Association of serum 25-hydroxyvitamin D status with bone mineral density in 0-7 year old children.

Objective: To describe the status of serum 25-hydoxyvitamin D [25(OH) D] concentrations and identify the relationship between 25(OH) D and bone mineral density (BMD). In an effort to explore the appropriate definition of vitamin D (VD) deficiency in 0-7 year old children. Results: The median serum 25(OH) D concentrations was 62.9 nmol/L and 28.9% of the children had a low 25(OH) D (< 50 nmol/L). And a linear relation between 25(OH) D concentrations and BMD was surveyed (r = 0.144, P < 0.001). After adjusting for the confounders, serum 25(OH) D was positively associated with BMD (beta = 172.0, 95% CI = 142.8-201.2, P < 0.001), and low 25(OH) D (< 75 nmol/L) had a high stake for low BMD (OR = 1.424, 95% CI = 1.145-1.769, P = 0.001). Additionally, there was a nonlinear relation between 25(OH) D and low BMD, and a critical value for 25(OH) D of 75 nmol/L appeared for low BMD. The prevalence of low BMD was 14.1% in children with 25(OH) D >= 75 nmol/L, much lower than that of the concentrations between 50-75 nmol/L and < 50 nmol/L. Materials and Methods: A total of 4,846 children 0-7 years old were recruited in Jiangsu Province, China. BMD and serum 25(OH) D concentrations were determined by quantitative ultrasound and enzyme-linked immunosorbent assay, respectively. Linear regression and logistic regression analyses were used to assess the association of 25(OH) D concentrations with BMD. Conclusions: Serum 25(OH) D concentrations was related with BMD and 25(OH) D concentrations < 75 nmol/L might be a more appropriate definition of VD deficiency in 0-7 year old children.