Osteoporosis is a bone disease. Patients experience loss of bone mineral density followed by loss of bone strength.
Osteoporosis is a disease that has no noticeable symptoms until the weakening of the bones leads to problems with posture, lower back pain, and brittle or easily broken bones. Although osteoporosis can appear at any age, it is most commonly a disease of adults. It develops when the wearing-out and removal of old bone—a process known as resorption—outpaces the production of new bone tissue.
In most people, the bones become stronger and heavier during childhood and adolescence until they reach their maximum density and strength (peak bone mass) around age thirty. After that point, the bones gradually lose their density. People's peak bone mass and the rate at which they lose it in later life affects their risk of developing osteoporosis. The higher the peak bone mass at age thirty, the lower the risk of osteoporosis later in life.
Doctors divide osteoporosis into three categories or types. Types 1 and 2 are considered primary because they are not caused by other diseases or conditions. Type 3 osteoporosis is sometimes called secondary
osteoporosis because it results from taking certain drugs or having other diseases.
- Type 1: This type occurs in women after menopause and results from declining levels of estrogen and other sex hormones in the body.
- Type 2: This type of osteoporosis occurs in elderly men as well as elderly women because of decreased bone formation due to aging.
- Type 3: Type 3 osteoporosis is caused by long-term use of certain medications—particularly steroids and drugs given to treat epilepsy—and by such conditions as malnutrition, Klinefelter syndrome, Turner syndrome, thyroid disorders, hemophilia, Marfan syndrome, rheumatoid arthritis, lupus, and lymphoma.
The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) estimates that 10 million people in the United States have osteoporosis as of 2008, with another 34 million having low bone density, a condition called osteopenia. Osteopenia can develop into osteoporosis if it is not treated. Osteoporosis is responsible for more than 1.5 million fractures annually, including 300,000 hip fractures, 700,000 vertebral fractures, 250,000 wrist fractures, and more than 300,000 fractures in other parts of the body. The costs of treating osteoporosis and the fractures that it causes come to $14 billion each year.
Some people are at greater risk than others of developing osteoporosis. Some of these risk factors can be changed, while other factors cannot be altered. Risk factors that cannot be changed include:
- Sex. Women are at greater risk than men, particularly after the menopause.
- Race/ethnicity. Asian and Caucasian women have a higher risk of osteoporosis than African American or Hispanic women.
- Body build. Small-boned people of either sex are at greater risk of osteoporosis than people with average or heavy bones.
- Age. Both men and women have an increased risk of osteoporosis as they get older.
- Genetic factors. A tendency for bones to fracture easily appears to run in some families.
Osteoporosis in Men
Like anorexia, osteoporosis is usually considered a women's disease. However, men over the age of fifty have a one-in-four chance of having a bone fracture due to osteoporosis. In addition, men who take certain medications—particularly cortisone and other steroid drugs—have the same risk of developing osteoporosis as women who take these medications. More than two million American men have osteoporosis as of 2008; each year, 80,000 of these men will suffer a hip fracture, and one-third of them will die within a year.
One of the men who developed osteoporosis at a young age from taking steroid medications was U.S. President John F. Kennedy (1916–1963). Kennedy developed colitis, a chronic disease of the lower intestinal tract, and was treated for it in the 1930s and 1940s with steroid medications. It was not known at that time that long-term use of these drugs can damage bone. By the time Kennedy was elected to the presidency in 1960, he had three fractured vertebrae in his lower back due to osteoporosis. Medical records that were opened to historians in 2003 showed that he was routinely given seven or eight shots of procaine (the drug that dentists use to numb patients' mouths) before press conferences because the pain in his back was so intense.
Risk factors for osteoporosis that people can change include:
- Low sex hormone levels. These can be raised in both men and women by hormone replacement therapy.
- Eating disorders, particularly anorexia.
- Depression. Emotional depression can be treated, most often with a combination of medication and psychotherapy.
- Low intake of calcium and vitamin D. People can change their eating habits and take vitamin or calcium supplements.
- Smoking and alcohol intake. People can quit smoking and drink in moderation.
- Getting the right amount of exercise. Bed rest or inadequate exercise can weaken bones, but so can too much exercise (such as marathon running).
- Medications. People who are taking medications that increase their risk of osteoporosis can ask their doctor about alternatives.
The basic cause of osteoporosis is that the loss of bone tissue occurs faster than the production of replacement bone. The increased rate of bone loss can be particularly critical if the person had a low or inadequate peak bone mass originally. A low peak bone mass can result from malnutrition in childhood; inadequate intake of calcium or vitamin D (necessary for the body to make use of calcium in the diet); an eating disorder in adolescence, when the body's need for calcium is at its height; or lack of exercise.
Osteoporosis can proceed for a long time without any noticeable symptoms. Some older adults simply notice that their height is shrinking. This loss of height is caused by compression of the bones in the spinal column. Sometimes the vertebrae fracture as they come closer together. This type of injury is called a compression fracture and may produce noticeable back pain.
Another common symptom of osteoporosis is a fragility fracture. Fragility fractures occur when a person falls from his or her standing position or a lower height and breaks a bone that would not break in a person with healthy bone. The most common locations of fragility fractures in people with osteoporosis are the wrists, the hips, and the vertebrae in the spine. The patient may experience the pain in various ways. Some describe it as sharp while others describe it as dull or nagging. In some cases, the pain gets worse when the patient is trying to walk or move around.
Osteoporosis is most likely to be diagnosed following a fragility fracture. The doctor will take a careful history of the patient's risk factors, including a possible family history of easily broken bones as well as a medication history and questions about such lifestyle factors as exercise, diet, smoking, and drinking.
The doctor may order a blood test to rule out a thyroid disorder or to check the levels of sex hormones in the blood. An x ray of the affected part of the body will be taken. The definitive diagnostic test, however, is a test of bone mineral density, sometimes called a bone densitometry test. To take this test, the patient lies on an examination table while two x-ray beams of different intensities are aimed at the bones. The result is called a T-score. It is calculated by comparing the patient's bone mineral
density to that of a healthy thirty-year-old of the same sex and race. A T-score of −1.0 or higher is normal. A score between −1.0 and −2.5 indicates osteopenia. A score below −2.5 indicates osteoporosis.
Treatment of osteoporosis includes a combination of lifestyle changes and medications for most patients. With regard to medications, hormone replacement therapy (HRT) used to be considered the main way of treating osteoporosis in women. But newer studies show that HRT increases the risk of heart disease and cancer in some women. So other medications that work by slowing the process of bone loss or by increasing bone density over time are more widely prescribed. Some of these medications have the additional advantage of working well in men with osteoporosis and in people who must take steroid drugs for other health problems.
Recommended lifestyle changes that can reduce the rate of bone loss include regular exercise, particularly weight-bearing forms of exercise like walking, dancing, treadmill exercises, and jumping. Other measures include quitting smoking, taking supplemental vitamin D and calcium, and watching one's alcohol intake.
The prognosis for osteoporosis depends on its type and cause; the patient's age, sex, and ethnicity; the presence of other diseases or disorders; and the patient's willingness to follow the doctor's recommendations about medications and lifestyle changes.
People do not die from osteoporosis itself but from complications from bone fractures. These complications can include chronic pain, pneumonia, blood clots in the deep veins of the leg, or breathing disorders caused by the stooped posture that results from compression fractures in the spine. The death rate within the first six months after a hip fracture is 14 percent. Even patients who survive often have a greatly lowered quality of life.
People cannot change such risk factors for osteoporosis as age, sex, and race, but they can eat properly, exercise regularly, and ask their doctor about vitamin D and calcium supplements. Women who have not yet gone through menopause should get at least 1,000 milligrams (mg) of
elemental calcium and a minimum of 800 international units (IU) of vitamin D every day. Women who have completed menopause, anyone who must take steroid medications, and all men and women over 65 should aim for 1,500 mg of elemental calcium and at least 800 IU of vitamin D daily.
Older adults should also try to reduce their risk of falls whether or not they have osteoporosis. There are balance and strength exercises that older adults can practice at home. In addition, safety measures should be taken, including wearing properly fitted shoes with non-slip soles; checking one's house for loose rugs, poor lighting, and other hazards; installing grab bars in shower stalls; and keeping a cordless phone within easy reach in case of an accident.
WORDS TO KNOW
Compression fracture : A fracture caused by the collapse of a vertebra in the spinal column, usually caused either by trauma or by weakening of the bone in osteoporosis.
Fragility fracture : A fracture that occurs as a result of a fall from standing height or less. A person with healthy bones would not suffer a broken bone falling from a standing position.
Osteopenia : The medical name for low bone mass, a condition that often precedes osteoporosis.
Resorption : The removal of old bone from the body.
T-score : The score on a bone density test, calculated by comparing the patient's bone mineral density to that of a healthy thirty-year-old of the same sex and race.
Vertebra (plural, vertebrae) : One of the segments of bone that make up the spinal column.
Osteoporosis is likely to continue to be a serious health concern because of the aging of the American population. As people continue to live longer, the number of people with Type 2 (age-related) osteoporosis will increase. In addition, people who are at risk for osteoporosis because of sex, race, or a family history of weak bones may not be completely able to prevent the disease even by careful attention to diet and exercise. It is possible that more effective medications to prevent bone loss or restore bone density will be developed.
Goldmann, David R. American College of Physicians Home Medical Guide to Osteoporosis. New York: Dorling Kindersley Publishers, 2000.
Hoffman, Gretchen. Osteoporosis. Tarrytown, NY: Marshall Cavendish Benchmark, 2008.
American Family Physician Patient Handout. Osteoporosis. Available online at http://www.aafp.org/afp/20040301/1207ph.html (posted March 1, 2004; accessed April 27, 2008).
3D Health Animations. Osteoporosis. Available online at http://www.healthscout.com/animation/68/48/main.html (accessed April 27, 2008). Animation has a playing time of a minute and a half.
History Channel. JFK's Secret Illness. Available online at http://www.history.com/media.do?id=presidents_jfk_secretillness_broadband&action=clip (accessed April 28, 2008). This is a three-and-a-half-minute video clip about President Kennedy's osteoporosis and other illnesses.
KidsHealth. Osteoporosis. Available online at http://www.kidshealth.org/kid/grownup/conditions/osteoporosis.html (updated April 2008; accessed April 27, 2008).
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Osteoporosis Overview. Available online in PDF format at http://www.niams.nih.gov/Health_Info/Bone/Osteoporosis/overview.pdf (updated December 2007; accessed April 27, 2008).
National Institutes of Health (NIH). Check Up on Your Bones. Available online at http://www.niams.nih.gov/Health_Info/Bone/Optool/index.asp (accessed April 27, 2008). This is an interactive Web site for people of all ages to identify personal risk factors for osteoporosis and suggest possible approaches for reducing risk. It takes about five minutes to answer the questions and obtain a personal profile of bone health.