NOT PEER REVIEWED
He et al cite (ref 43 in their paper) our meta-analysis of the association between e-cigarette use and smoking cessation [1} to support the statement, "[e-cigarettes] have demonstrated potential in recent years in helping smoking cessation." Quite the contrary, the abstract of this paper concludes, "As consumer products, in observational studies, e-cigarettes were not associated with increased smoking cessation in the adult population."

A subsequent meta-analysis [2] concluded the same thing.

Both these meta-analyses include the other paper (ref 44 in their paper) He et al cite to support their statement that e-cigarettes assist smoking cessation [3].

The authors need to accurately represent the literature and stop promoting the myth that e-cigarettes as consumer products increase cigarette smoking cessation. They also need to correct their paper to avoid perpetuating the literature.

REFERENCES

1. Wang RJ, Bhadriraju S, Glantz SA. E-cigarette use and adult cigarette smoking cessation: a meta-analysis. Am J Public Health 2021;111:230–46. doi:10.2105/AJPH.2020.305999

2. Hedman L, Galanti MR, Ryk L, et al. Electronic cigarette use and smoking cessation in cohort studies and randomized trials: a systematic review and meta-analysis.
Tob Prev Cessat 2021;7:62.

3. Zhuang Y-L, Cummins SE, Sun JY, et al . Long-term E-cigarette use and smoking cessation: a longitudinal study with US population. Tob Control 2016;25:i90–5. doi:10.1136/tobaccocontrol-2016-053096

NOT PEER REVIEWED
We acknowledge receipt of a private e-mail message from JLI regarding our paper (Yassine et al., 2022). Given the industry‘s long history of industry obfuscation, interference, and deception regarding research on tobacco products, we decided that the most transparent approach to the private e-mail that we received from an employee of a tobacco product manufacturer would be for us to report our results independently and respond to any public discussion of our work if and when it arose. Now that public discussion has arisen, we are pleased to respond to it.

We very recently analyzed the menthol and nicotine content of samples of liquid from six menthol flavor pods purchased in 2020. Three of these were liquids extracted from the pods in June 2021 for our paper and had been stored since in sealed amber glass containers at 5°C in the dark. The other three pods had been stored in their original sealed packages and were taken from the same batches as the pods analyzed in June 2021. These unopened packages were stored in the dark at room temperature over the intervening 18 months. The data from this small sample demonstrate a 24% reduction in menthol content over that period (12.01±0.46 vs 9.15±0.22 mg/ml), which helps to explain the results we reported (Yassine et al., 2022). We also found a 5% reduction in nicotine content (62.47±0.63 vs 59.52±0.49 mg/ml), as well as discoloration of the liquid in the pods that were stored at room temperature that suggests the possibility of other time-dependent changes in liquid constituents that we have not had an opportunity to evaluate comprehensively.

We acknowledge that the differences in menthol concentrations in JUUL products that were purchased across a three-year period, reported in Yassine et al., 2022, are consistent with changes in product composition that can occur during storage. A correction to the manuscript is now being published.

Our findings highlight that tobacco product manufacturers should be required to release to the public and the scientific community everything they know about their products, including product ingredients, abuse liability, potential adverse health consequences, and time- and temperature-dependent degradation of quality. For example, much of this information may be available in Premarket Tobacco Product Applications submitted to the Food and Drug Administration’s Center for Tobacco Products, and thus could be shared easily on each company’s website. This vital information should be available to all. In the meantime, our original article (Yassine et al., 2022), the industry response (Gillman, 2022), and this reply provide needed archival documentation for the scientific record.

References

Yassine A, El Hage R, El-Hellani A, Salman R, Talih S, Eissenberg T, Shihadeh A, Saliba N. Did JUUL alter the content of menthol pods in response to US FDA flavour enforcement policy? Tob Control. 2022 Nov;31(Suppl 3):s234-s237. doi: 10.1136/tc-2022-057506. PMID: 36328458; PMCID: PMC9641543.

NOT PEER REVIEWED
I would like to make three comments by way of a brief post-publication review.

1. The impacts of vaping tax on smoking have been completely overlooked

For a study of e-cigarette taxation to have any public health relevance, it must consider the impact of e-cigarette prices on *cigarette* demand. Cigarettes and e-cigarettes are economic substitutes. The demand for one responds to changes in the price of the other, an idea well understood in economics and quantified through the concept of cross-elasticity. The paper appears to pay no regard to the impact of vaping taxes on cigarette demand, Yet such effects might easily overwhelm any benefits from reduced e-cigarette use - in fact, impact on demand for other tobacco products and the development of informal markets are by far the most important impacts of a vaping tax. By way of example, a 2020 paper by Pesko et al. [1] concluded:

"Our results suggest that a proposed national e-cigarette tax of $1.65 per milliliter of vaping liquid would raise the proportion of adults who smoke cigarettes daily by approximately 1 percentage point, translating to 2.5 million extra adult daily smokers compared to the counterfactual of not having the tax."

2. The case for reducing adult vaping by taxation has not been made

The authors have based their paper on an unexamined assumption that it is a justifiable goal of policy to lower rates of adult e-cigarette use. Why should this be a policy goal any more than reducing caffeine use or moderate alcohol use? The goal of public health policy is to address significant harms or self-destructive patterns of use, not to modify behaviours that the authors find distasteful. What are the harms that justify state intervention to reduce adult vaping with a tax? Further, they appear indifferent to welfare costs and the distributional impact of imposing a regressive tax burden on people who use vaping products. Tobacco control advocates should become more familiar with the idea that punitive policies impose harm on users, even though these users are supposed to be the intended beneficiaries. For example, a vaping tax harms families by drawing on the household budget of those who continue to vape.

3. The analysis to support the policy recommendations is wholly inadequate

The authors make over-confident policy recommendations without considering the full range of impacts of the measures they are proposing.

"Our findings suggest that adopting a vaping product excise tax policy may help reduce ENDS use and suppress the increase of ENDS use prevalence among young adults. Considering that there are still a number of US states that have not implemented vaping product excise tax policy, wider adoption of such policy across the nation would likely help mitigate ENDS use prevalence."

Without considering all the possible responses to the tax they support, they may easily be proposing tobacco control policies that do more harm than good. In fact, the most important public health impact of this policy is entirely excluded from the analysis. That is the effect of a vaping tax on smoking or other tobacco use. Given the two orders of magnitude difference in risk between smoking and vaping, only a tiny uptick in smoking would be needed to completely offset the benefits, if any, arising from reduced vaping

References

[1] Pesko MF, Courtemanche CJ, Maclean JC. The effects of traditional cigarette and e-cigarette tax rates on adult tobacco product use. J Risk Uncertain 2020;60(3):229–258. https://link.springer.com/article/10.1007/s11166-020-09330-9

NOT PEER REVIEWED

We appreciate the comments from Bates and the opportunity for us to respond and clarify.

First, Bates' argument heavily relies on the assumption that e-cigarettes and combustible cigarettes are substitutes, which is theoretically possible as some consider vaping as a harm reduction alternative to combustible cigarettes. Empirically, however, there have been mixed findings about whether e-cigarettes and combustible cigarettes are substitutes (or complements). Bates cited Pesko et al. (2020) that concludes e-cigarettes and combustible cigarettes are substitutes, whereas other studies have shown that they are complements. For example, Cotti et al. (2018) found that higher cigarette excise taxes, in fact, decrease sales of both e-cigarettes and combustible cigarettes, suggesting that they are complements. Such mixed results abate Bates' argument that taxing ENDS could lead to more use of combustible cigarettes.

Second, Bates might have ignored that our study focused on young adults aged 18-24 years rather than general adults when examining the effect of vaping product tax on e-cigarette use. Although Pesko et al. (2020) suggests that e-cigarettes and combustible cigarettes are substitutes, the findings are based on the general adult population (average age: 55 years) which may not be generalizable to the young adult population. In fact, one study conducted by Abouk and Adams (2017) indicates that e-cigarettes and combustible cigarettes are not substitutes for young people. Established cigarette smokers may use e-cigarettes as a cessation tool but it is less common in young adults. In addition, even if e-cigarettes and combustible cigarettes are substitutes to some degree, the direction of substitution as well as co-use versus subsequent use should not be overlooked. Studies have shown that e-cigarettes may serve as a gateway to future combustible cigarette smoking among young people. For example, a study conducted by Hair et al. (2021) shows that youth and young adults who reported ever e-cigarette use had significantly higher odds of ever cigarette use one year later. Therefore, e-cigarette use versus combustible cigarette smoking is not simply an issue of substitution in particular among young people.

Disclosure: We did not receive any funding from the tobacco industry.

References:
1. Abouk, R., & Adams, S. (2017). Bans on electronic cigarette sales to minors and smoking among high school students. Journal of Health Economics, 54, 17-24.
2. Cotti, C., Nesson, E., & Tefft, N. (2018). The relationship between cigarettes and electronic cigarettes: Evidence from household panel data. Journal of Health Economics, 61, 205-219.
3. Hair, E. C., Barton, A. A., Perks, S. N., Kreslake, J., Xiao, H., Pitzer, L., ... & Vallone, D. M. (2021). Association between e-cigarette use and future combustible cigarette use: Evidence from a prospective cohort of youth and young adults, 2017–2019. Addictive Behaviors, 112, 106593.
4. Pesko, M. F., Courtemanche, C. J., & Maclean, J. C. (2020). The effects of traditional cigarette and e-cigarette tax rates on adult tobacco product use. Journal of Risk and Uncertainty, 60(3), 229-258.