Relationships between serum 25-hydroxyvitamin D and quantitative ultrasound bone mineral density in 0–6 year old children

Abstract

The relationship between serum 25-hydroxyvitamin D and quantitative ultrasound bone mineral density in young children remains unclear. In addition, consensus has not been reached with regard to the concentration of 25(OH)D to define vitamin D deficiency for infants and children. In the present study, 203 children 0–6years old were recruited in Shanghai, China. The concentrations of serum 25(OH)D, weight, length, and quantitative ultrasound bone mineral density (BMD) of left mid-tibia were determined. Low BMD was defined as <20th percentile of given age and sex. Low 25(OH)D was defined as 25(OH)D<20ng/ml. The results showed that median serum 25(OH)D level was 19.0ng/ml, and 58.6% had a serum 25(OH)D below 20ng/ml. After adjusting for potential confounders, a linear relationship between serum 25(OH)D and BMD was observed. Serum 25(OH)D was positively associated with BMD (ß=323.3, 95% CI=201.0–445.7, p<0.001), and low 25(OH)D (<20ng/ml) had a high risk for low BMD (OR=5.5, 95% CI=2.5–12). In addition, there is a nonlinear relationship between 25(OH)D and low BMD, and a threshold for 25(OH)D of 20ng/ml existed for low BMD. The prevalence of low BMD was 47.1% in the group of 25(OH)D<20ng/ml, much higher than 16.7% in the group of 25(OH)D≥20ng/ml (p<0.05). The results suggested that quantitative ultrasound BMD could be an indicator for vitamin D status in young children, and also provided further evidence to define vitamin D deficiency for infants and children.