Title: Effects of sleep pattern, duration, and quality on premenstrual syndrome and primary
dysmenorrhea in Korean high school girls
Version: 1 Date: 08 Jul 2023
Reviewer's report:
Thank you for the opportunity to review this work entitled “Effects of sleep pattern, duration, and
quality on premenstrual syndrome and primary dysmenorrhea in Korean high school girls during
the COVID-19 pandemic”. This challenge would be significance; however, further additions
and corrections are needed.
Major concerns
1. It is necessary to describe clearly what the hypothesis of this study is. With the current logic,
it appears that the study was only conducted because there are no studies that have examined
the association between sleep problems and menstrual symptoms in adolescent girls. That does
not seem to be a sufficient contribution to the development of science as a study. It seems to
me that an appropriate hypothesis can be derived from the numerous studies on sleep problems
and menstrual symptoms in adults.
2. How many female students were classified as having dysmenorrhea or premenstrual syndrome
respectively? Both are concepts that require a medical diagnosis. Therefore, the number and
percentage of students meeting each diagnostic criterion should be described. In addition,
multiple regression analysis requires a minimum of 15 cases per explanatory variable. If more
explanatory variables than the limit are entered into the regression equation, the results become
unreliable due to overfitting.
3. The 'stepwise method' (sequential selection method) is a method whereby statistical software
automatically selects a model with a good fit by adding and subtracting explanatory variables
one at a time. This method should generally not be used. Using the stepwise method is done by
people who do not know clinical practice. The correct method is to force-in as many explanatory
variables as possible that are clinically suggestive of an association with the explained variable,
based on the findings of previous studies and clinical judgement. In other words, in multivariate
regression analysis in clinical research, it is essential to select explanatory variables that are
considered clinically important by mobilizing all the expertise and knowledge in the individual
clinical fields.
4. The most important risk factors for dysmenorrhea and premenstrual syndrome should be
summarized in a table. This is redundant and confusing in the text.
5. I think it should be recognized that the results of this study were obtained during the lockdown
of COVID-19, and even if an association between sleep problems and menstrual symptoms was
found in female students, it is difficult to generalize. In addition, the conclusion should clearly
describe that this study was conducted during the COVID-19 lockdown.
6. The method in the abstract should state that it was conducted during the COVID-19 lockdown.
7. Although multiple risk factors were measured in this study, there is no evidence as to why
each factor is a risk factor for dysmenorrhea or premenstrual syndrome.
8. With regard to the reasons for participants being excluded from the analysis, the number of
participants for each reason should be clearly described. Consideration should also be given to
summarizing the results in a participant flow as a figure.
9. The authors classify each sleep variable (ie, bedtime, wake time, sleep time, and PSQI) as a
categorical variable, but provide no rationale for this classification.
10. Table 4 is confusing; bedtime, wake time, and sleep duration appear to be the only
independent variables. If so, no problem, but if not, it should be modified to make it clearer to
the reader.
Minor concerns
11. Write down the number of pages.
12. P5, L2: because of aca-demic… -> academic