Peer Review History
| Original SubmissionJanuary 27, 2026 |
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-->PONE-D-26-02685-->-->Changes in tobacco sales before, during, and after the COVID-19 pandemic in Japan: an interrupted time series analysis-->-->PLOS One Dear Dr. Kondo, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by May 25 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript:-->
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Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. --> Reviewer #1: Partly Reviewer #2: Partly ********** -->2. Has the statistical analysis been performed appropriately and rigorously? --> Reviewer #1: Yes Reviewer #2: No ********** -->3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.--> Reviewer #1: Yes Reviewer #2: Yes ********** -->4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.--> Reviewer #1: Yes Reviewer #2: Yes ********** -->5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)--> Reviewer #1: The authors used several data sources to provide evidence on changes in cigarette sales and smoking in Japan before and after the COVID-19 pandemic. The authors found increases in cigarette sales and purchase after the pandemic compared to the pre-pandemic levels and trends. There are some major and minor concerns (not listed in order) that need to be considered. 1. Can you explain the data clearly, providing detailed information on what is available and how you used it in your analysis? 2. Model specification: I am not sure about the controls in the model, but the model should account for seasonality. For example, quarterly or monthly FE should be included in the models to account for seasonality. I suggest writing a formal model and defining terms. 3. Lines 104 to 106: Cite methodological studies that presented this approach as valid and how they are interpreted. Here is one of such studies: https://journals.sagepub.com/doi/abs/10.1177/00131640021970358 4. From Figure 1 and the results reported in Table 1, it is clear that the increase was not temporary. The effect of the pandemic on cigarette sales is a permanent change in the rate of decline, which lasted through 2024. I am not sure about how this was described as temporary. That change in slope never went away throughout the sample period. In Figure 2, we see a permanent shift in the level after the onset of the pandemic. That gap between the expected (counterfactual) and actual trends, although diminishing over time, persisted and even widened after May 2023. 5. Lines 205 – 207: Should be in the intro before setting up the hypothesis. 6. Line 217: Again, I don't know why the authors claim there was a temporary increase. You moved up to a different intercept and continued with the same trend. Levels never shifted to the original, so how is that temporary? It was a rather permanent increase in the level. 7. The figure title and captions in the text are more confusing and make reading difficult to distinguish. Add “Note:” to figure captions. Reviewer #2: This paper uses segmented interrupted time series (ITS) models to analyze three national-level data sources (cigarette sales, household tobacco expenditures, and smoking prevalence) to examine how the COVID-19 pandemic affected smoking behavior in Japan. The authors report that the declining trend in cigarette sales decelerated after the first state of emergency (April 2020) and household tobacco expenditures spiked by approximately 19%, but smoking prevalence did not meaningfully change. The topic is policy-relevant, and the multi-data-source design is a strength. However, there are several concerns that should be addressed. 1. Autocorrelation and seasonality. Monthly and quarterly time-series data are expected to exhibit autocorrelation, and tobacco purchasing has well-documented seasonal patterns. Standard OLS-based segmented regression will produce incorrect standard errors and p-values if autocorrelation is not addressed. The manuscript mentions that only in the limitations section as a caveat, rather than having it tested or corrected. Seasonality was likewise not modeled. I recommend the authors account for autocorrelation and seasonality adjustments, and provide standard diagnostic tests (e.g., Durbin-Watson statistic, Ljung-Box test) for the residuals. 2. Absence of sensitivity analyses. There is no exploration of alternative model specifications, for example, different polynomial functions (now is all assumed linear). ITS results can be sensitive to polynomial choices. 3. Overstatement of conclusions relative to the data. The abstract and conclusion state that "smoking behavior among smokers appeared to intensify" and that these effects "persisted beyond May 2023." Neither claim is adequately supported by the data results. First, the sales/expenditure variables measure purchasing, not consumption. The authors themselves acknowledge that "these data cannot distinguish stockpiling from a true increase in cigarettes consumed per smoker," yet the abstract and conclusion reassert the intensification interpretation. Second, the "persistence" claim rests on a non-significant result at the second intervention point. This is a type II error concern: the non-significant estimate reflects absence of evidence, not evidence of persistence. I recommend the authors revise the abstract and conclusions to focus on changes in sales/purchasing patterns (even just to be more consistent with your title), with the “intensifying” and “persistence” interpretations discussed just as possibilities rather than conclusive findings. 4. The 153 JPY increase is translated to a ~19% rise, but the pre-treatment average of 800 JPY is calculated across all households with two or more members, even including non-smoking households. To aid interpretation, the authors should report (or estimate from published data) what fraction of Japanese households include a current smoker. This would allow readers to gauge the approximate per-smoker-household effect. Additionally, since it also excludes single-person households, the authors should note what proportion of Japanese households are single-person (e.g., approximately 38% as of the 2020 Population Census of Japan) and discuss how this exclusion may affect generalizability. Particularly, single-person households may have very different smoking patterns. 5. The authors note that heated tobacco products (HTPs) are excluded from the analysis, though its revenue now represents approximately 80% of conventional cigarette revenue in Japan, a substantial market shift occurring over the study period. If smokers transitioned between cigarettes and HTPs during the pandemic, the observed changes in the cigarette sales/expenditure could be partially attributable to cross-product substitution. I know that the authors cite one Osaka survey showing low switching rates (2.2%), but this is limited evidence from a single city during a short window and cannot be generalized to the national level over a longer time period. This limitation should be discussed more prominently and explicitly acknowledged as a potential confounder in the ITS results, rather than treated as a secondary limitation. 6. The NDB Open Data include only adults aged 40+, excluding younger adults (i.e., 20–39), a demographic likely with very different tobacco use patterns and pandemic-related behavioral changes compared to older adults. In Japan, smoking prevalence among younger men has historically been higher than among older age groups, and younger adults may be more responsive to social and environmental changes. This limitation is mentioned only briefly; it should be more explicitly flagged when interpreting the prevalence trends, and the authors should discuss the direction in which this exclusion might bias their findings. ********** -->6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.--> Reviewer #1: No Reviewer #2: No ********** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation. NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications. |
| Revision 1 |
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<p>Changes in tobacco sales before, during, and after the COVID-19 pandemic in Japan: an interrupted time series analysis PONE-D-26-02685R1 Dear Dr. Kondo, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Fabrizio Ferretti, Ph.D. Academic Editor PLOS One Additional Editor Comments (optional): Reviewers' comments: |
| Formally Accepted |
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PONE-D-26-02685R1 PLOS One Dear Dr. Kondo, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS One. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Fabrizio Ferretti Academic Editor PLOS One |
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