Basal Luteinizing Hormone Combined with Age and BMI as a Simplified Screening Model for Central Precocious Puberty in Girls

Jiayu Li,1,2,* Yali Cui,3– 5,* Jiaji Shuai,6 Wei Li,1 Yingying Li,3 Ziyi Yan,3,7 Tao Yu1,6 1Department of Child Healthcare, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China; 2Department of Child Healthcare, Angel Women’s and Children’s Hospital, Chengdu, People’s Republic of China; 3Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China; 4Department of Laboratory Medicine, Sichuan Provincial Children’s Hospital (Sichuan Provincial Children’s Medical Center), Meishan, People’s Republic of China; 5Department of Laboratory Medicine, Meishan Women and Children’s Hospital, Meishan, People’s Republic of China; 6Department of Child Healthcare, Meishan Women and Children’s Hospital, Meishan, People’s Republic of China; 7Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Ziyi Yan, Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China, No. 20, Section 3, South Renmin Road, Chengdu, Sichuan, People’s Republic of China, Email [email protected] Tao Yu, Department of Child Healthcare, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China, No. 1416, Section 1, Chenglong Road, Chengdu, Sichuan, People’s Republic of China, Email [email protected]: The gonadotropin-releasing hormone (GnRH) stimulation test is regarded as the diagnostic gold standard for central precocious puberty (CPP); however, its invasiveness and limited accessibility restrict its routine use in clinical practice. Moreover, reported cutoff values for basal luteinizing hormone (LH) vary across studies, and simple screening models applicable to everyday clinical settings remain limited. This study aimed to evaluate routinely available clinical, biochemical, and imaging indicators and to develop a simplified screening model for early differentiation of CPP from premature thelarche (PT) in girls.Patients and methods: This retrospective study included 429 girls aged 4– 8 years presenting with early breast development between January 2019 and January 2023. Basal sex hormone levels, anthropometric parameters, bone age, and pelvic ultrasound findings were collected. Univariable analysis, multivariable logistic regression, and receiver operating characteristic (ROC) curve analysis were performed to assess the screening performance of individual indicators and a combined model.Results: Girls with CPP exhibited significantly higher age, BMI, bone age advancement, basal LH levels, and ovarian volumes than those with PT did (all p< 0.05). Multivariable analysis identified age, BMI, and basal LH concentration as independent factors associated with CPP. Among individual indicators, basal LH concentration showed the strongest discriminatory ability (AUC=0.842), with a cutoff value of 0.15 IU/L. A simplified combined model integrating basal LH concentration, age, and BMI further improved screening performance (AUC=0.880). Pelvic ultrasound parameters did not emerge as independent predictors in multivariable analyses.Conclusion: A simplified screening model incorporating basal LH concentration, age, and BMI may serve as a practical initial screening tool to identify girls at higher risk of CPP and to reduce unnecessary GnRH stimulation testing. Prospective multicenter studies are required to validate the generalizability of this approach before broader clinical implementation.Keywords: breast development, basal LH, body mass index, precocious puberty, ovarian volume