Changes in quantitative ultrasound in preterm and term infants during the first year of life.

Since most of in utero bone mass accretion occurs during the third trimester and postnatal need for bone nutrients is increased, preterm infants have an increased risk of low bone mass. Early identification of the risk is of crucial importance. Quantitative ultrasound, which is a relatively inexpensive, portable, noninvasive, and radiation-free method, gives information about bone density, cortical thickness, elasticity and microarchitecture. The aim of this study was to obtain quantitative ultrasound measurements of tibial speed of sound of preterm and term infants and to assess clinical factors associated with these measurements during the first year of life. Seventy-eight preterm and 48 term infants were enrolled in this study. Measurements were made on the 10th day of life in both groups, and were repeated on the 2nd, 6th and 12th months for preterm infants and on the 12th month for the term infants. Speed of sound on preterm infants was significantly decreased on the 2nd month but significantly increased on the 12th month (P=0.00). Comparing speed of sound of term and preterm infants, 10th day measurements were significantly different (P=0.00), but there was not any significant difference between the 12th month values (P=0.26). There was not any relation between biochemical parameters and speed of sound. The technique has potential clinical value for assessment of bone status. Further studies with long term follow up are needed to evaluate the value of quantitative ultrasound with other bone markers to predict the risk of fracture.