Osteoporosis is a condition in which a decrease in the density of bones weakens the bones, making breaks (fractures) likely.
- Aging, estrogendeficiency, low vitamin D or calcium intake, and certain disorders can decrease the amounts of the components that maintain bone density and strength.
- Osteoporosis may not cause symptoms until a bone fracture occurs.
- Fractures can occur with little or no force and may occur after a minor fall.
- Although fractures are often painful, some fractures of the spine do not cause pain but can still cause deformities.
- Doctors diagnose people at risk by testing their bone density.
- Osteoporosis can usually be prevented and treated by managing risk factors, ensuring adequate calcium and vitamin Dintake, engaging in weight-bearing exercise, and taking bisphosphonates or other drugs.
Bones contain minerals, including calcium and phosphorus, which make them hard and dense. To maintain bone density (or bone mass), the body requires an adequate supply of calcium and other minerals and must produce the proper amounts of several hormones, such as parathyroid hormone, growth hormone,calcitonin, estrogen, and testosterone. An adequate supply of vitamin D is needed to absorb calcium from food and incorporate it into bones. Vitamin D is absorbed from the diet and also manufactured in the skin using sunlight.
So that bones can adjust to the changing demands placed on them, they are continuously broken down and reformed. This process is known as remodeling. In this process, small areas of bone tissue are continuously removed and new bone tissue is deposited. Remodeling affects the shape and density of the bones. In youth, the bones grow in width and length as the body grows. In later life, bones may sometimes enlarge in width but do not continue to grow longer.
Because more bone is formed than is broken down in the young adult years, bones progressively increase in density until about age 30, when they are at their strongest. After that, as breakdown exceeds formation, bones slowly decrease in density. If the body is unable to maintain an adequate amount of bone formation, bones continue to lose density and may become increasingly fragile, eventually resulting in osteoporosis.
Prevention of Osteoporosis
Prevention of osteoporosis is generally more successful than treatment because it is easier to prevent loss of bone density than to restore density once it has been lost. Osteoporosis prevention involves
- Managing risk factors (for example, quitting smoking and avoiding excess alcohol and caffeine use)
- Consuming adequate amounts of calcium and vitamin D
- Engaging in weight-bearing exercise (such as walking, climbing stairs, or weight training)
- Taking certain drugs (for some people)
Certain measures can help prevent fractures. Many older people are at risk of falls because of poor coordination, poor vision, muscle weakness, confusion, and use of drugs that cause light-headedness when people stand or cause confusion. Modifying the home environment for safety and working with a physical therapist to develop an exercise program can help. Strengthening exercises may help improve balance.
Treatment of Osteoporosis
- Calcium and vitamin D
- Weight-bearing exercise
- Treatment of fractures
Osteoporosis treatment involves ensuring adequate intake of calcium and vitamin D and engaging in weight-bearing exercises. All people being treated need to take drugs. When treating people who have osteoporosis, doctors also manage conditions and risk factors that can make osteoporosis worse.
Most of the same drugs are used for prevention and treatment.
Bisphosphonates (alendronate, risedronate, ibandronate, and zoledronic acid) are useful in preventing and treating all types of osteoporosis and are usually the first drugs used. Bisphosphonates have been shown to increase bone density in the spine and hips and reduce the risk of fractures. Alendronate and risedronate can be taken by mouth (orally). Zoledronic acid can be given by vein (intravenously). Ibandronate can be taken orally or intravenously.
An oral bisphosphonate must be swallowed on an empty stomach with a full glass of water (8 ounces) after arising for the day. No other food, drink, or drug should be consumed for the next 30 to 60 minutes because food in the stomach may decrease the absorption of the drug. Because oral bisphosphonates can irritate the lining of the esophagus, the person must not lie down for at least 30 minutes (60 minutes for ibandronate) after taking a dose. Certain people, including those who have difficulty swallowing, gastrointestinal symptoms (for example, heartburn or nausea), and certain disorders of the esophagus or stomach, should not take the bisphosphonates orally. These people can be given ibandronate or zoledronic acid intravenously. In addition, the following people should not take bisphosphonates:
- Women who are pregnant or nursing
- People who have low levels of calcium in the blood
- People who have severe kidney disease
At this time, doctors do not know how long people should take bisphosphonates. Most people need to take these drugs for 3 to 5 years, and some people may need to take them for up to 10 years. The determination of how long taking the drugs is likely to be helpful is made by the doctor and is based on a person’s medical condition and risk factors for fracture. After stopping, doctors usually do periodic tests to determine whether bone mass is decreasing. If bone mass is decreasing, treatment with a bisphosphonate or another drug may be restarted.
Osteonecrosis of the jaw is a rare condition that has occurred in some people who take bisphosphonates. In this condition, the jaw bone breaks down, particularly in people who have had extensive dental work or injury, take bisphosphonates intravenously, who have had radiation therapy to the head and neck to treat cancer, or a combination are at highest risk. However, it is not truly clear whether bisphosphonates cause osteonecrosis of the jaw and, if they do, which particular drugs are most likely to cause it. There is no evidence that stopping bisphosphonates before having dental work helps. The risk of developing osteonecrosis of the jaw is exceptionally low in people taking bisphosphonates, and the likely benefits in treating to prevent bone fractures usually far outweigh the potential harms.
Long-term use of bisphosphonates may increase the risk of developing unusual fractures of the thighbone (femur). However, bisphosphonates, when used as prescribed, prevent many more fractures than they may cause.
Calcitonin, which inhibits the breakdown of bone, is another drug used for treatment but not frequently. Calcitonin has not been shown to reduce fracture risk, but it can help relieve pain caused by vertebral fractures. Calcitonin is usually taken by nasal spray. Its use can decrease blood levels of calcium, so these levels must be monitored.
Hormonal therapy (for example, with estrogen) helps maintain bone density in women and can be used for prevention or treatment. This therapy is most effective when started within 4 to 6 years after menopause, but starting it later can still slow bone loss and reduce the risk of fractures. However, because the risks of hormonal therapy exceed its benefits for most women, hormonal therapy is usually not the treatment option used. Decisions about using estrogen replacement therapy after menopause are complex.
Raloxifene is an estrogen-like drug that may be useful in preventing and treating bone loss, but it does not have some of estrogen’s negative side effects. Raloxifene is used in people who cannot or prefer not to take bisphosphonates. Raloxifene can reduce the risk of vertebral fractures and may reduce the risk of invasive breast cancer.
Men do not benefit from estrogen but may benefit from testosterone replacement therapy if their testosterone level is low.
A synthetic form of parathyroid hormone called teriparatide can be injected daily in small amounts. Teriparatide increases the formation of new bone, increases bone density, and decreases the likelihood of fractures. This therapy is used in some people who
- Develop marked bone loss or new fractures while being treated with a bisphosphonate
- Cannot take bisphosphonates
- Have unusually severe osteoporosis or many fractures (particularly vertebral fractures)
- Have osteoporosis caused by corticosteroids
Denosumab is a newer drug. It is an alternative to other drugs used to treat osteoporosis. Denosumab is given as an injection under the skin in a doctor’s office two times a year.