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Scientists still do not know much about the long-term effects of "vape juice", the liquid used in electronic cigarettes and vaporizers. But researchers analyzing the liquid and vapor produced when heated say some types of e-liquids respond to irritating chemicals called acetals as they sit on shelves.
More than 3 million young people, as well as some adults, use e-cigarettes, according to the Centers for Disease Control and Prevention. Many of them could inhale these compounds regularly. And that could be annoying or even damage their lungs, according to Yale and Duke University researchers.
The study, published on Tuesday, looked specifically eight flavors of Juul e-liquids containing a different mixture of solvents than many others. brands e-liquid. These new findings are based on similar work by a research group published in October 2018 for other brands of e-liquids.
Acetals are formed from alcohol and aldehydes, chemicals used for flavoring and perfuming foods and other commercial products. Although some are considered harmful, many are generally accepted as safe to eat and touch, says Hano Eritropel, lead author and research associate at the Yale Chemical and Environmental Engineering Division. Little is known about the effects of aldehydes and acetals when inhaled in this way, Erythropel added, although some studies indicate that acetals can irritate the airways more than the aldehydes from which they were formed. And this irritation can trigger an inflammatory reaction in the respiratory system.
Unlike the small amounts of acetals you get through food, Erythropel says with a wapping: "you inhale that. We never imagined that people would inhale fragrant compounds. to the level they are now. We have very little information. "
At this point, the FDA does not require electronic fluid manufacturers to present or list all the ingredients in their products. Thus, Yale chemists should" reverse engineer "E-liquids by separating and quantifying their chemical constituents.
Through this process, researchers found the presence of acetals in one of the eight Juul flavors they tested: Crème brûlée. This fragrance, which uses vanillin for a vanilla-like odor "It contains relatively high levels of vanillin acetals, scientists say. Other flavors may also contain acetals and aldehydes, they say, but they have not tested in this study for all possible aldehydes."
Julie Zimmerman, Principal Investigator of the study and Professor at the Department of Chemical and Environmental Engineering at Yale, stresses that much more research needs to be done before conclusions can be drawn about the safety of electronic liquids. Such studies should consider the possibility of chemical reactions between different chemical constituents of e-liquids, she says, which can lead to altered products.
Dr. Robert Jackler, a professor of forthorhinolaryngology at Stanford who has studied the rapid rise of e-cigarettes among young people, says the document "contributes to the multiplicity of evidence documenting the toxicological effects of e-cigarette vapor by specifically testing the sweet and fruity aromas of e-cigarettes." JUUL that are so popular with teens. "Erythropel, however, is careful to note that any flavored product may contain aldehydes – even generic" tobacco flavored. "
This finding and the like suggest that it may have a long term health implications for young people, says Dr. Christina Sadreamelli, a pediatric assistant at Johns Hopkins University and a pediatric pulmonologist, said that e-cigarette makers have long positioned vaping as a far safer alternative to cigarettes, with little effect on cigarettes.
But "this notion [that] 'it's just water vapor and nicotine and flavorings' is very wrong," she says, "Electronic cigarette money contains a lot of harmful chemicals, heavy metals. [and] ultra fine particles.
The discovery of acetals in e-liquids, according to her, "raises another reason to worry about what's in the vape aerosol and how it can harm the developing lung."
Asked for the findings of the study, Lindsay Andrews, a spokesman for Julie, says that the acetate levels that researchers consider harmful exceed the "real world" exposures of Juul pods. Perhaps one would need to consume seven or more e-liquid pods per day to meet a threshold that researchers find harmful, says Andrews.
Although little is known about the long-term effects of vaping, some health fears have begun to surface. Last week, Wisconsin Children's Hospital announced that eight teens were hospitalized with "severely damaged lungs" in July.
Symptoms that led to their hospitalization include "shortness of breath, fatigue, chest pain, cough and weight loss," according to the hospital. Although all teenagers have improved with treatment and the exact cause of their symptoms remains unknown, everyone reported having been vaping weeks and months before being hospitalized.
Zimmerman, Erythropel and their colleagues hope to do more research on the health effects of inhaling acetals. But it will probably take many years for health experts to understand the full effects of acetal inhalation and vaping more broadly, says Jackler.
"Teens who become accustomed to the daily use of e-cigarettes driven by nicotine addiction can have adverse health effects over time," the doctor says. "That means we won't know the full impact of the e-cigarette epidemic on teenagers for decades."
Susie Neilson is an intern at NPR's science bureau. Follow her on Twitter here: @susieneilson.