Bone density in women with spinal and hip fractures

Bone density in the lumbar spine and distal radius of 98 postmenopausal women was measured by quantitative computed tomography and in the distal radius by gamma ray attenuation. Nineteen had spinal fragility fractures, 30 had recent hip fractures while 49 were healthy control subjects. The trabecular bone density in spines of the control subjects showed a linear correlation with age corresponding to an annual decrease of 1 per cent and total decrease of 44 per cent between 46 and 86 years of age. Both patient groups had bone density reduction at the spine and peripheral measuring sites as compared with controls. In the distal radius, the reduction in bone density was of the same magnitude in both patients groups but in the spine, the reduction in patients with spinal fracture was more extensive than that in patients with hip fracture. Trabecular bone density in the distal radius and spine correlated in control and hip fracture patients, but not in spinal fracture patients. The results support the opinion that two forms of osteoporosis exist. One is characterised by excessive trabecular bone loss in the axial skeleton leading to spinal fractures; the second is due to equal extents of axial and peripheral osteopenia, found in connection with hip fractures.