The difference of bone mineral density of lumbar spine and wrist in the preterm and full-term infants: using dual energy X-ray absorptiometry

To assess the differences in bone mineral density (BMD) of lumbar spine and wrist between preterm infants of postconceptional age 40 weeks and normal full-term infants.Sixty-eight preterm infants born at conceptional age 26-36 weeks and 31 normal full-term infants born at 38-42 weeks were investigated. Bone mineral densities of the lumbar spine (from the second to the fourth segment) and wrist were measured by dual energy X-ray absorptiometry. In preterm infants, the corrected age of 0 month was defined as postconceptional 40 weeks. Full-term infants were compared. In the preterm group, birth weight and conceptional age were correlated with lumbar spinal and wrist bone mineral densities. Data were analyzed by student's t-test and Pearson's correlation coefficient, and a p value of less than 0.05 was considered significant. In preterm infants, the values of bone mineral densities of the lumbar spine and wrist were 0.137 ± 0.018 g/cm2 (0.061-0.202 g/cm2) and 0.089 ± 0.013 g/cm2 (0.065-0.123 g/cm2), respectively, while the respective values for full-term infants were 0.214 ± 0.030 g/cm2 (0.160-0.296 g/cm2) and 0.118 ± 0.014 g/cm2 (0.096-0.162 g/cm2). In the preterm group, lumbar spinal BMD correlated significantly with conceptional age (r=3D0.384, p less than 0.05) and birth weight (r=3D0.438, p less than 0.05). While wrist BMD correlated significantly with birth weight (r=3D0.281, p less than 0.05), its correlation with conceptional age was not significant (r=3D0.223, p greater than 0.05). The lumbar spinal and wrist BMDs of preterm infants at corrected age 0 were lower than those of normal full-term infants. In the preterm group, BMD values for the lumbar spine were lower in infants of lower conceptional age and birth weight. (author)