Newswise — Yale researchers found in a study that one in four high schoolers who use electronic cigarettes are inhaling vapors produced by dripping e-liquids directly onto heating coils, instead of inhaling from the e-cigarette mouthpiece, possibly increasing exposure to toxins and nicotine.

This form of e-cigarette use, known as “dripping,” is gaining in popularity among youth, who report it produces thicker clouds of vapor, a stronger hit in the back of the throat when inhaled, and a more pleasurable taste, according to the study, published online Feb. 6 in the journal Pediatrics.

Applying the liquid directly to the battery-powered coil heats it at a higher temperature than inhaling from a cartridge or tank, possibly increasing exposure to harmful chemicals like formaldehyde, acetaldehyde, and acrolein in the vapors, according to other existing research.

The Yale study, the first to look at dripping rates among teens, recommends that more analysis be done on the toxicity of hot vapors produced by dripping, and that regulators consider imposing restrictions so e-cigarettes cannot be modified for uses like dripping.

“One of the concerns I have is when you are looking at the safety and risk of e-cigarettes, one really has to look at the risks of alternative uses also,” said Suchitra Krishnan-Sarin, professor of psychiatry at Yale and first author of the study. “What we are discovering with our work with youth is that kids are actually using these electronic products for other behaviors, not just for vaping e-liquids from cartridges or tanks.”

Researchers reviewed survey responses from 1,080 e-cigarette users at eight Connecticut high schools and learned that 26.1% had tried dripping.

Males, white students, teens who had tried multiple tobacco products, and those who used e-cigarettes on more days in the past month were more likely to use the devices for dripping, according to the study.

The researchers did not assess whether the students added nicotine to the e-liquids used for dripping, or how frequently e-cigarettes were used for dripping.

Krishnan-Sarin said in general people who use e-cigarettes tend to puff on them throughout the day, and that researchers don’t know the short- and long-term consequences of exposing lungs to the vapors.

She said further studies are needed to assess possible health risks of e-cigarettes and of alternative uses like dripping.

“Everybody assumes vaping is a safer way (than cigarettes) of administering nicotine, but we know so little about the risks of vaping,” she said.

Research reported in this publication was supported by the NIH and FDA Center for Tobacco Products (CTP). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or the Food and Drug Administration.