The paper titled“Comparison of the serum vitamin D level in patients with iron deficiency anemia, beta thalassemia with the control subjects”  was assesesd and the following needs to be explained(1).

Usually , the rational for the research should be explaied in  introduction part. This part is too long and contains unnecessary information which  does not help to address the possible association of vitamin D deficiency, neither with  a genetic condition such as beta thalassemia a minor, nor with  iron deficiency anemia. to address these issues, the writer should refer to  some physiologic or pathophysiologic explanation of the research.

Regarding the design method, I should say that; there is not such a method as “descriptive-analytical cross sectional” design. Cross sectional descriptive researche is  meant to answer epidemiologic questions and have some obligations such as random sampling, which was not the case in this study (2). On the other hand,  analytical studies are designed to find the role of a risk factor in developing an outcome. Case-control studies and cohort  studies are the examples of analytical designs. In this case,  vitamin D deficiency is not the risk factor for neither iron deficiency nor the beta thalassemia. Thus, there is  no reason for selecting such a method. However, an association of two nutritional disorders is well known and is addressed in the discussion of the paper (1). I believe this paper is the result of an irrational sampling.

The sample size should be explained in any research methodology whether the  study is cross-sectional or analytic, but in this article  the sample size  is not rationalized.

Given an important point in analytical researche is the way that confounding variables are being dealt with,  this paper does not mentioned these variables such as job, sun exposure, diet and specially using nutritional supplement are not addressed. However, two important variants of age and gender have been matched (1).

There are a  large number of researche regarding vitamin D deficiency in Iran that are not addressed in this paper. In some of these, the definition of vitamin D deficiency is on the basis of serum parathyroid hormone (PTH) (3). In a systematic review and meta analysis of Heshmat et al. 77% of Iranian population had vitamin D deficiency (4). This high prevalence could be associated with any, even unrelated condition.

Result should be started with introducing the groups including the matched variables such as age and gender. For showing the results, table is better than the the text. without statistical tests and P values, explaining the difference is  not acceptable in scientific writings.

Discussion part of the paper was mostly the repetition of the introduction. I was not convinced by the discussion. It seems that the concept of “association” was confused with " causation" .

Kosarian, M. (MD)

Professor of Pediatrics, Thalasemia Research Center,

Mazandaran University of Medical Sciences, Sari, Iran

            The main objective of this study was to compare the lack of vitamin D or association of iron deficiency anemia with healthy individuals.

the case group were the  patients with iron deficiency anemia and the  two controls  were Thalassemia Minor and  Healthy people.  The Thalassemia Minor Group, in  a microcytic anemia, was similar to the control group. the cause of microcytic is genetic  rather  iron deficiency.

 The Sampling was census.The  participants were the students who have been enrolled in that year; therefore, the Random sampling is not considered.

The design of a research  defines the  type of the study.

The printed research was designed in two categories: Cross sectional study (The Nutritional Target) and Analytic (comparison between the three groups)

Sinct all the participants  were students, the impact of the job, nutrition and… other factors, were the same.

Considering the prevalence of vitamin D deficiency, less than 50 percent, in control group shows that this deficiency could be varied in different groups.

This study basically was designed just to express the association or lack of association of iron deficiency anemia.

As shown in the results and discussion, The amount of vitamin D deficiency in patients with iron deficiency was more than the control group.

Given that Vitamin D deficiency in patients with iron deficiency brings about  Various complications for Growth and health, this study largely emphasizes follow-up of these patients.