['To evaluate bone quantity and quality in postmenarchal adolescents treated for idiopathic central precocious puberty (CPP) in childhood with a gonadotropin-releasing hormone analog (GnRHa) and to determine the serum concentrations of bone remodeling markers.', 'This cross-sectional study included 53 postmenarchal adolescent girls who were divided into 2 groups: 27 adolescents who were treated with GnRHa in childhood for idiopathic CPP (the CPP group) and 26 women who presented with physiological development of secondary sex traits (the control group).', 'None.', 'Weight, height, body mass index, age at menarche, time since menarche, body composition, bone mineral density (BMD), bone quality, and serum insulin, glucose, osteocalcin, and carboxyl-terminal telopeptide of type I collagen concentrations were compared in the 2 groups. BMD data were analyzed by using both dual-energy x-ray absorptiometry (DXA) and osteosonography, and body composition was measure with the use of DXA and electrical bioimpedance.', 'BMD and bone quality did not differ significantly between the CPP and control groups when analyzed by using DXA or osteosonography. Serum osteocalcin concentration was significantly lower (P = .02) in the CPP than in the control group. Insulin was higher in the CPP group, and hyperinsulinemia was an independent predictor of bone quantity and quality assessed by using osteosonography. Body mass index and percent fat were determined by using DXA, and the duration of use of GnRHa treatment and the time since GnRHa discontinuation were not independent predictors of bone quantity and quality.'] Is use of a Gonadotropin-releasing Hormone Analog to Treat Idiopathic Central Precocious Puberty Associated with Changes in Bone Structure in Postmenarchal Adolescents?