Relationships between Vitamin D and Selected Cytokines and Hemogram Parameters in Professional Football Players—Pilot Study

Round 1

Reviewer 1 Report

Authors aims at investigating the relationship between 25(OH)D concentration and selected cytokines, hemogram parameters in high-rank football players. Authors found that football players from Poland are not protected against vitamin D insufficiency in winter months; and Vitamin D deficiency may be associated with an increased pro-inflammatory risk in well-trained athletes.

This is a nice article, well written, concise. Methodology is robust. Statistical analysis is well conducted.

Some minor issues:

 

- I would suggest commenting on the relationship between vitamin D levels and cardiac/vascular structure and the potential interplay between VitD/cytokines/cardiovascular structures (J Clin Endocrinol Metab. 2012 Oct;97(10):3717-23.; J Intern Med. 2013 Mar;273(3):253-62.).

- Can you correlate vitD/cytokines data with any performance indexes?

- Can you specify whether the cutoff of 20ng/ml for Vit D has been used?

Author Response

Dear Reviewer,

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Dr. Książek and Dr. Słowińsk –Lisowska

Thanks for your manuscript on vitamin D and cytokines in professional football players.

First, please make a table to summarize the characters of the participants. (Line 80-82).

Now, let us go over the  Newcastle-Ottawa Scale (NOS), which is used for assessing the quality of pilot studies.

 

Cohort Star Template	Selection of cohorts				Comparability of cohorts	Outcome			Rank
Study	Representativeness of the exposed cohor	Selection of the non exposed cohort	Ascertainment of exposure	Demonstration that outcome of interest was not present at start of study	Comparability of cohorts on the basis of the design or analysis	Assessment of outcome	Was follow up long enough for outcomes to occur	Adequacy of follow up of cohorts	Thresholds for converting the Newcastle-Ottawa scales to AHRQ standards (good, fair, and poor):
Before modification	*	NA	*	NA	*	*	NA	NA	Poor quality
After  modification	*	NA	*	*	*	*	*	NA	good quality or at less fair quality

 

Please answer the question below,

1. To get the star for “ Demonstration that outcome of interest was not present at the start of study”, did you measure the baseline of the vitamin D and cytokines and hemogram factors you observed in another season as a baseline ? Just to confirm all the participants are not vitamin D insufficient or deficiency at the beginning of the enrollment. If not, please cite some data from other studies in the summer or just write it as a limitation.
2. This is for the star about “ Was follow up long enough for outcomes to occur”. As you mentioned, “our study were evaluated in December and January “. ( Line 175) Could you mention December and January in the “ blood test” paragraph ( Line 100)? Could you mention a little bit why you choose this time for the discussion part? Please give evidence whether is it long enough for vitamin D (insufficient or deficiency happen?)

 

Thank you so much again and I am looking for your answers.

Author Response

Dear Reviewer,

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I accepted the present form. Best of luck in your future endeavors!