Work

Incidence and epidemiological characteristics of congenital adrenal hyperplasia in Hangzhou newborns, China (2014–2024): a population-based cross-sectional study

Year: 2026

Type: article

Abstract: Background Congenital adrenal hyperplasia (CAH) is a rare but potentially life-threatening autosomal recessive disorder. Its incidence varies by region and ethnicity. This study aimed to evaluate the birth incidence, trends, and clinical characteristics of neonatal classic CAH in Hangzhou (2014–2024) to support regional clinical prevention and management. Methods This retrospective population-based study collected data from Hangzhou's information systems. Classic CAH cases were identified through newborn screening and clinical follow-up to age 3, with diagnosis confirmed by pediatric endocrinologists. Incidence was calculated per 100,000 live births. Categorical variables were compared using chi-square or Fisher's exact test. Temporal trend was assessed by Poisson regression. Results Among 1,235,815 live births, 40 CAH cases were identified, giving an incidence of 3.24/100,000. The annual incidence ranged from 0/100,000 (2020) to 6.56/100,000 (2017), with no significant temporal trend ( P = 0.297). The incidence was highest in urban (4.28/100,000), followed by suburban (2.37/100,000) and rural areas (1.93/100,000) ( P = 0.16). Males accounted for 65% (26/40) of cases and females 35% (14/40), with a male-to-female ratio of 1.86:1. The incidence was 4.03/100,000 in males and 2.37/100,000 in females ( P = 0.104). Among the 40 cases, salt-wasting (SW) was the predominant phenotype (33/40, 82.5%), and 21-hydroxylase deficiency accounted for 95% (38/40) of cases. Two neonates (5%) presented with salt-wasting crises, and two female infants with the simple virilizing (SV) form were initially misclassified as male. Prenatal ultrasound showed increased nuchal translucency in 6 cases (15%), adrenal enlargement in 3 cases (7.5%), and ambiguous genitalia in 1 case (2.5%). CAH was strongly associated with congenital heart defects (OR: 13.93, P < 0.001), and congenital hypothyroidism (OR: 42.26, P < 0.001). Conclusion The incidence of classic CAH in Hangzhou (3.24/100,000) was lower than many global estimates. Although temporal and regional differences were not statistically significant, the predominance of SW cases, the occurrence of adrenal crises, and the presence of comorbidities (congenital heart defects, hypothyroidism, and cognitive developmental delay), highlight the need for improved early recognition, strengthened diagnostic capacity in suburban and rural areas, and long-term multidisciplinary management.

Source: Frontiers in Pediatrics

DOI: 10.3389/fped.2026.1869920