Bone status assessment in preterm and term infants by dual-energy X-ray absorptiometry

We assessed the bone status of preterm and term infants by measuring their bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Thirty neonates weighing 699–3590 g were selected as subjects. Infants with multiple anomalies or severe chronic lung disease were excluded. Using the corrected term age (35–48 weeks), we measured their lumbar spinal BMD (L1–L4) by DXA. Alkaline phosphatase (ALP) and skeletal alkaline phosphatase (B-ALP) were measured at the same time. In addition, we compared the BMD values with growth parameters and chemical markers. The term BMD correlated significantly with the birth weight (r = .90), height (r = .85), and gestational age (r = .76). The birth weight correlated more closely with the BMD than with the weight at the time of BMD measurement. The B-ALP level showed an inverse correlation with BMD (r = −0.41). The preterm infants apparently acquired lower BMDs during intrauterine life. The inverse correlation of B-ALP with BMD may be found only in the neonatal period. The BMD measured by DXA and the B-ALP level are very useful parameters for assessing bone status in infants, including extremely low birth weight infants. Received: Aug. 21, 1997 / Accepted: Nov. 6, 1997