Review for 10.1186/s12876-020-01261-8 (2020)

Reviewer’s report
Title: Gastroesophageal reflux disease in a typical African population A symptom-based multicenter
study.
Version: 1 Date: 31 May 2019
Reviewer: Serhat Bor
Reviewer's report:
I read the manuscript entitled "Gastroesophageal reflux disease in a typical African population A
symptom-based multicenter study of 3520 subjects". 
There is a strong need for epidemiologic studies from Africa. Practically data is missing. As Auyhors
already mentioned, there are great difficulties to achieve such a clear result. However there are some
issues, needs to be clarified. First of all as I mentioned at the end of this comment, I have difficulties to
understand this GERD study with overlapping Rome-related other diagnosis since no details have been
submitted. 
Title should be changed, no need to mention the number of subjects.
Abstract: No need to mention the statistical softwares here. 
Introduction is long and unnecessary data are presented such as general GERD information s "Other
features include chest pain, cough, laryngitis, asthma and dental erosions etc". Should be truncutated.  
Method: I understant the difficulty to reach a significant representetive population for the study. As far
as I understand there are 36x6= 216 geopolitical zones. "From each state 2 Local Government Areas
(LGA) were picked and from each LGA, 2 communities or clusters were evaluated". What were the
criteria for the selection of these areas? How were the subjects selected at the end? Any quato applied?
Language should be a barrier for such a study in Nigeria. Were the questionnaires translated esp Rome
IIIs? How many languages? The term "heartburn" is not well-known in many languages, what is the
situation in Nigeria? This is a very interesting issue.
"Alcohol consumption" should be explained. What are the criteria? Waist/Hip ratio was not mentioned
at all in the results. 
Results: Table 1 shows 6 areas but table 3 refers the results of 4 only. Some data from North areas are
zero. However, North East area has the highest rate of GERD. What is the reason for zero values?
Linguistic problems?
Nothing mentioned about the data quality. Is that a reason for the zero or missing values?
Table 3 needs statistic significance.
Discussion: The definition of GERD differs according to the questionnaire as well as frequency and
severity.  Authors  should discuss the prevalence of the disease with the studies  which used same
questionnaire and same definition following the general epidemiologic data either in introduction but
preferably in discussion.
I agree about the role of H pylori is very important in relationship with GERD in Africa. Its role is not
mentioned in introduction however very long. The importance or relation of CagA issue is missing. 
Age-related speculations are not directly related with the manuscript since none of them were actually
measured. 
This sentence is not related with text; "Similarly, a meta-analysis showed that there was no significant
association between alcohol consumption and Barrett's esophagus36". 
A recent  metaanalysis  showed  a  significant  relation  between  GERD  and  alcohol.  I  suggest  to
incorporate. 
ROME III PART OF THE MANUSCRIPT: I could not understand clearly how all these Rome data
come from. The whole Rome III measurements should be explained in a separate session including all
the methodologic points I raised above for GERD questionnaire. I think this was performed as a
separate study and somehow incorporate this one for the overlapping issues. If this is the case I suggest
to write a separate manuscript about Rome data and compare two studies. Otherwise all Rome issue
needs such a big clarification and details. 
There is no need to discuss GERD phenotypes since this is a questionnaire-based study. 
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
No
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you recommend an additional
statistical review?
If  an  additional  statistical  review  is  recommended,  please  specify  what  aspects  require  further
assessment in your comments to the editors.
I recommend additional statistical review
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
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