Osteoporosis or porous bone is a condition that occurs when bone is no longer replaced as quickly as it is removed. Bones are continually forming in the body through a process called remodeling. Remodeling consists of tearing down small parts of the bones, and then re-forming them. This process helps the body to attain and maintain bone density and peak bone mass. This occurs throughout life for about the first twenty-five to thirty years. Abnormally reduced bone mass is osteoporosis.