Pediatric reference values for serum zinc concentration in Iranian subjects and an assessment of their dietary zinc intakes Asghar Ghasemi a , Saleh Zahediasl a, ⁎, Firoozeh Hosseini-Esfahani b , Leila Syedmoradi a , Fereidoun Azizi a a Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran b Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran abstract article info Article history: Received 30 April 2012 received in revised form 24 June 2012 accepted 5 July 2012 Available online 20 July 2012 Keywords: Adolescent Children Reference value Serum zinc Zinc intake Objectives: To determine pediatric reference values for serum zinc concentration in Iranian subjects. Design and methods: Serum zinc concentration was measured by flame atomic absorption spectrometry in 699 children and adolescents. Reference values for serum zinc were determined according to the Clinical and Laboratory Standards Institute/International Federation of Clinical Chemistry guidelines. Dietary zinc in- take was assessed using a validated semiquantitative food frequency questionnaire. Results: Overall 95% reference values for serum zinc concentrations were 9.7–31.5, 9.2–30.9, and 9.3– 31.1 μmol/L in boys, girls, and total population respectively. Serum zinc concentrations were comparable in boys and girls (17.5 ± 5.3 μmol/L vs. 17.2 ± 5.6 μmol/L, p = 0.242). The dietary zinc intake of 7.6% (4.9% boys and 10.2% girls, p b 0.01) was lower than the estimated average requirement. Conclusions: This study presents pediatric reference values for serum zinc concentrations, values that could help diagnose and manage zinc deficiency in pediatrics. © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Introduction Zinc, an essential trace element, plays a key role in growth rates of children and adolescents [1]. Zinc deficiency, one of the ten major fac- tors contributing to disease burden in developing countries [2], un- derscores the urgent need for identifying countries at increased risk for zinc deficiency [3]. The consultation workshop held by the World Health Organiza- tion (WHO), the International Atomic Energy Association (IAEA), and the United Nations Children's Fund (UNICEF), has assessed avail- able indicators of population zinc status including biochemical, die- tary, and functional assessments [3]. Dietary assessment per se should not be used to define zinc status but could be used for deter- mining the risk of zinc deficiency in a population [3]; when dietary assessment is combined with biochemical indicators of zinc status such as serum zinc, conclusions regarding level of zinc deficiency and need for intervention may be reached [3]. Currently plasma/ serum zinc level is the most practical and widely used indicator for determining zinc deficiency [4]. Appropriate reference intervals are necessary for pediatric practice and could be used for interpretation and clinical management of zinc disorders [1]. Recently it has been reported that relatively limited data have been presented regarding zinc status in pediatrics, even in the United States [1]. Normal ranges for trace elements vary for different population and should be established regionally [5]. To the best on our knowledge, there is no population-based report of pediatric refer- ence values for serum zinc concentration in Iran. The aim of this study was therefore to establish reference values for serum zinc in a healthy population of children and adolescents. In addition, we evaluated indi- vidual dietary zinc intake and its relation to serum zinc concentration. Materials and methods Subjects Study participants were 699 children and adolescents, aged 3–18 years, randomly selected from the cohort of the Tehran Lipid and Glucose Study between July 2008 and July 2011. Subjects with conditions that affect serum zinc concentrations, were excluded from the total population [4]. After excluding those with cancer, diar- rhea, those using medications and subjects who had been hospital- ized during the past 3 months, 672 subjects (boys = 323 and girls = 349) remained in the analyses. None of the participants was smokers, diabetics, pregnant, or lactating. The study was approved by the ethics committee of the Research Institute for Endocrine Sciences of Shahid Beheshti University of Medi- cal Sciences. Informed written consents were obtained from both par- ents and adolescents, aged ≥15 years; informed assent was obtained from participants b 15 years of age. This study was conducted in accor- dance with the principles of the Declaration of Helsinki. Clinical Biochemistry 45 (2012) 1254–1256 ⁎ Corresponding author at: Endocrine Physiology, Endocrine Research Center, Re- search Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, No. 24, Parvaneh Street, Velenjak, P.O. Box 19395‐4763, Tehran, Iran. Fax: +98 21 22402463. E-mail address: zahedi@endocrine.ac.ir (S. Zahediasl). 0009-9120/$ – see front matter © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2012.07.086 Contents lists available at SciVerse ScienceDirect Clinical Biochemistry journal homepage: www.elsevier.com/locate/clinbiochem