Thanks to e-cigs, teen cigarette (not e-cig) smoking has started increasing after decreasing for years. Teens that would have never started smoking are introduced to it with e-cigs.
I don't know how these 2 phenomenons balance out. Does the number of cigarette smokers moving to e-cigs counterbalance the number of younger people starting to smoke cigarettes because of it ?
In all cases, I have no issue with more studies on the direct impact on e-cigs themselves.