Reviewer's report
Title:Correlation of body mass index levels with menarche in adolescent girls in
Shaanxi, China: a cross sectional study
Version:2Date:30 September 2015
Reviewer: Lisa Iversen
Reviewer's report:
The study seems to have employed thorough data collection methods but the
paper is let down by lack of: rational for the study, critical discussion of the
findings and clear explanation of the women included in the study.
Major compulsory revisions
1.The Background does not discuss why it is important to investigate age at
menarche, it would strengthen the paper to explain its importance particularly for
women’s health in later life.
2.The rationale for including the adult women is missing (also not mentioned in
the statistical analyses).
3.Sampling: the authors need to be explicit about the total number of adult
females and adolescents sampled and therefore be able to state the proportion
of those sampled who actually participated in the study.
4.Further description and presentation of the generalised linear model would be
helpful.
5.Methods indicate that interviews were repeated if logic errors were found. How
many and what proportion of interviews were repeated?
6.The Discussion lacks in-depth critique (both in terms of study limitations and
strengths). Discussion paragraph 3 states “our findings suggest that social and
economic development along with ongoing improvement in living standards in
both urban and rural areas are lowering the age of menarche” – it is not clear
how this small cross-sectional study suggests this. Effect modification of the
associated of BMI with age at menarche by socio-economic status is suggested
– did the authors try to examine this at all? The paper suggests that a study
limitation is that post-menarcheal participants were measured at different times of
the menstrual cycle – why is this a limitation and what impact would it have on
the study findings? No information is presented about women who were sampled
and did not participate so there should be discussion about how generalisable
the findings might be.
Minor essential revisions
1.The authors need to check that the references have been cited at the
appropriate points throughout the text, for example reference 16 has been used
in the Background to describe northern European data but the citation refers to a
study in urban and rural China.
2.It would be helpful to state the definition of adolescence used in the study.
3.The data in Figures 1 and 2 would benefit from being described more in the
text of the results.
4.Results: rather than say there are statistically significant differences between
menstruating and non-menstruating girls BMI Z-scores in terms of a number of
different factors, it would be more informative to describe the direction of the
differences or at least describe an example so the reader can interpret what the
differences actually say.
5.The presentation of the age at menarche by birth cohort before the height,
weight and BMI data for the current group of adolescents studied is confusing.
Recommend presenting all results relating to the adolescents first then the birth
cohort information.
Discretionary revisions
1.Some attention should be given to the labelling of the Tables/Figures – e.g.
Table 3 are the figures presented means (SD)? If so, it should be stated.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests