Assessment of serum vitamin D levels in children aged 0–17 years old in a Chinese population: a comprehensive study

Abstract Vitamin D deficiency and insufficiency pose global public health challenges, yet research on serum vitamin D levels in the 0–17-year-old age group in southeastern China remains limited. This study aimed to fill this gap by investigating serum 25(OH)D levels in children in the region aged 0–17 years, contributing crucial data for understanding vitamin D nutritional status. Liquid chromatography‒mass spectrometry/mass spectrometry (LC‒MS/MS) technology was used. Vitamin D testing was integrated into routine diagnostic procedures for 11,116 children in Wujiang District, Suzhou City. Among the 0–17-year age group, comprising 6348 boys and 4768 girls, the prevalence of serum 25(OH)D deficiency and insufficiency was 21.4% and 31.0%, respectively. The median serum 25(OH)D concentration was 29.72 ng/mL (21.84–39.84 ng/mL) in boys compared to 28.48 ng/mL (20.65–39.23 ng/mL) in girls. Seasonal variations were observed, with median serum 25(OH)D concentrations of 29.02 ng/mL (20.73–39.72 ng/mL) in spring, 28.79 ng/mL (21.53–39.37 ng/mL) in summer, 30.12 ng/mL (22.00–39.70 ng/mL) in autumn, and 28.58 ng/mL (19.97–39.46 ng/mL) in winter. Statistically significant differences were noted in the serum 25(OH)D levels during autumn and winter. In conclusion, the rate of adequate vitamin D levels in local children was 47.5%, revealing a relatively high prevalence of vitamin D deficiency (21.4%) and insufficiency (31.0%), especially during the post-preschool period. Advocating for vitamin D supplementation in children is crucial for ensuring adequate vitamin D support.