Change in body mass index and insulin resistance after 1-year treatment with gonadotropin-releasing hormone agonists in girls with central precocious puberty

PURPOSE Gonadotropin-releasing hormone agonist (GnRHa) is used as a therapeutic agent for central precocious puberty (CPP); however, increased obesity may subsequently occur. This study compared body mass index (BMI) and insulin resistance during the first year of GnRHa treatment for CPP. METHODS Patient group included 83 girls (aged 7.0-8.9 years) with developed breasts and a peak luteinizing hormone level of ≥5 IU/L after GnRH stimulation. Control group included 48 prepubertal girls. BMI and insulin resistance-related indices (homeostasis model assessment of insulin resistance [HOMA-IR] and quantitative insulin sensitivity check index [QUICKI]) were used to compare the groups before treatment, and among the patient group before and after GnRHa treatment. RESULTS No statistical difference in BMI z-score was detected between the 2 groups before treatment. Fasting insulin and HOMA-IR were increased in the patient group; fasting glucose-to-insulin ratio and QUICKI were increased in the control group (all P<0.001). In normal-weight subjects in the patient group, BMI z-score was significantly increased during GnRHa treatment (-0.1±0.7 vs. 0.1±0.8, P<0.001), whereas HOMA-IR and QUICKI exhibited no differences. In overweight subjects in the patient group; BMI z-score and HOMA-IR were not significantly different, whereas QUICKI was significantly decreased during GnRHa treatment (0.35±0.03 vs. 0.33±0.02, P=0.044). CONCLUSION Girls with CPP exhibited increased insulin resistance compared to the control group. During GnRHa treatment, normal-weight individuals showed increased BMI z-scores without increased insulin resistance; the overweight group demonstrated increased insulin resistance without significantly altered BMI z-scores. Long-term follow-up of BMI and insulin resistance changes in patients with CPP is required.