Cut off Value for Parathormone Level in Children with Vitamin D Deficiency

Background: When serum level of ۲۵-hydroxy vitamin D [۲۵(OH) D] decreases, intact Parathormone (iPTH) level increases compensatory. This study aimed to determine the cut off value for iPTH level in ۲-۱۴-year-old children with vitamin D (VD) deficiency. Methods: This cross-sectional study was performed on ۱۵۳ children aged ۲-۱۴ years old who referred to the endocrinology clinic of Amirkola Children's Hospital for growth assessment. Census sampling was conducted from January ۲۰۱۶ to June ۲۰۱۷ according to the eligibility criteria including height and weight above the percentile of ۳% of growth charts and normal serum of calcium level (>۸.۵ mg/dl). Laboratory parameters such as serum calcium, ۲۵(OH) D and iPTH levels were assessed. The children were divided into three groups based on serum levels of ۲۵(OH) D as mild, moderate and severe VD deficiency. The Receiver Operating Characteristic (ROC) curve was used to analyze the cut-off point of iPTH and ۲۵(OH) D. P-Value< ۰.۰۵ was considered significant. Results: The mean VD and iPTH levels in children were ۱۱.۸ ± ۴.۵۹ ng/ml and ۲۸.۳ ± ۱۳.۳ pg/ml, respectively. At the iPTH serum level of ۲۳.۵ pg/ml, with a sensitivity of ۶۶.۱%, there was a possibility of moderate to severe VD deficiency. In the severe deficiency group, at the iPTH serum level of ۲۳.۵ pg/ml and above, with a sensitivity of ۷۸.۹%, there was a possibility of severe VD deficiency. The cut-off point of ۲۵(OH) D and iPTH, at the serum VD level ≤۱۰ ng/ml were determined. Conclusions: The results of the present study showed that the cut-off value for iPTH in children with VD deficiency is serum level of ۲۵OHD≤۱۰ng/ml.

Keywords:

Children , Parathormone , Vitamin D deficiency