Osteoporosis is a bone disease that increases the risk of developing fractures (broken bones). It is defined as a decrease in bone mineral density (BMD) and bone strength.
Osteoporosis is the major cause of fractures in postmenopausal women and the elderly. (See How Bones Work)
Fractures related to osteoporosis are most likely to occur in the bones of the hip, spine and wrist, but any bone can be affected. Hip fractures are especially disabling.
Osteoporosis can progress slowly without any symptoms until a bone breaks or one or more vertebrae (bones in the spine) collapse. Collapsed vertebrae can result in severe back pain, loss of height, or a hunched posture. Bones affected by osteoporosis may become so fragile that fractures occur spontaneously or as the result of minor trauma or movement.
Osteoporosis is largely preventable and people who already have osteoporosis can slow its progression and reduce their risk of developing fractures.
Who gets Osteoporosis?
The risk of developing osteoporosis increases with age. 4 out of 5 people who develop osteoporosis are women. 50% of women and as many as 25% of men over age 50 will have a fracture related to osteoporosis some time in the lives.
Consider talking to your doctor about osteoporosis if:
- You are a man or woman over age 45 or a postmenopausal woman and you break a bone.
- You are a woman age 65 or older.
- You have lost height, developed a stooped or hunched posture, or experienced sudden back pain with no apparent
- You have been taking a corticosteroid, such as prednisone, for 2 months or longer or are taking other medications known to
- You have had anorexia nervosa or a history of this eating disorder.
- You are a premenopausal woman, not pregnant, and your menstrual periods have stopped, are irregular, or never started when you reached puberty.
Causes of Osteoporosis
The major cause of osteoporosis is less than optimal bone growth during childhood and adolescence. This results in a failure to reach optimal peak bone mass.
People who enter early adulthood with greater reserves of bone (higher peak bone mass) are less likely to develop osteoporosis later in life when bone mass decreases as result of aging, menopause, or other factors. Conversely, those who reach their early adulthood with insufficient bone reserves are at greater risk of developing osteoporosis in their fifties and sixties.
Other causes of osteoporosis are bone loss due to a greater than expected rate of bone resorption, a decreased rate of bone formation, or both.
A major contributor to bone loss among women later in life is the reduction in estrogen production that occurs with menopause. This is referred to as postmenopausal osteoporosis.
In men, sex hormone levels also decline after middle age, but the decline is more gradual. These declines probably also contribute to bone loss in men after around age 50.
Osteoporosis can also result from bone loss that may accompany a wide range of disease conditions, eating disorders, and certain medications and medical treatments. For instance, osteoporosis may be caused by long-term use of some anti-epileptic medications (anticonvulsants) and glucocorticoid medications such as prednisone and cortisone. Glucocorticoids are anti-inflammatory drugs used to treat many diseases, including rheumatoid arthritis, lupus, asthma, and Crohn's disease. Other causes of osteoporosis include alcoholism, anorexia nervosa, abnormally low levels of sex hormones, hyperthyroidism, kidney disease, and certain gastrointestinal disorders. Sometimes osteoporosis results from a combination of causes.
In the past, osteoporosis could only be detected if you broke a bone. Today, several tests are available for the diagnosis of osteoporosis.
Bone Mineral Density Tests
A bone mineral density (BMD) test is the best way to determine your bone health. It painlessly measures bone density at your hip and spine. During the test, an extremely low energy source is passed over all or part of the body. A computer program evaluates the information and allows the doctor to see how much bone mass you have.
Bone mineral density tests can determine your risk for fractures, and measure your response to osteoporosis treatment.
The most widely used bone mineral density test is called a dual-energy x-ray absorptiometry, or DXA test. Although no bone density test is 100% accurate, this type of test is the single most important predictor of whether a person will have a fracture in the future.
A bone scan may be ordered in some cases. A bone scan involves injecting a dye that allows a scanner to identify differences in the conditions of various areas of bone tissue. A bone scan can show the doctor changes in bone tissue that may indicate cancer, bone lesions, inflammation, or new fractures.
If you have back pain, your doctor may order an x-ray of your spine to determine whether you have had a fracture.
A number of lab tests may be performed on blood and urine samples. The results of these tests can help your doctor identify conditions that may be contributing to your bone loss.
The primary goal in treating people with osteoporosis is preventing bone fractures. A comprehensive treatment program includes a focus on proper nutrition, exercise, and prevention of falls that may result in fractures. (See Osteoporosis Prevention)
Your doctor may also prescribe one of several medications that have been shown to slow or stop bone loss or build new bone, increase bone density, and reduce fracture risk. If you take medication to prevent or treat osteoporosis, it is still essential that you also obtain the recommended amounts of calcium and vitamin D. Exercising and maintaining other aspects of a healthy lifestyle are also important.
There are several medications available for the prevention or treatment of osteoporosis. These have all been shown to reduce the risk of developing fractures due to osteoporosis. Some work to prevent the resorption of bone, and others work to build bone.
Bisphosphonates are group of osteoporosis medications that slow down the breakdown of bone, increase bone density, and decrease the amount of calcium released from the bones into the blood. In postmenopausal women with osteoporosis, bisphosphonates increase bone density in both the spine and hip, and reduce the risk of fracture. Side effects may include digestive system problems.
Alendronate (Fosamax) and risedronate (Actonel) are approved for treating osteoporosis in men and those with osteoporosis caused by prolonged use of glucocorticoids.
Biphosphonates are poorly absorbed by the stomach and must be taken on an empty stomach with no food or drink to be consumed in the next 30 minutes.
Reclast (zoledronic acid) is a bisphosphonate that is administered by IV infusion once each year.
Selective Estrogen Receptor Modulators (SERMs)
Selective estrogen receptor modulators (SERMs) are a class of medications that act on the estrogen receptors throughout the body in a targeted fashion. These drugs are not estrogens, but they mimic the effects of estrogen on bones and slow down the osteoclast cells that break down bone tissue. SERMs have been shown to prevent bone loss, have beneficial effects on bone mass, and reduce the risk of spine fractures.
Additionally, they do not have estrogen's potentially harmful effects on breast tissue or the uterus. In fact, they have been shown to reduce the risk of developing invasive breast cancer.
Evista (raloxifene) is a SERM that is approved for the treatment and prevention of osteoporosis. It is taken as a tablet once a day. Side effects may include hot flashes, sweating, clot formation in some blood vessels, muscle soreness, weight gain, or a rash.
Prolia (denosumab) is a monoclonal antibody that binds to a particular RANKL receptive on the bone to reduce the resoprtion of bone. It is approved for the treatment of women with postmenopausal osteoporosis at high risk of developing a fracture.
Prolia is administered every 6 months via subcutaneous injection, similar to some vaccines.
Prolia lowers calcium levels in the blood so cannot be used by women with low blood calcium levels. Hypocalcemia (low blood calcium levels) may treated with calcium and vitamin D supplements before starting Prolia.
Bone Anabolic Agents
Forteo (teriparatide) is an injectable, recombinant form of human parathyroid hormone (PTH) that stimulates osteoblast cells in the bone to grown create new bone tissue.
It is used primary for people with osteoporosis who have already experienced a bone fracture, have a particularly low bone mineral density, or cannot tolerate biphosphonates.
Forteo is administered as a once-a-day injection.
Calcitonin (Miacalcin, Fortical) is another medication that slows down bone resorption by slowing down the osteoclast cells in the bone.
Calcitonin is approved for the treatment of osteoporosis in women who are at least 5 years beyond menopause. It is taken as a single daily nasal spray or as an injection under the skin. In women who are at least 5 years beyond menopause, calcitonin slows bone loss and increases spinal bone density. Some patients report that calcitonin also relieves pain from bone fractures. The effects of calcitonin on fracture risk are still unclear.
Estrogen replacement therapy has been shown to be effective in preventing osteoporosis, but it may not be prescribed unless there are other medical indications because of the health risks may outweigh the benefits.
© 2010 Vivacare. Last updated April 22, 2011.
Reference: The National Institute of Arthritis and Musculoskeletal and Skin Diseases
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Osteoporosis and Related Bone Diseases (link to NIH)
Osteoporosis Overview (link to NIH)
Osteoporosis Summary (link to American College of Rheumatology)
Glucocorticoid-Induced Osteoporosis (link to American College of Rheumatology)
Denosumab (Prolia) Injection Overview (link to NIH)
Evista (raloxifene) Handout (link to NIH)
Teriparatide (Forteo) injection (link to NIH)
Book: Mayo Clinic on Osteoporosis (link to )
- Interactive Programs
Bone Health Check Up (link to NIH)
- Support & Research Groups
National Osteoporosis Foundation (link to NOF)
- En Espanol
Denosumab inyectable (link to NIH)
Evista (Raloxifeno) (link to NIH)
Inyeccion de teriparatida (origen ADNr) (link to NIH)
La osteoporosis (link to American College of Rheumatology)
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