The researchers examined data from the Tobacco Products and Risk Perceptions Survey, which was administered by the Georgia State University Tobacco Center of Regulatory Science, and the Health Information National Trends Survey, which was administered by the National Cancer Institute. Both are nationally representative surveys conducted annually by US adults.
The findings "highlight the urgent need to communicate the risks of e-cigarettes to the public", the authors express concern that e-cigarettes are more harmful to cigarettes than a cigarette, but less willing to to make the transition from one to the other.
Electronic cigarettes work by heating a pure liquid called e-juice – consisting of aromas, propylene glycol, glycerin and often nicotine – until it evaporates. The resulting steam is much less offensive to both smokers and non-smokers.
The vision of those who call Glantz "e-cigarette optimists" is that smokers switch completely from cigarettes to e-cigarettes. Cigarettes, he said. However, contrary to their hopes, about two-thirds of adult e-cigarette users continue to use both.
"The risks of using e-cigarettes are in addition to the risks of flammable cigarettes," he added. This means that people who use both have a higher risk of heart and lung disease than those who smoke only normal cigarettes.
As the long-term effects of the use of e-cigarettes continue to be understood, the change in public risk perception can benefit above all a group of people: adolescents and young adults.
Adolescents who have a negative attitude to e-cigarettes use them less frequently, which is important for limiting their use in this group, according to Glantz.
"In terms of overall public health impact, this explosion of youth exceeds any harm reduction that adults experience when switching from cigarettes to e-cigarettes."
Sandee LaMotte of CNN contributed to this report.