published between 2018 and 2021
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We would like to thank Mr. Wang for his feedback on our paper, Indicators of dependence and efforts to quit vaping and smoking among youth in Canada, England and the USA.
With regards to the ‘discrepancies’ in vaping and smoking prevalence between those reported in Table 1 and an earlier publication , we have previously published these same estimates , along with a description of the survey weighting procedures—which were modified since the first estimates were published (as outlined in a published erratum to the cited publication ). Briefly, since 2019, we have been able to incorporate the smoking trends from national ‘gold standard’ surveys in Canada and the US into the post-stratification sampling weights. A full description is provided in the study’s Technical Report , which is publicly available (see http://davidhammond.ca/projects/e-cigarettes/itc-youth-tobacco-ecig/).
Mr. Wang has also noted a change in the threshold used for a measure of frequent vaping/smoking: ≥20 days in past 30 days rather than ≥15 days, as previously reported . We have adopted the convention of reporting using ≥20 days in past 30 days to align with the threshold commonly used by the US Centers for Disease Control for reporting data from the National Youth Tobacco Survey (NYTS), as well as the Population Assessment of Tobacco and Health (PATH) Study and the Mo...
Mr. Wang has also noted a change in the threshold used for a measure of frequent vaping/smoking: ≥20 days in past 30 days rather than ≥15 days, as previously reported . We have adopted the convention of reporting using ≥20 days in past 30 days to align with the threshold commonly used by the US Centers for Disease Control for reporting data from the National Youth Tobacco Survey (NYTS), as well as the Population Assessment of Tobacco and Health (PATH) Study and the Monitoring the Future (MTF) survey—three of the most widely cited sources of data for youth vaping.[5,6,7]
Mr. Wang questioned whether the process for ascertaining parental consent may bias the survey responses. Ascertaining parental consent among minors is a common and required practice in most jurisdictions. To the extent that young respondents may not have provided honest responses due to concerns about confidentiality, the likely impact would be to under-report smoking and vaping status. However, the recruitment process has not changed over the course of the study; thus, this is unlikely to account for the trends over time reported in our paper. In addition, the trends in the ITC Youth Tobacco and Vaping Surveys are very similar to the trends in vaping reported by national surveillance surveys in the US, Canada, [8,9,10] and England.
Regarding Mr. Wang’s assertion that “when asking participants quitting plans, it is better to clarify the quitting of traditional tobacco products or quitting nicotine products”, we can confirm that questions about intentions to quit and cessation were indeed asked separately for smoking and vaping. Thus, if a youth reported smoking cigarettes and vaping e-cigarettes, they would have been asked cessation-related questions in different sections of the survey for each of cigarettes and e-cigarettes/vaping.
Finally, Mr. Wang has noted seasonal variation in smoking and vaping rates. Despite some variations in the exact survey timing, the ITC Youth Tobacco and Vaping Surveys have been conducted over a similar time period in each year. For example, across the first three waves of the survey, 64%, 79% and 74% of surveys, respectively, were conducted in the month of August. As noted above, trends in vaping prevalence over time from the ITC surveys align very closely with other national surveys over the same period. With respect to specific findings reported in our Tobacco Control manuscript, we would not expect any material differences in levels of dependence, cessation-related outcomes or vaping brands due to the minor variation in data collection periods.
We hope this additional information will provide context for interpreting the study results and feedback on the manuscript.
1. Hammond D, Reid JL, Rynard VL, Fong GT, Cummings KM, McNeill A, Hitchman S, et al. Prevalence of vaping and smoking among adolescents in Canada, England, and the United States: repeat national cross sectional surveys. BMJ. 2019; 365: l2219. doi: 10.1136/bmj.l2219.
2. Hammond D, Rynard V, Reid JL. Changes in prevalence of vaping among youth in the United States, Canada, and England, 2017 to 2019. JAMA Pediatr. 2020;174(8):797-800. doi: 10.1001/jamapediatrics.2020.0901.
3. Published Erratum: Prevalence of vaping and smoking among adolescents in Canada, England, and the United States: repeat national cross sectional surveys. BMJ. 2020 Jul 10;370:m2579. doi: 10.1136/bmj.m2579.
4. Hammond D, Reid JL, Rynard VL, Burkhalter R. ITC Youth Tobacco and E-Cigarette Survey:
Technical Report – Wave 3 (2019). Waterloo, ON: University of Waterloo, 2020. http://davidhammond.ca/wp-content/uploads/2020/05/2019_P01P3_W3_Technica...
5. Park-Lee E, Ren C, Sawdey MD, et al. Notes from the Field: E-Cigarette Use Among Middle and High School Students — National Youth Tobacco Survey, United States, 2021. MMWR Morb Mortal Wkly Rep 2021;70:1387–1389. DOI: http://dx.doi.org/10.15585/mmwr.mm7039a4.
6. Hyland A, Kimmel HL, Borek N, on behalf of the PATH Study team. Youth and young adult acquisition and use of cigarettes and ENDS: The latest findings from the PATH Study (2013-2019). Society for Research on Nicotine & Tobacco Annual Conference, March 2020
7. Miech R, Johnston L, O’Malley PM, Bachman JG, Patrick ME. Trends in adolescent vaping, 2017-2019. N Engl J Med. 2019;381(15):1490-1491. doi:10.1056/NEJMc1910739.
8. Government of Canada. Detailed tables for the Canadian Student Tobacco, Alcohol and Drugs Survey 2016-17. Available from https://www.Canada.ca/en/health-Canada/services/canadian-student-tobacco...
9. Government of Canada. Canadian Tobacco, Alcohol and Drugs Survey (CTADS): Summary of Results for 2017. 2017. Available from https://www.Canada.ca/en/health-Canada/services/canadian-tobacco-alcohol....
10. Statistics Canada. Canadian Tobacco and Nicotine Survey, 2019. Available from https://www150.statcan.gc.ca/n1/daily-quotidien/200305/dq200305a-eng.htm.
11. Action on Smoking and Health UK. Use of e-cigarettes among young people in Great Britain, 2021. June 2021. Available from https://ash.org.uk/wp-content/uploads/2021/07/Use-of-e-cigarettes-among-...
There’s a published paper by Hammond and colleagues in 2019 using the same survey results, but there are some discrepancies.
1. The Table 2 of the 2019 paper, prevalence of vaping in 2018 for ever, past 30 days are 37.0% (1425), 14.6% (562) in Canada, 32.7% (1276), 8.9% (346) in England and 33.6% (1360), 16.2% (655) in the US, respectively. However, in this article’s Table 1, for vaping in the same year 2018 for ever, past 30 days are 33.2% (1275), 12.1% (463) in Canada, 33.1% (1283), 9.0% (351) in England and 33.1%(1336), 15.7% (635) in the US. More discrepancies can be found on cigarette smoking section as well. These numbers warrant further explanation particularly why numbers in Canada and the US decreased while numbers in England increased? Considering previous correction of numbers to the 2019 paper has raised serious concern among some readers, such timely clarification in this article will be very necessary.
2. The 2019 paper use the criteria of ≥15 days in past 30 days but the current paper adopts different criteria of ≥20 days in past 30 days, for both vaping and cigarette smoking. Further explanation is needed for such change.
Additionally, a few considerations on possible limitations of the paper’s findings:
1. Since the invitations were sent to nearly twice more parents than youth themselves according to the technical report, responds to survey questions might be biased because study has shown many...
1. Since the invitations were sent to nearly twice more parents than youth themselves according to the technical report, responds to survey questions might be biased because study has shown many parents are unaware of their children’s e-cigarette use. Young participants who receive the questionnaire from their parents, in suspicion of their parents might know, may be unwilling to fill out honestly.
2. A clearer definition of stop smoking/quitting. In Table 3, when asking participants quitting plans, it is better to clarify the quitting of traditional tobacco products or quitting nicotine products. As some youth may treat vaping itself as quitting and some may not, the survey result might therefore, be ambiguous.
3. Seasonality. Previous studies have indicated seasonal variations in the initiation of smoking among adolescents, Unsupervised time out of school during the first months of summer vacation is a period of increased smoking behavior. However, significantly lower rates during September were observed which seem to be related to the beginning of school. Survey for this study were conducted July/August in 2017, August/September in 2018 and 2019. As cross-sectional study only offers a snapshot of the situation, to conduct surveys at different months with fluctuating trends would inevitably lower the liability of the result.
 Hammond, D., Reid, J. L., Rynard, V. L., Fong, G. T., Cummings, K. M., McNeill, A., Hitchman, S., et al. (2019). Prevalence of vaping and smoking among adolescents in Canada, England, and the United States: repeat national cross sectional surveys. BMJ (Clinical Research Ed.), 365, l2219.
 Hammond D, Reid JL, White CM. ITC Youth Tobacco and E-Cigarette Survey:
Technical Report – Wave 3 (2019. Waterloo, ON: University of Waterloo, 2020. http://
 Wu T and Chaffee BW. Parental Awareness of Youth Tobacco Use and the Role of Household Tobacco Rules in Use Prevention. Pediatrics. 2020;146(5): e20194034
 Colwell, B., Ramirez, N., Koehly, L., Stevens, S., Smith, D. W., & Creekmur, S. (2006). Seasonal variations in the initiation of smoking among adolescents. Nicotine & Tobacco Research, 8(2), 239–243.
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We thank Mr. Clive Bates (1) and Dr. Moira Gilchrist (2) for their reconsideration of our work (3) and previous response where we corrected some errors (4). We also reiterate that all data informing our Industry Watch are publicly available at Tobacco Watcher (https://tobaccowatcher.globaltobaccocontrol.org/) for anyone to analyze. As with any analyses of observational data, there are limitations and we do not disagree with some of the limitations that Gilchrist and Bates point out in our analyses (as we addressed nearly all of these in our previous response (4)). However, we remain unchanged in our conclusion that, as the title of our initial article stated, “Philip Morris International used the e-cigarette, or vaping, product use associated lung injury (EVALI) outbreak to market IQOS heated tobacco” (3).
While statistical analysis indicated a correlation between (a) PMI’s public statements regarding EVALI and their IQOS brand of heated tobacco posted to their corporate “media center” (5) and (b) trends in news coverage of EVALI and IQOS, our primary assertion is that PMI used EVALI to market IQOS. The necessary and sufficient analysis to substantiate this assertion is reporting what PMI publicly claimed, which we did by analyzing the statement made by PMI which promoted IQOS through mentioning, contrasting or describing it along with EVALI and/or vaping.
The full text...
The full text of the PMI’s public statement is available in the appendix of our original piece (the version available presently on the PMI website has been changed) and we analyze excerpts to make our case below.
PMI’s statement recounted the EVALI outbreak beginning: “Skepticism and fear around vaping has emerged following the cases of respiratory illness and deaths in the US associated with the use of e-cigarettes.” PMI then contrasted this against their IQOS heated tobacco product, writing “on April 30 2019, the FDA authorized IQOS for sale in the US, finding that marketing of the product would be ‘appropriate for the protection of public health’ [quotes used in the original release].” As we previously argued, some readers (especially novice consumers) can interpret this as implying the FDA endorses IQOS and such statements are not allowed. The Food, Drug and Cosmetic Act prohibits ‘any expressed or implied statement...that either conveys, or misleads or would mislead consumers into believing that [a tobacco] product is approved by the Food and Drug Administration’ (ACT 21 U.S.C. § 331(tt)). The same “appropriate for the protection of public health” statement also implies that IQOS is safer than vaping, a claim disallowed by the FDA.
While Bates and Gilchrist may still object to our assertions that PMI’s intent in publishing their statement was to promote IQOS using EVALI, this objection contrasts with public statements PMI executives have made that are perhaps even clearer in their intent. For example, a Wall Street Journal article began “tobacco giant Philip Morris International Inc. says vaping fears in the U.S. should give a boost to the recent launch of its IQOS smoking alternative” and cited PMI executives discussing how EVALI could be a boon for IQOS promotion just days after PMI published the materials we studied (6).
Bates and Gilchrist may similarly still object that other events (such as the failed merger talks between Altria and PMI (7)) may be responsible for news coverage of IQOS and EVALI. However, generating earned media about an issue is not a one-shot game. Any public relations expert could attest that a multi-modal strategy is required to get an issue in the news media agenda including a media statement, follow-up interviews, case studies, activations, integrations, etc.
Our assertion is that the EVALI outbreak was used by PMI as part of an overall strategy to promote IQOS - a fact we discovered in our Industry Watch piece. For example, the Irish Times reported that PM had called off merger talks with Altria, “…after it became apparent the US government crackdown on vaping could have a negative impact given Altria’s stake in Juul.” André Calantzopoulos, PMI’s chief executive, said that they had decided to focus on its launch of IQOS, which was not a vaping product (8) --thereby again leveraging EVALI to promote its new product.
We echo our previous call for the FDA to investigate the statement PMI published and subsequent news coverage for compliance and if a violation has occurred appropriate regulatory actions be taken. We call on the tobacco control community to invest in surveillance of industry speech and research on the potential impacts of industry speech that can inform additional regulations governing marketing channels such as websites, online news sources and other digital media.
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Thank you for the corrections and for acknowledging the omission. The additional analysis performed by ITC is greatly appreciated and provides further insight into the impact of both interventions. Although unstated, Canada’s regional characterizing flavour bans contributed significantly to the development of a national menthol additive ban as chronicled by the U.S. Tobacco Control Legal Consortium . I look forward to reading the full analysis when published.
1. Kerry Cork, Tobacco Control Legal Consortium, Leading from Up North: How Canada Is Solving the Menthol Tobacco Problem (2017). https://www.publichealthlawcenter.org/sites/default/files/resources/tclc...
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Reducing smoking rates in older smokers will achieve a far greater reduction in deaths & disease and do this much earlier than reducing already much lower smoking rates in teens & young populations. Tobacco harm reduction (THR) options, such as vaping, Heated Tobacco Products (HTP), snus & nicotine pouches, all avoid inhalation of smoke from tobacco combustion and are less risky than smoking cigarettes which are responsible for the death of more than 50% of long term smokers. Cigarette sales in Japan declined by over 40% in five years after HTPs entered the Japanese market in 2016. There are now many other examples of other THR options substituting for deadly cigarettes in other countries.
New drug harm reduction interventions usually face fierce opposition for many years after their introduction. Needle syringe programs to reduce HIV spread among and from people who inject drugs were still strongly resisted long after the evidence for their effectiveness, safety and cost effectiveness was incontrovertible. It is not surprising to me therefore, as a veteran of many battles over new drug harm reduction interventions, to observe the acrimonious debate over THR.
If it is made easy for older smokers to switch to THR options, the benefits will not only be an acceleration in the decline of smoking related deaths and disease, but also a more rapid decline in cigarette sales.
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In his comment, Les Hagen brings up an important distinction between two types of restrictions on menthol: a menthol additive ban, and a menthol characterizing flavour ban. Canada's menthol ban across the provinces did indeed involve both types. Between May 2015 and July 2017, Nova Scotia, Alberta, Quebec, Ontario, Prince Edward Island, and Newfoundland & Labrador implemented characterizing flavour bans, whereas New Brunswick implemented a menthol additive ban . When the Federal Government implemented a menthol additive ban in October 2017  , it applied only to the remaining provinces—British Columbia, Saskatchewan, Manitoba—as well as Nunavut, Yukon, and the Northwest Territories. Thus, the "menthol cigarette ban" in Canada is a mixture of the two types.
Our article  evaluated the impact of menthol bans implemented between the 2016 and 2018 waves of the Canadian arm of the ITC Four Country Smoking and Vaping Surveys. Hagen incorrectly stated that "the analysis was performed exclusively on provincial characterizing flavour bans." In fact, the provinces evaluated in our study included both those that implemented characterizing flavour bans (Quebec, Ontario, Prince Edward Island, Newfoundland & Labrador) and those that implemented the Federal menthol additive ban (British Columbia, Saskatchewan, Manitoba).
In our original study, we did not test for differences between the two kinds of bans, beca...
In our original study, we did not test for differences between the two kinds of bans, because the number of menthol smokers across the seven provinces in our evaluation study was low (N=138). However, we did report that there were no statistically significant differences in smoking cessation outcomes between menthol and non-menthol smokers across the seven provinces, consistent with the possibility that there were no differences between a characterizing flavour ban and an additive ban. Hagen's comment did prompt us to do the explicit analysis, comparing the four provinces with characterizing flavour bans to the three provinces with menthol additive bans.
Consistent with our previously reported findings of no differences across the seven provinces, the explicit comparison found no significant differences in smoking cessation outcomes among daily and among all smokers between menthol smokers and non-menthol smokers in provinces with menthol additive bans vs provinces with menthol characterizing flavour bans. Thus, the findings do indeed, as Hagen aimed to highlight, point to the positive impact of the characterizing flavour ban, being not different from that of the national menthol additive ban ─ with the caution that the small sample sizes afforded low statistical power to test for differences.
Our follow-up analysis also showed that a significantly higher percentage of pre-ban menthol smokers reported that they still smoked menthols at follow-up in provinces with menthol characterizing flavour bans, compared with provinces with menthol additive bans (25.3% vs 8.4%, p=0.02). We will describe these results more fully in a forthcoming paper.
There are complexities in the distinctions between a characterizing flavour ban and an additive ban. Each would call upon different kinds of regulatory oversight. For example, the European Union's characterizing flavour ban under the 2016 Tobacco Products Directive  required the establishment of an Independent Advisory Panel to determine whether a particular tobacco product has a characterizing flavour, with input from a technical group of sensory and chemical assessors, whose methodology is "based on a comparison of the smelling properties of the test product with those of reference products."  In contrast, regulating an additive ban requires product testing to determine the presence of a banned additive.
As jurisdictions consider measures to eliminate the well-documented impact of menthol in increasing attractiveness and reducing harshness of combustible tobacco products , these differences in regulatory capacity need to be considered.
1. Canadian Cancer Society. Overview summary of federal/provincial/territorial tobacco control legislation in Canada, 2017. Available: http://convio.cancer.ca/documents/Legislative_Overview-Tobacco_Control-F...
2. Government of Canada. Order amending the schedule of the tobacco act (menthol), 2017. Available: http://www.gazette.gc.ca/rp-pr/p2/2017/2017-04-05/html/sor-dors45-eng.php
3. Chung-Hall J, Fong GT, Meng G, et al. Evaluating the impact of menthol cigarette bans on cessation and smoking behaviours in Canada: longitudinal findings from the Canadian arm of the 2016–2018 ITC Four Country Smoking and Vaping Surveys. Tobacco Control Published Online First: 05 April 2021. doi: 10.1136/tobaccocontrol-2020-056259
4. European Parliament and the Council of the European Union. Directive 2014/40/ EU. Off J Eur Union 2014. Available: https://ec.europa.eu/health/sites/health/files/tobacco/docs/dir_201440_e...
5. European Commission. Technical Group of sensory and chemical assessors. Available: https://ec.europa.eu/health/tobacco/products/characterising_flavours/tec...
6. Tobacco Products Scientific Advisory Committee. Menthol cigarettes and public health: review of the scientific evidence and recommendations. Rockville, MD: Food and Drug Administration, 2011.
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We thank Pesko for his comments and the opportunity for us to respond and clarify.
First, we appreciate Pesko’s clarification that Cotti et al. (2020) clustered standard errors to account for clustering. In the present study, we used multilevel analysis not only to account for clustering of respondents (i.e., design effects) but also to incorporate different error terms for different levels of the data hierarchy which yields more accurate Type I error rates than nonhierarchical methods where all unmodeled contextual information ends up pooled into a single error term of the model.
Second, we understand that Cotti et al. (2020) evaluated the magnitude of e-cigarette tax values, which does not contradict to our statement because our study focused on the effects of e-cigarette excise tax policies on individual e-cigarette use and prevalence rather than aggregated sales at state or county levels. We also clearly described the reason why we examined the e-cigarette excise tax policy implementation indicator rather than its magnitude in our paper’s discussion section.
Third, our study used a nationally representative sample of young adults (rather than a nationally representative sample of general adult population). While we understand Pesko’s concern that a sample’s representativeness might be lost when subgroups are explored, we believe our use of sampling weights in analysis has reduced such a concern.
Fourth, in Table 3,...
Fourth, in Table 3, please note that vaping product excise tax policy indicator is a time-variant variable in Model 1. However, to present results of a standard difference-in-differences model with a binary indicator, the policy implementation status was operationalized as a time-invariant variable in Model 2, which is not unusual.
Disclosure: We did not receive any funding from the tobacco industry.
1. Cotti, C. D., Courtemanche, C. J., Maclean, J. C., Nesson, E. T., Pesko, M. F., & Tefft, N. (2020). The effects of e-cigarette taxes on e-cigarette prices and tobacco product sales: evidence from retail panel data. National Bureau of Economic Research. NBER Working Paper No. w26724.
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 ci...
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.
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.
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I have a number of concerns with the paper as currently written.
1) The authors write: “Besides, none of the previous studies except Pesko et al (15) that examined the associations between vaping product excise tax adoption and ENDS use has accounted for the clustering of respondents within the same localities…” This is not accurate, as citation 19 also clusters standard errors at the locality level in all specifications.
2) The authors write: "A working paper reported reduced ENDS sales, but not ENDS use prevalence or behaviours, after implementation of a vaping product excise tax policy. (19)” This is not accurate, as the cited study uses the magnitude of e-cigarette tax values, rather than an indicator variable for tax implementation. States have adopted e-cigarette taxes of different magnitudes and a number of them (such as California) have changed the magnitudes of these taxes after adoption. All of this variation is used in citation 19, contrary to the current study’s description. It's also unclear from the sentence whether citation 19 studied use and found imprecise estimates, or did not study use. It's the latter and this should be clarified. It's also unclear why the authors did not use magnitude of e-cigarette taxes themselves in the current paper, as has been commonly done in the referenced literature.
3) Authors write they use a “nationally representative sample of US young adults.” I do not beli...
3) Authors write they use a “nationally representative sample of US young adults.” I do not believe this is not accurate. The TUS-CPS sample itself may be nationally representative, but this representativeness may be lost when subgroups are explored.
4) The “vaping product excise tax policy” variable in Table 3 appears to be re-defined mid-table. Based on the discussion of the results, in column 1 it appears that this variable is an indicator equal to 1 only at the time when a state has an e-cigarette tax in place. In column 2 though, this indicator equals 1 when a state ever has an e-cigarette tax in place (even prior to it being in place). The use of the same row for a variable that changes across columns is unusual and can easily lead to the wrong interpretation.
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This article does not distinguish between characterizing flavour (menthol) bans that were implemented in Canadian provinces between 2015 and 2017 and the implementation of a national ban on menthol additives in Canada in October 2017. Although unreported, the analysis was performed exclusively on provincial characterizing flavour bans. This significant distinction should be reported to ensure that researchers and policy makers are aware of the potential impact of a characterizing flavour ban and to ensure that this policy measure is not dismissed or discounted.