Osteoporosis is the most common metabolic bone disease in the United States. It is a skeletal disease in which the bones become brittle and prone to fracture. Bone density is decreased to the point where fractures occur without severe stress or injury to the bones. This disease is usually overlooked and undertreated due to its silent presentation and is most commonly diagnosed after a fracture has occurred.
Until approximately age 40, the process of breaking down and building up bone works harmoniously. As a person ages, or in the presence of certain conditions, this system breaks down and the two processes become dysfunctional. The reasons for this occurrence are not clear, but declining levels of hormones in particular sex hormones are thought to be a factor. Some adults have a very high turnover rate of bone, some have a very gradual turnover, but the breakdown of bone eventually overtakes the build-up and results in osteoporosis.