others received.