Prevalence of vitamin D deficiency and insufficiency among 460,537 children in 825 hospitals from 18 provinces in mainland China.

This study was conducted to estimate the 25-hydroxyvitamin D (25 (OH)D) levels and explore factors related to vitamin D deficiency/insufficiency. This was a multicenter, hospital-based, cross-sectional observational study. Children admitted to hospitals for health examination were included for vitamin D measurement and the 25(OH)D concentration results were categorized into 3 groups: deficiency (<30 nmol/L), insufficiency (30-50 nmol/L), and sufficiency (>50 nmol/L). Four lakh sixty thousand five hundred thirty-seven children in 825 hospitals from 18 provinces participated in this study. The prevalence of vitamin D deficiency, insufficiency, and sufficiency were 6.69%, 15.92%, and 77.39%, respectively. Vitamin D deficiency was the most severe in the central region, followed by the north, and southwest regions; however, data for the western region were lacking.Logistic regression showed that vitamin D status was worse in girls, newborns, and those visiting the hospital in the winter. In conclusion, the prevalence of vitamin D deficiency is high among Chinese children and adolescents. Studies on population estimates, cost-effective screening strategies, and interventions for high-risk cases are needed.