Reviewer ’s report  
 
Title:  Factors associated with deep infiltrating endometriosis versus ovarian endometrioma in 
China: A subgroup analysis from the FEELING study  
 
Version: 1 Date: 18 May 2018 
 
Reviewer:  Maria  Elisabetta Coccia  
 
Reviewer’s report:  
 
I read with great interest this study about the factors associated with deep infiltrating 
endometriosis versus ovarian endometrioma in a gr oup of Chinese women. Deep endometriosis 
and ovarian endometrioma are probably two different entities and analysis of factors associated 
in the pathologies might help the understanding of the pathogenesis. The conclusion of the study 
is quite surprising as  women eating a greater number of fruit/vegetables per day were more likely 
to be diagnosed with DIE and eating organic food was related to the diagnosis of OMA.  
 
 
The paper is well -written in general, but I have some concerns regarding:  
 
Abstract: Conclusions  are too general and should highlight the most relevant results.  
 
Materials and Methods: You selected a subgroup analysis among 546 Chinese women including 
156 women classified as OMA and 78 patients as DIE. But what about the remaini ng 156 
patients?  
 
Background: line 14, when you specify a prevalence it would be better cite the author who 
obtained the value than the review.  
 
Line 45 please specify what do you mean with 'definite disease'  
 
 
Materials and methods  
 
Could you write the inclus ion criteria of the FEELING study?  
 
I wonder the absence of age at menarche in the analysis, could you explain the reason? A 
younger age at menarche is a recognized risk factors for endometriosis and pain recurrence after 
surgery (see also Long -term follow -up after laparoscopic treatment for endometriosis: 
multivariate analysis of predictive factors for recurrence of endometriotic lesions and 
pain.Coccia ME, Rizzello F, Palagiano A, Scarselli G.Eur J Obstet Gynecol Reprod Biol. 2011 
Jul;157(1):78 -83.). 
 
 
Resul ts: 
The authors should explain better the study group (Please include table of characteristics of 
patients) and after the results of the survey. For example we don't know the size of 
endometrioma the severity of endometriosis, presence/absence of painful s ymptoms and their 
severity.  
 
I do not understand why you choose to categorize the BMI differently than WHO and why do 
you adopt as a reference group an intermediate category.  
 
 
Conclusions  
 
The surprising results of the study 'Women eating a greater number of  fruit/vegetables, having 
any siblings and gastrointestinal symptoms during menstruation were more likely to be 
diagnosed with DIE, while eating organic food and being under stress were major factors that 
potentially associated with the diagnosis of OMA'  might be referred to the retrospective nature 
of the study and the lack of a control group (patients without endometriosis). That is to say, 
women with a diagnosis of endometriosis with the more severe stage of disease tend to eat 
"healthy food" and thus b oth fruit, vegetables and organic food.  
 
I think that the authors should arguments on these results and propose possible correction for a 
future survey.  
 
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 you r comments to the authors.  
 
No 
 
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 qual ity 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 t hat I have no competing interests' 
below. If your reply is yes to any, please give details below.  
 
none  
 
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 websi te 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