I'll try to explain here. We already had this good discussion in our community pt. It is a complex subject and involves several subjects at the same time. To stay on the line, it is important to note that all medical research has ** Levels of Evidence **. It has several types of study / research as well. Biomedicine has followed a path that is called evidence-based medicine, this site of Oxford, explains a little of that. The meta-analysis is more important, for a study to have credibility in the scientific community. That's why blockchain has great potential in the medical field. An isolated study first has to evaluate which type, then the variables, then the number of people, and several other aspects. If there is no production, there is no counter argument. Science is done like this. Sites such as scielo, in my country,has gather studies, which are then taken to metanalysis, being considered the type of study. And the risk and protection factors, will be evidenced after analysis of multiple studies reliable by the specialists of the area. Many studies are strongly criticized in the community, the vast majority of them, and there is a very demanding regulation nowadays to publish a study. These studies by the press, to a great extent are sensationalists, as the traditional press does. Scientific journals such as Jama, and New England Journal of Medicine. They are periodical, demanding and well-respected in the scientific community.I'm not from that area. So I do not know much about the repercussion of the e-cigarette. But I know that only time and study will give us this result. I find it difficult to be the same as conventional cigarettes, but I find it very difficult not to do any harm. In life everything that interferes with the biological has repercussion, food is a great example. It is up to individuals to have their choice to expose themselves to risks. Who knows who knows about programming, do not make a scientific community decentralized, with income, and rigid in relation to research. Since the journals quoted, and many other scientists have to pay to have access.