PCLM-D-25-00486

The impact of extreme temperatures on respiratory mortality in Brazil: evaluating regional adaptations to different thermal environments

PLOS Climate

Dear Dr. G. Coelho,

Thank you for submitting your manuscript to PLOS Climate. After careful consideration, we feel that it has merit but does not fully meet PLOS Climate’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 15th February 2026. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at climate@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pclm/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

We look forward to receiving your revised manuscript.

Kind regards,

Teodoro Georgiadis

Academic Editor

PLOS Climate

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Additional Editor Comments (if provided):

The reviewers found the article to be of interest in terms of its general topic, but one of them made several comments regarding its structure and methodology. The reviewer clearly indicated the steps that the authors need to take to improve their manuscript and bring it up to the level of quality required for publication. I believe that the authors can make this additional effort to achieve this level of quality, and I suggest a major revision.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does this manuscript meet PLOS Climate’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #2: No

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: No

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3. Have the authors made all data underlying the findings in their manuscript fully available (please refer to the Data Availability Statement at the start of the manuscript PDF file)?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception. 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

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS Climate 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

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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 article analyzes the relationship between ambient temperature and respiratory mortality in 520 Brazilian municipalities (2010–2020), addressing the lack of national data for tropical climates. It applies DLNM models and meta-analysis, identifying a U-shaped association with increased risks for both cold and heat, accounting for 2.89% of deaths attributable to non-optimal temperatures.

The study is notable for its methodological rigor and the robustness of its sample (over one million deaths). The inclusion of race/ethnicity as a variable reveal that Black populations are more vulnerable to heat, while the “cold paradox” observed in warmer regions (North/Northeast) provides an original and impactful contribution to climate adaptation policies.

I suggest the following recommendations for improvement:

1. Increase the number of references to at least 40 to strengthen the analysis, justify the study’s relevance, and enable comparisons with previous research. Consider discussing methodological differences to support the choice of comparing mortality data with mean temperatures.

2. Specify the temperature threshold defined as “cold” in the context of the “cold paradox” in warm regions. A climate classification table based on existing literature is recommended.

3. Maintain third-person narrative for a more formal academic tone. If first-person is used, restrict it to expressing opinions on specific references.

4. Clarify how missing data were handled. The text mentions selection based on “data completeness” but does not explain how missing days were addressed (e.g., linear interpolation or exclusion). Indicate the threshold for gaps (e.g., <10%) and whether interpolation or reanalysis data (such as ERA5) were used. Add a sentence specifying whether days with gaps were excluded or imputation techniques applied.

5. Explicitly state the software used in the analysis. Although R packages (dlnm, mvmeta) are mentioned, the use of R should be clearly indicated in the methodology.

6. Explain why arithmetic means were chosen instead of maximum and minimum values, as this may obscure biologically relevant variations. Include in the Discussion or Limitations the potential impact of thermal amplitude, since the daily mean can be identical for a day with constant temperature and for a day with a sudden cold front. The human body responds differently to persistent cold versus thermal shock. Using the mean may underestimate the intraday variability effects on respiratory mortality.

7. Enrich the discussion with more detailed information on housing infrastructure in the North and Central-West regions to better explain the regional risks observed.

8. Provide a climate classification table for each region, either in the main text or as supplementary material. This addition would enhance the article’s value and increase its potential for future citations.

The study is robust and of high quality, suitable for public health purposes, as INMET follows World Meteorological Organization (WMO) standards. The use of mean temperature is consistent with standard practice in the literature (Gasparrini et al.), as it better represents continuous thermal exposure over 24 hours than isolated peaks of heat or cold. However, this rationale should be explicitly stated in the text.

Reviewer #2: The study has conducted a comprehensive nationwide assessment on temperature-driven respiratory mortality in Brazil, the idea of this research study is good, but the manuscript reported the study like a laboratory experiment report and not comprehensively enough to be published. Below, I have some concerns and questions about result findings and discussion part of this study. The major problem of the manuscript is about the organization and depth of scientific investigation. Please see the following comments to re-structure and improve the manuscript with more in-depth analysis and discussion on the relationships between extreme temperatures and respiratory mortality.

(1) For Exposure and outcome definitions (Line 100), can authors explain why choosing 10th and 90th percentiles of temperature distribution as the extreme cold or hot situations? Are there any sensitivity experiments between the selection of percentiles?

(2) Please elaborate and further explain what secondary, de-identified administrative data were used in the analysis, and how the involvement contribute or improve the data competency of your study? (Session “Patient and public involvement”)

(3) For line 148 to 150: “The Southeast region contributed the largest share of deaths. Mean temperatures ranged from 20.5°C in the South to 26.8°C in the North and Northeast”, what are the linkage and relationships between the annual mortality / death rate and climatology described here? If authors would like to provide more demographic and climatological information about the study area, please try to separate the (1) mortality and (2) climatology information, and provide further details instead of just a sentence of mean temperature.

(4) Many discussion sections are discontinuous and fragmented, and each sub-topic only have several sentences with vague and general explanations. It is like reading a laboratory report with many statistical values, but without much discussion and rationale explanations. Please re-organize the contents and provide more in-depth analysis and discussion in Results.

(5) Please make sure you are using the same and appropriate font type in the manuscript, many of the sentences were mixed with different font, which made the paragraphs very hard to read. For example, in Abstract (P.3), Session “Subgroup and sensitivity analyses (P.8)”, “Study population and descriptive characteristics (P.10)”, “Subgroup analyses (P.11)” and “Strengths and limitations (P.14).

(6) Please improve the connecting sentences between different sections, and re-organize the content.

(7) Please increase the font size for figures.

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Reviewer #1: No

Reviewer #2: No

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Figure Resubmissions:

While revising your submission, we strongly recommend that you use PLOS’s NAAS tool (https://ngplosjournals.pagemajik.ai/artanalysis) to test your figure files. NAAS can convert your figure files to the TIFF file type and meet basic requirements (such as print size, resolution), or provide you with a report on issues that do not meet our requirements and that NAAS cannot fix.

After uploading your figures to PLOS’s NAAS tool - https://ngplosjournals.pagemajik.ai/artanalysis, NAAS will process the files provided and display the results in the "Uploaded Files" section of the page as the processing is complete. If the uploaded figures meet our requirements (or NAAS is able to fix the files to meet our requirements), the figure will be marked as "fixed" above. If NAAS is unable to fix the files, a red "failed" label will appear above. When NAAS has confirmed that the figure files meet our requirements, please download the file via the download option, and include these NAAS processed figure files when submitting your revised manuscript.

PCLM-D-25-00486R1

The impact of extreme temperatures on respiratory mortality in Brazil: evaluating regional adaptations to different thermal environments

PLOS Climate

Dear Dr. Coelho,

Thank you for submitting your manuscript to PLOS Climate. After careful consideration, we feel that it has merit but does not fully meet PLOS Climate’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 10th March. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at climate@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pclm/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

We look forward to receiving your revised manuscript.

Kind regards,

Teodoro Georgiadis

Academic Editor

PLOS Climate

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments (if provided):

The reviewers asked only for a readability of the figures and some minor issues on the text. After the completion of these issues the paper will be worthy of publication.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Does this manuscript meet PLOS Climate’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available (please refer to the Data Availability Statement at the start of the manuscript PDF file)?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception. 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

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS Climate 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

**********

6. 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: This study provides a comprehensive national assessment of temperature-attributable respiratory mortality in Brazil, based on more than one million deaths. The methodological framework—using a two-stage DLNM approach combined with multivariate meta-analysis—is rigorous and aligned with the most advanced practices in environmental epidemiology. A notable strength is the focus on daily mean temperature rather than solely on extreme heat events, allowing the quantification of the sustained health burden associated with non-optimal thermal exposure. The sensitivity analysis incorporating minimum and maximum temperatures further reinforces the robustness of the chosen temperature metric.

I suggest 4 points for Improvement

1. Although the study follows an ecological design, the Discussion could more explicitly address how socioeconomic conditions modulate vulnerability to temperature-related health impacts. It would be valuable to expand the explanation of how precarious housing—characterized by insufficient thermal insulation, poor ventilation, and indoor dampness—may intensify the association between temperature and respiratory mortality, particularly in the North and Northeast. Limited access to primary healthcare services should also be acknowledged as a relevant factor. These pathways should be highlighted as priorities for future research employing individual-level data.

2. The rationale for using daily mean temperature should be stated more clearly. It would be helpful to emphasize that this metric captures continuous physiological stress on the respiratory system and reflects the cumulative burden of thermal exposure over 24 hours, which often poses a greater public health impact than isolated extreme events.

3. Regarding the instability reported for the Minimum Mortality Temperature (MMT) in the Center West region, the Discussion would benefit from a concise explanation. Possible contributing factors include reduced thermal variability or limitations related to the density and uniformity of available data. Introducing such hypotheses would help readers better interpret the regional inconsistencies.

4. The conclusion could be strengthened by recommending avenues for future studies that integrate environmental exposures with social and behavioral determinants. Such work might explore interactions between thermal stress, air pollution, housing conditions, and lifestyle factors (including the use of solid fuels), thereby offering a more comprehensive understanding of respiratory risks in tropical climates.

Reviewer #2: The authors had attempted to address the concerns raised in the first reviewing process, and efforts could be observed on reorganizing the whole manuscript to improve the readability. However, the figures are still in a very low resolution, and there is no indication for Figure numbers, which is difficult for readers to follow with the illustrations. Some sessions in the manuscript are still using non-standard text, please make sure the standardization of the whole content.

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7. 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.

Do you want your identity to be public for this peer review? If you choose “no”, your identity will remain anonymous but your review may still be made public.

For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

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[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.]

Figure Resubmissions: While revising your submission, we strongly recommend that you use PLOS’s NAAS tool (https://ngplosjournals.pagemajik.ai/artanalysis) to test your figure files. NAAS can convert your figure files to the TIFF file type and meet basic requirements (such as print size, resolution), or provide you with a report on issues that do not meet our requirements and that NAAS cannot fix.

After uploading your figures to PLOS’s NAAS tool - https://ngplosjournals.pagemajik.ai/artanalysis, NAAS will process the files provided and display the results in the "Uploaded Files" section of the page as the processing is complete. If the uploaded figures meet our requirements (or NAAS is able to fix the files to meet our requirements), the figure will be marked as "fixed" above. If NAAS is unable to fix the files, a red "failed" label will appear above. When NAAS has confirmed that the figure files meet our requirements, please download the file via the download option, and include these NAAS processed figure files when submitting your revised manuscript.

The impact of extreme temperatures on respiratory mortality in Brazil: evaluating regional adaptations to different thermal environments

PCLM-D-25-00486R2

Dear Mr Coelho,

We are pleased to inform you that your manuscript 'The impact of extreme temperatures on respiratory mortality in Brazil: evaluating regional adaptations to different thermal environments' has been provisionally accepted for publication in PLOS Climate.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow-up email from a member of our team.

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

IMPORTANT: The editorial review process is now complete. PLOS will only permit corrections to spelling, formatting or significant scientific errors from this point onwards. Requests for major changes, or any which affect the scientific understanding of your work, will cause delays to the publication date of your manuscript.

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 climate@plos.org.

Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Climate.

Best regards,

Teodoro Georgiadis

Academic Editor

PLOS Climate

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Additional Editor Comments (if provided):

The Authors have fully and satisfactorily replied to all the comments and suggestions proposed by the reviewers. The manuscript is worthy of publication

Reviewer Comments (if any, and for reference):