According to a new electronic cigarette survey study reported at the 2015 FAMRI meeting, as many as 18% of current electronic cigarette users are ex-smokers who may have quit smoking completely as a result of their e-cigarette use. Such a finding would represent perhaps the strongest evidence to date that not only are e-cigarettes helping smokers quit, but that the magnitude of this effect at a population level is massive and is likely to be associated with profound public health benefits.
The key finding of the Harvard study was that in 2014, 20.7% of current electronic cigarette users were former smokers. The important question, of course, is whether these represent ex-smokers who re-initiated nicotine use with e-cigarettes or whether these represent smokers who quit smoking using e-cigarettes and thus are now identified as former smokers who use e-cigarettes.
To try to tease this out, the researchers ascertained how long ago the respondent had quit smoking. One would assume that if the individual had quit smoking many years ago, then their e-cigarette use probably represents a return to nicotine use (i.e., a bad outcome). On the other hand, for more recent quitters, it is likely that the e-cigarette use represents the results of a successful quit attempt (i.e., a good outcome).
For the purposes of their analysis, the researchers set the differentiation of these two groups at quitting more or less than six years ago. Those who quit more than six years ago are almost certainly ex-smokers who have been enticed to return to nicotine use via e-cigarettes. Those who quit less than six years ago could represent smokers who used e-cigarettes to become former smokers.
Using this breakdown, the researchers reported that only 2.8% of current e-cigarette users represent distant former smokers who were presumably attracted back to nicotine use via e-cigarettes. In contrast, 17.9% of current e-cigarette users represent recent former smokers who could conceivably have quit smoking using e-cigarettes.