Osteoporosis

Abstract

Osteoporosis (thin bones) is a disease caused by loss of bone mass and microarchitectural deterioration of the skeleton, leading to enhanced bone fragility and increased risk for fractures with minimal or no trauma at all. Conventionally, the disease is diagnosed when the bone mineral density is 2.5 standard deviations below the young adult mean. A bone mineral density between 1 and 2.5 standard deviations below the young adult mean is termed “osteopenia.” Osteoporosis is the most common disease of the musculoskeletal system. Fifty-four percent of postmenopausal women in the United States have osteopenia and another 30% have osteoporosis. Up to 20% of patients with osteoporosis die after hip fractures and 40% can no longer live independently. Although not a rheumatic disorder, osteoporosis is of major interest to rheumatologists, as the arthritic processes that affect the cartilage surfaces and the synovial lining may also involve the subchondral bone and the joint capsule. Moreover, rheumatic diseases such as osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, and the spondyloarthropathies may involve not only skeletal tissues at juxtaarticular and subchondral sites but also produce generalized effects on bone remodeling that affect the entire skeleton.