Pediatric reference curves for multi-site quantitative ultrasound and its modulators

More than 85% of peak skeletal mass is accrued by the age of 18 years, making bone growth during childhood and adolescence a critical process. The purpose of this study is to establish pediatric reference curves for bone Speed of Sound (SOS) as measured by multi-site quantitative ultrasound. Analysis was performed on a total of 1085 healthy subjects ages 0-18 years (595 females, 490 males). Demographic and anthropometric parameters (height and weight), as well as data on calcium intake and physical activity, were collected. Ultrasound bone measurements were performed at the mid-shaft tibia and the distal third of the radius (Sunlight Omnisense(R) 7000P). An age-related speed of sound (SOS) curve that describes SOS changes at the tibia and radius in both genders was demonstrated. SOS showed a steep increase during the first 5 years of life in both genders at the tibia and radius. The period between the ages of 6-11 years is characterized with a very shallow increase in SOS at both sites. Thereafter, during the pubertal period, there is a second growth burst in SOS, starting at age 11 for girls and age 14 for boys. No significant meaningful correlation was found between the anthropometric parameters (height, weight and BMI) and the SOS measurements after the age parameter was controlled. Subjects who reported low physical activity levels were found to have lower Z-scores than their counterparts (P<0.05). The SOS of pre-menarche girls was significantly lower than that of post-menarche girls at the radius and tibia (P<0.05). The level of calcium intake did not correlate with bone SOS. Intra-operator precision measurements were 0.36% (0.25-0.47%) at radius and 0.30% (0.20-0.40%) at the tibia. To date, there is no widely accepted classification or clinical working guidelines for children's bone health assessment or prediction of fracture risk based on bone strength measurements in children. This study establishes a pediatric reference curve for the Omnisense, and therefore supports the feasibility of using Sunlight Omnisense(R) 7000P, a multi-site bone sonometer, for the assessment of pediatric bone properties. Further studies mainly in different diseased children groups should further support the use of such a basic tool for clinical evaluation, assisting the physician to work towards healthy bones for his patients.