Pediatric Hematology and Oncology, Early Online:1–2, 2015 C Informa Healthcare USA, Inc. Copyright  ISSN: 0888-0018 print / 1521-0669 online DOI: 10.3109/08880018.2015.1022916

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Low Vitamin D Levels: Are Associated with both Iron Deficiency and Anemia in Children and Adolescents? ¨ ˘ Kartal2 Omer Kartal1 and Ays¸e Tugba 1

Aksaz Military Hospital, Department of Pediatry, 48750, Mugla, Turkey; 2 Marmaris State Hospital, Department of Pediatry, 48750, Mugla, Turkey

We have read, with great interest, the recent article by Lee. In this excellent study, the authors investigated the association between vitamin D deficiency and anemia in a nationally representative sample of Korean children and adolescents. They concluded that vitamin D deficiency is associated with increased risk of anemia, especially iron deficiency anemia, in healthy female children and adolescents. We appreciate and congratulate the authors for having addressed such an important issue. However, we have some concerns regarding this report, which we would like to share with you. As a result, further studies are needed for the association between vitamin D deficiency and anemia. Factors affecting Vitamin D status and anemia such as measurement method, nutrition, medications, and infections should be considered to conclude an association between vitamin D and anemia. Therefore, we think that considering these confounders would add value to this well-written article. Keywords

Anemia, HPLC, Iron deficiency, LC-MS, Vitamin D

TO THE EDITOR We have read with great interest the recent article by Lee [1]. In this excellent study, the authors investigated the association between vitamin D deficiency and anemia in a nationally representative sample of Korean children and adolescents. They concluded that vitamin D deficiency is associated with increased risk of anemia, especially iron deficiency anemia, in healthy female children and adolescents. We appreciate and congratulate the authors for having addressed such an important issue. However, we have some concerns regarding this report, which we would like to share with you. Initially, there are several methods for testing blood levels of Vitamin D; however, reliability of these methods are controversial [2]. Vitamin D status can be determined by using high-performance liquid chromatography (HPLC), liquid chromatographymass spectroscopy (LC-MS), immunoassay, and Vitamin D binding protein based enzymatic assay [2]. Such varied testing technologies may yield different result, with inter-assay variation reach as much as 10% [2–3]. Therefore, HPLC or LC-MS methods, which were reported gold standard techniques for testing blood levels of Vitamin D could be used to decrease bias [3]. Received 20 January 2015; accepted 27 February 2015. ¨ Address correspondence to Omer Kartal, MD; Aksaz Military Hospital, Department of Pediatry, Mugla/Turkey; Tel: +905424610715. E-mail: [email protected]



¨ Kartal and A. T. Kartal  O.

Pediatr Hematol Oncol Downloaded from informahealthcare.com by McMaster University on 08/10/15 For personal use only.

Secondly, Vitamin D deficiency is a common condition between children who are dark skinned, on vegetarian and unusual diets, using anticonvulsant or antiretroviral medications [4]. Furthermore, major causes of anemia seen in children are infections, chronic diseases, and medications [5–6]. However, authors did not mention neither these factors that may affect Vitamin D status nor major causes of anemia seen in children. As a result, further studies are needed for the association between vitamin D deficiency and anemia. Factors affecting Vitamin D status and anemia such as measurement method, nutrition, medications, and infections should be considered to conclude an association between vitamin D and anemia. Therefore, we think that considering these confounders would add value to this well-written article. Declaration of Interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article. REFERENCES [1] Lee JA, Hwang JS, Hwang IT, et al. Low vitamin D levels are associated with both iron deficiency and anemia in children and adolescents. Pediatr Hematol Oncol. 2014; doi:10.3109/08880018.2014.983623. [2] Singh RJ. Quantitation of 25-OH-vitaminD (25OHD) using liquid tandem mass spectrometry (LC-MSMS). Methods Mol Biol. 2010;603:509–517. [3] de la Hunty A, Wallace AM, Gibson S, et al. UK Food Standards Agency Workshop Consensus Report: the choice of method for measuring 25-hydroxyvitamin D to estimate vitamin D status for the UK National Diet and Nutrition Survey. Br J Nutr. 2010;104:612. [4] Gr¨ober U, Kisters K. Influence of drugs on vitamin D and calcium metabolism. Dermatoendocrinol. 2012;4:158–166. [5] Brotanek JM, Gosz J, Weitzman M, et al. Secular trends in the prevalence of iron deficiency among US toddlers, 1976-2002. Arch Pediatr Adolesc Med. 2008;162:374. [6] Northrop MS, Agarwal HS. Ceftriaxone-induced hemolytic anemia: Case report and review of literature. J Pediatr Hematol Oncol. 2015;37:e63–66.

Pediatric Hematology and Oncology

Low Vitamin D Levels: Are Associated with Both Iron Deficiency and Anemia in Children and Adolescents?

We have read, with great interest, the recent article by Lee. In this excellent study, the authors investigated the association between vitamin D defi...
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