ESPE Abstracts

Background: The lack of agreement in the definition of vitamin D deficiency may be due to differences in the study populations or in the assays used to measure 25OHD.

Objective and hypotheses: The aim of this study is to evaluate the relationship between 25OHD and PTH, and define the level of vitamin D deficiency in a paediatric population.

Method: Retrospective medical record of children (age: 0.1–18years, n=193) who visited to EUMC and underwent simultaneous measurement of serum 25-OHD and PTH levels was reviewed.

Results: Serum 25OHD was positively correlated with serum calcium (r=0.359, P<0.001), phosphorus (r=0.359, P<0.001). The serum PTH was negatively correlated with serum 25OHD level (r=−0.406, P<0.001). The best inflection point of serum 25OHD for maximal suppression of PTH was a level of 18.0 ng/ml (CI 14.2–21.7 ng/ml). Median PTH level of children with 25OHD <18.0 ng/ml was higher compared to children with 25OHD ≧18.0 ng/ml (62.1 (5.6–445.1) ng/l vs 24.2 (4.4–201.8) ng/l, P<0.0001). Median calcium level of children with 25OHD <18.0 ng/ml was lower compared to children with 25OHD ≧18.0 ng/ml (9.1 (5.6–10.5) mg/dl vs 9.4 (7.9–10.8) mg/dl, P=0.0001). Median phosphorus level of children with 25OHD <18.0 ng/ml were lower compared to children with 25OHD ≧18.0 ng/ml (4.9 (2.3–7.8 mg/dl)mg/dL vs 5.2 (2.1–8.2) mg/dl, P=0.0460). The children with 25OHD <18.0 ng/ml had 49.2% hyperparathyroidism, 39.3% hypokalemia, hypophosphatemia 24.6 and 9.8% rickets.

Conclusion: These data suggest that vitamin D level of 18.0 ng/ml should be the deficiency level of 25OHD in children which is based on PTH elevation.