Reviewer ’s report  
 
Title: Low v itamin D levels are associated with high viral loads in patients with chronic hepatitis 
B: A systematic review and meta -analysis  
 
Version: 0 Date: 23 Jul 2018  
 
Reviewer: Guntars Pupelis  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload a s attachments annotated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
Reviewer report: BMGE -D-18-00351"L ow vitamin D levels are associated with high viral loads 
in patients with chronic „.hepatitis B: A systematic review and meta -analysis  
The manuscript presents meta -analysis to compare the vitamin D levels between patients with 
chronic hepatitis B (CHB) an d healthy controls and to determine whether vitamin D levels were 
correlated with HBV viral loads significantly.  
The purpose of the study is fulfilled partially due to the heterogeneity of the study material. 
Currently the vitamin D deficit is the hot topi c internationally and the beneficiaries of the 
announcements that low levels of vitamin D are wide spreading disregarding the population and 
continents are manufacturers of the vitamin D. However the topic is really important. It is 
difficult to evaluate, even when the literature data are in place, whether ….."Approximately one 
third of world's population has been infected, 70 and over 350 million patients are suffering from 
chronic HBV infection [1 -3]"…..  
The important and well known point is that … "Alth ough there is no consensus on optimal levels 
of vitamin D in serum, a 25OHD 88 level [7, 9]. Vitamin D deficiency results in abnormalities in 
calcium, phosphorus, 90 and bone metabolism".  
It means that the problem is at the worldwide level.  
Some confusion is regarding the controversial statement that: …."No language restrictions were 
applied 114 and the last search was performed on September 28, 2017".  
And…"All the studies 172 were observational studies and were reported as full -text articles in 
English".  
The manuscript otherwise is well prepared and the message is clear.  
The manuscript merits publication in BMC gastroenterology.  
Are the metho ds 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.  
 
Yes 
 
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 futu re? 
 
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 a ccepted 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://creativecomm ons.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: Low v itamin D levels are associated with high viral loads in patients with chronic hepatitis 
B: A systematic review and meta -analysis  
 
Version: 0 Date: 23 Jul 2018  
 
Reviewer: Guntars Pupelis  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload a s attachments annotated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
Reviewer report: BMGE -D-18-00351"L ow vitamin D levels are associated with high viral loads 
in patients with chronic „.hepatitis B: A systematic review and meta -analysis  
The manuscript presents meta -analysis to compare the vitamin D levels between patients with 
chronic hepatitis B (CHB) an d healthy controls and to determine whether vitamin D levels were 
correlated with HBV viral loads significantly.  
The purpose of the study is fulfilled partially due to the heterogeneity of the study material. 
Currently the vitamin D deficit is the hot topi c internationally and the beneficiaries of the 
announcements that low levels of vitamin D are wide spreading disregarding the population and 
continents are manufacturers of the vitamin D. However the topic is really important. It is 
difficult to evaluate, even when the literature data are in place, whether ….."Approximately one 
third of world's population has been infected, 70 and over 350 million patients are suffering from 
chronic HBV infection [1 -3]"…..  
The important and well known point is that … "Alth ough there is no consensus on optimal levels 
of vitamin D in serum, a 25OHD 88 level [7, 9]. Vitamin D deficiency results in abnormalities in 
calcium, phosphorus, 90 and bone metabolism".  
It means that the problem is at the worldwide level.  
Some confusion is regarding the controversial statement that: …."No language restrictions were 
applied 114 and the last search was performed on September 28, 2017".  
And…"All the studies 172 were observational studies and were reported as full -text articles in 
English".  
The manuscript otherwise is well prepared and the message is clear.  
The manuscript merits publication in BMC gastroenterology.  
Are the metho ds 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.  
 
Yes 
 
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 futu re? 
 
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 a ccepted 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://creativecomm ons.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: Low v itamin D levels are associated with high viral loads in patients with chronic hepatitis 
B: A systematic review and meta -analysis  
 
Version: 0 Date: 23 Jul 2018  
 
Reviewer: Guntars Pupelis  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload a s attachments annotated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
Reviewer report: BMGE -D-18-00351"L ow vitamin D levels are associated with high viral loads 
in patients with chronic „.hepatitis B: A systematic review and meta -analysis  
The manuscript presents meta -analysis to compare the vitamin D levels between patients with 
chronic hepatitis B (CHB) an d healthy controls and to determine whether vitamin D levels were 
correlated with HBV viral loads significantly.  
The purpose of the study is fulfilled partially due to the heterogeneity of the study material. 
Currently the vitamin D deficit is the hot topi c internationally and the beneficiaries of the 
announcements that low levels of vitamin D are wide spreading disregarding the population and 
continents are manufacturers of the vitamin D. However the topic is really important. It is 
difficult to evaluate, even when the literature data are in place, whether ….."Approximately one 
third of world's population has been infected, 70 and over 350 million patients are suffering from 
chronic HBV infection [1 -3]"…..  
The important and well known point is that … "Alth ough there is no consensus on optimal levels 
of vitamin D in serum, a 25OHD 88 level [7, 9]. Vitamin D deficiency results in abnormalities in 
calcium, phosphorus, 90 and bone metabolism".  
It means that the problem is at the worldwide level.  
Some confusion is regarding the controversial statement that: …."No language restrictions were 
applied 114 and the last search was performed on September 28, 2017".  
And…"All the studies 172 were observational studies and were reported as full -text articles in 
English".  
The manuscript otherwise is well prepared and the message is clear.  
The manuscript merits publication in BMC gastroenterology.  
Are the metho ds 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.  
 
Yes 
 
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 futu re? 
 
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 a ccepted 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://creativecomm ons.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