Do e-cigarettes help current smokers quit, or do they just become an additional nicotine habit? [...] a new study of more than 30,000 adults in Sweden indicates that traditional smokers use both methods.
[...] smokers who do both were also more likely to have respiratory symptoms. The researchers noted that e-cigarette use as a smoking cessation tool is not yet established. Their hypothesis was that use of e-cigarettes was most common among former smokers, since that is how e-cigarette companies market the devices.