Review for 10.1186/s12876-024-03520-4 (2024)

Title: The Association between Non- and Pro-Healthy Diet Indices and the Risk of Colorectal
Cancer: A Case-Control Study
Version: 0 Date: 24 Sep 2024
Reviewer:  Alejandro Oncina-Cánovas
Reviewer's report:
The present study by Ranjbar-Zahedani et al. is of significant public interest, as it explores the
association between two novel diet quality indices and colon cancer risk in a hospital-based
sample of the Iranian population. While the article appropriately addresses this question from
a methodological perspective, certain ideas require clearer expression, specific decisions need
further justification, and additional relevant information should be provided. Below are some
comments that may help improve the article.
General Comment:
The English language requires revision, and certain expressions and sentences should be
reformulated to adopt a more formal and scientific tone.
Abstract:
Lines 33-34: The aim should be reformulated as follows: "This study aims to evaluate the
association between adherence to pHDI and nHDI and colorectal cancer (CRC) risk in the Iranian
population."
Line 40: It would be desirable to include details about the statistical analysis here.
Lines 43-54: I suggest reformulating this sentence as: "In contrast, individuals in the highest
tertile (T3) of the nHDI showed a higher risk of CRC compared to those in the lowest tertile
(T1) (OR = 2.62; 95% CI: 1.09-6.27) in the adjusted model." It is also recommended to maintain
consistency in terms (e.g., highest vs lowest tertiles and risk rather than odds) throughout the
manuscript.
Lines 46-48: The conclusions should be reformulated as follows: "The present study showed that
higher adherence to pHDI and nHDI is associated with lower or higher CRC risk, respectively.
These results provide valuable insights into the role of healthy and unhealthy diets in CRC
prevention."
Introduction: This section is in general well-written and effectively describes the problem
(colorectal cancer) and a potential solution (diet), while also highlighting the lack of knowledge
about dietary patterns that assess diet quality. Below are some points that could be improved:
Lines 62-63: This paragraph needs a clearer introduction. I suggest starting by discussing how
recent research has shifted focus from isolated foods to overall diet, followed by addressing diet
quality and the ongoing controversy regarding its relationship with CRC. Then, introduce the
concepts of nHDI and pHDI.
Lines 65-71: How do these indices contribute compared to other diet quality indices?
Lines 78-79: The meaning here is unclear and should be clarified.
Lines 79-81: Repeat the objective as stated in the abstract.
Methods: This section should be improved by including more relevant information.
Line 87: Remove the word "limitation."
Lines 87-88: Could you provide more details about the diagnosis (e.g., types of diagnostic tests
used)?
Lines 90-92: This sentence should be rewritten for clarity (e.g., "at the same time" is ambiguous).
Line 98: I suggest changing "and they had an incomplete food frequency questionnaire" to "and
they provided incomplete dietary intake data."
Lines 116-117: Please provide a justification for this decision.
Line 119: The meaning is unclear and should be reformulated.
Lines 122-124: Please provide more information on how these variables were categorized.
Lines 137-140: It seems something is missing here (e.g., "In the second..."). I also recommend
adding information about variables not previously mentioned (e.g., cooking methods). Why you
use these covariables for the adjusted model and not others? Please provide a justification. Did
you consider examining the association using these indices as continuous variables? This would
provide valuable insights.
Results: The clarity and expression of results should be improved. Consistency in formatting
is also recommended.
Line 142: Ensure consistency in how "pHDI" is written (check the capitalization of the "P").
Lines 142-144: Could you clarify this statement? For example, specify that the control group
showed higher fiber intake.
Lines 145-148: Avoid using "first" or "last"; instead, use "highest" vs "lowest tertiles." It may
also be useful to highlight which components are most significant in each index.
Lines 150-158: I suggest using the same formula as in the abstract: "Based on the data presented
in Table 2, the results indicate that individuals in the highest tertile (T3) of the pHDI showed
a lower CRC risk compared to those in the lowest tertile (T1)." Additionally, avoid describing
crude model results.
Discussion: This section effectively compares the study's results with existing literature,
highlights the novelty of the findings, and discusses potential mechanisms involved. Strengths
and limitations are also noted. Below are some suggestions and questions regarding certain
details:
Lines 161-164: I recommend replacing "relationship" with the more accurate term "association".
Lines 165-170: This information is crucial. Would it be more appropriate in the Methods section
under "Diet quality scores"?
Line 173: "Has been confirmed" may be better phrased as "studied" or "explored." Please verify.
Line 174: I suggest replacing "In accordance with our findings" with "In line with our
results" and "revealed" with "showed." Additionally, I recommend moderating terms like
"demonstrated" or "exhibited" for a more measured tone.
Lines 187-193: As mentioned earlier, this information might fit better in the Methods section
under "Diet quality scores."
Lines 230-232: How does this align with your statement in the introduction that CRC is one of
the most common cancers?
Conclusions: This section could benefit from more specific dietary recommendations for CRC
prevention, considering the study's limitations.
Lines 236-240: Use "association" rather than "correlation." Additionally, avoid the term
"significant" and use "risk" instead of "likelihood."