All osteoporosis involves the loss of bone mineral density that leads to weak, fragile bones. It can help to understand the different terms doctors use to describe osteoporosis that begins at different ages or has different causes. Treatment depends on what type of osteoporosis someone has.
Osteopenia is thinning of the bones that is not yet severe enough to be considered osteoporosis. Osteopenia and osteoporosis are diagnosed based on the results of a bone mineral density (BMD) test. The result of a BMD test is known as the T-score.
Thresholds for T-scores are defined as:
Although someone with osteopenia does not yet have osteoporosis, they are at significant risk for developing the condition.
Osteoporosis that does not have a direct cause but occurs with aging is described as primary osteoporosis. Primary osteoporosis is the most common type. There are two subtypes of primary osteoporosis, type I and type II.
Type I osteoporosis is much more common in women. For this reason, type I is also known as postmenopausal osteoporosis. It develops between the ages of 50 and 70 when the protective effects of estrogen in women begin to fade. Wrist and spine fractures are common in type I.
Type II osteoporosis is also known as senile osteoporosis. Type II osteoporosis develops after the age of 70. In type II osteoporosis, hip and spine fractures are the most common.
There is some overlap between type I and type II osteoporosis.
When osteoporosis is caused by another health condition or medical treatment, it is said to be secondary osteoporosis. Conditions including kidney failure, leukemia, and thyroid disease are among those that can cause osteoporosis. Medical treatments that can cause osteoporosis include corticosteroids such as Prednisone, some breast cancer medications, and Depo-Provera (Medroxyprogesterone). In some cases, secondary osteoporosis caused by medication may be reversed if it is identified early enough and the causative medication is stopped.
Osteoporosis associated with pregnancy occurs rarely when an otherwise healthy woman develops unusual fractures as a result of lowered bone mineral density while pregnant or shortly after childbirth. Fractures associated with this type of osteoporosis may involve severe pain and fractures in the spine or hip. Women who develop osteoporosis associated with pregnancy usually recover fully. It is unclear why some women develop osteoporosis during pregnancy.
Osteoporosis can occur in children. Secondary osteoporosis is most common, and it may be caused by conditions including anorexia nervosa and leukemia or by medications used to treat other health problems. Children may develop osteoporosis as a result of rare conditions including the genetic disorders osteogenesis imperfecta and osteoporosis pseudoglioma syndrome. Osteoporosis in children with no clear cause is termed idiopathic juvenile osteoporosis, and it is extremely rare.
Transient migratory osteoporosis can cause severe pain and fractures in one part of the body at one time, and in another part later on. For instance, someone with transient migratory osteoporosis may experience a fracture and pain in one hip. Later on, they may experience pain and a fracture in one foot. Bone mineral density scans are usually normal in other areas, but show a loss of density in the affected area. Transient migratory osteoporosis is also known as bone marrow edema syndrome.