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

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.