OSTEOPOROSIS

DEFINITION

The word "osteoporosis" literally means "porous bones." Osteoporosis (pronounced OSS-tee-o-puh-RO-sis) occurs when bones begin to lose some of their essential elements. The most important of these elements is calcium. Over time, bone mass decreases. As a result, bones lose their strength, become fragile, and break easily. In extreme cases, even a sneeze or a sudden movement may be enough to break a bone.

DESCRIPTION

Osteoporosis is a serious health problem. About 28 million people in the United States have the condition. It is responsible for about 1.5 million fractures (broken bones) each year. The most common locations where breaks occur are the hip, spine, and wrist. Hip and spine injuries are the most serious. They often require hospitalization and major surgery. They may also lead to other serious consequences, including permanent disability and death.

To understand osteoporosis, it is helpful to understand how bones form. Bone is living tissue that is constantly renewed in a two-stage process. The first stage is formation. During formation, new bone tissue is built up from nutrients present in the bloodstream. The second stage is resorption. In this stage, bone cells break down. The elements of which are returned to the blood and other body fluids.

For about the first thirty years of life, bone formation takes place faster than resorption. Bones grow to be larger and stronger during this period. After middle age, resorption takes place faster and bones become smaller and weaker.

Osteoporosis is a continuation of this process. The balance between resorption and formation becomes very one-sided. Almost no new bone is formed, but bone continues to be removed. When bones are made smaller and weaker by this mechanism, the process is called primary osteoporosis.

Osteoporosis can also occur in another way. Some drugs and diseases can increase the rate at which resorption occurs. The end result is the same: bones become smaller and weaker. In this case, however, the process is called secondary osteoporosis.

Osteoporosis occurs most commonly in older people. It affects nearly half of all men and women over the age of seventy-five. Women are five times more likely than men to develop the condition. They have smaller, weaker bones to begin with, so resorption of bone material in women's bodies has a greater effect than in men's bodies.

Another important factor in osteoporosis is menopause. Menopause is the period in a woman's life when she stops menstruating. During this period, she also stops producing the hormone estrogen. Estrogen helps prevent the resorption of bone. As levels of estrogen fall in a woman's body, she is at greater risk for osteoporosis.

CAUSES

As outlined, osteoporosis is caused when the rate of bone resorption becomes greater than the rate of bone formation. This process is a normal part of aging. There are certain factors, however, that increase a person's risk for osteoporosis. These factors include:

• Gender. Women are more likely to have osteoporosis than men. Women commonly lose 30 percent to 50 percent of their bone mass over their lifetimes. Men lose about 20 percent to 35 percent of their bone mass.
• Race. Caucasian and Asian women are at somewhat higher risk for osteoporosis than are African American and Hispanic women.
• Body structure. Individuals with smaller, thinner bones are at higher risk for osteoporosis.
• Early menopause. Women who go through menopause earlier start losing bone mass earlier. Early menopause may be caused by a number of factors, such as heredity, surgery, vigorous exercise, anorexia (see anorexia nervosa entry), and bulimia (see bulimia nervosa entry).
• Lifestyle. Alcohol consumption and tobacco use are thought to increase risk for osteoporosis. Lack of exercise may have the same effect.
• Diet. Two important nutrients needed for bone formation are protein and calcium. A diet low in either of these nutrients may lead to osteoporosis.

SYMPTOMS

Osteoporosis is sometimes called the "silent disease." The term reflects the fact that the condition usually has no symptoms. People often don't know they have the disorder until they break a bone during some minor accident.

As osteoporosis develops, changes in body structure may occur. A person may actually grow shorter. This change occurs when vertebrae (bones in

Illustration of osteoporosis bone matrix. (© 1997. Reproduced by permission of

Custom Medical Stock Photo

.)

the spine) deteriorate and collapse. Loss of vertebrae mass can also result in the condition known as "dowager's hump" or "widow's hump." This condition is characterized by the hunchbacked appearance often seen in older women.

DIAGNOSIS

The only way to diagnose osteoporosis with certainty is with X rays. Ordinary X-ray techniques, like those used for chest X rays, are usually not very helpful. They do not show bone loss until the disease has progressed and extensive damage has occurred.

Computed tomography (CT) scans may be more helpful. In a CT scan, a specific region of the body is X-rayed from many angles. A computer then combines the various X-ray photographs. CT scans are not the best choice for diagnosing osteoporosis, however, because they require relatively high levels of radiation. Another common name for a CT scan is a computerized axial tomography (CAT) scan.

A better method for diagnosing osteoporosis is densitometry (pronounced DEN-si-TOM-i-tree). Densitometry is also a technique for X-raying bones. However, the amount of radiation used is very low. The X rays are taken from different angles and can show how much bone has been lost.

Some doctors recommend that people be tested on a regular basis for bone loss. For women, those tests should begin after menopause. For men, they should begin after the age of sixty-five. Such tests are important since there are seldom other signs of osteoporosis.

TREATMENT

Treatment depends on the form of osteoporosis a patient has. If a patient has secondary osteoporosis, treatment is aimed at curing the disease that has caused osteoporosis. In the case of primary osteoporosis, medications are used to adjust the balance between bone resorption and bone formation. Treatment may also be necessary for bone fractures resulting from osteoporosis. The most common treatment for such fractures is surgery.

Drugs

For women who have gone through menopause, the first line of treatment may be hormone replacement therapy (HRT). In hormone replacement therapy, a woman is given the estrogen that her body no longer produces on its own. The estrogen can be given orally (by mouth) or by injection. Many women choose HRT for other reasons as well. It helps ease the symptoms of menopause. It can also protect against heart disease, the number-one killer of women in the United States. HRT does have some harmful side effects, however. For example, it may increase a woman's risk for breast cancer (see breast cancer entry).

Other medications can be used to treat osteoporosis. These medications reduce the rate of bone resorption and/or increase the rate of bone formation. The two most common drugs used for these purposes are alendronate and calcitonin. These drugs may be given by injection or in the form of nose sprays.

Surgery

In advanced stages of osteoporosis, major fractures are common. In such cases, surgery may be required to repair the fracture. One of the most common procedures is hip replacement surgery. Hip replacement surgery is used to repair a broken hip. The original hip is removed and replaced with an artificial metal and/or plastic hip. Hip replacement surgery is usually quite successful. Patients can often return

Illustration showing atrophy of a hip bone. (© 1993

Patrick McDonnel

. Reproduced by permission of

Custom Medical Stock Photo

.)

to a relatively normal life. However, the surgery carries some serious risks. The death rate following such surgery may be 5 percent to 20 percent greater than for others of the same age group who have not had surgery.

Alternative Treatment

The primary approach for most alternative practitioners is the same as it is in traditional medicine. The goal is to make sure that individuals receive the nutrients they need to build strong bones in their daily diet. This means a diet rich in calcium and protein, including foods such as dairy products, dark-green leafy vegetables, sardines, salmon, and almonds. Nutritional supplements such as vitamin D, calcium, and magnesium may also be recommended.

Herbalists and Chinese medicine practitioners believe that certain herbs can slow the rate of bone loss. Among the products they recommend are horsetail, oat straw, alfalfa, licorice, marsh mallow, yellow dock, and Asian ginseng. Homeopathic practitioners recommend minerals such as Calcarea carbonica or silica. A substitute for HRT is to obtain hormones from natural sources, such as soybeans and wild yams.

PROGNOSIS

There is no cure for osteoporosis. However, it can be controlled quite well once it has been diagnosed. Medications, nutritional supplements, and a diet rich in calcium and protein can help slow the progress of the disorder.

PREVENTION

To a significant extent, osteoporosis is a preventable disease. People can take a number of steps beginning early in life to build strong bones. By continuing those practices as they grow older, they can reduce the rate of bone loss. Some of these steps include:

• Get calcium in foods. Foods rich in calcium include milk, cheese, yogurt, and other dairy products; green leafy vegetables; tofu; shellfish; Brazil nuts; sardines; and almonds.
• Take calcium supplements. A person can be certain of getting enough calcium by taking supplements in the form of pills.
• Get enough vitamin D. Vitamin D helps the body absorb calcium. The easiest way to get vitamin D is from sunshine. A fifteen-minute walk each day usually provides all the vitamin D one needs. Foods rich in vitamin D include liver, fish oil, and milk fortified with vitamin D.
• Avoid or limit smoking and the use of alcohol. Both smoking and alcohol use seem to increase the rate of bone loss. By limiting both activities, the risk of osteoporosis may be reduced.
• Exercise. Regular exercise builds strong bones. The forms of exercise likely to be most effective include aerobics, dancing, jogging, stair climbing, tennis, walking, and lifting weights. Experts recommend twenty to thirty minutes of exercise three to four times a week.

FOR MORE INFORMATION

Books

Brown, Susan E. Better Bones, Better Body: A Comprehensive Self-Help Program for Preventing, Halting, and Overcoming Osteoporosis. New Canaan, CT: Keats Publishing, 1996.

Notelovits, Morris, with Marsha Ware and Diana Tonnessen. Stand Tall! Every Woman's Guide to Preventing and Treating Osteoporosis, 2nd ed. Gainesville, FL: Triad Publishing Co., 1998.

Periodicals

Bilger, Burkhard. "Bone Medicine." Health Magazine (May–June 1996): pp. 125–28.

Braun, Wendy. "Do Your Bones Pass the Test?" Saturday Evening Post (March–April 1997): pp. 18–22+.

Organizations

Arthritis Foundation. 1330 West Peachtree Street, Atlanta, GA 30309. (404) 872–7100. http://www.arthritis.org.

National Institutes of Health. Osteoporosis and Related Bone Diseases: National Resource Center. 1232 22nd St. NW, Suite 500, Washington, DC 20037-1292. (800) 624-BONE. http://www.osteo.org.

National Osteoporosis Foundation. 1232 22nd Street NW, Washington, DC 20037-1292. (202) 223-2226. http://www.nof.org.