Avaliação das concentraçôes de vitamina D em pacientes pediátricos com deficiência de hormônio do crescimento

Abstract

Introduction: Parathyroid hormone (PTH) and the active form of vitamin D, 1,25 OH vitamin D are the main regulators of bone homeostasis. Growth hormone (GH) and insulin like growth factor type-1(IGF-1) have also a role in the regulation of bone metabolism, and during the prepubertal period are determinants of linear growth, skeletal maturation and bone mass acquisition. Vitamin D is a hormone responsible for linear growth and also modulates IGF-1 and possibly IGF-binding protein type 3 (IGFBP-3) levels. The role of GH and IGF-1 in vitamin D regulation is not fully explained. Recent data demonstrate high prevalence of vitamin D insufficiency worldwide including well- developed countries and some sunny countries, such as Brazil. Despite the importance of this subject we found few reports addressing the relationship of vitamin D and bone health of children with growth hormone deficiency (GHD). Objective: To determine vitamin D sufficiency in pediatric patients with GHD receiving human recombinant growth hormone (rhGH). Subjects and Methods: a cross-sectional study of bone health of 36 GHD patients (75% male) and 45 controls (62,2% male), matched by age and gender, according to: ethnic group, sunlight exposure, socioeconomic status, BMI, and pubertal stage. Blood calcium, phosphorus, magnesium, alkaline phosphatase, urea, creatinine, PTH and 25 OH vitamin D were analyzed. Results: Most of the patients (72,2%) and controls (64,5%) were vitamin D deficient (22,2% and 17,8%, respectively) or insufficient (50,0% and 46,7%, respectively), according to Endocrine Society criteria. No statistical difference was found between groups neither in relation to vitamin D concentrations, nor in relation to bone metabolism parameters. Conclusions: High prevalence of vitamin D insufficiency was found in the studied population. Considering the importance of vitamin D for children's growth, further research on vitamin D sufficiency in GHD patients are needed for better understanding its consequence on treatment outcomes.