This Soneji meta-analysis  dealing with e-cigarettes and subsequent teen smoking,1 summarized data from nine studies, all of which share the same flaws, leading to an incorrect conclusion.
These studies did not differentiate one-time or occasional use from consistent daily use. None compared smoking at follow-up in e-cigarette experimenters with kids who had experimented with or otherwise used cigarettes at baseline. Such a comparison would have reflected rates of smoking at follow-up in these same populations, had e-cigarettes not been available.
Given these flaws, the only conclusion that can reasonably be drawn from the individual studies or this meta-analysis is that teens who are inclined to experiment with products disapproved by adult leadership are more likely to use both e-cigarettes and cigarettes than kids not prone to such experimentation. Neither the individual studies nor this meta-analysis give us reason to expect that reducing access to e-cigarettes or making them unattractive to potential users would reduce the numbers of teens recruited to nicotine addiction.
The question as to whether e-cigarettes recruit American teens to nicotine addiction has already been answered. In June 2017, the Centers for Disease Control and Prevention (CDC) published its sixth annual report showing use of tobacco-related products by high school students, by type or product, including e-cigarettes.2 During this period, e-cigarette use has gone from 1.5 percent of high school students in 2011 to 16.0 percent in 2015 and 11.3 percent in 2016, with significant reductions in cigarette use almost every year and no significant change in the percentage of high school students using any tobacco-related product. The data on middle school students reflects the same pattern, with much smaller numbers. If, as alleged by Soneji et al, e-cigarettes were attracting significant numbers of teens who otherwise would not have used tobacco products, there would have been significant year to year increases in the percent of teens using tobacco-related products. This did not occur. The fact that this has occurred year after year validates the impression that the teens attracted to e-cigarettes are those who would have used cigarettes, had e-cigarettes not been available.
The time has come for public health authorities to consider the possibility that e-cigarettes, while not risk free, could be promoted for prevention of smoking and smoking cessation among teens inclined to smoke, without attracting yet more teens to nicotine experimentation.
- Soneji S, Barrington-Trimis JL, Wills TA et al. Association Between Initial Use of e-Cigarettes and Subsequent Cigarette Smoking Among Adolescents and Young Adults. JAMA Pediatrics. 2017 June 26:E1-E10. doi:10.1001/jamapediatrics.2017.1488
- Jamal A, Getrzke A, Hu SS et al. Tobacco Use Among Middle and High School Students — United States, 2011-2016. Morbidity and Mortality Weekly Report. 2017;66(23) (June 16):597-603. https://www.cdc.gov/mmwr/volumes/66/wr/pdfs/mm6623a1.pdf 
- “meta-analysis”: https://www.ncbi.nlm.nih.gov/pubmed?term=%22JAMA+pediatrics%22%5BJour%5D+AND+2017%5Bpdat%5D+AND+Soneji+S%5Bfirst+author%5D&cmd=DetailsSearch&log$=activity
- “https://www.cdc.gov/mmwr/volumes/66/wr/pdfs/mm6623a1.pdf”: https://www.cdc.gov/mmwr/volumes/66/wr/pdfs/mm6623a1.pdf