Title: Serum Selenium and Fasting Blood Glucose: A Cross-Sectional Study in Women of
Different Menopause Status
Version: 1 Date: 27 Jan 2024
Reviewer's report:
The problem touched in the paper is important. Recently, more and more evidence appears
highlighting the possible side effects of selenium supplementation or even direct selenium
toxicity, especially, regarding insulin resistance and related pathologies. Unfortunately, there
are some issues, some of them could be corrected, other should be discussed as limitations of
the study.
The text requires accuracy correction.
Introduction is insufficient. It does not provide clear mechanisms of the influence of selenium
status on T2D progression. The association of serum selenium with menopausal period also
remains uncovered.
For evaluation of selenium intake, the Authors used a double 24h-recall method, averaging
obtained results. The Authors provide some arguments pro the method and few words contra
in the limitation part. First of all, it should be said that the choice of the method for intake
assessment is still a subject for hot discussions. At the same time, saying honestly, the method
Authors used gave us the information about the selenium intake in two separate days, which can
be far from the average intake. And what is the average intake? There is no information about
the season when the dietary anamnesis was collected. But the season highly impacts the daily
products set. So, should we consider these levels of selenium intake as average for some exact
month? Or yearly average intake?
Moreover, there is no information if the dietary recall was controlled by a dietician or the patients
filled the questionnaires by their own.
I do not believe the above could be the basis for rejection, however I suppose that the Authors
should pay much more attention to the discussion of the limitations of the methods and why the
results should not be overestimated.
By the way, the selenium intake analysis did not provide any significant results unlike serum
selenium levels.
The choice of statistical methods should be explained in more detail.
The Authors show that selenium concentrations have different impact on FBS depending on
menopausal status. However, selenium metabolism is highly dependent on the body mass, while
BMI differed between groups which could be the source of bias. This should be at least discussed.
The Authors clearly demonstrate the association of serum selenium with FBS and T2D
prevalence regardless of all the covariates. However, I suppose valuable results could
be obtained if Authors compared subjects with normal/increased/reduced selenium blood
concentrations. Which clinical results do we have knowing the association of selenium serum
levels with FBS? Should we maintain fewer selenium blood levels in such patients? Then on
which exact levels? The Authors suggest not to take blind selenium supplementation in the
US population. However, it seems, that conclusions could be more precise if any numbers (of
selenium concentrations) were provided.
The Authors mentioned this but it should be marked more clearly: the sample size was rather
small. Moreover, the subgroups were not equal. The premenopause group contained of only 54
subjects. At the same time the inclusion criteria were not too strict.
Throughout the study the Authors sometimes refer to animal studies without mentioning this.
Taking into account that this research was in humans referring to investigations in animals the
Authors should mark that those results were obtained not in humans.