Incidence of central precocious puberty and the role of body mass index in Korea.

PURPOSE: This study aimed to evaluate national trends in central precocious puberty (CPP) incidence in Korean children and to examine the association between early childhood obesity and CPP using linked population-based datasets. METHODS: Data were obtained from the National Health Insurance Service (NHIS, 2012-2020) and the Infant/Toddler Health Check-up Program (2013-2016). CPP was defined operationally as having an International Classification of Diseases, 10th Revision code for precocious puberty, NHIS registration for CPP, and at least one year of gonadotropin-releasing hormone agonist treatment initiated before age 8 in girls and 9 in boys. Children with at least 3 health screenings before 6 years of age were included for body mass index (BMI) analysis. Multivariable logistic regression was used to estimate odds ratios (ORs) for CPP across BMI categories. RESULTS: A total of 195,892 CPP cases were identified. The incidence of CPP increased steadily from 2012 to 2020 in both sexes. In BMI analysis (n=35,766), CPP risk was significantly higher in the overweight (85th-94th percentile) and obese (≥95th percentile) groups compared to the normal-weight group (5th-84th percentile). The association was strongest in obese boys (OR, 2.573; 95% confidence interval, 2.417-2.739). Underweight status (<5th percentile) was associated with reduced CPP risk. CONCLUSION: CPP incidence in Korea has increased in recent years. Early childhood obesity is a strong, independent risk factor for CPP, particularly in boys. Early weight management strategies may help reduce CPP risk.a.