Differential effects of menopause and metabolic disease on trabecular and cortical bone assessed by peripheral quantitative computed tomography (pQCT)

The usefulness of peripheral quantitative computed tomography (pQCT) was in vestigated in the diagnosis of metabolic bone diseases, including osteoporo sis, and especially in the different diagnostic values in trabecular and co rtical components, The subjects were 460 Japanese women aged 20-86 years, i ncluding 318 healthy volunteers, 58 osteoporotics with fracture and 84 pati ents with diseases including amenorrhoea, steroid-induced osteoporosis, ren al osteodystrophy (ROD) and primary hyperparathyroidism. Bone mineral densi ty (BMD) was measured for more than 4 years in 74 of the healthy volunteers . BMD was measured by spinal QCT, dual X-ray absorptiometry (DXA) of the sp ine, radius, and heel, and pQCT of the radius and tibia. High resolution im ages were obtained for geometry of the radius. Radial pQCT showed a higher correlation with radial DXA than with spinal QCT, and spinal QCT showed a h igher correlation with spinal DXA than with radial pQCT. The annual bone lo ss rates at predominantly trabecular bone sites were accelerated in both th e axial and appendicular skeleton. In the fracture study, radial pQCT showe d a higher odds ratio (OR=4.4) than radial DXA, and cortical area ratio see med to be a good predictor of fracture risk (OR=5.2). Amenorrhoea and stero id-induced osteoporosis predominantly affected trabecular bone, ROD predomi nantly affected cortical bone and hyperparathyroidism affected both compone nts, especially the cortical component. pQCT is useful for assessing both t rabecular and cortical bone, to provide information on individual bone chan ges in metabolic bone disease and to estimate the risk of fracture.