ESPE Abstracts

Context: Optimal levels of 25-OH-Vitamin D (25OHD) for children are unknown. Prevalent population levels of 25OHD are likely to be sub-optimal since sun exposure is reduced in modern living.

Objective: To deduce recommended levels of 25OHD by testing, in children, the level at which 25OHD optimally effects calcium, phosphate and parathyroid hormone levels in a population-based data.

Design: An observational retrospective "big-data" study.

Methods: We analyzed 49,935 25OHD tests from children sampled in Clalit Health Services, Jerusalem district between 2009 and 2019. Associated data were available in the following number of samples: corrected calcium – 18,869, phosphorus – 1,241, calciumXphosphorus product – 698, and PTH - 449. We tested correlations between each parameter and 25OHD.

Results: There was a positive correlation between 25OHD levels and each of the parameters tested. The level at which increase in 25OHD continued to cause significant alteration in the corresponding parameter was: 1. For calcium – beyond 100 nmol/l (40 ng/ml), 2. For phosphorus up to 100 nmol/l (40 ng/ml), beyond this there was no further increase, 3. PTH there was a significant negative correlation up to 100 nmol/l. Beyond this, the trend continued the numbers were too small to reach significance.

Conclusion: 25OHD levels above 100 nmol/l are associated with improvement in parameters known to be associated with increased bone mineralization. Therefore, one should aim for a 25OHD level of 100 nmol/l or above.