Effect of Vitamin D level on growth velocity of RHGH treated children

Abstract

Objective Recent studies have shown a relationship between vitamin D status, growth hormone and insulin-like growth factor 1 axis. Aims of the study are: 1- To evaluate the vitamin-D blood level in children on substitution treatment with rhGH. 2. To find out correlation between the vitamin D level and growth velocity with rhGH therapy, height, height SDS, height/height SDS after 1 year of treatment Methods The study included 173 prepubertal children, with short stature on treatment with rhGH (90 girls and 81 boys), aged between 2 and 10.3 years. To determine vitamin D status we measured serum 1,25-OH vitamin D by taking a single blood sample in the morning, in a fasting stage. Growth velocity over the year of observation, starting height, height SDS, height at the end of the year and its SDS all were calculated and correlated to vitamin D level. Results In the present study: 56 patients had vitamin D deficiency (<10 ng/ml); 54 had vitamin D insufficiency (10–20 ng/ml) and 63 had vitamin D sufficiency (>20 ng/ml). No statistical significance correlation was found between vitamin D level and height, height SDS, follow up height, and follow up height SDS (P.09, .066, .455, .927 respectively) Significant positive correlation was found between vitamin D and growth velocity (r .445 and P.0001). Conclusions Optimizing vitamin D level in patients with short stature under growth hormone therapy may improve growth velocity and response to growth hormone.