Reviewer ’s report  
 
Title: Vaginal douching in Zambia: A risk or benefit to women in the fight against cervic al cancer:  
A retrospective cohort study  
 
Version: 2 Date: 03 Aug 2019  
 
Reviewer: Katie O'Brien  
 
Reviewer's report:  
 
Again, I found that this paper addresses an important and interesting resea rch gap, but I am still 
very confused about the definition of douching and the use of those who douche with water as the 
referent group for the analysis of the effects of douching on cervical lesions. I would like to see 
this better explained and justified  or otherwise modified to address my concerns.  
 
As written, the last analysis currently addresses the question: "among women who use douche, 
how is douching with a specific solution relative to douching with water associated with risk of 
cervical lesions. " What I think you want to address is "how is douching in general related to 
cervical lesions, and what type of douche is associated with the highest risk".  
 
Major concern:  
Please be consistent about the definition of douching. Page 5 you say that "douchin g was defined 
as any act involving the introduction of water or any solution into the vagina", yet in the results 
(page 6) and Table 1 you restrict the definition to those who douched with a solution other than 
water.  If you keep your definition as "douch ed with a solution other than water", make this more 
clear in the column heading of table 1 (i.e. get the word "water" in there somewhere) and in the 
definition on page 5.  
 
You also never provide the numbers/ %s of women who douche only using water. One wa y to do 
this would be to add a column to Table 3 showing the n's for each category by cervical lesion 
status. I actually don't think your paper ever states the total number of women with cervical lesions.  
 
Unless this is most of the sample, I still think t here may be important differences between those 
who douche with water and those who do not douche at all, yet your analyses appear to either 
group these two together (Tables 1 and 2) or exclude non -douchers entirely (Table 3). The reasons 
for this are real ly not clear to me. I'm guessing your analysis would be much better powered if you 
used non -douchers as the referent group in Table 3.  
 
Conclusions (page 17): As above, I am still very confused with the intended research question 
here. You talk about the a ssociation between douching or certain types of douching and the risk of 
cervical lesions, but since your referent group is those who douched with plain water, all you can 
really talk about is how douching with some substances may be worse than douching wi th water. 
You cannot make any statements about the health effects of douching in general.  
 
Page 4, starting line 107  
"Through this program, cervical cancer screening services are being for free at most of the public 
health facilities across the country." should be something like  
"Through this program, cervical cancer screening services are freely available at most of th e public 
health facilities across the country."  
 
Page 5 - HIV status: You state that anyone with incomplete information on HIV status was 
excluded, yet a large proportion of the sample is listed as HIV status unknown in Table 1. Please 
clarify in the text (i.e. the difference between "unknown" and "missing").  
 
Results page 8 and Table 2 - The interpretation of the findings from the unadjusted analysis are 
nearly identical to those from the univariate analysis in Table 1, and very similar to the adjusted 
results, which you also present.  Please consider limiting your write -up to the adjusted results to 
avoid this redundancy.  
 
Are t he 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.  
 
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 manus cript or would you recommend an additional 
statistical review?  
If an additional statistical review is recommended, please speci fy 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, f ees, funding, or salary from an 
organisation that may in any way gain or lose financial ly from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation t hat 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 receiv ed 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 i n relation to this paper?  
 
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If your reply is yes to any, please give details below.  
 
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