We assessed bone mineral density (BMD) and body composition in 121 Korean girls with central precocious puberty (CPP) before, during, and after 1 year of treatment with gonadotropin-releasing hormone (GnRH) agonist. BMD, bone mineral content (BMC), lean body mass (LBM), and fat mass (FM) were measured at baseline and after 1 year of treatment with dual energy x-ray absorptiometry (DEXA) and were expressed as standard deviation scores (SDS). Bone age and biochemical and hormonal profiles were assessed at baseline, after 6 months and 1 year of treatment.
Mean BMC and LBM were significantly lower than zero at baseline while FM and percent body fat (% FM) were higher than zero at baseline for both chronological and bone age. After 1 year of treatment, the differences for chronological age were decreased while the differences for bone age were persisted. The BMD SDS of each region of interest (ROI) including lumbar spine for chronological age were significantly higher than zero at baseline and increased after 1 year of treatment, while BMD SDS for bone age was significantly lower than zero at baseline and increased after 1 year of treatment.
Girls with CPP showed high %FM before and after GnRH agonist treatment for both chronological and bone age. The risk of obesity seems to be started before GnRH agonist treatment. Through this study, we concluded that pituitary-gonadal axis suppression by GnRH agonist does not reverse the progression of bone mass acquisition in children with CPP.