Osteoporosis is a disease that weakens bones to the point where they break easily—most often, bones in the hip, backbone (spine), and wrist. Osteoporosis is called a “silent disease” because you may not notice any changes until a bone breaks. All the while, though, your bones had been losing strength for many years.
Bone is living tissue. To keep bones strong, your body breaks down old bone and replaces it with new bone tissue. Sometime around age 30, bone mass stops increasing, and the goal for bone health is to keep as much bone as possible for as long as you can. As people enter their 40s and 50s, more bone may be broken down than is replaced.