Reviewer’s report
Title: Gastroesophageal reflux disease in a typical African population A symptom-based multicenter
study.
Version: 1 Date: 01 Jan 2019
Reviewer: Siavosh Nasseri-Moghaddam
Reviewer's report:
Dear Editor
Thank you or sending me this paper for review. The topic is a long awaited one, GERD prevalence in
an African country. The authors have done a very good and systematic job in obtaining their data from
different parts of the big and diversely populated country and should be congratulated on that. Overall
the paper is fine and there is no major problem with it. The following are my suggestions for its
improvemment:
1) The "Introduction" is better to be shortened and some redundant and unnecessary information being
omitted from it.
2) The data presented in the tables are better to be elaborated somewhat more in the "Results" section",
especially the multivariable regression.
3) Some more information on the details and rational for the multivariable regression analysis is needed
in the "Methods" section.
4) There is good information on epidemiology of GERD from middle-eastern countries and the Persian
gulf region which is better to be referred to in this paper and comparisonsbe made with them. Some
good papers are as follows:
    Arch Iran Med. 2007 Jul;10(3):289-94   Nouraie et al
    Am J Gastroenterol. 2007 Jul;102(7):1353-60
    Turk J Gastroenterol. 2012 Aug;23(4):323-32.
    Turk J Gastroenterol 2017; 28(Suppl 1): S1-S2
    J Clin Med Res. 2018 Mar; 10(3): 221-225
5) An interesting finding in this work is that farmers had a higher risk of GERD. Nitrogen fertilizers are
progressively used for improvement of farming crops and fruit and this has led to higher and higher
contents  of nitrates  in the drinking water and vegetables and edible roots  (J  Environ Qual 2014
May;43(3):895-907).  There  are  some  information  linking  high  nitrate  content  of  water  to  higher
prevalence of GER (Arch Iran Med 2011;14(5):312-14). In addition, it has been shown that high nitrate
in rat's diet exposes them to esophageal injury (Scand J Gastroenterol, 2009; 44: 527-537) and human
data for this link is also available (Dig Dis Sci (2012) 57:413-418). The authors can use these data to
explain the finding of higher GERD prevalence among farmers alongside with their other explanations.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
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 am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1. Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this
manuscript, either now or in the future?
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose
financially from the publication of this manuscript, either now or in the future?
3. Do you hold or are you currently applying for any patents relating to the content of the
manuscript?
4. Have you received reimbursements, fees, funding, or salary from an organization that holds
or has applied for patents relating to the content of the manuscript?
5. Do you have any other financial competing interests?
6. Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If
your reply is yes to any, please give details below.
I declare that I have no competing interests.
I agree to the open peer review policy of the journal. I understand that my name will be included on my
report to the authors and, if the manuscript is accepted for publication, my named report including any 
attachments I upload will be posted on the website along with the authors' responses. I agree for my 
report to be made available under an Open Access Creative Commons CC-BY license 
(http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments which I do not wish to 
be included in my named report can be included as confidential comments to the editors, which will not
be published.
I agree to the open peer review policy of the journal
Reviewer’s report
Title: Gastroesophageal reflux disease in a typical African population A symptom-based multicenter
study.
Version: 1 Date: 01 Jan 2019
Reviewer: Siavosh Nasseri-Moghaddam
Reviewer's report:
Dear Editor
Thank you or sending me this paper for review. The topic is a long awaited one, GERD prevalence in
an African country. The authors have done a very good and systematic job in obtaining their data from
different parts of the big and diversely populated country and should be congratulated on that. Overall
the paper is fine and there is no major problem with it. The following are my suggestions for its
improvemment:
1) The "Introduction" is better to be shortened and some redundant and unnecessary information being
omitted from it.
2) The data presented in the tables are better to be elaborated somewhat more in the "Results" section",
especially the multivariable regression.
3) Some more information on the details and rational for the multivariable regression analysis is needed
in the "Methods" section.
4) There is good information on epidemiology of GERD from middle-eastern countries and the Persian
gulf region which is better to be referred to in this paper and comparisonsbe made with them. Some
good papers are as follows:
    Arch Iran Med. 2007 Jul;10(3):289-94   Nouraie et al
    Am J Gastroenterol. 2007 Jul;102(7):1353-60
    Turk J Gastroenterol. 2012 Aug;23(4):323-32.
    Turk J Gastroenterol 2017; 28(Suppl 1): S1-S2
    J Clin Med Res. 2018 Mar; 10(3): 221-225
5) An interesting finding in this work is that farmers had a higher risk of GERD. Nitrogen fertilizers are
progressively used for improvement of farming crops and fruit and this has led to higher and higher
contents  of nitrates  in the drinking water and vegetables and edible roots  (J  Environ Qual 2014
May;43(3):895-907).  There  are  some  information  linking  high  nitrate  content  of  water  to  higher
prevalence of GER (Arch Iran Med 2011;14(5):312-14). In addition, it has been shown that high nitrate
in rat's diet exposes them to esophageal injury (Scand J Gastroenterol, 2009; 44: 527-537) and human
data for this link is also available (Dig Dis Sci (2012) 57:413-418). The authors can use these data to
explain the finding of higher GERD prevalence among farmers alongside with their other explanations.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
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 am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1. Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this
manuscript, either now or in the future?
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose
financially from the publication of this manuscript, either now or in the future?
3. Do you hold or are you currently applying for any patents relating to the content of the
manuscript?
4. Have you received reimbursements, fees, funding, or salary from an organization that holds
or has applied for patents relating to the content of the manuscript?
5. Do you have any other financial competing interests?
6. Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If
your reply is yes to any, please give details below.
I declare that I have no competing interests.
I agree to the open peer review policy of the journal. I understand that my name will be included on my
report to the authors and, if the manuscript is accepted for publication, my named report including any 
attachments I upload will be posted on the website along with the authors' responses. I agree for my 
report to be made available under an Open Access Creative Commons CC-BY license 
(http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments which I do not wish to 
be included in my named report can be included as confidential comments to the editors, which will not
be published.
I agree to the open peer review policy of the journal
Please review this paper.
user
Reviewer’s report
Title: Gastroesophageal reflux disease in a typical African population A symptom-based multicenter
study.
Version: 1 Date: 01 Jan 2019
Reviewer: Siavosh Nasseri-Moghaddam
Reviewer's report:
Dear Editor
Thank you or sending me this paper for review. The topic is a long awaited one, GERD prevalence in
an African country. The authors have done a very good and systematic job in obtaining their data from
different parts of the big and diversely populated country and should be congratulated on that. Overall
the paper is fine and there is no major problem with it. The following are my suggestions for its
improvemment:
1) The "Introduction" is better to be shortened and some redundant and unnecessary information being
omitted from it.
2) The data presented in the tables are better to be elaborated somewhat more in the "Results" section",
especially the multivariable regression.
3) Some more information on the details and rational for the multivariable regression analysis is needed
in the "Methods" section.
4) There is good information on epidemiology of GERD from middle-eastern countries and the Persian
gulf region which is better to be referred to in this paper and comparisonsbe made with them. Some
good papers are as follows:
    Arch Iran Med. 2007 Jul;10(3):289-94   Nouraie et al
    Am J Gastroenterol. 2007 Jul;102(7):1353-60
    Turk J Gastroenterol. 2012 Aug;23(4):323-32.
    Turk J Gastroenterol 2017; 28(Suppl 1): S1-S2
    J Clin Med Res. 2018 Mar; 10(3): 221-225
5) An interesting finding in this work is that farmers had a higher risk of GERD. Nitrogen fertilizers are
progressively used for improvement of farming crops and fruit and this has led to higher and higher
contents  of nitrates  in the drinking water and vegetables and edible roots  (J  Environ Qual 2014
May;43(3):895-907).  There  are  some  information  linking  high  nitrate  content  of  water  to  higher
prevalence of GER (Arch Iran Med 2011;14(5):312-14). In addition, it has been shown that high nitrate
in rat's diet exposes them to esophageal injury (Scand J Gastroenterol, 2009; 44: 527-537) and human
data for this link is also available (Dig Dis Sci (2012) 57:413-418). The authors can use these data to
explain the finding of higher GERD prevalence among farmers alongside with their other explanations.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
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 am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following questions:
1. Have you in the past five years received reimbursements, fees, funding, or salary from an
organisation that may in any way gain or lose financially from the publication of this
manuscript, either now or in the future?
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose
financially from the publication of this manuscript, either now or in the future?
3. Do you hold or are you currently applying for any patents relating to the content of the
manuscript?
4. Have you received reimbursements, fees, funding, or salary from an organization that holds
or has applied for patents relating to the content of the manuscript?
5. Do you have any other financial competing interests?
6. Do you have any non-financial competing interests in relation to this paper?
If you can answer no to all of the above, write 'I declare that I have no competing interests' below. If
your reply is yes to any, please give details below.
I declare that I have no competing interests.
I agree to the open peer review policy of the journal. I understand that my name will be included on my
report to the authors and, if the manuscript is accepted for publication, my named report including any 
attachments I upload will be posted on the website along with the authors' responses. I agree for my 
report to be made available under an Open Access Creative Commons CC-BY license 
(http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments which I do not wish to 
be included in my named report can be included as confidential comments to the editors, which will not
be published.
I agree to the open peer review policy of the journal
assistant