PONE-D-19-34389

Associations between sleep duration and insulin resistance in European children and adolescents considering the mediating role of abdominal obesity

PLOS ONE

Dear Dr. Ahrens,

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Domenico Tricò, M.D.

Academic Editor

PLOS ONE

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Additional Editor Comments (if provided):

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. 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: 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?

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

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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

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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 paper by Thumann et al. analyzed the association between sleep duration and visceral obesity and insulin resistance. To this end, they longitudinally evaluated 3900 children aged 2-15 years. Waist circumference was used as expression of visceral adiposity, whereas HOMA-IR as measure of insulin resistance. Furthermore, they tested the direct and indirect effects of sleep on insulin resistance. The title and abstract are appropriate for the content of the text. Furthermore, the article is well constructed, the analysis was well performed, and the results are clearly presented.

Reviewer #2: In this study, the authors aimed to investigate the potential mediating role of abdominal obesity (waist circumference measurement) in the association between nocturnal sleep duration (measured by patient/parent report on questionnaire) and insulin resistance (HOMA-IR) in a cohort of children and adolescents. Their results do not support an association between short sleep duration and insulin resistance independent of abdominal obesity, in both cross-sectional and longitudinal analyses.

The study explores an interesting topic in a large pediatric population. Strengths of the study include (1) the large sample size and (2) the inclusion of both cross-sectional and longitudinal analyses. Also, the investigators performed appropriate sensitivity analyses.

Major Comments:

1) Analyses are based on a subjective measure of sleep duration (patient/parent report on questionnaire). This is a major limitation of the study that can affect reproducibility and the quality of the data. While given the large sample size, it would not be feasible to have performed more objective measures of sleep duration, the authors should elaborate more in the discussion section on how their measure of sleep duration may differ from the gold standard, and how this may impact results and their interpretation.

2) They use surrogate markers for insulin resistance (HOMA) and visceral fat (waist circumference). These markers although widely used are not very accurate and the authors need to discuss that.

3) The definition of puberty is not appropriate because 1) is self-reported and 2) for girls is based on menarche and for boys defined as change in voice. These phenomenon occur 2-3 years after puberty has started. Therefore, the investigators cannot really use puberty as a variable in the study neither they can draw any conclusions on the effect of puberty on the studied phenomenon.

4) The z-scores were based on their group of patients, rather than on larger healthy population.

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Reviewer #1: No

Reviewer #2: No

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PONE-D-19-34389R1

Associations between sleep duration and insulin resistance in European children and adolescents considering the mediating role of abdominal obesity

PLOS ONE

Dear Ms. Thumann,

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.

The manuscript has been evaluated by one of the original reviewers who raised concerns in the first round of review. According to our editorial policy,  it has been also examined by a biostatistician, whose comments were overall positive and are reported below. Please address his comments by providing more information on HOMA z-score and possibly by moving some relevant data from the supplements to the main manuscript. 

We would appreciate receiving your revised manuscript by Jun 28 2020 11:59PM. When you are 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.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

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

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Domenico Tricò, M.D.

Academic Editor

PLOS ONE

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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 #2: All comments have been addressed

Reviewer #3: (No Response)

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2. 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 #2: Yes

Reviewer #3: (No Response)

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

Reviewer #2: Yes

Reviewer #3: (No Response)

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4. 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 #2: Yes

Reviewer #3: (No Response)

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5. 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 #2: Yes

Reviewer #3: (No Response)

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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 #2: Thank you for addressing all comments thoroughly particularly with regard to limitations of the study.

Reviewer #3: Important note: This review pertains only to ‘statistical aspects’ of the study and so ‘clinical aspects’ [like medical importance, relevance of the study, ‘clinical significance and implication(s)’ of the whole study, etc.] are to be evaluated [should be assessed] separately/independently.

Happy to note that HOMA-IR was standardised according to age and sex (HOMA z-score) [as a Biostatistician I would like you add in brief ‘how done and what effect’]. Since separate reference curves were estimated for HOMA-IR depending on the assessment method used, little more on this would have been appreciated, I guess. How about adding few diagrams (showing ‘path’ including mediating role of abdominal obesity)? [I see that there is lot of material in supplementary files, can some be in main?].

Otherwise the study is absolutely faultless and manuscript/draft of this article communicates the efforts well.

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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.

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 #2: No

Reviewer #3: Yes: Dr. Sanjeev Sarmukaddam

[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 be viewed.]

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Attachments

Attachment

Submitted filename: renamed_5094f.docx

Associations between sleep duration and insulin resistance in European children and adolescents considering the mediating role of abdominal obesity

PONE-D-19-34389R2

Dear Dr. Thumann,

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.

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Kind regards,

Domenico Tricò, M.D.

Academic Editor

PLOS ONE