Review for 10.1186/s12876-022-02353-3 (2022)

Title: The Association between Dietary Inflammation Scores and Non-alcoholic Fatty Liver
Diseases in Iranian Adults
Version: 0 Date: 21 Feb 2022
Reviewer's report:
Hossein et al. have conducted a study on diet-derived proinflammatory scores and NAFLD risk.
The study is suitable, timely, and necessary for a broader understanding of diet significance
on health and disease events. However, there are critical omissions in the reporting. First, the
background for the study was short of identifying critical gaps and justification for the current
study. Second, vital details of the study design, recruitment, how participants were selected,
statistical analyses, etc., in the study were largely omitted. Third, the result descriptions lacked
detailed reporting of vital summary statistics in the result section. Some parts of the discussion
section were not within the frame of the study findings. Extra interpretations that were outside
the study objective were included in the discussion. Of note is the use of dietary pattern analysis
and the tedious distinction between DII and DIS in the study were entirely beyond the scope of
the study. Also, the discussion lacks the potential pathophysiology of the association of DIS and
EDIP with NAFLD. The following are comments and suggestions for the authors' consideration.
Title
Please remove 'risk of' in the title.
Abstract
Line 8: ‘reliable’ and ‘valid’ more or less meant the same thing.
Lines 6-9: Critical details of the study design, population, exposure and outcome definitions,
statistical analysis, etc., were omitted in the method section of the abstract.
Line 15-16: The authors mentioned tertiles but only presented a single OR and 95% CI. Where
are the OR for the other tertiles?
Background
Line 33: In my opinion, it is not appropriate to itemize that dietary patterns are inappropriate.
It is better to mention poor dietary choices.
Line 34: 'the' should be removed.
Line 39: please change 'originated' to 'designed'
Line 51-52: the statement is not entirely true as there are numerous studies on this subject but
perhaps not in the Iranian population.
Line 53: please change 'an’ to ‘a’
Generally speaking, the background is short of gaps and justification for this study.
Materials and methods
Lines 59-71: Vital aspects of the study design were omitted and should be included to aid the
readers understanding.
Line 71: what is the difference between excluded and replaced? How was the replacement carried
out?
Lines 81-83: Please include the citation for the FCTs, particularly the USDA and Iranian FCT
Line 85: a brief description of the DIS by Byrd et al. will be necessary. Also, how DIS was
computed in this study was omitted.
Line 93: principles guiding the development of the EDIP score was omitted
Line 95: please change ‘do’ to ‘did’
Line 119: is smoking status current or lifetime use? This should be clearly defined
Line 140: WHR was mentioned in the covariates but how it was assessed and derived was
omitted in the assessment of variables. The same goes for the waist circumference.
Results
Line 149-151: any bivariate analysis to compare the median scores between cases and controls?
This appears to be omitted in the statistical analysis.
Line 154; what is WC? It appears this is the first time it is mentioned in the manuscript.
Lines 152-170: it might be useful if some of the critical summary estimates could be included
in the narrative without reverting to the table.
Line 171-174: the details of the OR for the tertiles were omitted. For example, which tertile was
used as a reference for comparison? Also, the OR presented belonged to which tertile. It will be
vital to include the entire spectrum of OR across the tertile in a consecutive manner.
Line 174: Was the final model adjusted for BMI? Any basis for selecting WHR as against the
overall significance of body composition?
Line 185-186: The authors' assertion is not necessarily valid because of several pieces of
literature on the diet inflammatory index. Perhaps this is the first among Iranian adults.
Line 191: ‘… effective in increasing the risk of T2D’ Please revise the statement.
Discussion
Lines 191-208: Several studies were cited, which is commendable, but a paragraph on the
pathophysiology of this association might be necessary.
Line 212: please remove ‘was’
Line 217; DII and DIS, what is the difference? Permit me to say that both are derived from
objective or subjective scores in most cases. The very fact that they all derived from diet excludes
the comparison. Moreover, this study was not designed to compare the two methods' efficacy
as asserted by the author.
Line 220-221: This study to my understand did not answer this objective. I did not see any
methodology relating to a dietary pattern in this study.
Line 234: ‘inversely’ should come before ‘associated’
Line 244: This study design is not case-control. It is cross-sectional in design.
Line 256: The authors should avoid using the term dietary patterns.
References
Some of the references are very old as there are new studies on this subject. The authors should
consider revising their citations to include recent studies.
Minor comments
This manuscript will benefit from an editorial review by an English editor to avoid a pockets
of grammatical errors.
Table 1 and 2: why is n= ??? missing?