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International Journal of Endocrinology
Volume 2013 (2013), Article ID 631845, 5 pages
http://dx.doi.org/10.1155/2013/631845
Clinical Study

Vitamin D Deficiency and Insufficiency in Obese Children and Adolescents and Its Relationship with Insulin Resistance

1Department of Pediatrics, Medical Faculty, Bezmialem Vakif University, Fatih 3409, Istanbul, Turkey
2Department of Pediatric Endocrinology and Metabolism, Medical Faculty, Bezmialem Vakif University, Fatih 3409, Istanbul, Turkey
3Department of Pediatric Nephrology, Medical Faculty, Bezmialem Vakif University, Fatih 3409, Istanbul, Turkey

Received 24 January 2013; Revised 7 March 2013; Accepted 8 March 2013

Academic Editor: Ajai Kumar Srivastav

Copyright © 2013 Emel Torun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives. We aimed to determine the relationship between insulin resistance and serum 25-hydroxyvitamin D (25-OHD) levels in obese children and their nonobese peers. Materials and Methods. Included in the study group were 188 obese children (aged 9–15 years), and 68 age- and gender-matched healthy children of normal weight as control group. Anthropomorphic data were collected on patients and fasting serum glucose, insulin, serum lipids, alanine aminotransaminase (ALT) and 25-OHD were measured. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated in both groups. Results. The levels of 25-OHD in the obese group were significantly lower than those of the nonobese ( ). HOMA-IR, triglycerides, low-density lipoprotein, and ALT levels in the obese group were significantly higher than values of control group ( and , resp.). In the obese group, vitamin D deficiency, insufficiency, and sufficiency (25-OHD < 10 ng/dl, < 20, >10 ng/dl; > 20 ng/dl, resp.) were not correlated with HOMA-IR ( , ). HOMA-IR was negatively correlated with BMI, BMI SDS, and BMI%, and triglycerides, low-density lipoprotein, and ALT levels ( ). Conclusion. The insulin resistance of the obese subjects who were vitamin D deficient and insufficient did not statistically differ from those with vitamin D sufficiency. Low 25-hydroxyvitamin D levels were not related with higher insulin resistance in obese children and adolescents. In obese subjects, insulin resistance was affected more from BMI, BMI SDS, and BMI% than from 25-hydroxyvitamin D levels.