E-Cigs and ‘dripping’: What Science isn’t Saying

There’s a new study doing the rounds at the moment. Well, I say “study” but it isn’t really. It’s yet another survey, with participants selected from eight southeastern Connecticut high schools from spring 2015. “This study is the first systematic evaluation of the use of dripping among teens,” says the lead author Suchitra Krishnan-Sarin, professor of psychiatry at the Yale University School of Medicine.

That does beg the first question, why is a professor of psychiatry even looking at e-cigs? I suspect I already know the answer, as do most of my regular readers.

As for the rest of the survey, the usual questions are present - “have you tried an e-cigarette” (which of course equals “use”) and the usual past 30-day use (to “calculate frequency of use). Unlike most other e-cigarette surveys in the US, a few new questions popped up. As you’d expect, they are of course loaded questions to guide the participant down a set path of answers.

“Have you ever used the dripping method to add e-liquid to your e-cigarette?”

Now don’t get me wrong, dripping is just another aspect of vaping. I’ve dripped myself on occasion, although I don’t actually own a dripper (I borrowed from a friend), and it is a completely different experience in terms of hit and flavour. However, this is where it gets a little wonky in the science.

The only “study” (and as always, I use that term loosely) cited in this paper related to dripping is this one where the researchers believe that you can ‘drip’ on a CE4 style tank by dropping e-liquid down the mouthpiece. Of course, shock horror, when you vape in such a way (at the ridiculous levels carried out in that paper), you get high levels of aldehydes and other nasties. Which you would get because the CE4 style tank has a few flaws for that kind of usage:

  1. It’s got very little airflow, as you’d expect with it being a tank meant for “mouth to lung” usage, so the coil will get significantly hotter when used constantly
  2. For dripping, the vaper would (usually) direct-lung inhale the vapour through a large mouthpiece/chuff-cap. The CE4 style doesn’t have a large mouthpiece.

As one news article puts it:

E-cigarettes heat liquid and turn it into vapor, which a user inhales and then exhales in a large puffy cloud.

The normal process of vaping relies on an e-cig’s reservoir and wick, both of which automatically feed liquid to the heating coil within the device, minus any effort or intervention on the part of the user.

Aficionados sometimes prefer to bypass the usual battery-operated process and substitute a more hands-on approach - essentially an artisanal version of vaping.

“Dripping is a more labor-intensive method of vaping in which the user manually applies a few drops of liquid directly to the exposed heating coil of the e-cig every so many puffs,” said Alan Shihadeh, a professor of mechanical engineering and director of the Aerosol Research Laboratory at the American University of Beirut.

For once, the media gets it close to correct. Close, but no cigar. Especially this comment:

Dripping generates higher heating coil temperatures than conventional use of e-cigarettes - and this is a safety concern. “Higher temperatures lead to greater emissions of a class of harmful chemicals known as volatile aldehydes,” including formaldehyde and acrolein, Shihadeh said.

This is of course in relation to “dripping” with a CE4 style tank - that being the only investigation tobacco control scientists have made into this area. The vast majority of vapers that drip regularly don’t do it on a 2.5 Ohm coil. Nor do they drip with a CE4 style tank. The idea of dripping with a CE4 is, quite frankly, bonkers.

But of course, the media had to get some tasty soundbites from the lead author of “unrelated study” as you’d expect, simply because that one “discovered” that “dripping” generates high levels of aldehydes and other nasties, so they had to throw in “dripping bad mmmkay?” type narratives. Which then became “A quarter of teens use dangerous e-cig technique” in a variety of other online media outlets.

So where did this “a quarter of teens” thing come from?

Well, it came from this seemingly innocuous statement in the results section:

Among ever e-cigarette users (n = 1080), 26.1% (n = 282) reported they had used dripping, 48.7% (n = 526) reported that they had never used dripping, and 25.2% (n = 272) reported that they did not know whether they had ever used dripping.

The entire study was geared to asking about dripping by “exploring reasons for dripping” with the question:

Why do you use the dripping method?

The allowed answers:

  1. I do not use dripping
  2. It makes the flavour taste better
  3. It makes a stronger throat hit
  4. It makes a thicker cloud of vapour
  5. I was curious
  6. Other

The “other” allowed for such open-ended responses as “friends use it”, “tried it once” and “don’t know” (seriously?).

According to the study text, the total number of “dripping users” totalled 282, out of 1080 - which is 26.1% (hence the “a quarter of teens” thing), but here’s the kicker (there’s always something) - the math doesn’t add up.

Demographic information on “Ever E-cigarette use”

The sex demographic only totals 277, while the race demographic totals the 282. So there’s a five non-sexual students out there that drip. If those kids are using CE4’s to drip, I might actually have some worries, but I somehow doubt that they are.

Once again, the “science” doesn’t tell the whole story. Of course, the authors admit the “study” has limitations, one of which should have made them question the methodology:

Moreover, our question for assessing dripping may not have been clear to some youth because 25.2% reported that they did not know whether they had participated in this behavior; in fact, it is possible that this limitation may have led to lower estimates of the behavior.

So they admit they have no idea what it is they are studying, and that the question(s) they asked are likely to skew the results, yet they went ahead anyway.

But then, it’s never been about health.