A Harvard School of Public Health report claims, according to Reuters, “most young people in the United States who use newer smokeless tobacco products are smoking cigarettes.” In fact, the article, published in Pediatrics, contains no specific information on cigarettes.

It is common knowledge that a high proportion of U.S. smokeless tobacco (ST) users – both men and boys – also smoke, as I have previously discussed here and here.  So the main message of this study, that youth ST users are also smokers, is not new.

The study, led by Dr. Gregory Connolly, could be seen as having one purpose – to fuel the campaign against tobacco harm reduction. The journal article and the attendant media coverage are tainted by unscientific bias.

The authors observed that 72 percent of ST users also “smoke,” a finding that the media reported as smoking cigarettes.  The authors, however, defined a smoker as anyone using any of these combustible products on one of the past 30 days: cigarettes, cigars, pipes, bidis, kreteks, roll-your own, flavored cigarettes, clove cigarettes, flavored cigars or hookah/waterpipe.  Results were reported for this entire group of “combustible” products, not for cigarettes alone.

The inclusion of the other products is just one of several tactics to maximize the percentage of ST users who smoked.  Another was the definition of a tobacco user. For all forms, it was anyone who used the product on at least one day in the past 30, a broadly inclusive definition.

The most disturbing part of the media coverage of this study is the use of its results to attack tobacco harm reduction.  There is nothing in these findings that is damaging, or even relevant, to tobacco harm reduction, but it is clear that Dr. Connolly was campaigning to insert the “gateway” speculation – the fictitious idea that ST use causes smoking.  I have dealt with it previously here.  According to Reuters, Dr. Neal Benowitz, “who was not involved in the current research, noted that studies have shown use of smokeless tobacco among U.S. youth can indeed be a gateway to cigarette smoking.”

This is nonsense.  Dr. Benowitz cannot cite even one legitimate study showing that ST is a gateway to smoking.  Few cross-sectional or longitudinal surveys in the United States or Sweden have specific information on the order in which ST and cigarettes were first used – data that is required to demonstrate that ST use causes smoking.  ST users may also smoke, but this does not mean that ST use causes smoking.  Two studies that have examined the causal pathway document that ST use may be protective against smoking.

Why do so many ST users smoke?  Dr. Connolly’s study, ironically, gives us a clue, as he notes that 67 percent of all ST users wrongly believe that all tobacco products are equally harmful.  (Ninety-two percent of nonusers of ST share the same mistaken view.)

American children, like their parents, are routinely misinformed about the risks of ST use and smoking.  Journal reviewers and editors, as well as journalists, should view biased and shallow research with a more critical eye.

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