Dear Dr. Kelly,

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.

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We look forward to receiving your revised manuscript.

Kind regards,

Hidetaka Hamasaki

Academic Editor

PLOS ONE

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2. As required by our policy on Data Availability, please ensure your manuscript or supplementary information includes the following:

A numbered table of all studies identified in the literature search, including those that were excluded from the analyses.

For every excluded study, the table should list the reason(s) for exclusion.

If any of the included studies are unpublished, include a link (URL) to the primary source or detailed information about how the content can be accessed.

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All data extracted from each study for the reported systematic review and/or meta-analysis that would be needed to replicate your analyses.

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An explanation of how missing data were handled.

This information can be included in the main text, supplementary information, or relevant data repository. Please note that providing these underlying data is a requirement for publication in this journal, and if these data are not provided your manuscript might be rejected.

3.  Thank you for stating the following financial disclosure:

[R.L. and S.G are supported by PhD Studentships from the Department for the Economy, Northern Ireland.].

Please state what role the funders took in the study.  If the funders had no role, please state: ""The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.""

If this statement is not correct you must amend it as needed.

Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf.

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[R.L. and S.G are supported by PhD Studentships from the Department for the Economy, Northern Ireland.]

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[R.L. and S.G are supported by PhD Studentships from the Department for the Economy, Northern Ireland.].

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5. In the online submission form, you indicated that [The data underlying the results presented in the study are available from the corresponding author upon request (Dr Catriona Kelly, c.kelly@ulster.ac.uk).here].

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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?

Reviewer #1: Partly

Reviewer #2: Yes

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

Reviewer #1: N/A

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

Reviewer #1: No

Reviewer #2: Yes

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

Reviewer #1: No

Reviewer #2: Yes

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Reviewer #1: The manuscript is technically correct, methodologically rigorous, and uses correct statistical analyses.

No meta-analysis, cross-sectional data, and confounders left unexamined limit the strength of the inferences.

Most conclusions are backed by the data, but more work is required to validate some claims (like that obesity plays a role in lung function).

The manuscript could be improved (meta-analysis, confounding variables, and causal interpretations) if the authors clarify the limitations.

Outcome consistency is affected by heterogeneity among included studies (e.g., different methodologies, diagnostic criteria, and population characteristics). The reliance on cross-sectional studies (87 of 109 studies) precludes an established causal relationship.

This publishing goes against the findings from several previous studies showing how obesity is harmful with regard to lung function decline. The authors recognize this, but are not sufficiently clear about what might explain the difference.

The analysis may not fully adjust for confounding factors (e.g., smoking, medication use, disease duration). The trial does not descriptively assess for publication bias that may affect the reported findings.

Reviewer #2: The manuscript entitled “The role of obesity and Type 2 diabetes in lung health: A systematic review” focuses on the study of comorbidities, seeking to differentiate the role of different variables that the literature has indicated are associated. This systematic review concludes that type 2 diabetes, independently of the influence of obesity, significantly impairs lung function and proposes that periodic monitoring of lung function may be beneficial in this population.

This reviewer considers that the authors performed a careful review of the literature that justifies this research and followed a very careful methodology considering the PRISMA guidelines. Finally, the results and discussion are written in congruence with the objectives of the study.

Only two observations are made:

1. Review the first line of the introduction to ensure the wording “...Type 2 diabetes is due to microvascular and microvascular complications” is correct.

2. In the results section, subtitled “Association of Type 2 diabetes and/or obesity with lung function: Review of the literature”, it is mentioned “Initial analysis was performed on all studies...”. Please clarify the discrepancy between the total number of articles to be analyzed (109) and the breakdown of articles in this section (170).

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Reviewer #1: Yes: Anees Alyafei

Reviewer #2: No

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The role of obesity and Type 2 diabetes in lung health: A systematic review

PONE-D-25-07836R1

Dear Dr. Kelly,

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.

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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,

Hidetaka Hamasaki

Academic Editor

PLOS One

Additional Editor Comments (optional):

Thank you for submitting the revised manuscript.

I apologize for the delay in reaching a publication decision. As we did not receive a response from Reviewer 1, I carefully evaluated your replies to the reviewers myself. Many of your responses were incorporated as study limitations, and therefore they do not fully address all of the reviewers’ requests. However, given the inherent limitations related to the study design, these issues can only be discussed as limitations.

Overall, the manuscript is scientifically sound, and I am pleased to inform you that it has been accepted for publication. We hope that future studies will address the issue of heterogeneity and enable the conduct of a meta analysis.

Reviewers' comments: