Ask the Doctors

Dear Doctor: Would you kindly address the risks of e-cigarettes compared to regular cigarettes? I am opposed to both because of the potential for nicotine addiction and other health issues. Some of my adult relatives, however, are convinced e-cigs are not harmful, even though they clearly seem addicted.

Dear Reader: On the surface, e-cigarettes appear to be a good idea. After all, they contain no combustible substances to become residue and enter the lungs. Instead, the devices feature a cartridge filled with a nicotine liquid that is vaporized and inhaled. Nicotine concentrations vary in the cartridges from 6 to 24 milligrams per milliliter. E-cigarettes also contain propylene glycol, which is used to prevent the liquid from evaporating, and flavorings that make the vapor more palatable.

As for their safety, first, let's assess the risk from nicotine. It's true that nicotine raises the pulse rate and increases the workload of the heart, but while smoking cigarettes is a significant risk factor for coronary artery disease and heart attacks, nicotine does not appear to be the culprit. In fact, studies have shown that people who use nicotine replacements in the form of gum, lozenges or patches have no change in their risk of heart attacks. Note, however, that rates of nicotine toxicity have substantially increased since the introduction of e-cigarettes. This occurs when someone uses too much nicotine or when someone, such as a child, ingests the liquid in one of the vials.

Second, let's assess what we don't know: the long-term effects of inhaling e-cig vapor. Acute exposure to the vapor does lead to a small increase in lung flow resistance, and the vapor could lead to more inflammation of the airways. Surveys of students in Hong Kong and in the United States have shown an increased rate of chronic cough and bronchitis among those using e-cigarettes. The vapor itself does have trace amounts of carcinogenic compounds, but at much lower levels than in combustible cigarettes.

Because the risk for lung cancer would appear to be smaller for e-cigs than for traditional cigarettes, they definitely have the edge in that respect. Additionally, e-cigarettes, like nicotine gums and patches, can decrease the desire to smoke combustible cigarettes. Studies of people using e-cigarettes to stop smoking have found rates of smoking cessation of 7.3 to 12.5 percent. And even if e-cigarettes don't actually help people stop smoking, they could theoretically decrease the number of regular cigarettes consumed. So, for those who smoke cigarettes already, e-cigarettes could provide a health benefit.

The bigger problem lies in e-cigarettes' risk to young people. Studies have shown that adolescents and young adults who use e-cigs have three times the risk of initiating regular cigarette smoking than those who don't use e-cigs. This may be due to the nicotine, of course, but regardless, it points to the potential connection between e-cigs and a lifelong nicotine addiction, with e-cigs being a gateway. Because of this potential, many doctors and anti-smoking activists have advocated banning advertisements geared toward adolescents.

In summary, perhaps the harm to your adult relatives depends on their smoking status and age. In any case, allow me to reiterate: While e-cigs seem healthier than traditional cigarettes, the long-term health effects are not known.

(Send your questions to, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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