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Facts About Electronic Cigarettes

What are electronic cigarettes?

Electronic cigarettes, or e-cigarettes, are battery-powered devices that heat up liquid nicotine and other additives (like stabilizers and flavorings) and turn them into a vapor that can be inhaled. The vapor looks like smoke, but no tobacco is burned in the products. E-cigarettes are also sometimes called “vapes” or electronic nicotine delivery systems. Many are designed to look like regular cigarettes--complete with a glowing end that signifies the device is “lit”—but others look like pens, USB drives or other designs.

What kinds of chemicals are in e-cigarettes?

Unlike regular cigarettes, e-cigarettes don’t contain cancer-causing tar because they don’t burn tobacco. But they do contain nicotine, the addictive substance in cigarettes. Most e-cigarette brands offer a variety of cartridges with different levels of nicotine. In general, e-cigarettes contain less nicotine than in a regular, combustible cigarette. One study determined that it would take about 30 “puffs” on an e-cigarette to deliver the one milligram of nicotine contained in a regular cigarette.

The nicotine usually is dissolved in a compound like propylene glycol or glycerin. Researchers have also uncovered a large number of other cancer-causing chemicals in e-cigarette aerosols or vapor, including formaldehyde, toluene, acetaldehyde, and acrolein, heavy metals such as cadmium, lead and nickel, nitrosamines, and tiny particles of matter that can lodge themselves in the deepest parts of the lung.

Flavoring chemicals are also found in most e-cigarette nicotine cartridges. The World Health Organization estimates that e-cigarette makers offer more than 8000 flavors of their product, including flavors like bubble gum and popcorn. Some researchers worry that these flavorings will make e-cigarettes more attractive to children and teens, and encourage more young people to become addicted to nicotine.

E-cigarettes and regular cigarettes contain many of the same cancer-causing chemicals. For the most part, the levels of these chemicals are lower in e-cigarettes than in regular cigarettes. However, there are some data that suggest that toxins such as formaldehyde are produced at increased levels in higher voltage, “tank system” e-cigarettes compared to standard e-cigarette devices.

It’s difficult to know exactly how much of these chemicals are being inhaled by e-cigarette users, says Brad Drummond, M.D., an assistant professor of medicine at Johns Hopkins. “There haven’t been enough studies yet to know how users use these devices—how often they smoke, how many puffs at a time, and whether they inhale differently—but it does seem to be different from combustible cigarettes.”

What are the health risks of using e-cigarettes?

Drummond says it is a mistake to think that e-cigarettes are harmless.

“Many of the studies that have been completed demonstrate that there are harmful toxins and carcinogens in electronic cigarettes, and it’s still unclear how these exposures might translate to long-term harm,” he says.

E-cigarette vapor contains lower levels of cancer-causing chemicals such as formaldehyde and toluene, as well as carcinogens such as nitrosamines, than regular cigarettes. “What’s not clear, though, is how these lower levels may translate to reduced harms,” Drummond says. He notes that more studies are needed to know if there is a safe level of exposure to these chemicals.

Drummond also cautions that “nicotine itself is not an inherently safe substance.” Nicotine has been linked to health risks such as heart disease and problems with fetal development in many other studies.

Glycerin and propylene glycol in e-cigarettes can irritate the airways when inhaled, and have been linked to some loss of lung function. A recent study found that the vapor from e-cigarettes can cause human bronchial cells to grow more rapidly than normal cells, similar to the cancer-like accelerated growth rates seen in throat cells exposed to tobacco smoke.

Johns Hopkins researchers also found that mice exposed to e-cigarette vapor had weaker immune responses in their lungs. Other studies have found that e-cigarette vapor seems to strengthen antibiotic-resistant bacteria, and that flavorings such as cinnamon in e-cigarettes can cause lung cell inflammation.

Children may especially be at risk from poisoning through ingesting or being exposed through the skin to the liquid nicotine used in e-cigarettes.

Is there any danger from secondhand exposure to e-cigarette vapor?

E-cigarettes don’t produce sidestream smoke—the smoke that comes out of a cigarette that is burning but not being inhaled. But a person could be exposed to the exhaled secondhand aerosol if she or he was near a user of electronic cigarettes, according to Drummond.

The few studies of secondhand aerosol show that “ there are measurable levels of nicotine and ultra fine particulate matter in secondhand aerosol from e-cigarettes that can be delivered to the far parts of lung and absorbed,” Drummond says, “But again, the long term consequences of this remain unknown.”

Is it OK to use e-cigarettes while pregnant?

As with most of the risks related to e-cigarettes, there isn’t enough data yet to know exactly how using e-cigarettes could affect fetal health or a woman’s health during pregnancy. However, nicotine has been shown in several studies to affect the growth and brain development of the fetus, and researchers have also linked nicotine exposure to preeclampsia, a potentially dangerous condition for pregnant women and fetuses.

Can e-cigarettes help smokers quit?

Drummond says there have not been enough studies yet to confirm whether e-cigarettes can help regular smokers quit the habit. Some studies suggest that using e-cigarettes can help smokers at least cut back on regular smoking, while others have shown no link between e-cigarette use and quitting smoking.

Some people who try using e-cigarettes to quit continue to smoke regular cigarettes, and Drummond says the risks of this “dual use are not really well understood at all.”

The bottom line, Drummond says, is that e-cigarettes have not been shown to be “any more effective than proven methods of nicotine replacement therapy, like patches or gum, to help smokers quit.”

Smokers who are trying to quit should use an FDA-approved nicotine replacement therapy rather than an e-cigarette, because these therapies “are well-studied and have a much better safety profile” than e-cigarettes, Drummond says.

The levels of nicotine found in nicotine replacement therapies are much lower than in cigarettes, and Drummond says they don’t reinforce the behavior of smoking by looking and feeling like a cigarette. They also do not contain the same mix of toxins and carcinogens as e-cigarette vapor.

Can I get addicted to e cigarettes?

“There’s significant concern that electronic cigarettes, while being perceived to be safe, would be used by individuals who would never have considered using a combustible cigarette,” Drummond says. “If you’ve never used any nicotine containing product, you should avoid electronic cigarettes just like you should avoid combustible cigarettes or oral snuff products, because they all have addictive potential.”

**Sources: American Association of Poison Control Centers, Tobacco-Related Disease Research Program, American Cancer Society, Journal of Addiction Medicine, Circulation, WHO, Boston University Research, Cochrane Collaboration, JAMA Internal Medicine, New England Journal of Medicine

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