Review for 10.1186/s12876-025-04180-8 (2025)

Title: Association between gastrointestinal disorders and sleep-related problems: the mediating
effect of depression
Version: 3 Date: 30 May 2025
Reviewer's report:
Critical Review and Comments
General Assessment
The manuscript investigates the association between gastrointestinal (GI) disorders and sleep
disorders using a large, nationally representative dataset (NHANES 2005–2018). The study
is well-motivated, addresses a relevant public health question, and utilizes robust statistical
methods. However, there are several areas where the manuscript could be improved to meet the
standards of a high-impact journal.
Strengths
The use of a large, nationally representative sample (n=19,456) enhances the generalizability
of the findings.
The statistical approach, including multivariate logistic regression and mediation analysis, is
appropriate for the research question.
Subgroup and mediation analyses add depth to the findings, particularly regarding the role of
depression.
Major Weaknesses and Concerns
Clarity and Language
The manuscript contains numerous grammatical errors and awkward phrasing, which impede
readability and comprehension. For example, phrases like "If the answer is, then identified as
suffering from gastrointestinal disease" are unclear and need revision.
The writing style is often repetitive and lacks conciseness. Sentences are sometimes overly long
and convoluted.
Study Design and Causality
The cross-sectional design precludes any inference of causality between GI disorders and sleep
disorders. This limitation should be explicitly acknowledged and discussed in the limitations
section.
There is insufficient discussion of potential reverse causality (i.e., whether sleep disorders could
contribute to GI symptoms).
Definition and Measurement of Variables
The exposure and outcome variables are both based on self-reported, single-item questions,
which may introduce misclassification bias. The potential impact of this limitation should be
discussed.
The operationalization of variables such as "drinking status" and "smoking" lacks clarity and
should be more precisely defined.
Covariate Adjustment
Although the models adjust for a range of covariates, there is a risk of residual confounding. For
example, physical activity and dietary factors, which are relevant to both GI and sleep disorders,
are not mentioned.
The rationale for selecting specific covariates and the handling of missing data should be
described in more detail.
Presentation of Results
The results section is dense and difficult to follow. Tables are referenced but not included in the
excerpt, making it hard to evaluate the findings.
The reporting of odds ratios (ORs) and confidence intervals is appropriate, but the clinical
significance of these findings should be discussed, not just statistical significance.
Discussion and Interpretation
The discussion is limited and does not adequately contextualize the findings within the existing
literature.
The potential mechanisms underlying the observed associations (beyond mediation by
depression) are not explored in sufficient detail.
Formatting and Structure
The manuscript would benefit from clearer section headings and better organization, especially
in the methods and results sections.
Figures and tables should be clearly labeled and referenced appropriately in the text.
Specific Comments
Abstract: The abstract is generally informative but could be more concise. The objectives,
methods, results, and conclusions should be clearly delineated.
Methods: More detail is needed on the selection of participants, handling of missing data, and
the specific NHANES variables used.
Results: The presentation of baseline characteristics is useful, but the text should be streamlined.
Consider moving some details to supplementary materials.
Conclusion: The conclusion is supported by the data but should be more cautious regarding
causality.
Final Recommendation
Major Revision Required
The manuscript addresses an important topic and employs a robust dataset and methodology.
However, substantial revisions are needed to improve the clarity of writing, address
methodological limitations, and enhance the interpretation and presentation of results. The
authors should seek professional language editing and thoroughly revise the manuscript to
address the concerns outlined above.