Review for 10.1186/s12876-017-0721-7 (2017)

Reviewer ’s report  
 
Title : Psychological wellbeing and physical activity in children and adolescents with 
inflammatory bowel disease compared to healthy controls  
 
Version: 0 Date: 13 Oct 2016 
 
Reviewer:  OCISK OVÁ  MARIE  
 
Reviewer’s report:  
 
Dear authors,  
 
It was a pleasure to review your paper. I hope that you find my comments useful and that they 
further improve your text.  
 
Title: I sugges t uniting the capitalization of the words - "well -being" and "physical activity" are 
capitalized, other words are not - either capitalize only the first word of the title, or capitalize all 
relevant words.  
 
 
Abstract: The abstract is clear and concise.  
 
 
Back ground: The Background is also very well written. The empirical bases of all hypotheses are 
clear. I found several minor typos (e.g. "25%" where "25 %" should be or a lack of commas in 
several sentences).  
 
 
Methods: Procedure: Please elaborate on how you found the participants. Were they your 
patients who were invited to participate in the study? Or did you look for them elsewhere? 
Where did you find the controls? In a local school? Or somewhere else? When did the study took 
place? What was its duration?  
 
  Sample: The sample is small. However, it is fully justifiable in the study with this 
population. Please, state if the sample sizes of the three subgroups were large enough for the 
statistical analyses you made. Also mention inclusion and exclusion criter ia for both the clinical 
and control group. Also, state how many patients had CD and how many dealt with UC.  
 
  Tools: What was the Cronbach´s alpha in your translation of the KIDSCREEN? 
The same goes for the ChilD -S. 
 
  Statistical analyses: Were the data n ormally distributed? This is a condition for 
the use of ANOVA (which is especially important in small samples such as yours). Another 
condition of the ANOVA use is the group size. It should be higher than ten for each group 
entering the analysis. One of yo ur groups only consists of 8 participants. Please, re -evaluate your 
statistical procedures. Either find several reliable sources, that back up your statistical decisions, 
or use another method instead of ANOVA (the Welch test, the Kruskal -Wallis H test, de pending 
on the characteristics of the sample...). Also, were you able to use the Pearson´s correlation? You 
cannot apply the central limit theorem in your study so you really need to analyse the normality 
of your data or find strong sources claiming that t he normality violations are not a big deal in a 
study design such as yours.  
 
 
Results: I will review this part as if you wouldn´t change the statistical procedures. If you do it (it 
might be recommendable), this part, along with the Discussion, should be re viewed again.  
 
"As shown in Table 2, there were no significant differences between the three groups." - Please, 
specify what differences weren´t significant.  
 
Table 4: "Difference from norm  7.08 ± 131.32" - A typo. I believe that there should be one 
more nu mber in this result, as the other groups reached 80.8 and 65.5 points and the between -
group difference was medium.  
 
The effect sizes in the tables are very nice.  
 
Anyway, I suggest putting more emphasis on the p values. I understand that they tend to be 
overrated. However, you often omit the results of the Bonferroni corrections and focus largely on 
the effect sizes. You should argue why the effect sizes were more preferable and, more 
importantly, not to forget to state the p values in the text where only the  effect sizes are now 
mentioned (they should be a part of the interpretation as well). Otherwise, the results will remain, 
statistically speaking, a bit confusing.  
 
 
Discussion:  This part seems nice. It has a logical structure and properly discusses all im portant 
findings.  
 
The list of the factors of low albumin values - please, add citations.  
 
"Therefore, the 322 present data do not match those studies showing a lower overall HRQOL 
among patients with IBD." - You only cite one study, you should add another o r fix the sentence.  
 
 
Conclusion: The conclusion is also clear and concise.  
 
To sum it up, the study seems very nice. The main problems, that need to be addressed, are the 
applied statistical analyses and the presentation of the results (the p values).  
 
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 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 pub lication 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 decla re 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  
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on my re port to the authors and, if the manuscript is accepted for publication, my named report 
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to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal