Many of the most vehement critics of e-cigarettes including the CDC have expressed fear the devices could prove to be a gateway drug and will raise the risk of non-smoking vapers being lured into trying the real thing. A recent study by the CDC suggests the fears are misplaced; the study found no evidence that “never-smokers” who vape are therefore more likely to become smokers or that the rising popularity of e-cigarettes has given a boost to conventional cigarettes. To the contrary, vaping and smoking rates are moving in opposite directions. The CDC’s survey data suggest that’s more than a coincidence: Not only was vaping much more common among current and former smokers than among never-smokers, but current smokers who had tried to quit in the previous year were more likely to be vapers than those who had not.
Details here: CDC Study