Reference data for bone speed of sound in Portuguese girls and boys aged 9-13 years.

The objective of this study was to provide reference data for quantitative ultrasound (QUS, Sunlight Omnisense; BeamMed Ltd., Petach-Tikva, Israel) of the radius and tibia in Portuguese subjects. The evaluation was conducted with QUS in 430 healthy participants (213 girls and 217 boys) aged between 9 and 13yr. The results indicate that 13-yr-old girls had higher radial and tibial speed of sound (SOS) than younger girls and higher tibial SOS than boys of the same age (p<0.05). Regression analysis revealed positive associations between radial and tibial SOS and skeletal maturity in girls and negative association between tibial SOS and fat mass in both sexes and average intensity of physical activity in girls (p<0.01). The young Portuguese subjects showed an age-related variation in SOS similar to that seen in some of the eastern Mediterranean countries. Children with a history of fracture of lower (n=24) or upper limbs (n=43) did not show a significant decrease of SOS values in any of the bone sites evaluated (tibia Z-score: -0.23 standard deviations [SDs]; radius Z-score: -0.21 SDs; p>0.05).