Wednesday, August 06, 2014

Politicians Lie to the Public About the Scientific Evidence Regarding Whether E-Cigarettes are a Gateway to Smoking

In a press release issued Monday by 13 members of Congress, a group of politicians claimed that there is "more" evidence that electronic cigarettes are a gateway to smoking.

The press release was entitled: "Members of Congress: More and More Children Being Exposed To E-Cigarette Marketing Are Picking Up Habit; FDA Urged to Protect Children as More Evidence Shows E-cigarettes Serve as Gateway to Tobacco Products."

After claiming that there is now abundant scientific evidence that electronic cigarettes are a gateway to smoking, these politicians go on to urge the FDA to ban flavorings in e-cigarettes and to ban the online sale of these products.

The Rest of the Story

What is the new "evidence" that e-cigarettes are a gateway to smoking? According to the letter sent by these politicians to the FDA: "What’s even more troubling is that these products serve as a gateway to traditional tobacco products.  A recent JAMA Pediatrics study found that middle and high-school students who used e-cigarettes were more likely to smoke traditional cigarettes and less likely to quit smoking.[2]"

The reference which supports this assertion is a study by Dutra and Glantz which purports to provide data showing that electronic cigarettes are "aggravating the tobacco epidemic among youth."

The article reports the results of a cross-sectional sample of adolescents interviewed in 2011 and 2012 in the National Youth Tobacco Survey. Youths were asked to report their smoking status as well as their e-cigarette use, both any use and current use (at least once in the past month).

The study finds that e-cigarette use is associated with smoking status. In addition, e-cigarette use is associated with heavier smoking and with fewer periods of smoking abstinence.

The study concludes that "e-cigarette use is aggravating rather than ameliorating the tobacco epidemic among youths."

(See: Dutra LM, Glantz SA. Electronic cigarettes and conventional cigarette use: a cross-sectional study. Published online March 6, 2014. JAMA Pediatr. doi:10.1001/jamapediatrics.2013.5488.)

The authors of this study make one of the most cardinal errors in all of epidemiology. They ignore the principle that "correlation does not equal causation."

Here, they find a correlation between e-cigarette use and higher and more sustained levels of smoking. But because this is a cross-sectional study, they cannot determine which came first. In other words, what is the direction of the causal relationship? Does the e-cigarette use precede, and cause, the smoking? Or does the smoking precede, and cause, the e-cigarette use?

The problem is that in this cross-sectional study, there is no way to determine the direction of the observed relationship.

The authors admit this in the paper. They write: "This is a cross-sectional study, which only allows us to identify associations, not causal relationships."

Furthermore, later in the paper they reinforce this point more specifically, writing: "the cross-sectional nature of our study does not allow us to identify whether most youths are initiating smoking with conventional cigarettes and then moving on to (usually dual use of) e-cigarettes or vice versa...".

Thus, the authors readily acknowledge that it is impossible from this study to determine whether or not e-cigarettes lead to smoking or whether smoking leads to e-cigarette experimentation.

Nevertheless, this does not stop the authors from drawing a conclusion. They conclude, despite their acknowledged inability to draw such a conclusion, that: "e-cigarette use is aggravating rather than ameliorating the tobacco epidemic among youths."

In other words, despite acknowledging that they cannot tell from their study whether e-cigarette use precedes smoking or whether smoking precedes e-cigarette use, they nonetheless draw the conclusion that e-cigarette use precedes smoking.

The truth is that this paper provides no evidence whatsoever that e-cigarette use is a gateway to smoking. Instead, it is entirely possible - and quite likely - that youths who use e-cigarettes are more likely to be heavier and more resistant smokers.

By relying on this false evidence, the politicians are essentially lying to the American public. They are misrepresenting the scientific evidence, twisting it to try to support their pre-determined conclusion.

The rest of the story is that there simply is no evidence at the current time that electronic cigarettes are serving as a gateway to youth smoking. It may actually be the case that electronic cigarettes serve as an inhibitor of smoking initiation by getting a youth used to a flavorful experience, thus making it less likely - not more likely - that the youth will move on to the harsh taste of tobacco.

These politicians should stop lying to the American public in order to support their pre-determined agenda. Science, not politics, should guide public health policy in this nation.

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