Did West et al really show that there is not an epidemic of youth nicotine addiction?

Several people have emailed me asking what I thought of the analysis “Epidemic of youth nicotine addiction? What does the National Youth Tobacco Survey reveal about high school e-cigarette use in the USA? (Preprint)” that Robert West, Jamie Brown, and Martin Jarvis posted to a non-peer reviewed preprint server.  They did this analysis to debunk concerns expressed by FDA and others that e-cigarettes are expanding the nicotine epidemic based on the huge increase in e-cig use by youth last year.  West et al’s  bottom line is: “Data from the NYTS do not support claims of a new epidemic of nicotine addiction stemming from use of e-cigarettes, nor concerns that declines in youth tobacco addiction stand to be reversed after years of progress.”

1. The way that they analyzed the NYTS is incomplete and misleading.
2. The proper way to do this would be to look at the psychosocial characteristics of the never-smoking kids who are not using e-cigs.  When we did this proper analysis, we found that three-quarters or more of kids who initiated with e-cigs had a profile that predicted cigarette smoking.  (There are several other papers cited in our paper that found the same thing using different population samples.)
3. Their conclusion that “Among current e-cigarette users who had never tried tobacco products, responses consistently pointed to minimal dependence” ignores the fact that had the low risk kids not been attracted to e-cigarettes, they would not have had any dependence.  Kids I talk to find the fourth generation of e-cigarettes (Juul and Juul knock-offs) highly addictive.
4. The conclusion that other tobacco product use is associated with e-cigarette use is true but, as West, Jarvis, Brown and other e-cigarette advocates love to point out, you cannot draw causal conclusions from cross-sectional studies.  There are a ton of longitudinal studies showing that kids who initiate nicotine use with e-cigs are 3-4 times more likely to add cigarettes later.  So, the association they report is likely to be due to low risk kids initiating nicotine with e-cigs then adding cigarettes (reverse causality in terms of the conclusion they draw).
5. The focus on heavy use is a standard trick that e-cig advocates use to artificially depress the fraction of kids who are using the product.  Any use of cigarettes in the past 30 days among adolescents predicts smoking in their 20s.   Very few kids smoke cigarettes every day or most days.  Using that standard would lead to grossly underestimating the amount of smoking in the population as well as understating the future impact of the epidemic.
6. The statement that the introduction of e-cigs has not affected the decline in smoking is just wrong.  Look at their Figure 1 (below).  The steady decline in ever trying smoking stopped after 2011, the same year they show e-cig use increasing.  The steady decline in current smoking stopped in 2014.  (Our earlier paper using data through 2014 said there was no effect of e-cigs on this variable; our new paper that is in peer review goes through 2018.)  These patterns are exactly what one would expect if e-cigs were attracting low-risk kids to nicotine addiction, some of whom then added cigarettes.

And, of course, this paper is not peer reviewed.