Reference range of random urinary calcium creatinine ratio in North Indian children and adolescents

Urinary calcium creatinine ratio (UCaCrR) is a reliable indicator for monitoring hypercalciuria following vitamin D supplementation. However, the reference range varies from region to region. Previous studies did not take vitamin D and parathyroid hormone status into account while evaluating UCaCrR. Hence, we undertook this study to establish the 95th percentile of UCaCrR as an indicator of hypercalciuria in North Indian children and adolescents. Four hundred seventy-three participants (boys 62.2%, girls 37.8%) with adequate dietary calcium intake, normal serum levels of 25-hydroxy-vitamin D (>20 ng/mL), and without secondary hyperparathyroidism following supplementation were selected for evaluation of UCaCrR. The mean age and body mass index of subjects were 11.2±2.6 years and 18.0±3.6 kg/m2, respectively. The 95th percentile of UCaCrR in the study population was 0.126. The mean, median, and 95th percentile of UCaCrR was significantly higher in prepubertal children (age ≤10 years) (0.0586±0.0374, median=0.0548, 95th percentile=0.136) compared to those >10 years old (0.0503±0.0363, median=0.0407, 95th percentile=0.123, P=0.02). No significant difference in UCaCrR was observed between genders and different weight categories. UCaCrR of 0.13 defines the cutoff value for hypercalciuria in North Indian children and adolescents with adequate dietary intake of calcium and sufficient serum vitamin D levels.