Reviewer's report
Title:Age at Menarche and the Menstrual pattern of secondary school
adolescents in North Western Ethiopia
Version: 2Date:16 June 2009
Reviewer: Dan Apter
Reviewer's report:
The topic of the paper is, as the title indicates, age at menarche and menstrual
pattern of secondary school pupils in a specified region in Ethiopia. As described
in the introduction, age at menarche depends on several factors. It is of interest
to obtain data from various parts in the world in specified circumstances. The
paper is therefore of potential interest.
The main result is age at menarche of 15,31 years, which is surprisingly high.
Major concerns
Unfortunately, there are several methodological problems. The authors have
used a recall method calculating mean. The most appropriate method to estimate
age at menarche is considered the age by which 50% of the subjects have
reached menarche. This requires that age at menarche has been exactly
recorded. In the attached questionnaire is asked “How old were you when you
started menstruating” This can be answered in many ways. No instructions are
presented. Were any provided? The most common way of answering could be
age in full years reached at last birthday before menarche. Some could provide
age at following birthday. Both are too inexact. 15 could mean anything from 15.0
to 15.9. Please describe in detail what the answers to question 7 were like. Are
births evenly distributed throughout the year? If so, in a large enough group the
mean age at menarche of those answering 15 would be close to 15,5. Was this
used? Preferable, date of birth and date of menarche should be registered, and
then age at menarche calculated.
The recall mean method is only possible to use in a population where all subjects
have reached menarche, and remember when that occurred. The authors state
that 47 (7,5%) with a mean age of 15,9 had not yet reached menarche, and were
excluded from further analysis. Thus the result of 15,31 is an underestimation.
If no decimals were known for age at menarche, the mean result should not be
given with 2 decimals.
Please provide a table with the number of subjects having had menarche at each
annual age group
Question 8. As many girls have variable cycle length, what instructions were
provided: to answer according to last cycle, or mean for recent cycles (for what
time period?)
Cycle length and regularity should be given not only in relation to age at
menarche, but also in relation to time since menarche (=”gynecological age”)
Please describe how the number of subjects with premenstrual symptoms was
obtained (any tick in 12?)
Top of page 12 says “PMS was not significantly associated with age at
menarche, duration of menses, cycle length (Table 4), marital status,
contraception use or
initiation of sexual activity (not shown on the table).”
How many subjects were using hormonal contraception? Were they not excluded
from the analyses of cycle length, dysmenorrhea etc?
Minor points
Introduction, end of first paragraph: For the first few years after menarche,
irregular and longer cycles are common. please provide reference
Suggest to delete, as not related to topic: A woman’s cycle tends to short and
become more regular with age. This variability will return 2-3 years before
menopause [3, 5, 6].
Sample size calculation, relevant for what?
Language needs corrections
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