Environmental neonicotinoid exposure and early gonadal development in girls with central precocious puberty

Environmental endocrine disruptors (EDCs), particularly prevalent pesticide residues, are suspected contributors to the increasing incidence of central precocious puberty (CPP). This study explored the associations of urinary neonicotinoid insecticides (NNs) with sex hormones and pelvic ultrasound indicators in girls with CPP.

Girls were divided into three subgroups: CPP, non-CPP pubertal and prepubertal groups. Urinary levels of nine pesticides were screened via Kruskal-Wallis H test with Dunn's test; only nitenpyram (NIT) with intergroup differences was further analyzed. Stratified correlation and adjusted linear regression assessed links between NIT and sexual development markers, while quartile-based logistic regression examined the dose-response association between NIT and CPP risk.

Thiamethoxam (THI), clothianidin (CLO), flupyradifurone (FPF), and sulfoxaflor (SUL) showed a 100 % detection rate, while thiacloprid (THIA) was the least detected (85.8 %). The NIT concentration was significantly higher in the CPP group (p<0.05). Stratified multivariate linear regression adjusted for age and BMI-SDS demonstrated that elevated NIT was independently positively associated with ovarian volume (OV) (B=0.73, 95 % CI: 0.15-1.31, p=0.014, β=0.294) and estradiol (E2) (B=116.64, 95 % CI: 49.58-183.70, p=0.002, β=0.682) only in CPP group, while no significant correlations were detected in non-CPP pubertal or prepubertal groups. Logistic regression revealed a significant ascending dose-response trend between elevated NIT quartiles and CPP risk (p for trend=0.048).

NIT exposure acts as an independent environmental risk factor for CPP in girls, and aggravates sex hormone disturbance and abnormal ovarian development only in children with CPP. Restricting daily children's exposure to NNs is clinically and public health meaningful.