Parathormone, bone alkaline phosphatase and 25-hydroxyvitamin D status in a large cohort of 1200 children and teenagers

Objectives 25-Hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and bone alkaline phosphatase (BALP) are biomarkers of calcium/phosphate metabolism and bone turnover. Although vitamin D deficiency is a well-known cause of secondary hyperparathyroidism, few studies have considered vitamin D status when establishing reference ranges. In this study, we report PTH levels according to the vitamin D status and BALP levels in a large cohort of 1200 children. Additionally, we provide PTH pediatric reference values according to 25(OH)D status as well as BALP pediatric reference ranges. Methods Serum samples from 1200 children (equally distributed from 5 months to 20 years old) who underwent blood sampling for allergy exploration were used to quantify 25(OH)D, PTH and BALP. Results The percentage of vitamin D deficient children (<20 ng/ml) progressively increased during childhood starting from 7% in the 0 to 2 year-old subgroup to a mean of at least 50% among teenagers. PTH levels inversely mirrored 25(OH)D concentrations for all age and gender subgroups, and 25(OH)D deficient subgroups presented higher PTH levels than their non-deficient counterparts. In the non-deficient 25(OH)D population, PTH levels were the highest at 11 years old for girls and 14 years old for boys. BALP results were slightly increased during childhood and showed a constant decrease during teenage years starting from 12 years old for girls and 14 years old for boys. Conclusion Our results highlight the inverse relationship between PTH and 25(OH)D in children and the need for a well characterized 25(OH)D population to establish pediatric reference ranges for PTH.

Automated summary

This study reports PTH levels and BALP levels in a large cohort of 1200 children according to their vitamin D status. The results highlight the inverse relationship between vitamin D deficiency and PTH levels in children, emphasizing the need for a well characterized pediatric population to establish reference ranges for PTH.