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

► A linear relationship between serum 25(OH)D and quantitative ultrasound bone mineral density (BMD) ► A nonlinear relationship between 25(OH)D and low BMD, and a threshold for 25(OH)D of 20 ng/ml existed for low BMD ► Quantitative ultrasound BMD can be an indicator for vitamin D status in young children ► Providing further evidence to define vitamin D deficiency for young children