Bone loss in premenopausal and postmenopausal women. A cross-sectional and longitudinal study using quantitative computed tomography.

Trabecular and total bone densities were determined by quantitative computed tomography in patients with untreated postmenopausal osteoporosis and in normal premenopausal and postmenopausal women. A special procedure was used for precise low-dose examinations of the distal end of the radius and the distal end of the tibia. The results indicate that the trabecular bone density of the peripheral skeleton is a reliable index of postmenopausal osteoporosis. In general, osteoporotic patients could be distinguished from patients with age-related bone loss based on differences in the magnitude of the decrease in trabecular bone density. Serial determinations of trabecular bone density in individual patients indicated that trabecular bone loss in postmenopausal osteoporotic patients shows a step-wise pattern in which phases of relative stability are followed by brief phases of bone loss. Quantitative computed-tomography measurements of bone density should provide a better understanding of the pathogenesis of postmenopausal osteoporosis and be useful in the assessment of different methods of treatment.