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: 1 Date: 27 May 2019  
 
Reviewer: Johannes Berkhof  
 
Reviewer's report:  
Methods.  
p.4. A VIA positive result is replaced by cervical lesion in the results section. Why not use the 
term: VIA -positive result throughout the paper?  
=&gt; p.5.l.11. Bivariate logistic regression analysis was employed to determine both the 
predictors of douching as well as identifying douches that were risk factors for abn ormal cervical 
lesions. We used a significance level of 10% for adjustment variables to be entered in the 
multivariable analysis and the  
=&gt; overall significance in the adjusted model was taken to be the traditional 5% significance 
level.  
 
This text is confusing. The paper only contains univariate logistic regressions with single or 
multiple covariates.  
=&gt; p.5. l.60. The majority were aged between 25 -34 (3,999).  
3,999 is not the majority of 11853.  
 
The second paragraph on page 6, in which Table 1 is explained, leaves much to be improved.  
In particular,  
=&gt; l. 16. The highest proportion of women who douched were older  
=&gt; (45-54 years old) and the elderly women (55 years or older) constituted th e least proportion  
=&gt; (14.4% and 5.2%), respectively.  
These numbers cannot be read from Table 1 and the sentences are not clear to me.  
 
=&gt;l.21. More women with secondary (41.1%) and primary education  
=&gt;(35.5%) used some form of solution while only  17.6% with tertiary education used the same.  
I do not understand this sentence. The percentages do not relate to proportions of vaginal douching 
and seem to be misinterpreted: the percentages are column percentages but they seem to be 
interpreted as row p ercentages.  
=&gt;l. 24. Women with two to five sexual partners, house wives and those who never used a 
condom with their regular sexual partners constituted the majority of women who douched (66%, 
45% and 51.2% respectively).  
45% is not a majority.  
 
Table  2. HIV status is not statistically significantly associated with douching. See Table 1 where 
the p -value is 0.105.  
After adjusting for multiplicity, the p -value in Table 2 will be larger than 0.05. I consider the p -
values in Table 2 confusing and suggest  to remove them. Or only report p -values for all categories 
of a covariate together!  
 
Table 2 and 3. Please merge these tables into one Table.  
 
I do not see any additional value of Table 4, please discard.  
 
The analysis of cervical lesions can also be improved.  
 
Table 5.  
 
Why are not all covariates used that were also used in Table 2/3?  
 
Show both crude and adjusted odds ratios!.  
 
HIV- is reference category whereas in Table 2/3, HIV+ is reference category.  
 
Only present p -value over all reference groups, not per reference group!  
 
 
Are t he 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 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 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:  
 
Needs some language corrections before being published  
 
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?  
 
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 conducted expert meetings of GSK and Merck and received travel funding from DDL. Expert  
meeting fees were incurred by my employer.  
 
I agree to the open peer r eview policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted f or 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 in cluded as confidential comments 
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal