Osteoporosis weakens the bones, making them more likely to break (fracture). Osteoporosis is often called the "silent disease" because bone loss occurs without symptoms. People may not know they have osteoporosis until their bones become so weak that a sudden strain, bump, or fall causes a fracture. Osteoporosis can affect any bone in the body, but fractures occur most often in the hip, wrist, and spine. A fracture in the spine may cause severe back pain, loss of height, or spinal deformities such as stooped posture or dowager's hump.