A recent study appearing in the current issue of JAMA Pediatrics now confirms what many researchers have long suspected: e-cigarettes are not safer than the combustible tobacco type, and do increase cancer risks. Not by themselves, but because they do indeed encourage young people to take up regular cigarettes.

The link between the use of e-cigarettes among teens and smoking combustible cigarettes in later life has been the focus of many investigations in recent years. Evidence to support this idea has been building – and the most recent study confirms it.

The study consisted of a meta-analysis of nine previous studies involving 17,400 young people between the ages of 14 and 30. The researchers found that more than 30 percent of those who smoked e-cigarettes were very likely to move on to the real thing. By contrast, fewer than 8 percent of those who have never used e-cigarettes ever start using tobacco cigarettes.

This flies in the face of claims by the e-cigarette industry, which has long claimed that its product is a “good way” to stop smoking. Dr. Samir Soneji Ph.D., an assistant professor at the Dartmouth University Medical School and co-author of the study, says the evidence is clear:

Teenagers who vape [smoke e-cigarettes] were substantially more likely to become cigarette smokers than their peers who did not vape. I am skeptical of such claims that e-cigarettes help adult smokers quit. The scientific evidence to support such a claim does not exist.”

The study isn’t clear on just why the use of e-cigarettes leads youth and young adults to start smoking tobacco cigarettes, but there is some speculation that the reasons may be both behavioral and physiological.

On the behavioral front, the act of smoking e-cigarettes is almost identical to smoking combustible cigarettes; it gives a person something to do with their hands and involves inhalation and exhalation. Physiologically, vape liquids contain highly-addictive nicotine, just like tobacco. Study co-author James Sargent said, “The finding is very consistent across studies. That, along with the strength of the association, makes it probable that e-cigarette use is one cause of cigarette smoking.”

Sargent adds, “E-cigarette use could affect population trends in youth smoking if use becomes more common, and that is the big public health concern.”

Sonjei recommends that stronger regulations be enacted, including restricting ads aimed at young people and discouraging the production of fruit and candy flavored vape liquids designed to appeal to younger users as well as the enforcement of stronger age verification requirements by online and retail vendors.