RESUMO
Treatment of true Precocious Puberty (PP) with GnRH agonist can improve final adult height by suppressing gonadotropin and sex hormone levels that delays the fusion of long bone epiphyseal growth plates. However, deprivation of estrogen may affect the acquisition of peak bone mass, especially in individuals with low calcium intake. Ten Thai girls with idiopathic true PP were evaluated for Bone Mineral Density (BMD) and body composition by DXA scanner (Hologic, Inc) before and after GnRH agonist therapy for 1 year. During treatment, all children were allowed to consume a normal diet without extra calcium supplementation. In addition, serum calcium, phosphate, alkaline phosphatase and osteocalcin were also measured. The results showed that GnRH agonist could improve predicted adult height from 149.4 +/- 5.4 to 153.6 +/- 6.8 cm (p < 0.001). Serum osteocalcin, representing the bone marker formation, decreased from 184.2 +/- 66.7 to 108.6 +/- 35.3 ng/mL (p = 0.012) However, the treatment had no negative effects on BMD lumbar spine and total BMD but increased percentage of fat mass from 25.7 +/- 5.2 to 31.6 +/- 5.5%. (p =0.007). In conclusion, treatment with GnRH agonist in Thai girls with true PP for 1 year can improve PAH without negative effects on BMD but a longer period of treatment needs to be studied.