Fans of electronic cigarettes often say they’re safer than conventional cigarettes, but emerging research suggests those claims aren’t necessarily true.  

In a study released today, researchers at the Harvard T.H. Chan School of Public Health found that more than 75 percent of flavored e-cigarettes and refill liquids contain a chemical linked to cases of a severe respiratory disease, bronchiolitis obliterans.

The chemical, diacetyl, is responsible for “popcorn lung,” a disease researchers found that occurred more commonly in workers at microwave popcorn manufacturing plants. Diacetyl is used in the popcorn’s butter flavoring and can be harmful if inhaled.

Ecig Chemicals

Joseph Allen, assistant professor of exposure assessment science at Harvard and lead author of the new study published in Environmental Health Perspectives, says the hazards associated with inhaling flavoring chemicals have been acknowledged for more than a decade. 

“However, diacetyl and other related flavoring chemicals are used in many other flavors beyond butter-flavored popcorn, including fruit flavors, alcohol flavors, and, we learned in our study, candy flavored e-cigarettes,” he said in a press release.

The U.S. Food and Drug Administration (FDA) has determined ingredients like diacetyl and its substitute 2,3-pentanedione are “generally recognized as safe” to be eaten, but the National Institute for Occupational Safety and Health say they pose different risks when inhaled.

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More Than Just Nicotine

E-cigarettes are designed to simulate the act of cigarette smoking without producing some of the harmful components of cigarette smoke, such as tar. They usually deliver nicotine, which is often the focus when discussing health risks associated with smoking.

While many cigarette smokers have turned to e-cigarettes and vaping as a way to kick the habit, there’s insufficient evidence to say they’re a safer way to ingest nicotine or if they’re an effective tool to help people quit smoking, according to the National Institute on Drug Abuse (NIDA).

The Harvard team tested 51 types of flavored e-cigarettes and liquids sold by leading brands. The air stream from each e-cigarette was captured in a sealed chamber and tested for the presence of diacetyl, acetoin, and 2,3-pentanedione.

Researchers say of the three chemicals at least one was detected in 47 of the 51 flavors tested. Diacetyl was detected in 39 of the flavors tested, acetoin in 46, and 2,3-pentanedione in 23.

“In addition to containing varying levels of the addictive substance nicotine, they also contain other cancer-causing chemicals, such as formaldehyde, and as our study shows, flavoring chemicals that can cause lung damage,” David Christiani, study co-author and professor of environmental genetics, said in a press release.

There are more than 7,000 varieties of flavored e-cigarettes and e-juice, refillable liquids that often contain nicotine, on the market. They are not regulated. The U.S. Food and Drug Administration (FDA) wants to extend its regulatory authority over tobacco and nicotine-containing products to include e-cigarettes.

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Use Triples Among Children

Health officials say flavored versions of e-cigarettes are intended to appeal to children. A study from the U.S. Centers for Disease Control and Prevention (CDC) in April found those concerns had merit.

Using data from the National Youth Tobacco Survey, researchers found that in 2013, more than 4 percent of high school students had used an e-cigarette at least once in the past 30 days. In 2014, that number jumped to more than 13 percent.

Among middle school students, the rate more than tripled from just over 1 percent in 2013 to nearly 4 percent in 2014, according to the CDC.In all, 2 million high school students and 450,000 middle school students used e-cigarettes in 2014.

“In today’s rapidly evolving tobacco marketplace, the surge in youth use of novel products like e-cigarettes forces us to confront the reality that the progress we have made in reducing youth cigarette smoking rates is being threatened,” Mitch Zeller, director of FDA’s Center for Tobacco Products, said in a press release. “These staggering increases in such a short time underscore why the FDA intends to regulate these additional products to protect public health.”

A separate study funded by the National Institutes of Health found students who begin using e-cigarettes by ninth grade are more likely to start smoking traditional cigarettes and other combustable tobacco products within a year.

“Parents and teens should recognize that although e-cigarettes might not have the same carcinogenic effects of regular cigarettes, they do carry a risk of addiction,” NIDA Director Dr. Nora D. Volkow said in a press release.

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