Electronic cigarettes (e-cigarettes) electrically heat and vaporize e-liquids to produce inhalable vapors. These devices are being used to inhale vapors produced by dripping e-liquids directly onto heated atomizers. The current study conducts the first evaluation of the prevalence rates and reasons for using e-cigarettes for dripping among high school students.
In the spring of 2015, students from 8 Connecticut high schools (n = 7045) completed anonymous surveys that examined tobacco use behaviors and perceptions. We assessed prevalence rates of ever using e-cigarettes for dripping, reasons for dripping, and predictors of dripping behaviors among those who reported ever use of e-cigarettes.
Among 1080 ever e-cigarette users, 26.1% of students reported ever using e-cigarettes for dripping. Reasons for dripping included produced thicker clouds of vapor (63.5%), made flavors taste better (38.7%), produced a stronger throat hit (27.7%), curiosity (21.6%), and other (7.5%). Logistic regression analyses indicated that male adolescents (odds ratio [OR] = 1.64), whites (OR = 1.46), and those who had tried multiple tobacco products (OR = 1.34) and had greater past-month e-cigarette use frequency (OR = 1.07) were more likely to use dripping (Ps < .05).
These findings indicate that a substantial portion (∼1 in 4) of high school adolescents who had ever used e-cigarettes also report using the device for dripping. Future efforts must examine the progression and toxicity of the use of e-cigarettes for dripping among youth and educate them about the potential dangers of these behaviors.
The results of the recent cross-sectional survey by Krishnan-Sarin et al.1 should not be interpreted as evidence that youth are "dripping" in high numbers. The concept is inadequately defined and it's likely that many or most respondents misunderstood a poorly constructed questionnaire item.
“Dripping” is conceptualized as "directly dripping e-liquids onto heated coils" and "vaporizing... e-liquid at high temperatures and then immediately inhaling the vapor that is produced."1 This is wholly inconsistent with what “dripping” refers to in e-cigarette use. Dripping onto a hot coil would result in an unpleasant experience and certainly preclude producing thicker clouds of vapor or better flavour. Specifically, “dripping” means applying drops of liquid onto an atomizer to saturate its wick prior to the coil heating. If the wick isn't saturated, the coil will burn the wick instead of vaporizing liquid, rendering any device unusable. It's obvious that “dripping” prevents (rather than increases, as the Authors imply) the risk of exposing users to high levels of toxic thermal degradation by-products.
The Authors wrongly assume “dripping” is new. The practice is nearly as old as e-cigarettes themselves. Many early devices (circa 2008-2011) required users to drip frequently to keep atomizers saturated. Since 2014, “dripping” is required by specialized "rebuildable dripping atomizers” (RDAs). Therefore, dripping behaviour is device specific. E-cigarettes aren’t “used for” dripping. They're either made for dripping or not. Measuring the practice would entail separating RDA use from far more popular refillable tanks that keep the wick saturated without manual dripping to an atomizer.2
Refilling” was highlighted in the survey's definition of e-cigarettes, yet “dripping method” seems left to interpretation. It’s unlikely that the question "Have you ever used the dripping method to add e-liquid to your e-cigarette?” isolated device-specific dripping: first, “dripping” not “the dripping method” is the typical way to refer to adding droplets of liquid to early atomizers or RDAs; second, all refillable devices are filled by adding e-liquid with a “dripping method”.
We believe students counted as “dripping” had instead refilled a device or tried one they’d seen refilled. And given the obviousness of a "dripping method" in a refilling context, we believe the question likely confused many respondents. This could explain why 25.2% of the sample reported, "I don't know." This study's original 26.6% rate of ever-users was similar to the 2015 NYTS average of 26.4%.3 The authors excluded a huge group from the final sample for inconsistencies (31.8% n=596) or failing to answer (10.6% n=198) the “dripping” question. Using the original number of ever-users, (n=1874), 15% answered yes to the dripping question, 28% answered no, and 57% were too confused to answer sensibly. Given the study’s weak translation of the specific dripping practice, and substantial oversight of the ubiquitous practice of refilling with dropper bottles, results don't indicate youth are "dripping" in the specific sense. Though we'd emphasize that if they were, there's no reason to assume this is any more or less risky than using other types of e-cigarettes.
References
1. Krishnan-Sarin S, Morean M, Kong G, et al. E-Cigarettes and “Dripping” Among High-School Youth. Pediatrics. 2017;139(3):e20163224.
2. Farsalinos KE, Polosa R. Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: a systematic review. Ther Adv Drug Saf. 2014;5(2):67–86.
3. US Department of Health and Human Services. E-Cigarette Use Among Youth and Young Adults: A Report of the Surgeon General. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2016.