The effect of GnRH analogs on body mass index in girls with central precocious puberty: a single-center retrospective study with literature review

Background/Objectives: Central precocious puberty (CPP) is defined by the premature onset of secondary sexual characteristics prior to the age of 8 and 9 years in girls and boys, respectively, due to early activation of gonadotropin-releasing hormone (GnRH) secretion. The administration of GnRH analogs (GnRH-a) has become a cornerstone in the management of CPP, but effects on metabolic processes, particularly body mass index (BMI), remain a subject of ongoing investigation. This study aimed to investigate the relationship between GnRH-a treatment and BMI changes in a cohort of Italian children with CPP. Methods: We conducted a retrospective cohort study of 34 children diagnosed with idiopathic CPP, all treated with GnRH-a. Anthropometric parameters including BMI were collected at three time points: baseline, one year after treatment, and one year after treatment cessation. Moreover, a comprehensive review of the medical literature concerning GnRH-a and BMI was performed. Results: Statistical analysis using the Wilcoxon and McNemar tests revealed a significant increase in BMI-for-age z-scores after one year of GnRH-a, with a slight increase observed also one year post-treatment of CPP. These findings suggest that GnRH-a treatment contributes to increase BMI, particularly in CPP children with normal weight at baseline, although the overall impact on progression of obesity remains minimal. A review of the existing literature supports the notion that changes in BMI during GnRH-a treatment are influenced by various factors, including baseline BMI, gender, and metabolic processes. Conclusions: Despite our findings suggested a potential impact of GnRH-a on BMI, further longitudinal studies with larger sample sizes are necessary to fully understand the long-term metabolic consequences of GnRH-a therapy in children with CPP.