Osteoporosis is the condition characterized by extremely low bone density and an increased risk of fractures.
The disorder affects the skeleton’s structure: bone mass falls and the internal architecture becomes more porous. Bone is constantly remodeled by osteoclasts, which remove old tissue, and osteoblasts, which build new tissue. With aging, resorption can outpace formation. The result is fragile bone that may break after a minor fall or ordinary movement.
Osteoporosis often has no warning symptoms, so it may first be discovered after a fracture, commonly in the hip, spine, wrist, or forearm. Menopause is a major risk factor because declining estrogen accelerates bone loss, though men can develop it too. Smoking, heavy alcohol use, inactivity, certain medicines, and some diseases also increase risk.
A common mix-up is osteomalacia, which involves poor mineralization of bone rather than the same pattern of low bone mass. Clinicians commonly assess osteoporosis with a DXA scan; a bone mineral density T-score of −2.5 or lower is the standard diagnostic threshold for osteoporosis in appropriate patients.