Vaping, smoking, the great question is, is one a complement to the other (complement, meaning that more of one leads to more of the other) or a substitute (more of one leads to less of the other)? Evidence:
Electronic cigarette use among U.S. middle and high school students tripled in 2014 while cigarette use fell to record lows, according to provocative new data that is likely to intensify debate over whether e-cigarettes are a boon or bane to public health.
No, that's not provocative data, that's conclusive data. A substitute not a complement.
Every public health advocate should now be pushing vaping. Anyone who claims to be such and is not is simply a Puritan.
By their actions shall ye know them.