Review for 10.1186/1471-230X-11-9 (2011)

Reviewer's report
Title:Dietary intakes in subjects with irritable bowel syndrome
Version: 1Date:4 October 2010
Reviewer: Christine Dancey
Reviewer's report:
The study seeks to clarify whether people with IBS have an adequate diet
(although the abstract implies that dietary exclusions will be focused on, see
below). I think this paper would be beneficial to those working in the IBS field,
and I hope the authors can address my comments below.
Dietary Assessment: I think it would be a good idea if you gave a bit more
information on the EPIC FFQ. We are told that the (modified) questionnaire
asked people to report their habitual intake of 134 food types over the previous
12 months. Why was it modified? In what way was it modified? What sort of
questions, or statements, are asked in this questionnaire? Without obtaining the
original reference, the reader does not know. Do you ask about exclusions? The
abstract states that “relatively few studies have undertaken a dietary assessment
in IBS sufferers to examine the wider impact of dietary exclusions” which seems
to suggest your study would be doing this, but although there is a brief mention of
this at the end of the discussion, this has not been addressed explicitly. Perhaps
you could add more about this?
Likewise, “ the FFQ data were entered into SPSS…..living in Newcastle” – The
reader will not be able to understand what has been done without reading the
original references. Just a bit more information on this would be beneficial to the
reader.
Statistical analysis: You have used a criterion value of p<.05 – did you consider
adjusting for multiple comparisons? I think you should defend this in the article.
I’m a bit confused about the statistical analysis and results. You say you used
ANOVA and unpaired t-tests, but I cant see any t-values, F values, or p values in
the results sections. On page 6 line above “Energy and macronutrients intake of
IBS Subjects” you say “p=.036 data not shown” – here I would expect to see t or
F values etc. The results section is the place for these statistics. It’s hard to
assess the discussion, without having an adequate results section.
Limitations
How likely are the participants to remember their intake of 134 food types over
the previous months? Wouldn’t a prospective study be a good idea for further
research? Sample – how representative is your sample?
The modified questionnaire – does validity hold once the questionnaire has been
modified?
These are points for discussion.
Minor points:
Could you please replace “subjects” with “participants” or “people with IBS”.
Could you clarify why you have used the Rome II criteria rather than III?
Page 4, first two lines: “…prior to an intervention trial fore pre-, pro- and
synbiotics”. Could this be reworded – it’s not quite right.
The use of initials rather than the full descriptions makes the text difficult to read
in places. Page 7 in particular includes many initials, e.g. EAR, NDNS, NSP.
Since there are no space constraints, the manuscript would be more readable
with the name in full, the first time it appears on a page, e.g. line 2 on page 7
would have NDNS in full, further mention would have the abbreviation on this
page. Likewise DRV and NSP. Similarly for other pages.
I look forward to seeing a revision.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I have no competing interests.