[Osteoporosis in rheumatoid arthritis].

Patients with rheumatoid arthritis (RA) develop both periarticular and generalized osteoporosis. Periarticular osteopenia in appendicular bones occurs early in the course of RA and is one of the earliest radiological signs of RA. An uncoupled state in bone resorption-formation linkage, contributes to the development of periarticular osteopenia and it might be mediated through an increased productions of cytokines and prostaglandins by synovium and bone marrow. Accordingly, early suppression of rheumatoid synovitis is necessary for the prevention of periarticular osteopenia. Generalized osteoporosis is also common in RA and leads to increased risk of fractures. Generalized osteoporosis considered to be multifactorial and factors contributing to lumbar osteoporosis might be different from those to loss of appendicular bones, such as femur and radius. Corticosteroids and menopausal state are important risk factors for lumbar osteoporosis. Rheumatoid activity and reduced physical activity are also important determinants. According to the previous studies, however, the influence of functional impairment is more prominent in the femoral BMD compared to spinal BMD. In addition to control of RA and maintenance of physical activity, hormone replacement therapy (HRT) and bisphosphonate are possible agents for the treatment of osteoporosis in RA patients, especially postmenopausal women.