Osteoporosis is a disease of the skeleton.
People with osteoporosis have a reduction in the mass and quality of their bone structure. These changes make such individuals highly prone to broken bones including disabling vertebral and hip fractures. While everyone s bone density starts to decrease after about age 30, people who develop osteoporosis likely start off with reduced bone quality or have more rapid bone degeneration than normal. At least 20 million people in the U.S. have osteoporosis. Women are more likely to develop it than men.