Reviewer’ s report
Title: Changes in six domains of cognitive function with reproductive and chronological ageing
and sex hormones: a longitudinal study in 2411 UK mid-life women
Version: 1Date: 31 Jan 2020
Reviewer: Dorota Raczkiewicz
Reviewer's report:
The article contains a large number of data, the topic is very interesting, but the presentation
requires a revision.The article is too long, there are too many tables (4 in the main text and 7 in the supplementarytext = 11 tables in total). When one reads the text, they must jump between the main and thesupplementary text, to refer to different tables. Therefore, it is not easy to follow what was theintention of the authors. The text doesn't flow.The whole article requires proper organisation.Some parts of the text are copied and used twice, for example Analysis strategy Main results...page 9 rows 20 to 58 and Supplementary text page 1 - the same.
The language used is not specific enough and leaves the reader with uncertainty.
Instead of "repeat measurements", the authors should use "repeated measurements".When the word "clinic" is used, the reader may think that the study was conducted in threedifferent clinics as units/hospitals, but not three times in every woman (at pre-menopause, at peri-menopause and at post-menopause).In the Results and Discussion sections, when "verbal episodic memory" is used, it is not clear
whether it refers to immediate or delayed memory.
Two expressions „cognitive function" and „change in cognitive function" are sometimes used as
synonyms. The same is true for hormones.A correlation between cognitive function and hormones serum concentration is not the same as acorrelation between cognitive function changes and hormones serum concentration changes.Change in reproductive hormones or change in hormone serum concentration?
Introduction section
Why have these 3 sex hormones (FSH, LH, AMH) been chosen? It should be explained in theIntroduction. Especially, why was not estradiol chosen. It could correlate with cognitive functions,too.Methods sectionThe first part is without subsection title. It should be called "Study group". Some informationabout the study group is placed in other parts of the article and should be moved into the Studygroup, for example the information about what was the period between assessments, is notincluded until page 9.Please use "Inclusion criteria...." and "Exclusion criteria...." - then Figure 1 from the
Supplementary text will not be needed.
There should be information in the Study group subsection, how many women were included at
least ones in the study), and also:how many women were examined 3 times (at pre-menopause, at peri-menopause and at post-menopause),how many at pre and peri-menopuse,how many at peri-and post-menopause,how many at peri- and post-menopause,how many only at pre-menopause,how many only at peri-menopause,
how many only at post-menopause.
There is the lack of information about race of the examined women.Methods section - Hormones - why were only 3 sex hormones examined? In what day of the
menstrual cycle were hormones tested?What was the methods of standardization?
Methods section - Cognitive tests and table 1:
There is a lack of information, which test has a positive direction (the more scores the bettercognitive function) and which test has a negative direction (the less scores the worse cognitivefunction). Working memory test seems to have a negative direction, whereas the other tests -positive.Thus, do the authors realize the fact that, if a test has a positive direction, negative change means adecrease in cognitive function. Adversely, if a test has a negative direction, negative change meansan increase in cognitive function.There is a lack of information, what was the range for every test (minimum value and maximumvalue).
Are there any interpretation's standards for every test, for example score from 0 to 3 means low
cognitive function, scores from ... to ... moderate, ... high?What was the methods of standardization for cognitive functions?
Methods section - Confounders would be better if pointed 1).. 2) etc.
Methods section - Analysis strategy should be better organised and called "Statistical methods". Inthis subsection the authors wrote only about multilevel regression, but they used more statisticalmethods in the article which also should be written about.
The Results section should be divided into subsections beginning with Sample characteristics
subsection in relation to menopause stages not to clinic assessments. The same should be done forhormones, as it was done for cognitive functions in table 3 - all with p-values.The conducted analysis, tables, figures and results description should be rearranged and shortened,in order to make it clearer by using my comments regarding the Methods section.There are too many regression models.
p-value should be added in all the statistical tests in all the tables.
A list of abbreviations should be provided.
Sample size and number of domains are not needed in the title of the article.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Unable to assess
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
YesAre the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
NoAre 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 furtherassessment in your comments to the editors.
I recommend additional statistical review
Quality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being publishedDeclaration of competing interests
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