PGPH-D-22-00825

Variation in the Incidence of Type 1 Diabetes Mellitus In Children and Adolescents by World Region and Country Income Group: A Scoping Review

PLOS Global Public Health

Dear Author,

Thank you for submitting your manuscript to PLOS Global Public Health. After careful consideration, we feel that it has merit but does not fully meet PLOS Global Public Health’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 review the feedback from the reviewers.  The revisions are minor and we welcome a resubmission of your manscript.

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Revisions required:

On page 16, paragraph 1, the authors start the sentence by “What explains the wider variability…”- while there is no harm starting the paragraph with a question, the sentence structure here is poorly done. Authors may need to restructure.

Also, while authors mention that access to healthcare in high income countries is key in timely diagnosis of T1D, and that strengthened healthcare system etc is important in ensuring access to data, authors need to expound further why lack of these two is an impediment in getting accurate or timely information on the T1D incidence in many LMICs.

I like how the author speculate that it may be possible that many children die earlier in SSA before diagnosis. Can authors build up on this and add relevant references.

Also, authors have associated lifestyle changes and obesity cases with T1D in developed countries. However, we know that under nutrition as well as eating unhealthy diets and physical inactivity are major issues contributing to NCDs in LMIC today. Can the author substantiate on this by comparing developed and developing countries?

Authors have mentioned few policy implications for this work. I feel this study is very important and authors should add a paragraph or so on the research implications especially in African countries. Also, we know that LMIcs are lagging behind in terms of research, databases, and data sharing principles. What need to be done?

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Please submit your revised manuscript by 31st August 2022. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at globalpubhealth@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pgph/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

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,

Kate Frazer

Academic Editor

PLOS Global Public Health

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6. 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):

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does this manuscript meet PLOS Global Public Health’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: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

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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: No

Reviewer #2: Yes

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

PLOS Global Public Health 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: Dear Authors,

This study is a scoping literature review on the incidence of type 1 diabetes in children, adolescents, and young adults (0-25 years) worldwide and explains the wide heterogeneity in incidence rates that differ by age, sex, world region, and country income classification. I took keen interest to read through this important study , which I find to be timely especially given that incidences of T1D globally and in SSA are not well documented. The authors did a great job in categorizing their analysis and results in terms of region, age etc and also used the IDF age classification to conduct their analysis. Findings from this study are important not only to readers of Plos GPH, but also scientists, policy makers and other stakeholders interested in the field of diabetes broadly and T1D specifically.

The introduction section is well summarized and the gap is well stated. However, authors should ensure that they include relevant references where necessary. For example, paragraph 1, after LMIC, authors should add a reference.

The methodology section is well explained. The authors have followed key steps of scoping review and processes of the scoping review are well presented. This study can easily be replicated by other researchers.

Results and discussion: these sections are presented in a logical fashion. The presentation is also easier to understand. Statistics and presentations are well done .

Overall, the writing style is good and in standard English. The language is consistent, short and meaningful paragraphs that makes it easy for the reader to follow the narrative.

I have few things that the may consider correcting to strengthen their manuscript:

On page 16, paragraph 1, the authors start the sentence by “What explains the wider variability…”- while there is no harm starting the paragraph with a question, the sentence structure here is poorly done. Authors may need to restructure.

Also, while authors mention that access to healthcare in high income countries is key in timely diagnosis of T1D, and that strengthened healthcare system etc is important in ensuring access to data, authors need to expound further why lack of these two is an impediment in getting accurate or timely information on the T1D incidence in many LMICs. I like how the author speculate that it may be possible that many children die earlier in SSA before diagnosis. Can authors build up on this and add relevant references.

Also, authors have associated lifestyle changes and obesity cases with T1D in developed countries. However, we know that under nutrition as well as eating unhealthy diets and physical inactivity are major issues contributing to NCDs in LMICs today. Can the author substantiate on this by comparing developed and developing countries?

Authors have mentioned few policy implications for this work. I feel this study is very important and authors should add a paragraph or so on the research implications especially in African countries. Also, we know that LMICs are lagging behind in terms of research, databases, and data sharing principles. What need to be done?

Reviewer #2: I thank the authors for sharing their work for publication.

In the present study, the authors have attempted to assess the Type 1 Diabetes Mellitus Incidence in Children and Adolescents Variation by World Region and Country Income Group. The review concludes T1D incidence rates vary significantly by geographic region, country economic level, and age.

Overall the study offers an important piece of information.

1. The title properly reflects the subject of the paper.

2. The abstract is short, accurate and clear. It provides an accessible summary of the paper.

3. The keywords accurately reflect the content.

4. Introduction is well written and Summarizes recent research related to the topic

5. The methods are replicable and follows the best practice standards

6. The result seems plausible and the study provides sufficient data, clear data tables and non-contradictory data that agree with the conclusions.

7. The referencing is accurate, adequate and balanced.

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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.

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.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PGPH-D-22-00825R1

Variation in the Incidence of Type 1 Diabetes Mellitus In Children and Adolescents by World Region and Country Income Group: A Scoping Review

PLOS Global Public Health

Dear Dr. Gomber,

Thank you for submitting your manuscript to PLOS Global Public Health. After careful consideration, we feel that it has merit but does not fully meet PLOS Global Public Health’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 October 11 of 2022. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at globalpubhealth@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pgph/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

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,

Claudio A. Mendez, MPH

Academic Editor

PLOS Global Public Health

Journal Requirements:

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):

[Note: HTML markup is below. Please do not edit.]

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 Global Public Health’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: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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

**********

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

PLOS Global Public Health 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: The authors have addressed all my questions. The manuscripts is well written and additional information added in text has made the manuscript stronger. Well done to this important work.

Reviewer #2: The manuscript has been improved, and all comments have been taken into account. I send my best wishes for publication.

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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: Yes: Edna N Bosire

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.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Variation in the Incidence of Type 1 Diabetes Mellitus In Children and Adolescents by World Region and Country Income Group: A Scoping Review

PGPH-D-22-00825R2

Dear Dr. Gomber,

We are pleased to inform you that your manuscript 'Variation in the Incidence of Type 1 Diabetes Mellitus In Children and Adolescents by World Region and Country Income Group: A Scoping Review' has been provisionally accepted for publication in PLOS Global Public Health.

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

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.

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

Best regards,

Claudio A. Mendez, MPH

Academic Editor

PLOS Global Public Health