The Usefulness of Whole Body Bone Mineral Densitometry in the Osteopenia of Preterm Infants: Comparison with the Wrist Radiography and Biochemical Parameters

ABSTRACT

PURPOSE: To evaluate the usefulness of whole body bone mineral densitometry in the diagnosis of frequent osteopenia of preterm infants by comparison with the wrist radiographs and biochemical parameters. MATERIALS AND METHODS: From January 1995 to January 1996, we obtained whole body bone mineral density(BMD) studies using dual energy X-ray absorptiometry(DXA) and wrist radiographs of 39 preterm infants. They were divided into three groups according to birth weight, under 1500g, 1501g to 2000g and above 2000g, and four grades of skeletal change, as seen on wrist radiography, according to the scoring method of Koo et al. Groups of birth weight and grades of skeletal change were then correlated with whole body BMD and biochemical parameters. For comparison, normal data were obtained from 13 infants born at full term. Data were analyzed by one way analysis of variation(ANOVA) and correlation and regression analysis. A p-value of less than 0.05 was considered significant. RESUTLS Whole body BMDs were significantly lower in the more premature and smaller birth weight infants(r=0.77, p=0.0000), and in the higher grade of skeletal change (r=-0.5276, p=0.0000). Aggravated skeletal changes were found in infants with lower birth weight(r=-0.3822, p=0.01). Interobserver variation in grading skeletal change was 42.9%, and intraobserver variation was 18.4%. Biochemical parameters such as serum calcium, phosphate, alkaline phosphatase, parathromone, calcitonin and 25-hydroxy-vitamine D did not vary significantly according to either birth weight or skeletal change (p>0.05). CONCLUSION: Premature osteopenia is more effectively diagnosed by measuring whole body BMD using DXA than by grading radiographical skeletal change or by biochemical parameters.