Is quantitative ultrasound a measure for metabolic bone disease in preterm-born infants? A prospective subcohort study.

In this study, we aimed to (a) evaluate postnatal changes in bone development in relation to growth and (b) to determine factors associated with bone development, from birth to 24 months of corrected age. The metacarpal speed of sound (mcSOS) and metacarpal bone transmission time (mcBTT) were used to evaluate bone development in 98 preterm infants, during hospitalization and follow-up. The mcSOS and mcBTT values not only declined in the first 6 weeks of hospitalization but also during follow-up. The mcSOS reached its lowest point at 12 months (β=-34.64), while the mcBTT reached a plateau between 12 and 24 months (β=0.06). Univariable analysis showed that gender (p=0.28), time (p<0.001), and growth parameters (p<0.001) were significant negative associated factors with mcSOS, whereas with mcBTT, time (p=0.009), length (p=0.063), length standard deviation scores (SDS) (p=0.027), head circumference (p=0.005), and head circumference SDS (p=0.007) were significant positive. The multivariable model revealed that time (β= -3.364, p=<0.001), weight (β=-0.007, p<0.001) and length (β=1.163, p<0.001) for mcSOS and length (β=-0.021, p<0.001), and length SDS (β= 0.066, p<0.001) and head circumference (β=0.049, p<0.001) for mcBTT remained highly significant associated factors.Conclusion: The most important finding is that mcSOS decreased and the mcBTT reached a plateau to 24 months. In both mcSOS and mcBTT, the growth parameters were significant factors.Clinical Trial Registration: N/A What is known: • Metabolic bone disease is one of the possible long term adverse outcomes after preterm birth. • Metacarpal speed of sound (mcSOS) and metacarpal bone transmission time (mcBTT) decline in the early postnatal period. What is new: • During follow-up, mcSOS further decreased and reached its lowest point at 12 months, while the mcBTT reached a plateau up to 24 months. • Postnatal nutrition in relation to comorbidity does not meet the optimal mineralization rate of the developing preterm bone.