Title: Association between Dietary Insulin Index and Postmenopausal Osteoporosis in Iranian
Women: A Case-Control Study
Version: 1 Date: 12 Mar 2024
Reviewer:  Negin Nikrad
Reviewer's report:
The work from Solgi et al aimed to investigate the relationship between dietary insulin index
and osteoporosis. The study is interesting, however, there are a couple of major issues that I am
concerned about that I feel need to be addressed. They are as follows:
Major issues:
• I would suggest that the title of the article could be improved for clarity and conciseness.
One possible revision could be: "Association between Dietary Insulin Index and Osteoporosis
in Postmenopausal Iranian Women: A Case-Control Study." This revised title provides a clearer
indication of the study's focus and the population being studied.
• I would recommend including a paragraph on the risk of bone disorders and the prevalence of
osteoporosis in postmenopausal women in the introduction section of the study. This information
is crucial for providing context and background for the research being conducted, especially
since the study is focused on postmenopausal women. By highlighting the importance of these
factors early on, readers will have a better understanding of the significance of the study and its
relevance to the target population. This can also help set the stage for the research objectives
and hypotheses that will be explored in the study. Including this information in the introduction
section will enhance the overall quality and impact of the research.
• Discrepancies between the number of items in the Food Frequency Questionnaire (FFQ) as
mentioned in the reference and the method section can lead to confusion and raise questions
about the reliability of the study. It is crucial to address this discrepancy and clarify the actual
number of items in the FFQ used in the study. The FFQ mentioned in the reference contains 168
items, if you have declared in the method section, it has 147 items.
• The discrepancy between the reference article by et al Sadeghi, which mentions using a 1,000-
kJ (239 kcal) portion for both the test food and reference food, and your statement about using
1000 kcal for the test meal and glucose reference food raises concerns about the methodology
used in the study. It is important to clarify and confirm the correct unit of measurement for the
portion sizes used in calculating the FII. If the reference article specifies using 1,000-kJ (239
kcal) portions, it is essential to adhere to this standard to ensure consistency and comparability
with existing research in the field. I recommend revisiting the methodology section, verifying
the correct portion sizes, and making any necessary corrections to align with the established
protocol for calculating the FII. This will help maintain the integrity and validity of the study
results.
• it is essential to address the critical role of nutrients such as vitamin D and calcium in
bone density and overall bone health. In reviewing the study, it is concerning that there is
no adjustment for these key nutrients, which are known to play a significant role in bone
health. Without accounting for the intake of vitamin D and calcium, the study may lack
important information that could impact the interpretation of the results related to bone density.
Furthermore, the absence of information on the levels of vitamin D intake and the duration of
exposure to sunlight is a notable limitation. Vitamin D synthesis through sunlight exposure is a
crucial factor in maintaining adequate levels of this essential nutrient for bone health. Without
details on vitamin D intake levels and sunlight exposure duration, it is challenging to fully assess
the impact of these factors on bone density outcomes in the study population.
• I recommend addressing these gaps in the study by considering adjustments for vitamin D
and calcium intake and providing information on vitamin D intake levels and sunlight exposure
duration. By incorporating these essential details, the study can enhance its validity and provide
a more comprehensive analysis of the relationship between nutrient intake, sunlight exposure,
and bone density.
• To avoid the wrong generalization of the results to different populations, it is better to highlight
in all the manuscript sections such as keywords and conclusion of the studied population
(postmenopausal women).