Measurement of bone mineral content and bone density in healthy twelve- year-old white females

Bone mineral content (BMC) and bone mineral density (BMD) measurements were made by dual-energy x-ray absorptiometry (DEXA) in 112 healthy 12-yr-old white girls for the purposes of: (1) establishing reference data on total- body mineral content of 12-yr-old girls and (2) comparing the lumbar spinal bone density values from a dedicated scan with the lumbar region of interest bone density values from a whole-body scan. Total BMC ranged from 799 g to 2083 g with mean and median values of 1276 g and 1218 g. Total-body bone density ranged from 0.75 to 1.03 g/cm² with mean and median values of 0.88 and 0.87 g/cm². The mean and median lumbar bone density values from the lumbar scan mode were 0.74 and 0.73 g/cm² and were not significantly different from the mean and median lumbar bone density values of 0.71 and 0.70 g/cm² obtained from the region of interest data from the total-body scan. These results establish baseline bone mass and bone density values for our longitudinal study of bone accretion in young women and validate the use of lumbar vertebral bone density values obtained from whole-body scans.