Endocrine Abstracts

Introduction: The start of GH (rhGH) treatment in children with GH deficiency (GHD) causes a significant increase in bone turnover and increases height velocity. The increase in IGF1 concentrations during rhGH treatment is a marker of the efficiency of treatment. Bone age delay at baseline is related to GHD and is a good predictor of height velocity during treatment. A significant increase in bone turnover during rhGH treatment results in an increased demand for vitamin D. It is important to determine proper supplementation doses of vitamin D in patients during catch-up growth.

Aim of study: The aim of the study is to evaluate the correlation between IGF1, bone age and 25-hydroxyvitamin D at baseline and in the 1st year of rhGH treatment, and height velocity before and during rhGH treatment.

Material and methods: The study group consisted of 76 children aged 3–16 years with GHD. IGF1 and 25-hydroxyvitamin D concentrations, bone age, and anthropometric parameters were measured at baseline and during 12 months of treatment.

Results: Vitamin D status at baseline correlated with height velocity before rhGH treatment (P<0.05, r=0.49). The mean 25-hydroxyvitamin D concentration at baseline was 19.57 ng/ml (±6.19 s.d.) and after 12 months of rhGH treatment with vitamin D supplementation it increased to 24.1 ng/ml (±6.88 s.d.). A negative correlation between Δ25-hydroxyvitamin D and ΔIGF1 (P<0.05, r=−0.38) was found.

Conclusions: Vitamin D status is related to height velocity and adequate vitamin D supplementation is important in patients with GHD during catch-up growth, when their bone turnover is increased as a result of rhGH treatment. Determining proper supplementation doses of vitamin D in such cases requires further research.