PONE-D-19-34553

Epidemiology, clinical features, and impact of food habits on the risk of hepatocellular carcinoma: A case-control study in Bangladesh

PLOS ONE

Dear Associate Professor Karim,

Thank you for submitting your manuscript to PLOS ONE. Please accept our apologise if the revision process has taken longer than expected.

This editor and the reviewers have found this study intriguing and the results of value. However, both the reviewers have raised substantial concerns (that I share) regarding some of the conclusions and have suggested additional analyses and clarification before the manuscript can be considered for publication. Therefore we all recommended a mayor revision and we invite the authors to resubmit the manuscript if the authors are able to address the comments.

In specific, the reviewer 1 (expert of nutrition/epidemiology) has raised concerns regarding the methodology of the nutritional analysis (the food intake can be better dissected according to FFQ; coffee to be stratified according to intake), the criteria for recruitment (this is also raised by reviewer 2); the logistic regression strategy and the exposure categories should also better clarified; he also suggested re-writing some of the sentences in light of state of the art literature.

The reviewer 2 (expert of hepatology/HCC) has provided the authors with important suggestions regarding the methodology to carry the analyses keeping in consideration the progression of chronic liver disease (thich is the major determinant of HCC risk!): HCC is rarely observed in a normal liver and dissecting the mutual relationship between nutrition/chronic liver disease/HCC is crucial for a sound interpretation of the results. It needs to be clarified 1) the nature of the control group (real controls? Chronic hepatitis without HCC? the latter group would be extremely precious ...); 2) how the authors dissect the interaction between the smoking/drinking behaviour and the underlying chronic liver disease in their analyses (this might require some re-thinking on the strategy to analyse the data as suggested); 3) Analysing independently those patients with viral hepatitis with those with other etiologies: especially in patients with ASH/NASH, nutritional factors will be per se a driver of chronic liver disease progression (and not only a contributing risk factor); 4) dissect in a multivariate fashion the role of nutrition on the development of cirrhosis vs. HCC and, as a consequence, how nutritional habits influence the development of HCC in patients that do not have cirrhosis yet.

I also think that, since some metabolic information is available (BMI, T2D), these factors should be considered (together with chronic liver disease) in the multivariate approaches suggested: considering the growing concern of the impact that the obesity epidemics will have on HCC risk (not only because of NASH, but also as obesity is a worsening factor of chronic liver disease from different etiologies), and given obesity is pretty much associated to nutritional habits, these analyses will help to better dissect the relationship between nutrition/obesity/chronic liver disease thus leading to HCC.

My opinion is that these are all reasonable suggestions that will greatly improve the impact of this manuscript; the outcome of these analyses will also provide suggestions to the scientific community for further studies to address the role of nutrition on HCC development thus not limiting the importance to the study to the impact for Bangladeshi community.

English should be revised by a native English; there are also multiple spelling errors and typos.

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Michele Vacca, M.D., Ph.D.

Academic Editor

PLOS ONE

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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: Partly

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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: Authors explored the association between food group intake in Bangladesh and risk of hepatocellular carcinoma (HCC) in a hospital-based case-control study.

Introduction is quite long, more attention should be payed rather to nutritional part.

Part from line 78-95 should be shortened.

Authors should provide an explanation why they did not consider the following food groups in their analysis: whole-grains and cereals, coffee, nuts and legumes. Authors should consider that moderate coffee intake has been associated with decreased risk of HCC (PMID: 28846640). I suggest that authors add analysis for this food groups as they were included in FFQ.

Introduction line 101-105 authors should rephrase the sentence and improve the cited bibliography as references 19-25 correspond motel to individual case-control studies (published 20 years ago!) rather than comprehensive studies. Authors should refer to recent umbrella reviews summarising knowledge regarding HCC from prospective cohort and case-control studies and providing the level of evidence, as well as the most recent meta-analysis. It should be:

“Different studies claimed inverse relation of milk (PMID: 31199182), fiber and whole-grains (PMID: 31964201), white meat (PMID: 24588342), fruits and vegetables (PMID: 30764679), and fish (PMID: 25534918) with HCC. On the contrary, high intake of red meat (PMID: 24588342) has been associated with increased risk of HCC, however, there is no sufficient evidence on the association between HCC and egg consumption (PMID: 31379223).”

Study population. It is necessary to specify city and country in which were enrolled the individuals. Design of the study should be clearly specified: hospital-based case-control study.

Table 5 present data from multiple logistic regression, please add all the variables used in the adjustment in the table’s footnote. Please present also unadjusted model of analysis. Adjustment covariates should be also listed in “statistical analysis section”.

I suggest authors revise English, as there are several misspellings along the manuscript.

It would be worth to provide exposure categories for example as g/day ml/day or serving/day.

Figures are fine.

Discussion seems fine.

Reviewer #2: The study is aimed to understand the present status of HCC in Bangladesh and more in detail to describe the role of different etiological factors in the development of HCC (viral agents, alcohol, smoking diabetes, food habits).

Main original elements are: the deep and appropriate analysis of food habits; the fact that it represents the first large study on this topic in Bangladeshi patients.

The collection of data is well carried out and the presentation of data ic clear and understandable.

Nevertheless, the study has some limitations and the authors should give further information:

1. Control subjects: it is not clear by which kind of people the control population is represented: are they normal subjects? are people affected by other tumors or other disease? are they represented by cirrhotic patients without HCC? This point is absolutely crucial in order to understand the results ot the table 1 of the work

2. Since smoking is considered a risk cofactor for tumors at all and for HCC (EASL, 2019), the author cannot state that the most common etiology for HCC was smoking (50% reporting) followed by the HBV infection. They need to better explain this concept, even because the so-called control group has a rather high percentage of smoking subjects (30%). Any consideration on the smoking as an etiological factor has to take into account the data that main etiological factor for HCC is the cirrhosis and the relationship between cirrhosis and smoking is not that clear.

3. What the authors mean for “alcohol consumption”? They have to better explain: is it intented as a general consideration on the possible role of alcohol consumption in the pathology of the patient or do they relate to a specific level of consumption?

Since the authors have carried out a very beautiful and detailed study on the food consumption, I would have expected some more details on this relevat etiological factor.

4. Surprisingly, 35 (44%) patients were discovered negative for both hepatitis B and hepatitis C infections: this is a very interesting data, but maybe the authors could analyse the data on food habits in this group of patients in comparison with the groups of patients with other established etiology (e.g. HBV and/or HCV). Their conclusions on the possible association between food habit and risk of HCC could be reinforced.

5. Are the authors able to distinguish between the role of food habits in the development of the underlying cirrhosis and the role in the comparison of HCC? This is not a peregrine observation, since cirrhosis is the most worldwide risk factor for HCC.

6. Actuallly, the authors need to clearly say how many HCC enclosed in this interesting work are to be considered primary or secondary to cirrhosis.

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Reviewer #1: No

Reviewer #2: Yes: Vincenzo O. Palmieri

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Epidemiology, clinical features, and impact of food habits on the risk of hepatocellular carcinoma: A case-control study in Bangladesh

PONE-D-19-34553R1

Dear Dr. Karim,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication.

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With kind regards,

Michele Vacca, M.D., Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Dear Authors

all the reviewers and this editor were satisfied by your analyses and for addressing our queries. I am thus happy to let you know that the manuscript is now accepted for publication.

Well done

Michele Vacca

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 #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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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 #1: Yes

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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 #1: Yes

Reviewer #2: Yes

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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 #1: Yes

Reviewer #2: Yes

**********

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 #1: Authors addressed all of the comments, and improved significantly the manuscript. I have no further comments.

Reviewer #2: The authors have widely satisflied the concerns I raised in my revision. I found very interesting their conclusion on the role of food habits, that is a very relevant issue in the study of pathogenesis of HCC.

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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 #1: No

Reviewer #2: Yes: Prof. Vincenzo O. Palmieri