Normal bone is dense, somewhat like a new sponge or honeycomb. Osteoporosis is a major public health threat for 25 million Americans. In fact, a woman's risk of hip fracture alone is equal to the combined risk of developing breast, uterine, and ovarian cancer.
Osteoporosis occurs when the amount of bone loss is greater than the amount of bone that's formed.
Throughout life, bone is continually renewed. During youth, bone renewal and growth is usually greater than bone loss. Around age 30, bone removal starts to overtake replacement and both men and women lose bone. The rate of loss is greater in women especially due to the loss of estrogen with menopause. Estrogen plays an important role in the bone renewal process, and often the sudden decline in estrogen production after menopause leads to rapid bone removal and osteoporosis.