Review for 10.1186/s12876-017-0696-4 (2017)

Reviewer ’s report  
 
Title:  Non-alcoholic fatty liver disease as a risk factor for cholangiocarcinoma:  A systematic 
review and meta -analysis  
 
Version: 0 Date: 18 Sep 2017 
 
Reviewer:  Atsushi  Nakajima  
 
Reviewer’s report:  
 
This manuscript shows interesting result that NAFLD may potentially increase the risk of CCA 
development. Particularly, this study has novelty in conducting detailed sub -analysis for 
countries and study quality, diagnostic pro cedure (images and/or histopathological 
examinations). However, we would recommend an emendation stated below.  
  
 Major point  
  
NAFLD is indeed a spectrum of liver disease, ranging from fatty liver to cirrhosis. However, 
NAFLD and NASH were not discrimi nated because of (as you mentioned limitation) deference 
of diagnostic methods of each study. In second paragraph of discussion, you mentioned that 
cirrhosis itself has recently been recognized as a risk factor for CCA. SO, the authors should 
mention in di scussion that this result had potential bias of cirrhosis itself.  
 
Are the methods appropriate and well descr ibed?  
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.  
 
No 
 
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 financia lly 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 y ou 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 an y, please give details below.  
 
I declare that I have no competing interests.  
 
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