Reference equations for ultrasound bone densitometry of the radius in Central European children and adolescents

Bone density measurements are important for evaluation and follow-up of children with alterations in their mineral status (increased risk for fractures and osteoporosis subsequently). Interpretation of these measurements relies on the availability of appropriate reference equations. We developed gender-specific, age-dependent reference values of bone density for Central European children. In recent years, there has been an increasing demand for the measurement of bone density in children exposed to an increased risk of early alterations in their bone status. These values must be compared to an adequate reference population. The aim of the present study was to create reference equations of radial speed of sound (SOS) for Central European children and adolescents. In this cross-sectional study, SOS values were measured at the distal third of the radius in 581 Swiss children and adolescents (321 girls and 260 boys) aged 6 to 16 years using the Sunlight OmnisenseA (R) 7000P quantitative ultrasound system. Gender-specific reference equations for SOS values were derived by polynomial regression and combined a cubic dependence of age and a linear dependence of height. The fitted SOS curves in our study population show a plateau period in both genders for younger ages followed by an increase phase beginning at the age of 12 in girls and 14 in boys. Neither the reported level of physical activity nor additional sport nor self-reported calcium intake influenced the reference equations. Our results show a good agreement with similar studies using the same measurement technique on other body parts, suggesting a wide applicability of the obtained reference curves over different European populations.