On 2016 Apr 28, Clive Bates commented:

Please note this comment is replicated on the PubMed entry for the Pediatrics version of this paper. See Singh T, 2016.

There are several weaknesses in the reasoning in this paper.

1. Singh et al assert: “exposure to e-cigarette advertisements might contribute to increased use of e-cigarettes among youths.” The study is cross-sectional and does not (and cannot) establish that advertising causes e-cigarette use. Even if the authors acknowledge that their study does not establish a causal relationship, that has not stopped them drawing conclusions as if it does.

2. The finding that higher advertising exposure would be associated with greater e-cigarette use is quite likely, but there are many possible explanations. It could be that e-cigarette users see more advertising because of the way they live and their interests direct them to where such advertising is visible. Alternatively, teenagers already using the products may just be more interested and have better recall of advertising they have seen, even if exposure is no different.

3. Marijuana is not advertised but its prevalence among high school students is higher (23.4%) than tobacco (22.4%) on the basis generally used by CDC (used at least once in the last 30 days) - see CDC Youth Risk Behavior Surveillance — United States, 2013. It may be that better explanatory variables than advertising exposure are needed to interrogate prevalence of youth risk behaviours.

4. Even if we allow that e-cigarette advertising may be increasing youth e-cigarette uptake, something that is far from established, the authors need to consider the likelihood that this is displacing cigarette smoking. Given that independent risk factors for teenage vaping and smoking are likely to be similar, it would be surprising if vaping was not adopted as an alternative to smoking, at least in some cases. In this event, the health effect of e-cigarette use is positive, and, therefore, so is any role that advertising plays in it.

5. The observed sharp decline in teenage cigarette smoking that has coincided with the sharp rise in teenage e-cigarette use does not establish a causal relationship between these trends, but it does suggest that it is a plausible hypothesis that vaping is reducing smoking and therefore that great care should be taken when designing policies that may attenuate this effect. See data: CDC Tobacco Use Among Middle and High School Students — United States, 2011–2014.

6. The authors jump to a policy conclusion that goes far beyond the limitations of their study: "Multiple approaches are warranted to reduce youth e-cigarette use and exposure to e-cigarette advertisements”.

7. Before making such policy proposals, the authors should consider several issues and potential unintended consequences beyond the scope of this paper: that young people might smoke instead of using e-cigarettes; that e-cigarette advertising might be an effective form of anti-smoking advertising; that such restrictions may reduce adult switching from smoking to vaping and thus create damage to adult health; that excessive restrictions on advertising protect incumbent industries (cigarettes) and reduce the returns to innovation in the disruptive entrants (e-cigarettes).

8. The assertive and unqualified nature of the policy proposal raises concerns of an unacknowledged investigator bias. This would not be that surprising. The authors are from CDC, and the media release that accompanied this survey abandoned all caution about causality or unintended consequences. It reflected the CDC’s adversarial prior policy stance on these issues, none of which are supported by the survey itself:

“The same advertising tactics the tobacco industry used years ago to get kids addicted to nicotine are now being used to entice a new generation of young people to use e-cigarettes,” said CDC Director Tom Frieden, M.D., M.P.H. “I hope all can agree that kids should not use e-cigarettes.”

Conclusions: CDC should adopt a more dispassionate and careful approach to both reporting and communicating survey findings. In publishing for peer-reviewed journals, CDC staff should disclose relevant CDC policy and advocacy positions as non-financial competing interests.

On 2016 Apr 28, Clive Bates commented:

Please note this comment is replicated on the PubMed entry for the Pediatrics version of this paper. See Singh T, 2016.

There are several weaknesses in the reasoning in this paper.

1. Singh et al assert: “exposure to e-cigarette advertisements might contribute to increased use of e-cigarettes among youths.” The study is cross-sectional and does not (and cannot) establish that advertising causes e-cigarette use. Even if the authors acknowledge that their study does not establish a causal relationship, that has not stopped them drawing conclusions as if it does.

2. The finding that higher advertising exposure would be associated with greater e-cigarette use is quite likely, but there are many possible explanations. It could be that e-cigarette users see more advertising because of the way they live and their interests direct them to where such advertising is visible. Alternatively, teenagers already using the products may just be more interested and have better recall of advertising they have seen, even if exposure is no different.

3. Marijuana is not advertised but its prevalence among high school students is higher (23.4%) than tobacco (22.4%) on the basis generally used by CDC (used at least once in the last 30 days) - see CDC Youth Risk Behavior Surveillance — United States, 2013. It may be that better explanatory variables than advertising exposure are needed to interrogate prevalence of youth risk behaviours.

4. Even if we allow that e-cigarette advertising may be increasing youth e-cigarette uptake, something that is far from established, the authors need to consider the likelihood that this is displacing cigarette smoking. Given that independent risk factors for teenage vaping and smoking are likely to be similar, it would be surprising if vaping was not adopted as an alternative to smoking, at least in some cases. In this event, the health effect of e-cigarette use is positive, and, therefore, so is any role that advertising plays in it.

5. The observed sharp decline in teenage cigarette smoking that has coincided with the sharp rise in teenage e-cigarette use does not establish a causal relationship between these trends, but it does suggest that it is a plausible hypothesis that vaping is reducing smoking and therefore that great care should be taken when designing policies that may attenuate this effect. See data: CDC Tobacco Use Among Middle and High School Students — United States, 2011–2014.

6. The authors jump to a policy conclusion that goes far beyond the limitations of their study: "Multiple approaches are warranted to reduce youth e-cigarette use and exposure to e-cigarette advertisements”.

7. Before making such policy proposals, the authors should consider several issues and potential unintended consequences beyond the scope of this paper: that young people might smoke instead of using e-cigarettes; that e-cigarette advertising might be an effective form of anti-smoking advertising; that such restrictions may reduce adult switching from smoking to vaping and thus create damage to adult health; that excessive restrictions on advertising protect incumbent industries (cigarettes) and reduce the returns to innovation in the disruptive entrants (e-cigarettes).

8. The assertive and unqualified nature of the policy proposal raises concerns of an unacknowledged investigator bias. This would not be that surprising. The authors are from CDC, and the media release that accompanied this survey abandoned all caution about causality or unintended consequences. It reflected the CDC’s adversarial prior policy stance on these issues, none of which are supported by the survey itself:

“The same advertising tactics the tobacco industry used years ago to get kids addicted to nicotine are now being used to entice a new generation of young people to use e-cigarettes,” said CDC Director Tom Frieden, M.D., M.P.H. “I hope all can agree that kids should not use e-cigarettes.”

Conclusions: CDC should adopt a more dispassionate and careful approach to both reporting and communicating survey findings. In publishing for peer-reviewed journals, CDC staff should disclose relevant CDC policy and advocacy positions as non-financial competing interests.