Teens - Since cigarettes were available there have always been rebelious teens who took up cigarettes. Something like 90% of smokers stated in their teens.
I don't doubt that some teens tried vaping prior to cigarettes. The data probably isn't out there about who among them may return to vaping. Some surely will.
What we are not seeing is statistical history of number of teens that ever smoked and how many smoke today.
We are not seeing statistics, though some probably exist on the number of teens taking up vaping vs. how many vape and move on to tobacco. As well, how many have smoked and then switch to vaping. Nor how many tried vaping and didn't take up either that or cigarettes for a sustained period. Quetionaires can be rahter broad. 'In the last 30 days have you used an e-cigarette <cigarette if you like>?' 'Yes...I walked past the gym and some classmates were leaning up agains the wall vaping. They asked if I wanted some...I took a puff...and went on to class.' Answers that truely require much more than a Yes or No response may not get reflected in the data...that's not stuff that can be crunched easily in stistical programs.
I guess studies that study groups of studies seems odd, though necessary, but I'm pleased to see the information go to Congress. No doubt a lot of studies studying studies goes on in many realms.
To say, 'Alarm! Alarm! Teens are taking up smoking after having tried e-cigarettes,' has no meaning without an overview of the numbers and in the context of historical patterns of teen smoking, 'perhaps' weighted by similar data for the overall population in regards to smoking trends and such...dunno.