Background: We have previously shown that bone age (BA) assessment by SonicBone BAUSTM, measuring the speed of sound (SOS) of US waves propagating along measured bone, is reproducible and comparable to both GP and TW3 x-ray assessment of BA. This provides a safe and irradiation-free method to the assessment of BA in healthy children.
Objective and hypothesis: We aimed to understand the dependency of BA on a childs height and BMI using sonometeric bone age (SBA), and hypothesized positive correlations.
Method: SBA was analysed separately and averaged for the wrist (radius-ulna epiphyses), metacarpal epiphyses and the phalanx ossification centers in 317 healthy girls and 333 boys, age range 415/417 resp., and the difference from chronological age was regressed onto their height SDS and BMI SDS.
Results: A childs height SDS is strongly and positively correlated with the SBA deviation from the chronological age in the wrist (r2=0.30, P<0.0001), metacarpals (r2=0.29, P<0.0001), phalanx (r2=0.47, P<0.0001), and the mean SBA (r2=0.40, P<0.0001). When 120 pre-pubertal girls age 48 and 147 boys age 49, are analysed separately, the correlation is reduced to r2=0.215, P=0.019 in girls but remains strong in boys, (r2=0.304, P<0.0001). A childs BMI SDS is also positively correlated with the SBA deviation from chronological age in the wrist (r2=0.25, p<0.0001), metacarpals (r2=0.17, p< 0.0001) phalanx (r2=0.13, P<0.001), and the mean SBA (r2=0.22, P<0.0001). In separate analysis of pre-pubertal children, the BMI correlations disappear.
Conclusions: i) Shorter and thinner pubertal but not pre-pubertal children have delayed BA as compared to taller and heavier children. ii) The full-length phalanx maturation is affected by height more than the wrist and metacarpals epiphyses. iii) The radius-ulna epiphyses are affected by BMI more than the metacarpals and phalanx. iv) These influences have now on to be accounted for in the assessment of a BA.
Conflict of interest: SO is employed by SonicBone, NKM and ZH are independent consultant.
Funding: The study was funded by SonicBone Ltd Rishon Lezion.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology