I remain mystified by the debate over whether electronic cigarettes and vaping are more safe than harmful. Especially when this debate involves medical professionals. In July, one of my favorite journals, Annals of Internal Medicine, carried pro and con opinion pieces on this very issue. Excuse me?

Data continues to accumulate showing the harms and risks of e-cigarettes. The fact that big tobacco companies have rapidly moved in to take over much of the e-cigarette industry should serve as large red flag billowing brightly in the breeze. The most recent evidence comes in the August 18, 2015, JAMA, in a study of youth in Los Angeles. Those who vape or use e-cigarettes are far more likely to begin using combustible tobacco products than those who do not use those products. The odds ratio over a 12-month time frame is 4.26. While the study does not prove a cause-and-effect relationship, it is highly suggestive that e-cigarettes do open the door to smoking. And they open it widely.

E-cigarette manufacturers claim their products are safer than cigarettes and are useful in helping smokers reduce or stop smoking. That was the gist of the recent Annals opine which tried to present these products in a favorable light. Let’s call this bluff right here, right now. If e-cigs are such an effective way to reduce aggregate demand for tobacco, why would big tobacco invest in them so heavily? Anyone formulating such a business plan would clearly be blowing smoke. And why does much of e-cig advertising rely on cartoon characters? Why are e-cigs marketed in bubble gum and fruit flavors?

The answer is not rocket science. E-cigs are a gateway to nicotine addiction. Young people can be lured into vaping because it is cool, it is tech-y, it doesn’t carry the social stigma of smoking, it has fun flavors, and it causes a small but enjoyable high. But vaping also introduces young people to nicotine, and after a person has been consuming nicotine for a few months, the addiction is well-established. Smoking cigarettes, cigars, or hookahs is no longer a stretch. E-cigarettes can help recruit young people into a lifetime of nicotine dependence.

Being a gateway to the nicotine highway is bad enough. But e-cigs are also directly harmful. The products inhaled by vaping likely predispose to cancer. E-cigarette heating systems are becoming more powerful, generating stronger concentrations of formaldehyde and acetaldehyde, both of which are known carcinogens.

It is time for the debate about e-cigarettes to cease. Physicians in particular should not pull any punches when asked about these products. We need to tell our patients how dangerous they are, especially for young people. For the occasional older person who wants to use them to stop smoking, fine, let them try. But if they find themselves unable to stop the e-cigarettes and continue to vape over the long term, there is no evidence they have reduced their risk of serious health problems.

Richard Fleming, MD