HOMA-IR and serum vitamin D in obese children with metabolic syndrome.

Background: Vitamin D deficiency was a risk factor of metabolic syndrome and insulin resistance which causes premature morbidity and mortality. It was associated with the action of vitamin D through its various cell receptor. Purpose: To examine the correlation between Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) and serum 25-hydroxyvitamin D (25-OH) D level in obese children with metabolic syndrome. Methods: A cross sectional study on 6 to 18 years old students was conducted during June until August 2017. The samples consisted of 43 children with metabolic syndrome and 40 children without metabolic syndrome based on Indonesian Pediatric Association criteria. Serum level of 25 (OH) D was measured using Enzyme-Linked Immunosorbent Assay. HOMA-IR was used to calculate insulin resistance. Vitamin D deficiency was defined as serum 25 (OH) D <20 ng/mL. Data were analyzed using IBM SPSS version 21. Results: Mean of vitamin D level in obese children with metabolic syndrome was 14.55 ng/mL, and without metabolic syndrome was 22.78 ng/mL. The frequency of metabolic syndrome was 70.6% in obese children with vitamin D deficiency, while in normal vitamin D status was 21.9% (p<0.001; OR=8.571 (CI 95% 3.054-24.060). It was negative correlation between level of 25 (OH) D with fasting plasma insulin (r=-0.587; p <0.001), as well as HOMA-IR (r=-0.481; p <0.001) for all subjects. Conclusion: Obese children with vitamin D deficiency were more risky to experience metabolic syndrome than obese children with normal vitamin D status. Level of 25 (OH) D was inverse correlation with fasting plasma insulin and HOMA-IR