A recent study by Yale researchers found that one in four high school teenagers who vape an electronic cigarette also use it for “dripping,” raising concerns about increased exposure to carcinogens.
E-cigarettes work by heating liquid nicotine and converting it into vapors that users inhale. Vapers “drip” by dropping the liquid directly onto the heating coil of the e-cigarette, producing a stronger, thicker puff.
Dripping exposes vapers to higher levels of nicotine and toxic chemicals, say researchers who warn of impacts ranging from cancer to brain damage.
Overheating e-liquids releases more cancer-causing substances, including formaldehyde, acetaldehyde, and acetone, according to the study published on Feb. 6 in the journal Pediatrics.
Why Students Use Dripping
The study, which surveyed 1,080 students who used e-cigarettes, found that about 64 percent said they “dripped” for the thicker smoke and 39 percent for the stronger flavor. About 22 percent said they did it out of curiosity.
Judith Zelikoff, professor at the NYU School of Medicine and an expert on the effects of inhaled toxicants, expected the trend of dripping to increase until more studies show the risks.
“When you ‘drip,’ you actually get a better flavor and more of a hit of the nicotine, so I think that adolescents like that,” she said.
“The problem when you drip is that it’s heating the chemicals much higher; you’re getting chemical conversion of the glycerin into other chemicals like aldehydes that consist of things like formaldehyde, and these are carcinogens.”
Even without the extra chemicals that come from dripping, there are neurological impacts from e-cigarettes, she said, citing a study she published on mice exposure.
“You can see that early life exposure with e-cigs in a mouse will lead to changes in behavior as the mouse gets older. So there are definite health effects … [and] defects linked with that.”
Critique of Study
A prominent researcher who finds that e-cigarettes are less harmful than regular cigarettes has raised doubts about the methods used in the Yale study.
Dr. Konstantinos Farsalinos, an international expert on e-cigarettes with research recognized by the European Union, said that too many studies on dripping have abused the heating element of the e-cigarette.
“In many studies, they overheat the liquid; it creates a very adhesive taste that no one can vape,” he said. “The results are correct, but it has nothing to do with realistic exposure and realistic use; no one can use the device in those conditions.”
“It’s nothing different from breaking a piece of meat and cooking it at temperatures to create a piece of charcoal, basically. Of course it’s going to be full of carcinogens. No one can eat that. So exactly the same thing is happening with the e-cigarettes,” he said.
Farsalinos also argues that vaping, while not risk-free, is better than smoking tobacco cigarettes.
“In normal conditions, we haven’t seen e-cigarettes generate high levels of toxins. I’m not saying there are zero; there is some residual risk. But the relative risk of e-cigarettes compared to tobacco cigarettes is 5 percent. So there’s a 95 percent risk reduction.”
But even if e-cigarettes are less harmful than cigarettes and the Yale study overstates the danger of dripping, the trend of dripping still poses an additional health risk.
Erika Sward, assistant vice president of national advocacy at the American Lung Association and an e-cigarette expert, said that the dripping trend is dangerous due to the nicotine exposure.
“The fact that this dripping is occurring is very troubling. For youth and young adults, nicotine exposure alters brain development, so there’s significant consequences. There’s no safe level of nicotine for youth and adolescents,” she said.
Sward said the best way to stop dripping is for the FDA to have authority over e-cigarette products.
“The best chance that we have is for the FDA to set requirements for how the product is manufactured.”
That could include design requirements that make it harder for e-cigarettes to be used for dripping.