And the important bit seems to be
>nicotine concentration between 0.001 mM and 4.0mM.
And they found an effect starting at 1.0mW. But, this is what I hate about pretty much all scientific papers that clearly set out with a purpose in mind (good or bad) is the abstract doesn't mention what the hell 1.0mW. Is that even a feasible amount? Is that one puff? Is that 100% nicotine being directly vaped? What on earth is it? None of this is mentioned, for free anyways.
The full study can be found as the first article in this pdf: http://tobacco.cleartheair.org.hk/wp-content/uploads/2018/01...
This says nothing about rates of other non-site specific cancers of course (pancreatic being a big one), or the other health risks that are still associated with smokeless tobacco (stroke, cardiovascular disease, impotency), but it's somewhat telling that even anti-nicotine advocacy groups rarely mention the risk of cancer for smokeless tobacco products in their publications.
My remark was about young people doing something that is idiotic (vaping to the degree they do it) who would not take a puff on a cigarette. Arguments that vaping is "less dangerous than smoking" are precisely "At least I'm not shooting heroin in my eyeballs", because at no point did I assert that they were equivalent.