Thursday, February 09, 2017

Tobacco Control Study Provides Strong Evidence that Vaping is Not a One-Way Bridge to Smoking

I have already shown (post 1; post 2) why the recently published study in Tobacco Control which purported to demonstrate that vaping is a "one-way bridge to cigarette smoking among youth" actually provides no evidence that e-cigarette experimentation is a gateway to smoking.

First, the exposed group consisted of any youth who had even puffed once on an e-cigarette in the past 30 days. Second, the outcome variable was having puffed even once on a cigarette in the past year. Thus, the study cannot document either that the "recent vapers" were actually regular vapers or that the youth who "initiated" smoking were actually smokers. A more likely explanation of the study findings is that youth who engage in e-cigarette experimentation are also more likely to try cigarettes.

Second, I revealed that the sample size of youth who were nonsmoking, recent vapers at baseline was only 13 and that the number of youth in this category who "initiated" smoking was only 4. Thus, the sweeping conclusion of the paper, which has been publicized internationally, was based on only 4 kids.

Today, I reveal that not only does the study fail to provide any evidence that vaping is a gateway to smoking, but it actually provides strong evidence that vaping is not a gateway to smoking.

The Rest of the Story

If you read the fine print in the paper, there is a key finding which is not mentioned anywhere in the abstract, the discussion, or in any of the newspaper articles written about this study. The fine print is this:

"Among the group of new smokers at follow-up who had recently vaped at baseline, all reported that they had smoked cigarettes at the level of ‘once or twice’ in the past 12 months at follow-up."

Another way of stating this is that:

"Among the group of new smokers at follow-up who had recently vaped at baseline, not a single one had smoked more than two cigarettes in the entire past year."

In other words, this study actually confirms that none of the nonsmoking, recent vapers became actual smokers. Apparently, they tried a cigarette or two, but not a single one of them continued to smoke beyond that!

What this means is that despite having a sample size of 347 high school seniors, this study could not find a single student who became an actual new smoker after having experimented with e-cigarettes. The few students (a grand total of 4) who did try a cigarette or two did not progress beyond having one or two cigarettes.

It is striking to me that this study, which provides strong evidence that vaping is not a gateway to smoking, could conclude quite definitively that vaping is a "one-way bridge" to smoking. It creates the appearance that the study reached a pre-determined conclusion and was going to twist the findings any way it could to come up with this conclusion.

It is puzzling that not a single reviewer nor editor at Tobacco Control was able to detect this sleight-of-hand.

How do you get from a finding that not a single nonsmoking youth who experimented with vaping at baseline progressed to become an actual smoker at follow-up (and that only 4 kids in that category even tried a cigarette in the first place) to a sweeping conclusion that vaping is a one-way bridge to cigarette smoking among youth?

The answer, and the rest of the story, is that this is essentially hocus pocus. And while it may have gotten by the peer reviewers and editors, it doesn't get by me or any of the many colleagues with whom I have discussed this study. Even my students with whom I have discussed this easily see what is going on here.

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