Our bodies are always breaking down bone and replacing it with new bone. In the reabsorption stage, the old bone is broken down and in the formation stage, new bone is built. It is constantly being renewed throughout our lives. As we age the replacement process slows down. Bone is a living tissue, which has little spaces which get larger as we lose bone density. To make matters worse, the outside of the bone thins as well. Calcium and phosphate are essential for bone formation. If you do not get enough calcium or your body does not absorb enough calcium, it will hurt bone production. Bone loss occurs in everyone as we get older. Bone forming cells begin to slow down, which causes bone to be lost at a faster pace than it is formed. Osteoporosis occurs as a result of an acceleration of this process, which is called primary osteoporosis. Secondary osteoporosis is caused by some medications and disease processes. Osteoporosis typically occurs in older people and women after menopause. The leading causes of osteoporosis are a decrease in estrogen in women at menopause and a drop of testosterone in men.