Bone Abstracts

Objectives: The correlation between vitamin D and GH–IGF1 axis is documented. Growing children, need extra Vit-D because it is required for growth. Severe deficiency in Vit-D generates poor growth. Height is usually more affected. Growth hormone (GH) deficiency in children causes severe growth retardation, Vit-D deficiency, and osteopenia. The aim of this presentation was: 1. To evaluate the Vit-D blood level to children in substitution treatment with rhGH. 2. To see if there is a correlation between the very low level of Vit.D (<10 ng/ml) and low answer (low velocity) to therapy with rhGH.

Methods: The study included 105 children and adolescents (56 girls and 49 boys), aged between 0 and 18 years, enrolled in our clinic in treatment with rhGH. To determine vitamin D status we measured serum 25-OH D3 by taking a single blood sample in the morning, in a fasting stage. We categorized vitamin D levels in three subgroups: deficiency (<10 ng/ml); insufficiency (10–20 ng/ml) and sufficiency (>20 ng/ml).

Results: The mean level of Vit-D was 18.7 ng/ml. 52% of subjects had the level of Vit-D less than 20 ng/ml, of which 10% with deficiency state. Of the total children followed, 59 were with growth hormone deficiency (GHD) (56%). Of these 54% were girls and 46% boys. At them 55.2% have had a Vit-D level >20 ng/ml and only 8.8% value <10 ng/ml. At the last of them we followed velocity on 12 months under treatment with rhGH and then another 12 months under rhGH treatment and with Vit-D supplementation: 500 IU×2 of vitamin D3 daily. The velocity increased in second year when GH therapy was associated with the supplement of vitamin D from a mean of 5.5 cm per year to a mean of 8.5 cm per year.

Conclusions: Insufficiency of Vit-D has been found in over 50% of children and adolescents followed by us. Slower growth in children already under replacement treatment with rhGH, could be caused by the low level of Vit-D. Supplementing with Vit-D can improve speed of growth in these children.

Disclosure: The authors declared no competing interests.