The medical name for the condition in which bones become weak and brittle due to loss of bone density is osteoporosis.
Bone is living tissue, constantly broken down by osteoclasts and rebuilt by osteoblasts. Osteoporosis develops when bone resorption outpaces new bone formation, reducing both mineral density and the internal, honeycomb-like structure of bone. The result is a higher risk of fractures, especially in the hip, spine, wrist, and forearm.
The condition often has no obvious symptoms until a fracture occurs, which is why it is sometimes called a silent disease. A DXA or DEXA scan measures bone mineral density; a T-score of -2.5 or lower is commonly used as the diagnostic threshold in postmenopausal women and older men.
Osteoporosis is not the same as osteomalacia, which involves defective mineralization of newly formed bone, or osteoarthritis, which primarily affects joint cartilage. Rickets is a related mineralization disorder occurring in children.