Impact of anthropometric, lifestyle, and body composition variables on ultrasound measurements in school children.

Quantitative ultrasound (QUS) measurement at hand phalanges was demonstrated to be a reliable method to assess skeletal maturation during childhood and adolescence. The aim of the study was to evaluate the influence of age, gender, puberty, lifestyle factors, and body composition on QUS parameters and to provide a normative database for QUS in school children in Lebanon. Measurements of phalangeal osteosonography were examined in 256 healthy subjects (132 boys and 124 girls) aged 11-18 years using an ultrasound device. In both genders, amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) increased significantly with age and pubertal stages. Girls had higher AD-SoS values than boys between 11 and 15 years of age and at Tanner stages III and IV; however, no differences were detected in the older age groups. AD-SoS and BTT showed a significant positive correlation with age and height in both genders (R = 0.41-0.66, P < 0.01). There was no correlation between physical activity, calcium intake, sun exposure, and any of the QUS parameters in either gender. Weight showed moderate positive correlation with AD-SoS in boys and with BTT in both genders (R = 0.31-0.47, P < 0.01). Lean mass showed significant positive correlation with AD-SoS and BTT (R = 0.2-0.68, P < 0.01) in both genders. Percentage body fat showed significant negative correlation with BTT and AD-SoS in boys (R = -0.25 to -0.37, P < 0.01). In the linear regression analyses, there was a significant negative correlation between percentage fat mass and both AD-SoS and BTT in both genders. In conclusion, QUS parameters of the phalanges in Lebanese children are related to growth variables such as height, age, and puberty in healthy children. The impact and magnitude of body composition variables and lifestyle factors on ultrasonometry derived variables differ from their effect on dual energy X-ray absorptiometry derived parameters.