E-Cig Study: Much Smoke, Little Light

New study shows that e-cigarette users are no more likely to quit smoking tobacco after a year than non-e-cigarette users. In fact, the trend is in the opposite direction – e-cigarette users are less likely to give up their regular cigarettes. I’m skeptical. r/science is skeptical. The experts are skeptical. Even the authors of the study sound maybe a little skeptical.

The study surveyed tobacco smokers for various information including whether they smoked e-cigarettes in addition to their tobacco. A year later, they went back and surveyed everyone again and asked them if they were still smoking tobacco. And the people smoking the e-cigarettes were no more likely to have quit than the others.

Let’s transition from reality to Hypothetical World. In Hypothetical World, there are only two kinds of smokers, Short Smokers and Long Smokers. The moment someone smokes their first cigarette, God flips a coin and assigns them into one of the two groups based on the result. Short Smokers are predestined to smoke for exactly one year before quitting; Long Smokers are predestined to smoke for exactly fifty years before quitting.

A scientist in Hypothetical World wants to discovery what percent of first-time-smokers become Short Smokers versus Long Smokers (the real proportion is 50-50 since God’s coin is fair, but she doesn’t know that). So she uses the same methodology as this study. She hangs around a tobacco shop and accosts the first thousand people who come in to buy cigarettes, getting their names and phone numbers. Then a year and a day later, she calls them all up to ask if they are still smoking – since anyone who keeps smoking for a year and a day must be a Long Smoker.

So she finds something close to 2% of people are Short Smokers and a whopping 98% are Long Smokers. She incorrectly concludes that God is rolling a d100 and only assigning Short Smoker status to those who come up 99 or 00.

Don’t see why she would make this mistake? Consider a particular generation of Hypothetical people over their lifetimes. The Short Smokers will only smoke a single year out of their lifetime; the Long Smokers will smoke fifty years. When the scientist does her study in a randomly selected year, she only has a 1/average_lifespan chance of catching any given Short Smoker, but a 50/average_lifespan chance of catching a Long Smoker. So, her original sample will contain fifty times more Long Smokers than Short Smokers, and she will mistakenly conclude that their pattern is fifty times more common.

Now transition back to reality. Suppose there are two types of e-cigarette users – successful and unsuccessful. The successful e-cigarette users try e-cigarettes, immediately decide they are better than regular cigarettes, and switch to using e-cigarettes exclusively within one month. The unsuccessful e-cigarette users try e-cigarettes but just don’t get everything they love about tobacco from them. They sort of futz around with e-cigarettes and regular cigarettes and tell themselves that one of these days, they’re really going to stop the regular ones entirely and transition totally to e-cigarettes. These people continue futzing for let’s say ten years before they either finally quit tobacco, give up on e-cigarettes, or die.

In that case, any sample of tobacco smokers taken at a particular time will include a hundred twenty times as many unsuccessful e-cigarette users as successful ones. We expect unsuccessful e-cigarette users to continue their past pattern of futzing around, so it’s not surprising that this sort of sample finds most e-cigarette users not only can’t easily quit tobacco using e-cigarettes, but actually have a harder time quitting tobacco than normal smokers – they’ve already been preselected as The Group That Even E-Cigarettes Can’t Help; as The Group That Tried Something Billed As An Anti-Smoking Aid But Failed At It. It’s a pretty general rule of medicine that people who failed treatment once are more likely to fail treatment a second time.

This is a very speculative explanation and I haven’t heard anyone respectable at a major institution advance it yet, but it seems to me like the most likely reason for these findings. All I have to go for with the study right now is a preliminary “research letter”, but hopefully we’ll know more when the real thing comes out.

Lest this post be entirely pro-drug, here’s a clip of my addiction-medicine teacher and sometime-boss lecturing people about marijuana on Fox News last weekend. He is a great doctor and it’s neat to see him finally getting some of the celebrity he deserves. Even though his politics are terrible.