BMI trajectories in idiopathic central precocious puberty during GnRHa therapy: who is most at risk?

Tugce Kandemir; Sarah Abdelmageed; Renuka Dias; Ruth Krone; Zainaba Mohamed; Melanie Kershaw; Jan Idkowiak; Ruchi Nadar; Chamila Balagamage

doi:10.1530/endoabs.111.P69

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Endocrine Abstracts (2025) 111 P69 | DOI: 10.1530/endoabs.111.P69

BSPED2025 Poster Presentations Pituitary and Growth (10 abstracts)

BMI trajectories in idiopathic central precocious puberty during GnRHa therapy: who is most at risk?

Tugce Kandemir ^1,2 , Sarah Abdelmageed ¹ , Renuka Dias ^1,3 , Ruth Krone ¹ , Zainaba Mohamed ¹ , Melanie Kershaw ¹ , Jan Idkowiak ¹ , Ruchi Nadar ¹ & Chamila Balagamage ¹

Author affiliations

¹Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, United Kingdom; ²Istanbul University Istanbul Faculty of Medicine, Department of Paediatric Endocrinology, Istanbul, Turkey; ³Department of Applied Health Sciences, University of Birmingham, Birmingham, United Kingdom

Background: Gonadotropin-releasing hormone analogue (GnRHa) therapy is the standard treatment for central precocious puberty (CPP). While weight gain during treatment is a recognised concern, its pattern, magnitude, and contributing factors remain incompletely understood.

Aim: To evaluate changes in BMI standard deviation score (SDS) during GnRHa therapy in children with idiopathic CPP and identify factors associated with increased weight gain.

Methods: This retrospective study included 73 children (66 girls, 90.4%) with idiopathic CPP treated with GnRHa. BMI SDS was recorded at baseline, after one year, and at end of treatment. BMI categories were defined as: underweight (≤ –2SDS), normal weight (> –2 to ≤ 1SDS), overweight (> 1 to ≤ 2SDS), and obese (> 2SDS), based on WHO reference standards. Associations between BMI SDS change and baseline BMI, treatment duration, age at initiation, ethnicity, and socioeconomic status were evaluated.

Results: The median age at treatment initiation was 8.39 years (IQR: 7.7–8.9), and the median treatment duration was 1.89 years (IQR: 1.2–2.58). Ethnicity distribution was 36.9% White, 32.8% Asian, 12.3% Black. Most participants (67.1%) were from the lowest three IMD deciles. BMI SDS increased significantly from baseline to one year (+0.22, P < 0.0001) and to end of treatment (+0.32, P = 0.0002), with gain correlated with treatment duration (r = 0.3083, P = 0.0080). Significant increases in BMI SDS were observed in children with both normal and elevated baseline BMI. Among those with a normal baseline BMI, the median BMI SDS increased from 0.39 to 0.75 (P = 0.0065). Following treatment, children, overweight/obese at baseline exhibited significantly higher BMI SDS compared to their normal/underweight counterparts (2.27 vs. 0.81, P < 0.0001). No significant associations were found with ethnicity (P > 0.99), deprivation (P > 0.99), or age group (<7 vs ≥7 years, P = 0.0693), although younger age showed a trend toward greater gain.

Conclusion: BMI SDS increases early in GnRHa therapy and tends to continue throughout treatment. These findings highlight the need for early and sustained lifestyle interventions, including nutritional counselling, physical activity, and behavioural support, particularly for children with excess weight at treatment initiation.

Keywords: Central precocious puberty, BMI SDS, GnRH analogue therapy, Weight gain