For more than eighty percent of American daily users, vaping on e-cigarettes is positive
A new study  published in Nicotine and Tobacco Research shows that the use of electronic cigarettes in the US provides significant positive effects on public health. The study is based on data gathered through the National Health Interview Survey (NHIS) in 2014, a major US population-based investigation.
Studying the data, the research team of scientists focussed on adults, their smoking status (smokers, former smokers and non-smokers) and their use of the electronic cigarette.
Michael Siegel exploited the results to examine the pattern of vapers in each category and determine whether the electronic cigarette is positive, negative or neutral. His conclusion is incontrovertible.
Among adults who use electronic cigarettes on a daily basis, 82.3% estimate a net benefit to their health, 8.2% think they are exposed to risk. For the remaining 9.5%, there is insufficient information to determine whether they draw a benefit or otherwise take a risk. These data allow the professor of public health to confirm that the use of the vaporizer within an adult population is a significant net profit of public health.
Concretely, for daily vapers Michael Siegel considers the health impact is positive for smokers and recent ex-smokers (respectively 49.9% and 32.4% of daily users). However, he accounts a negative impact for former smokers who had quitted smoking for over 4 years and nonsmokers (respectively 3.0% and 5.2% of daily users) who considered to be exposed to a risk they were no longer smoking. Finally, he takes no position with regard to ex-smokers of less than three years, that represent 9.5% of daily vapers who find a neutral impact in vaping.
Depending on the situation, the use of the electronic cigarette may be sensed as positive, negative or neutral
In the case of smokers and “recent” ex-smokers (for less than one year), daily vaping is sensed positive for health. Indeed, he says whenever the formers try to wean off tobacco or practice a double consumption, their chances of withdrawal are greater if they have already experienced e-cigarette. As for recent quitters and actual vapers, most of them used it to quit smoking.
However, Michael Siegel considers that the use of e-cigarettes by former smokers (over four years) and non-smokers is negative for health. With respect to these ex-smokers, it is assumed that they started vaping after smoking cessation. He modulates his remarks by wondering whether, in the absence of electronic cigarette, these former smokers would not have relapsed to the tobacco.
As for ex-smokers for two or three years vaping on e-cigarettes, he evaluates a neutral impact. It is not clear if they were smokers who stopped using the vaporizer or former smokers who started vaping after smoking cessation.
 Cristine D. Delnevo, Daniel P. Giovenco, Michael B. Steinberg, Andrea C. Villanti, Jennifer L. Pearson, Raymond S. Niaura, and David B. Abrams
Patterns of Electronic Cigarette Use Among Adults in the United States
Nicotine Tob Res first published online November 2, 2015 doi:10.1093/ntr/ntv237