Structural mechanisms of bone loss in iliac biopsies: comparison between rheumatoid arthritis and postmenopausal osteoporosis

To assess the mechanisms that cause generalized osteoporosis in rheumatoid arthritis (RA), 40 postmenopausal women with RA (46-74 years) and 40 age-ma tched controls with osteopenia underwent iliac bone biopsies. A structural analysis of histomorphometry and two-dimensional strut analysis were perfor med As compared to those with primary osteoporosis, there were a few unique characteristics in those with RA. Trabecular thickness and wall thickness declined with age, and this decline was especially accelerated by glucocort icoids. Decreased connectivity of the trabecular (Nd.Nd) was mon prominent than the disappearance of the nodes. The connectivity of cortical bone to t he nodes (Ct.Nd) and cortical thickness significantly decreased with age. W ith glucocorticoid therapy, the disappearance of the nodes was accelerated. In the case of vertebral compression fractures, the parameters of Nd.Nd an d Ct.Nd significantly decreased. Although a bone biopsy is needed to analyz e strut, this method is useful to evaluate the quality or intensity of the bone.