Osteoporosis

Definition

The word osteoporosis literally means "porous bones." It occurs when bones lose an excessive amount of their protein and mineral content, particularly calcium . Over time, bone mass, and therefore bone strength, is decreased. As a result, bones become fragile and break easily. Even a sneeze or a sudden movement may be enough to break a bone in someone with severe osteoporosis.

Description

Osteoporosis is a serious public health problem. Some 28 million people in the United States are affected by this potentially debilitating disease, which is responsible for 1.5 million fractures (broken bones) annually. These fractures, which are often the first sign of the disease, can affect any bone, but the most common locations are the hip, spine, and wrist. Breaks in the hip and spine are of special concern because they almost always require hospitalization and major surgery, and may lead to other serious consequences, including permanent disability and even death.

To understand osteoporosis, it is helpful to understand the basics of bone formation. Bone is living tissue that is constantly being renewed in a two-stage process (resorption and formation) that occurs throughout life. In the resorption stage, old bone is broken down and removed by cells called osteoclasts. In the formation stage, cells called osteoblasts build new bone to replace the old. During childhood and early adulthood, more bone is produced than removed, reaching its maximum mass and strength by the mid-30s. After that, bone is lost at a faster pace than it is formed, so the amount of bone in the skeleton begins to slowly decline. Most cases of osteoporosis occur as an acceleration of this normal aging process—a form referred to as primary osteoporosis. The condition can also be caused by other disease processes or prolonged use of certain medications that result in bone loss—a form called secondary osteoporosis.

Osteoporosis occurs most often in older people and in women after menopause . It affects nearly half of all men and women over the age of 75. Women, however, are five times more likely than men to develop the disease. They have smaller, thinner bones than men to begin with, and they lose bone mass more rapidly after menopause (usually around age 50), when they stop producing a bone-protecting hormone called estrogen. In the five to seven years following menopause, women can lose about 20% of their bone mass. By age 65 or 70, though, men and women lose bone mass at the same rate. As an increasing number of men reach an older age, they are becoming more aware that osteoporosis is an important health issue for them as well.

Causes and symptoms

A number of factors increase the risk of developing osteoporosis. They include:

• Age. Osteoporosis is more likely as people grow older and their bones lose tissue.
• Gender. Women are more likely to have osteoporosis because they are smaller and so start out with less bone. They also lose bone tissue more rapidly as they age. While women commonly lose 30–50% of their bone mass over their lifetimes, men lose only 20–33% of theirs.
• Race. Caucasian and Asian women are at higher risk for the disease than women of African or Hispanic ethnicities.
• Figure type. Women with small bones and those who are thin are more liable to have osteoporosis.
• Early menopause. Women who stop menstruating early because of heredity, surgery or a lot of physical exercise may lose large amounts of bone tissue early in life. Conditions such as anorexia and bulimia may also lead to early menopause and osteoporosis.
• Lifestyle. People who smoke or drink too much, or do not get enough exercise have an increased chance of getting osteoporosis.
• Diet. Those who do not get enough calcium or protein may be more likely to have osteoporosis. People who constantly diet are more prone to the disease. It has been shown that adolescent girls (but not boys) have insufficient calcium intake levels in the diet. This calcium deficiency occurs during a period of rapid bone growth, stunting the peak bone mass ultimately achieved; thus, these individuals are at greater risk of developing osteoporosis.
• Genetics. People with a family history of osteoporosis are more likely to contract the disease.
• Chronic use of medication. Certain types of medication, such as steroids, interfere with the body's ability to absorb calcium or accelerate calcium depletion, damaging bone density.

Osteoporosis is often called the "silent" disease, because bone loss occurs without symptoms. People often do not know they have the disease until a bone breaks, frequently in a minor fall that would not normally cause a fracture. A common occurrence is compression fractures of the spine. These can happen even after a seemingly normal activity, such as bending or twisting to pick up a light object. The fractures can cause severe back pain , but sometimes they go unnoticed—either way, the vertebrae collapse down on themselves, and the person actually loses height. The hunchback appearance of many elderly women, sometimes called "dowager's hump" or "widow's hump," is due to this effect of osteoporosis on the vertebrae.

Diagnosis

Certain types of doctors may have more training and experience than others in diagnosing and treating people with osteoporosis. These include geriatricians, who specialize in treating the aged; endocrinologists, who specialize in treating diseases of the body's endocrine system (glands and hormones); and orthopedic surgeons, who treat fractures, such as those caused by osteoporosis.

Before making a diagnosis of osteoporosis, the doctor usually takes a complete medical history, conducts a physical exam, and orders x-rays, as well as blood and urine tests, to rule out other diseases that cause loss of bone mass. The doctor may also recommend a bone density test. This is the only way to determine if osteoporosis is present. It can also show how far the disease has progressed.

Several diagnostic tools are available to measure the density of a bone. The most accurate and advanced of the densitometers uses a technique called DEXA (dual energy x-ray absorptiometry). With the DEXA scan, a double x-ray beam takes pictures of the spine, hip, or entire body. It takes about 20 minutes to do, is painless, and exposes the patient to only a small amount of radiation—about one-fiftieth that of a chest x ray . The ordinary x ray is one, though it is the least accurate for early detection of osteoporosis, because it does not reveal bone loss until the disease is advanced and most of the damage has already been done. Other tools that are more likely to catch osteoporosis at an early stage are computed tomography scans (CT scans ) and machines called densitometers, which are designed specifically to measure bone density. The CT scan, which takes a large number of x rays of the same spot from different angles, is an accurate test, but uses higher levels of radiation than other methods.

People should talk to their doctors about their risk factors for osteoporosis and if, and when, they should get the test. A woman should have bone density measured at menopause, and periodically afterward, depending on the condition of their bones. Men should be tested around age 65. Men and women with additional risk factors, such as those who take certain medications, may need to be tested earlier.

Treatment

There are a number of good treatments for primary osteoporosis, most of them medications. In addition, calcium (0.5 to 2 g/day) and vitamin D (400 to 800 IU/day) supplementation can reduce the rate of bone loss in women who are more than five years postmenopausal. Fracture reduction efficacy of calcium and vitamin D supplementation, administered independently, has been demonstrated in women older than 75 years of age.

For people with secondary osteoporosis, treatment may focus on curing the underlying disease.

Drugs

For most women who have gone through menopause, the best treatment for osteoporosis is hormone replacement therapy (HRT). Many women participate in HRT when they undergo menopause, to alleviate symptoms such as hot flashes, but hormones have other important roles as well. They protect women against heart disease, the number one killer of women in the United States, and they help to relieve and prevent osteoporosis. HRT increases a woman's supply of estrogen, which helps build new bone, while preventing further bone loss.

Some women, however, do not want to take or are not candidates for hormones, because some studies show they are linked to an increased risk of breast cancer or uterine cancer . Other studies reveal that risk is due to increasing age. (Breast cancer tends to occur more often as women age.) Whether or not a woman takes hormones is a decision she should make carefully with her doctor. Women should talk to their doctors about personal risks for osteoporosis, as well as their risks for heart disease and breast cancer.

Novel delivery systems of HRT have been developed. For example, Vivelle is a estradiol transdermal system that is used for prevention of osteoporosis. It uses a "patch" to continously deliver the hormone estradiol through the skin.

Studies have shown women who started taking HRT within five years of menopause show significantly reduced rates of hip fractures than women who began HRT more than five years postmenopausal. However, even while taking HRT, 10 to 20% of women continue to lose bone density and therefore may require additional intervention.

For people who cannot or will not take estrogen, other agents can be good choices. These include:

• bisphosphonates
• calcitonin
• selective estrogen receptor modulators
• sodium fluoride
• androgens

Although there are a number of bisphosphonates used for the treatment of various forms of osteoporosis and resorptive bone diseases, alendronate (sold under the brand name Fosamax), etidronate (sold under the brand name Didronel), and risedronate (sold under the brand name Actonel) are some of the agents most commonly used for therapeutic treatment of postmenopausal osteoporosis. Biphosphonates act by decreasing bone resorption or breakdown. For example, alendronate attaches itself to bone that has been targeted by bone-eating osteoclasts. It protects the bone from these cells. Osteoclasts help the body break down old bone tissue.

Alendronate has shown to be an effective agent in preventing bone loss and building bone in recently post-menopausal women and is especially useful in women who have contraindications for HRT. It has been licensed for the treatment and prevention of vertebral and nonvertebral postmenopausal osteoporosis. Alendronate has proven safe in very large, multi-year studies, but not much is known about the effects of its long-term use. Side effects are generally minimal with abdominal pain, nausea, dyspepsia, constipation and diarrhea occurring in 3% to 7% of patients treated with alendronate. It can be taken daily, and now a new formulation has been developed that can be taken weekly.

Etidronate has been shown to reduce the rate of new vertebral and nonvertebral fractures. It appears to be well tolerated in clinical studies.

Calcitonin is a hormone that has been used as an injection for many years. It is also marketed as a nasal spray. It also slows down bone-eating osteoclasts. Side effects are minimal, but calcitonin builds bone by only 1.5% a year, which may not be enough for some women to recover the bone they lose.

Selective estrogen receptor modulators (SERMs) such as raloxifene, droloxifene, idoxifene, and tamoxifen are used as alternatives to hormone replacement therapy (HRT) which commonly use estrogen. SERMs have been shown to protect against postmenopausal bone loss without the estrogenic side effects. Raloxifene was the first SERM to be approved in the osteoporosis market for prevention and treatment of osteoporosis. Raloxifene binds to estrogen receptors and mimics estrogen's action on bone by preventing bone loss, and improving cholesterol metabolism , therefore acting as an agonist. It also acts as an estrogen antagonist in the uterus and the breasts, by not imitating the action of estrogen. These drugs may thus improve blood lipid profiles and protect against breast cancer. There is an enhanced risk of venous thromboembolic events during raloxifene therapy, especially during the first four months of therapy. It also has a propensity to induce hot flashes, and leg pain.

Sodium fluoride has been used as an anabolic agent to stimulate bone formation. However, a high incidence of side effects, mainly gastrointestinal symptoms and lower extremity pain syndrome have occurred in clinical trials.

Androgens have been used for reducing bone loss. Androgens are classified as anabolic steroids, which include nandrolone, stanozolol and testosterone, are used as antiresorptive agents. Androgens are important for postmenopausal women as they serve as a substrate for the peripheral production of estrogens.

The treatments currently available are antiresorptive, which limits the ability to increase bone mass. Other bone-building agents are under investigation including parathyroid hormone which has been clinically evaluated but is still awaiting FDA approval as of March 2001. The biphosphonates have demonstrated the most dramatic reduction in fracture rates and may be the best choice for women with severe osteoporosis. Estrogen's effect may be similar, but has not been established in large randomized trials. Raloxifene may be particularly useful in women who wish to benefit from a breast cancer risk reduction. Calcitonin may be the least potent but may be useful in women who cannot tolerate other therapies.

Surgery

Unfortunately, treatment for osteoporosis is usually tied to fractures that result from advanced stages of the disease. For complicated fractures, such as broken hips, hospitalization and a surgical procedure are required. In hip replacement surgery, the broken hip is removed and replaced with a new hip made of plastic, or metal and plastic. Though the surgery itself is usually successful, complications of the hip fracture can be serious. Those individuals have a 5%–20% greater risk of dying within the first year following that injury than do others in their age group. A large percentage of those who survive are unable to return to their previous level of activity, and many end up moving from self-care to a supervised living situation or nursing home. Getting early treatment and taking steps to reduce bone loss are vital.

Alternative treatment

Alternative treatments for osteoporosis focus on maintaining or building strong bones. A healthy diet low in fats and animal products and containing whole grains, fresh fruits and vegetables, and calcium-rich foods (such as dairy products, dark-green leafy vegetables, sardines, salmon, and almonds), along with nutritional supplements (such as calcium, magnesium, and vitamin D), and weight-bearing exercises are important components of both conventional prevention and treatment strategies and alternative approaches to the disease. In addition, alternative practitioners recommend a variety of botanical medicines or herbal supplements. Herbal supplements designed to help slow bone loss emphasize the use of calcium-containing plants, such as horsetail (Equisetum arvense), oat straw (Avena sativa), alfalfa (Medicago sativa), licorice (Glycyrrhiza galbra), marshmallow (Althaea officinalis), and yellow dock (Rumex crispus). Homeopathic remedies focus on treatments believed to help the body absorb calcium. These remedies are likely to include such substances as Calcarea carbonica (calcium carbonate) or silica. In traditional Chinese medicine,

KEY TERMS

Alendronate —A nonhormonal drug used to treat osteoporosis in postmenopausal women.

Anticonvulsants —Drugs used to control seizures, such as in epilepsy.

Biphosphonates —Compounds (like alendronate) that slow bone loss and increase bone density.

Calcitonin —A hormonal drug used to treat post-menopausal osteoporosis.

Estrogen —A female hormone that also keeps bones strong. After menopause, a woman may take hormonal drugs with estrogen to prevent bone loss.

Glucocorticoids —Any of a group of hormones (like cortisone) that influence many body functions and are widely used in medicine, such as for treatment of rheumatoid arthritis inflammation.

Hormone replacement therapy (HRT) —Also called estrogen replacement therapy, this controversial treatment is used to relieve the discomforts of menopause. Estrogen and another female hormone, progesterone, are usually taken together to replace the estrogen no longer made by the body. It has the added effect of stopping bone loss that occurs at menopause.

Menopause —The ending of a woman's menstrual cycle, when production of bone-protecting estrogen decreases.

Osteoblasts —Cells in the body that build new bone tissue.

Osteoclasts —Cells that break down and remove old bone tissue.

Selective estrogen receptor modulator —A hormonal preparation that offers the beneficial effects of hormone replacement therapy without the increased risk of breast and uterine cancer associated with HRT.

practitioners recommend herbs thought to slow or prevent bone loss, including dong quai (Angelica sinensis) and Asian ginseng (Panax ginseng). Natural hormone therapy, using plant estrogens (from soybeans) or progesterone (from wild yams), may be recommended for women who cannot or choose not to take synthetic hormones.

It should be noted, however, that very few clinical trials are conducted on alternate therapies and therefore efficacy cannot be established.

Prognosis

There is no cure for osteoporosis, but it can be controlled. Most people who have osteoporosis fare well once they get treatment. The medicines available now build bone, protect against bone loss, and halt the progress of this disease.

Health care team roles

Doctors, nurses, physical therapists, radiation technologists, and dietitians all play roles in the process of controlling osteoporosis. Because osteoporosis is treatable but not curable, the main responsibility for controlling the progress of the disease rests with the patient. All of these team members play an important role in identifying risk of osteoporosis before it strikes and in convincing the patient to take appropriate steps (including lifestyle modification) to minimize the dangers of fracturing major bones.

Prevention

Building strong bones, especially before the age of 35, and maintaining a healthy lifestyle are the best ways of preventing osteoporosis. To build as much bone mass as early as possible in life, and to help slow the rate of bone loss later in life:

Get calcium in foods

Experts recommend 1,500 milligrams (mg) of calcium per day for adolescents, pregnant or breast-feeding women, older adults (over 65), and postmenopausal women not using hormone replacement therapy. All others should get 1,000 mg per day. Foods are the best source for this important mineral. Milk, cheese, and yogurt have the highest amounts. Other foods that are high in calcium are green leafy vegetables, tofu, shell-fish, Brazil nuts, sardines, and almonds.

Take calcium supplements

Many people, especially those who do not like or cannot eat dairy foods, do not get enough calcium in their diets and may need to take a calcium supplement. Supplements vary in the amount of calcium they contain. Those with calcium carbonate have the most amount of useful calcium. Supplements should be taken with meals and accompanied by six to eight glasses of water a day. Calcium supplements and antacids interfere with absorption of alendronate and should be taken at least one half hour later.

Get vitamin D

Vitamin D helps the body absorb calcium. People can get vitamin D from sunshine with a quick (15–20 minutes) walk each day or from foods such as liver , fish oil, and vitamin-D fortified milk. During the winter months it may be necessary to take supplements (400–800 IU/day).

Avoid smoking and alcohol

Smoking reduces bone mass, as does heavy drinking. To reduce risk, do not smoke and limit alcoholic drinks to no more than two per day. An alcoholic drink is1.5 oz (44 mL) of hard liquor, 12 oz (355 mL) of beer, or 5 oz (148 mL) of wine.

Exercise

Exercising regularly builds and strengthens bones. Weight-bearing exercises—where bones and muscles work against gravity—are best. These include aerobics, dancing, jogging, stair climbing, tennis, walking, and lifting weights. People who have osteoporosis may want to attempt gentle exercise, such as walking, rather than jogging or fast-paced aerobics, which increase the chance of falling. Try to exercise three to four times per week for 20–30 minutes each time. As physical activity improves muscle strength and coordination it may also aid in reducing the risk of fall-related fractures.

Those at risk should avoid medications known to compromise bone density, such as glucocorticoids, thyroid hormones and chronic heparin therapy.

Resources

BOOKS

Adams, John S. and Barbara P. Lukertet. Osteoporosis: Genetics, Prevention and Treatment. Boston: Kluwer Academic, 1999.

Kessler, George J., et al. The Bone Density Diet: 6 Weeks to a Strong Body and Mind. New York: Ballantine Books, 2000.

Krane, Stephen M., and Michael F. Holick. "Metabolic Bone Disease: Osteoporosis." In Harrison's Principles of Internal Medicine. 14th ed. Ed. by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.

Lane, Nancy E., ed. The Osteoporosis Book. New York: Oxford University Press, 1998.

McIlwain, Harris, et al. Osteoporosis Cure: Reverse the Crippling Effects With New Treatment. New York: Avon Books, 1998.

Notelovits, Morris, et al. Stand Tall! Every Woman's Guide to Preventing and Treating Osteoporosis. 2nd ed. Gainesville, FL: Triad Publishing Co., 1998.

PERIODICALS

Feder, G., et al. "Guidelines for the Prevention of Falls in People over 65." British Medical Journal 321 (2000): 1007-1011.

McClung, Michael R., et al. "Effect of Risedronate on the Risk of Hip Fracture in Elderly Women." The New England Journal of Medicine 344, no. 5 (2001): 333-40.

ORGANIZATIONS

Arthritis Foundation, 1330 W. Peachtree St., PO Box 7669, Atlanta, GA 30357-0669. (800) 283-7800. <http://www.arthritis.org>.

National Center for Complementary and Alternative Medicine (NCCAM), 31 Center Dr., Room #5B-58, Bethesda, MD 20892-2182. (800) NIH-NCAM. Fax: (301) 495-4957. <http://nccam.nih.gov>.

National Osteoporosis Foundation, 1150 17th Street, Suite 500 NW, Washington, DC 20036-4603. (800) 223-9994. <http://www.nof.org>.

Osteoporosis and Related Bone Diseases-National Resource Center. 1150 17th St., NW, Ste. 500, Washington, DC 20036-4603. (800) 624-BONE. <http://www.osteo.org>.

Crystal Kaczkowski, MSc

Osteoporosis

Definition

The word osteoporosis literally means "porous bones." It occurs when bones lose an excessive amount of their protein and mineral content, particularly calcium. Over time, bone mass, and therefore bone strength, is decreased. As a result, bones become fragile and break easily. Even a sneeze or a sudden movement may be enough to break a bone in someone with severe osteoporosis.

Description

Osteoporosis is a serious public health problem. Some 28 million people in the United States are affected by this potentially debilitating disease, which is responsible for 1.5 million fractures (broken bones) annually. These fractures, which are often the first sign of the disease, can affect any bone, but the most common locations are the hip, spine, and wrist. Breaks in the hip and spine are of special concern because they almost always require hospitalization and major surgery, and may lead to other serious consequences, including permanent disability and even death.

To understand osteoporosis, it is helpful to understand the basics of bone formation. Bone is living tissue that is constantly being renewed in a two-stage process (resorption and formation) that occurs throughout life. In the resorption stage, old bone is broken down and removed by cells called osteoclasts. In the formation stage, cells called osteoblasts build new bone to replace the old. During childhood and early adulthood, more bone is produced than removed, reaching its maximum mass and strength by the mid-30s. After that, bone is lost at a faster pace than it is formed, so the amount of bone in the skeleton begins to slowly decline. Most cases of osteoporosis occur as an acceleration of this normal aging process—a form referred to as primary osteoporosis. The condition can also be caused by other disease processes or prolonged use of certain medications that result in bone loss—a form called secondary osteoporosis.

Osteoporosis occurs most often in older people and in women after menopause. It affects nearly half of all men and women over the age of 75. Women, however, are five times more likely than men to develop the disease. They have smaller, thinner bones than men to begin with, and they lose bone mass more rapidly after menopause (usually around age 50), when they stop producing a bone-protecting hormone called estrogen. In the five to seven years following menopause, women can lose about 20% of their bone mass. By age 65 or 70, though, men and women lose bone mass at the same rate. As an increasing number of men reach an older age, they are becoming more aware that osteoporosis is an important health issue for them as well.

Causes and symptoms

A number of factors increase the risk of developing osteoporosis. They include:

• Age. Osteoporosis is more likely as people grow older and their bones lose tissue.

• Gender. Women are more likely to have osteoporosis because they are smaller and so start out with less bone. They also lose bone tissue more rapidly as they age. While women commonly lose 30-50% of their bone mass over their lifetimes, men lose only 20-33% of theirs.
• Race. Caucasian and Asian women are at higher risk for the disease than women of African or Hispanic ethnicities.
• Figure type. Women with small bones and those who are thin are more liable to have osteoporosis.
• Early menopause. Women who stop menstruating early because of heredity, surgery or a lot of physical exercise may lose large amounts of bone tissue early in life. Conditions such as anorexia and bulimia may also lead to early menopause and osteoporosis.
• Lifestyle. People who smoke or drink too much, or do not get enough exercise have an increased chance of getting osteoporosis.
• Diet. Those who do not get enough calcium or protein may be more likely to have osteoporosis. People who constantly diet are more prone to the disease. It has been shown that adolescent girls (but not boys) have insufficient calcium intake levels in the diet. This calcium deficiency occurs during a period of rapid bone growth, stunting the peak bone mass ultimately achieved; thus, these individuals are at greater risk of developing osteoporosis.
• Genetics. People with a family history of osteoporosis are more likely to contract the disease.
• Chronic use of medication. Certain types of medication, such as steroids, interfere with the body's ability to absorb calcium or accelerate calcium depletion, damaging bone density.

Osteoporosis is often called the "silent" disease, because bone loss occurs without symptoms. People often do not know they have the disease until a bone breaks, frequently in a minor fall that would not normally cause a fracture. A common occurrence is compression fractures of the spine. These can happen even after a seemingly normal activity, such as bending or twisting to pick up a light object. The fractures can cause severe back pain, but sometimes they go unnoticed—either way, the vertebrae collapse down on themselves, and the person actually loses height. The hunchback appearance of many elderly women, sometimes called "dowager's hump" or "widow's hump," is due to this effect of osteoporosis on the vertebrae.

Diagnosis

Certain types of doctors may have more training and experience than others in diagnosing and treating people with osteoporosis. These include geriatricians, who specialize in treating the aged; endocrinologists, who specialize in treating diseases of the body's endocrine system (glands and hormones); and orthopedic surgeons, who treat fractures, such as those caused by osteoporosis.

Before making a diagnosis of osteoporosis, the doctor usually takes a complete medical history, conducts a physical exam, and orders x rays, as well as blood and urine tests, to rule out other diseases that cause loss of bone mass. The doctor may also recommend a bone density test. This is the only way to determine if osteoporosis is present. It can also show how far the disease has progressed.

Several diagnostic tools are available to measure the density of a bone. The most accurate and advanced of the densitometers uses a technique called DEXA (dual energy x-ray absorptiometry). With the DEXA scan, a double x-ray beam takes pictures of the spine, hip, or entire body. It takes about 20 minutes to do, is painless, and exposes the patient to only a small amount of radiation—about one-fiftieth that of a chest x ray. The ordinary x ray is one, though it is the least accurate for early detection of osteoporosis, because it does not reveal bone loss until the disease is advanced and most of the damage has already been done. Other tools that are more likely to catch osteoporosis at an early stage are computed tomography scans (CT scans ) and machines called densitometers, which are designed specifically to measure bone density. The CT scan, which takes a large number of x rays of the same spot from different angles, is an accurate test, but uses higher levels of radiation than other methods.

People should talk to their doctors about their risk factors for osteoporosis and if, and when, they should get the test. A woman should have bone density measured at menopause, and periodically afterward, depending on the condition of their bones. Men should be tested around age 65. Men and women with additional risk factors, such as those who take certain medications, may need to be tested earlier.

Treatment

There are a number of good treatments for primary osteoporosis, most of them medications. In addition, calcium (0.5 to 2 g/day) and vitamin D (400 to 800 IU/day) supplementation can reduce the rate of bone loss in women who are more than five years post-menopausal. Fracture reduction efficacy of calcium and vitamin D supplementation, administered independently, has been demonstrated in women older than 75 years of age.

For people with secondary osteoporosis, treatment may focus on curing the underlying disease.

Drugs

For most women who have gone through menopause, the best treatment for osteoporosis is hormone replacement therapy (HRT). Many women participate in HRT when they undergo menopause, to alleviate symptoms such as hot flashes, but hormones have other important roles as well. They protect women against heart disease, the number one killer of women in the United States, and they help to relieve and prevent osteoporosis. HRT increases a woman's supply of estrogen, which helps build new bone, while preventing further bone loss.

Some women, however, do not want to take or are not candidates for hormones, because some studies show they are linked to an increased risk of breast cancer or uterine cancer. Other studies reveal that risk is due to increasing age. (Breast cancer tends to occur more often as women age.) Whether or not a woman takes hormones is a decision she should make carefully with her doctor. Women should talk to their doctors about personal risks for osteoporosis, as well as their risks for heart disease and breast cancer.

Novel delivery systems of HRT have been developed. For example, Vivelle is a estradiol transdermal system that is used for prevention of osteoporosis. It uses a "patch" to continously deliver the hormone estradiol through the skin.

Studies have shown women who started taking HRT within five years of menopause show significantly reduced rates of hip fractures than women who began HRT more than five years postmenopausal. However, even while taking HRT, 10 to 20% of women continue to lose bone density and therefore may require additional intervention.

For people who cannot or will not take estrogen, other agents can be good choices. These include:

• bisphosphonates
• calcitonin
• selective estrogen receptor modulators
• sodium fluoride
• androgens

Although there are a number of bisphosphonates used for the treatment of various forms of osteoporosis and resorptive bone diseases, alendronate (sold under the brand name Fosamax), etidronate (sold under the brand name Didronel), and risedronate (sold under the brand name Actonel) are some of the agents most commonly used for therapeutic treatment of postmenopausal osteoporosis. Biphosphonates act by decreasing bone resorption or breakdown. For example, alendronate attaches itself to bone that has been targeted by bone-eating osteoclasts. It protects the bone from these cells. Osteoclasts help the body break down old bone tissue.

Alendronate has shown to be an effective agent in preventing bone loss and building bone in recently postmenopausal women and is especially useful in women who have contraindications for HRT. It has been licensed for the treatment and prevention of vertebral and nonvertebral postmenopausal osteoporosis. Alendronate has proven safe in very large, multi-year studies, but not much is known about the effects of its long-term use. Side effects are generally minimal with abdominal pain, nausea, dyspepsia, constipation and diarrhea occurring in 3-7% of patients treated with alendronate. It can be taken daily, and now a new formulation has been developed that can be taken weekly.

Etidronate has been shown to reduce the rate of new vertebral and nonvertebral fractures. It appears to be well tolerated in clinical studies.

Calcitonin is a hormone that has been used as an injection for many years. It is also marketed as a nasal spray. It also slows down bone-eating osteoclasts. Side effects are minimal, but calcitonin builds bone by only 1.5% a year, which may not be enough for some women to recover the bone they lose.

Selective estrogen receptor modulators (SERMs) such as raloxifene, droloxifene, idoxifene, and tamoxifen are used as alternatives to hormone replacement therapy (HRT), which commonly uses estrogen. SERMs have been shown to protect against postmenopausal bone loss without the estrogenic side effects. Raloxifene was the first SERM to be approved in the osteoporosis market for prevention and treatment of osteoporosis. Raloxifene binds to estrogen receptors and mimics estrogen's action on bone by preventing bone loss, and improving cholesterol metabolism, therefore acting as an agonist. It also acts as an estrogen antagonist in the uterus and the breasts, by not imitating the action of estrogen. These drugs may thus improve blood lipid profiles and protect against breast cancer. There is an enhanced risk of venous thromboembolic events during raloxifene therapy, especially during the first four months of therapy. It also has a propensity to induce hot flashes and leg pain.

Sodium fluoride has been used as an anabolic agent to stimulate bone formation. However, a high incidence of side effects, mainly gastrointestinal symptoms and lower extremity pain syndrome, have occurred in clinical trials.

Androgens have been used for reducing bone loss. Androgens are classified as anabolic steroids, which include nandrolone, stanozolol, and testosterone, are used as antiresorptive agents. Androgens are important for postmenopausal women as they serve as a substrate for the peripheral production of estrogens.

The treatments currently available are antiresorptive, which limits the ability to increase bone mass. Other bone-building agents are under investigation. Parathyroid hormone received FDA approval in 2002. The biphosphonates have demonstrated the most dramatic reduction in fracture rates and may be the best choice for women with severe osteoporosis. Estrogen's effect may be similar, but has not been established in large randomized trials. Raloxifene may be particularly useful in women who wish to benefit from a breast cancer risk reduction. Calcitonin may be the least potent, but may be useful in women who cannot tolerate other therapies.

Surgery

Unfortunately, treatment for osteoporosis is usually tied to fractures that result from advanced stages of the disease. For complicated fractures, such as broken hips, hospitalization and a surgical procedure are required. In hip replacement surgery, the broken hip is removed and replaced with a new hip made of plastic, or metal and plastic. Though the surgery itself is usually successful, complications of the hip fracture can be serious. Those individuals have a 5-20% greater risk of dying within the first year following that injury than do others in their age group. A large percentage of those who survive are unable to return to their previous level of activity, and many end up moving from self-care to a supervised living situation or nursing home. Getting early treatment and taking steps to reduce bone loss are vital.

Alternative treatment

Alternative treatments for osteoporosis focus on maintaining or building strong bones. A healthy diet low in fats and animal products and containing whole grains, fresh fruits and vegetables, and calcium-rich foods (such as dairy products, dark-green leafy vegetables, sardines, salmon, and almonds), along with nutritional supplements (such as calcium, magnesium, and vitamin D), and weight-bearing exercises are important components of both conventional prevention and treatment strategies and alternative approaches to the disease. In addition, alternative practitioners recommend a variety of botanical medicines or herbal supplements. Herbal supplements designed to help slow bone loss emphasize the use of calcium-containing plants, such as horsetail (Equisetum arvense), oat straw (Avena sativa), alfalfa (Medicago sativa), licorice (Glycyrrhiza galbra), marsh mallow (Althaea officinalis), and yellow dock (Rumex crispus). Homeopathic remedies focus on treatments believed to help the body absorb calcium. These remedies are likely to include such substances as Calcarea carbonica (calcium carbonate) or silica. In traditional Chinese medicine, practitioners recommend herbs thought to slow or prevent bone loss, including dong quai (Angelica sinensis) and Asian ginseng (Panax ginseng). Natural hormone therapy, using plant estrogens (from soybeans) or progesterone (from wild yams), may be recommended for women who cannot or choose not to take synthetic hormones.

It should be noted, however, that very few clinical trials are conducted on alternate therapies and therefore efficacy cannot be established.

Prognosis

There is no cure for osteoporosis, but it can be controlled. Most people who have osteoporosis fare well once they get treatment. The medicines available now build bone, protect against bone loss, and halt the progress of this disease.

Health care team roles

Doctors, nurses, physical therapists, radiation technologists, and dietitians all play roles in the process of controlling osteoporosis. Because osteoporosis is treatable but not curable, the main responsibility for controlling the progress of the disease rests with the patient. All of these team members play an important role in identifying risk of osteoporosis before it strikes and in convincing the patient to take appropriate steps (including lifestyle modification) to minimize the dangers of fracturing major bones.

Prevention

Building strong bones, especially before the age of 35, and maintaining a healthy lifestyle are the best ways of preventing osteoporosis. To build as much bone mass as early as possible in life, and to help slow the rate of bone loss later in life:

Get calcium in foods

Experts recommend 1,500 milligrams (mg) of calcium per day for adolescents, pregnant or breast-feeding women, older adults (over 65), and postmenopausal women not using hormone replacement therapy. All others should get 1,000 mg per day. Foods are the best source for this important mineral. Milk, cheese, and yogurt have the highest amounts. Other foods that are high in calcium are green leafy vegetables, tofu, shellfish, Brazil nuts, sardines, and almonds.

Take calcium supplements

Many people, especially those who do not like or cannot eat dairy foods, do not get enough calcium in their diets and may need to take a calcium supplement. Supplements vary in the amount of calcium they contain. Those with calcium carbonate have the most amount of useful calcium. Supplements should be taken with meals and accompanied by six to eight glasses of water a day. Calcium supplements and antacids interfere with absorption of alendronate and should be taken at least one half hour later.

Get vitamin D

Vitamin D helps the body absorb calcium. People can get vitamin D from sunshine with a quick (15-20 minute) walk each day or from foods such as liver, fish oil, and vitamin-D fortified milk. During the winter months it may be necessary to take supplements (400-800 IU/day).

Avoid smoking and alcohol

Smoking reduces bone mass, as does heavy drinking. To reduce risk, do not smoke and limit alcoholic drinks to no more than two per day. An alcoholic drink is 1.5 oz (44 ml) of hard liquor, 12 oz (355 ml) of beer, or 5 oz (148 ml) of wine.

Exercise

Exercising regularly builds and strengthens bones. Weight-bearing exercises—where bones and muscles work against gravity—are best. These include aerobics, dancing, jogging, stair climbing, tennis, walking, and lifting weights. People who have osteoporosis may want to attempt gentle exercise, such as walking, rather than jogging or fast-paced aerobics, which increase the chance of falling. Try to exercise three to four times per week for 20-30 minutes each time. As physical activity improves muscle strength and coordination it may also aid in reducing the risk of fall-related fractures.

Those at risk should avoid medications known to compromise bone density, such as glucocorticoids, thyroid hormones, and chronic heparin therapy.

KEY TERMS

Alendronate— A nonhormonal drug used to treat osteoporosis in postmenopausal women.

Anticonvulsants— Drugs used to control seizures, such as in epilepsy.

Biphosphonates— Compounds (like alendronate) that slow bone loss and increase bone density.

Calcitonin— A hormonal drug used to treat post-menopausal osteoporosis.

Estrogen— A female hormone that also keeps bones strong. After menopause, a woman may take hormonal drugs with estrogen to prevent bone loss.

Glucocorticoids— Any of a group of hormones (like cortisone) that influence many body functions and are widely used in medicine, such as for treatment of rheumatoid arthritis inflammation.

Hormone replacement therapy (HRT)— Also called estrogen replacement therapy, this controversial treatment is used to relieve the discomforts of menopause. Estrogen and another female hormone, progesterone, are usually taken together to replace the estrogen no longer made by the body. It has the added effect of stopping bone loss that occurs at menopause.

Menopause— The ending of a woman's menstrual cycle, when production of bone-protecting estrogen decreases.

Osteoblasts— Cells in the body that build new bone tissue.

Osteoclasts— Cells that break down and remove old bone tissue.

Selective estrogen receptor modulator— A hormonal preparation that offers the beneficial effects of hormone replacement therapy without the increased risk of breast and uterine cancer associated with HRT.

Resources

BOOKS

Adams, John S. and Barbara P. Lukertet. Osteoporosis: Genetics, Prevention and Treatment. Boston, MA: Kluwer Academic, 1999.

Kessler, George J., et al. The Bone Density Diet: 6 Weeks to a Strong Body and Mind. New York: Ballantine Books, 2000.

Krane, Stephen M., and Michael F. Holick. "Metabolic Bone Disease: Osteoporosis." In Harrison's Principles of Internal Medicine, 14th ed. Ed. by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.

Lane, Nancy E., ed. The Osteoporosis Book. New York: Oxford University Press, 1998.

McIlwain, Harris, et al. Osteoporosis Cure: Reverse the Crippling Effects With New Treatment. New York: Avon Books, 1998.

Notelovits, Morris, et al. Stand Tall! Every Woman's Guide to Preventing and Treating Osteoporosis. 2nd ed. Gainesville, FL: Triad Publishing Co., 1998.

PERIODICALS

Feder, G., et al. "Guidelines for the Prevention of Falls in People Over 65." British Medical Journal 321 (2000): 1007-1011.

McClung, Michael R., et al. "Effect of Risedronate on the Risk of Hip Fracture in Elderly Women." The New England Journal of Medicine 344, no. 5 (2001): 333-40.

ORGANIZATIONS

Arthritis Foundation, 1330 W. Peachtree St., PO Box 7669, Atlanta, GA 30357-0669. (800) 283-7800. 〈http://www.arthritis.org〉.

National Center for Complementary and Alternative Medicine (NCCAM), 31 Center Dr., Room #5B-58, Bethesda, MD 20892-2182. (800) NIH-NCAM. Fax: (301) 495-4957. 〈http://nccam.nih.gov〉.

National Osteoporosis Foundation, 1150 17th Street, Suite 500 NW, Washington, DC 20036-4603. (800) 223-9994. 〈http://www.nof.org〉.

Osteoporosis and Related Bone Diseases—National Resource Center. 1150 17th St., NW, Ste. 500, Washington, DC 20036-4603. (800) 624-BONE. 〈http://www.osteo.org〉.

Osteoporosis

Definition

The word osteoporosis literally means "porous bones." It occurs when bones lose an excessive amount of their protein and mineral content, particularly calcium. Over time, bone mass, and therefore bone strength, is decreased. As a result, bones become fragile and break easily. Even a sneeze or a sudden movement may be enough to break a bone in someone with severe osteoporosis.

Description

Osteoporosis is a serious public health problem. Some 44 million people in the United States are at risk for this potentially debilitating disease, which is responsible for 1.5 million fractures (broken bones) annually. These fractures, which are often the first sign of the disease, can affect any bone, but the most common locations are the hip, spine, and wrist. Breaks in the hip and spine are of special concern because they almost always require hospitalization and major surgery, and may lead to other serious consequences, including permanent disability and even death.

To understand osteoporosis, it is helpful to understand the basics of bone formation. Bone is living tissue that is constantly being renewed in a two-stage process (resorption and formation) that occurs throughout life. In the resorption stage, old bone is broken down and removed by cells called osteoclasts. In the formation stage, cells called osteoblasts build new bone to replace the old. During childhood and early adulthood, more bone is produced than removed, reaching its maximum mass and strength by the mid-30s. After that, bone is lost at a faster pace than it is formed, so the amount of bone in the skeleton begins to slowly decline. Most cases of osteoporosis occur as an acceleration of this normal aging process, which is referred to as primary osteoporosis. The condition also can be caused by other disease processes or prolonged use of certain medications that result in bone loss. If so, this is called secondary osteoporosis.

Osteoporosis occurs most often in older people and in women after menopause. It affects nearly half of men and women over the age of 75. Women are about five times more likely than men to develop the disease. They have smaller, thinner bones than men to begin with, and they lose bone mass more rapidly after menopause (usually around age 50), when they stop producing a bone-protecting hormone called estrogen. In the five to seven years following menopause, women can lose about 20% of their bone mass. By age 65 or 70, though, men and women lose bone mass at the same rate. As an increasing number of men reach an older age, there is more awareness that osteoporosis is an important health issue for them as well. In fact, a 2003 report noted that one in every eight men over age 50 will suffer a hip fracture as a result of osteoporosis.

Causes and symptoms

A number of factors increase the risk of developing osteoporosis. They include:

• Age. Osteoporosis is more likely as people grow older and their bones lose tissue.
• Gender. Women are smaller and start out with less bone. They also lose bone tissue more rapidly as they age. While women commonly lose 30-50% of their bone mass over their lifetimes, men lose only 20-33%.
• Race. Caucasian and Asian women are most at risk for the disease, but African American and Hispanic women can get it too.
• Figure type. Women with small bones and those who are thin are more liable to have osteoporosis.
• Early menopause. Women who stop menstruating early because of heredity, surgery or lots of physical exercise may lose large amounts of bone tissue early in life. Conditions such as anorexia and bulimia also may lead to early menopause and osteoporosis.
• Lifestyle. People who smoke or drink too much, or do not get enough exercise have an increased chance of osteoporosis.
• Diet. Those who do not get enough calcium or protein may be more likely to have osteoporosis. That is why people who constantly diet are more prone to the disease.
• Genetics. Research in Europe reported in 2003 that variations of a gene on chromosome 20 might make some postmenopausal women more likely to have osteoporosis. Studies were continuing on how to identify the gene and use information from the research to prevent osteoporosis in carriers.

Osteoporosis is often called the "silent" disease, because bone loss occurs without symptoms. People often do not know they have the disease until a bone breaks, frequently in a minor fall that would not normally cause a fracture. A common occurrence is compression fractures of the spine. These can happen even after a seemingly normal activity, such as bending or twisting to pick up a light object. The fractures can cause severe back pain, but sometimes go unnoticed—either way, the vertebrae collapse down on themselves, and the person actually loses height. The hunchback appearance of many elderly women, sometimes called "dowager's" hump or "widow's" hump, is due to this effect of osteoporosis on the vertebrae.

Diagnosis

Certain types of doctors may have more training and experience than others in diagnosing and treating people with osteoporosis. These include a geriatrician, who specializes in treating the aged; an endocrinologist, who specializes in treating diseases of the body's endocrine system (glands and hormones); and an orthopedic surgeon, who treats fractures such as those caused by osteoporosis.

Before making a diagnosis of osteoporosis, the doctor usually takes a complete medical history, conducts a physical exam, and orders x rays, as well as blood and urine tests, to rule out other diseases that cause loss of bone mass. The doctor also may recommend a bone density test. This is the only way to know for certain if osteoporosis is present. It also can show how far the disease has progressed.

Several diagnostic tools are available to measure bone density. The ordinary x ray is one, though it is the least accurate for early detection of osteoporosis, because it does not reveal bone loss until the disease is advanced and most of the damage has already been done. Two other tools that are more likely to catch osteoporosis at an early stage are computed tomography scans (CT scans) and machines called densitometers, which are designed specifically to measure bone density.

The CT scan, which takes a large number of x rays of the same spot from different angles, is an accurate test, but uses higher levels of radiation than other methods. The most accurate and advanced of the densitometers uses a technique called DEXA (dual energy x-ray absorptiometry). With the DEXA scan, a double x-ray beam takes pictures of the spine, hip, or entire body. It takes about 20 minutes to do, is painless, and exposes the patient to only a small amount of radiation—about one-fiftieth that of a chest x ray.

Doctors do not routinely recommend the test, partly because access to densitometers is still not widely available. People should talk to their doctors about their risk factors for osteoporosis and if, and when, they should get the test. Ideally, women should have bone density measured at menopause, and periodically afterward, depending on the condition of their bones. Men should be tested around age 65. Men and women with additional risk factors, such as those who take certain medications, may need to be tested earlier.

Treatment

There are a number of good treatments for primary osteoporosis, most of them medications. Two medications, alendronate and calcitonin (in nose spray form), have been approved by the Food and Drug Administration (FDA). They provide people who have osteoporosis with a variety of choices for treatment. For people with secondary osteoporosis, treatment may focus on curing the underlying disease.

Drugs

For many women who have gone through menopause, the treatment of choice for osteoporosis has been hormone replacement therapy (HRT), also called estrogen replacement therapy. Many women choose HRT when they undergo menopause to alleviate symptoms such as hot flashes, but hormones increase a woman's supply of estrogen, which helps build new bone, while preventing further bone loss. A 2002 report from a large clinical trial called the Women's Health Initiative helped verify HRT's positive effects in preventing osteoporosis in postmenopausal women.

However, the WHI also revealed several risks with taking combined HRT (estrogen and progesterone). In fact, the trial was stopped early because the incidence of invasive breast cancer in women on HRT passed a threshold that was considered too risky for the benefits they were receiving. The study also found that the women on combined hormone therapy were at increased risk for coronary heart disease and stroke. Whether or not a woman takes hormones and for how long is a decision she should make carefully with her doctor. Women should talk to their doctors about personal risks for osteoporosis, as well as their risks for heart disease and breast cancer.

Since estrogen may no longer be recommended for prevention of osteoporosis, selective use of alendronate and calcitonin are possible alternatives. Alendronate and calcitonin both stop bone loss, help build bone, and decrease fracture risk by as much as 50%. Alendronate (sold under the name Fosamax) is the first nonhormonal medication for osteoporosis ever approved by the FDA. It attaches itself to bone that has been targeted by bone-eating osteoclasts, protecting the bone from these cells. Osteoclasts help the body break down old bone tissue.

Calcitonin is a hormone that has been used as an injection for many years. A new version is on the market as a nasal spray. It too slows down bone-eating osteoclasts.

Side effects of these drugs are minimal, but calcitonin builds bone by only 1.5% a year, which may not be enough for some women to recover the bone they lose. Fosamax has proven safe in large, multi-year studies, but not much is known about the effects of its long-term use. Several medications under study include other bisphosphonates that slow bone breakdown (like alendronate), sodium fluoride, vitamin D metabolites, and selective estrogen receptor modulators. Some of these treatments are already being used in other countries, but have not yet been approved by the FDA for use in the United States.

In early 2003, a report announced that the FDA had recently approved the first drug that could form bone in osteoporosis patients. The drug is a form of the human parathyroid hormone called teriparatide. It shows promise for those patients at highest risk for fracture from the disease. There are some patients who cannot use the drug, so all considering the new treatment must check with their physician and may need to undergo bone densitometry scans or other testing.

Surgery

Unfortunately, much of the treatment for osteoporosis is for fractures that result from advanced stages of the disease. For complicated fractures, such as broken hips, hospitalization and a surgical procedure are required. In hip replacement surgery, the broken hip is removed and replaced with a new hip made of plastic, or metal and plastic. Though the surgery itself is usually successful, complications of the hip fracture can be serious. Those individuals have a 5-20% greater risk of dying within the first year following the injury than do others in their age group. A large percentage of those who survive are unable to return to their previous level of activity, and many move self-care to a supervised living situation or nursing home. That is why getting early treatment and taking steps to reduce bone loss are vital.

Alternative treatment

Alternative treatments for osteoporosis focus on maintaining or building strong bones. A healthy diet low in fats and animal products and containing whole grains, fresh fruits and vegetables, and calcium-rich foods (such as dairy products, dark-green leafy vegetables, sardines, salmon, and almonds), along with nutritional supplements (such as calcium, magnesium, and vitamin D), and weight-bearing exercises are important components of both conventional prevention and treatment strategies and alternative approaches to the disease. In addition, alternative practitioners recommend a variety of botanical medicines or herbal supplements. Herbal supplements designed to help slow bone loss emphasize the use of calcium-containing plants, such as horsetail (Equisetum arvense ), oat straw (Avena sativa ), alfalfa (Medicago sativa ), licorice (Glycyrrhiza galbra ), marsh mallow (Althaea officinalis ), and yellow dock (Rumex crispus ). Homeopathic remedies focus on treatments believed to help the body absorb calcium. These remedies are likely to include such substances as Calcarea carbonica (calcium carbonate) or silica. In traditional Chinese medicine, practitioners recommend herbs thought to slow or prevent bone loss, including dong quai (Angelica sinensis ) and Asian ginseng (Panax ginseng ). Natural hormone therapy, using plant estrogens (from soybeans) or progesterone (from wild yams), may be recommended for women who cannot or choose not to take synthetic hormones.

Prognosis

There is no cure for osteoporosis, but it can be controlled. Most people who have osteoporosis fare well once they receive treatment. The medicines available now build bone, protect against bone loss, and halt the progress of this disease.

Prevention

Building strong bones, especially before the age of 35, and maintaining a healthy lifestyle are the best ways to prevent osteoporosis. To build as much bone mass as early as possible in life, and to help slow the rate of bone loss later in life, doctors advise:

Getting calcium from foods

Experts recommend 1,500 milligrams (mg) of calcium per day for adolescents, pregnant or breastfeeding women, older adults (over 65), and postmenopausal women not using hormone replacement therapy. All others should get 1,000 mg per day. Foods are the best source for this important mineral. Milk, cheese, and yogurt have the highest amounts. Other foods that are high in calcium are green leafy vegetables, tofu, shellfish, Brazil nuts, sardines, and almonds.

Taking calcium supplements

Many people, especially those who do not like or can not eat dairy foods, do not get enough calcium in their diets and may need calcium supplements. Supplements vary in the amount of calcium they contain. Those with calcium carbonate have the most amount of useful calcium. Supplements should be taken with meals and accompanied by six to eight glasses of water a day.

Getting vitamin D

Vitamin D helps the body absorb calcium. People can get vitamin D from sunshine with a quick (15-20 minute) walk each day or from foods such as liver, fish oil, and vitamin-D fortified milk. During the winter months it may be necessary to take supplements. Four hundred mg daily is usually the recommended amount.

Avoiding smoking and alcohol

Smoking reduces bone mass, as does heavy drinking. Avoiding smoking and limiting alcoholic drinks to no more than two per day reduces risks. An alcoholic drink is one-and-a-half ounces of hard liquor, 12 ounces of beer, or five ounces of wine.

Exercise

Exercising regularly builds and strengthens bones. Weight-bearing exercises—where bones and muscles work against gravity—are best. These include aerobics, dancing, jogging, stair climbing, tennis, walking, and lifting weights. People who have osteoporosis may want to attempt gentle exercise, such as walking, rather than jogging or fast-paced aerobics, which increase the chance of falling. Exercising three to four times per week for 20-30 minutes each time helps.

Resources

PERIODICALS

Doering, Paul L. "Treatment of Menopause Post-WHI: What Now?" Drug Topics April 21, 2003: 85.

Elliott, William T. "HRT, Estrogen, and Postmenopausal Women: Year-old WHI Study Continues to Raise Questions." Critical Care Alert July 2003: 1.

LoBuono, Charlotte. "New Osteoporosis Drug is First to Form Bone." Drug Topics January 6, 2003: 24.

"More Men at Osteoporosis Risk than Commonly Believed." Tufts University Health and Nutrition Letter August 2003: 8.

Nelson, Heidi D. "Postmenopausal Osteoporosis and Estrogen." American Family Physician August 15, 2003: 606.

"Osteoporosis Gene Identified." Diagnostics and Imaging Week March 13, 2003 4.

"Three Out of Four Women Currently Taking Prescriptions for Osteoporosis Are Not Receiving Full Treatment, According to Recent Data from a National Physician Audit." Drug Cost Management Report January 2003: 11.

KEY TERMS

Alendronate— A nonhormonal drug used to treat osteoporosis in postmenopausal women.

Anticonvulsants— Drugs used to control seizures, such as in epilepsy.

Biphosphonates— Compounds (like alendronate) that slow bone loss and increase bone density.

Calcitonin— A hormonal drug used to treat postmenopausal osteoporosis

Estrogen— A female hormone that also keeps bones strong. After menopause, a woman may take hormonal drugs with estrogen to prevent bone loss.

Glucocorticoids— Any of a group of hormones (like cortisone) that influence many body functions and are widely used in medicine, such as for treatment of rheumatoid arthritis inflammation.

Hormone replacement therapy (HRT)— Also called estrogen replacement therapy, this controversial treatment is used to relieve the discomforts of menopause. Estrogen and another female hormone, progesterone, are usually taken together to replace the estrogen no longer made by the body.

Menopause— The ending of a woman's menstrual cycle, when production of bone-protecting estrogen decreases.

Osteoblasts— Cells in the body that build new bone tissue.

Osteoclasts— Cells that break down and remove old bone tissue.

Selective estrogen receptor modulator— A hormonal preparation that offers the beneficial effects of hormone replacement therapy without the increased risk of breast and uterine cancer associated with HRT.

Osteoporosis

Definition

The word osteoporosis literally means porous bones. It occurs when bones lose an excessive amount of their protein and mineral content, particularly calcium . Over time, bone mass, and therefore bone strength, is decreased. As a result, the bones become fragile and break easily. Even a sneeze or a sudden movement may be enough to break a bone in someone with severe osteoporosis.

Description

Osteoporosis is a serious public health problem. Some 28 million people in the United States are affected by this potentially debilitating disease, which is responsible for 1.5 million fractures (broken bones) annually. These fractures, which are often the first sign of the disease, can affect any bone, but the most common locations are the hip, spine, and wrist. Breaks in the hip and spine are of special concern because they almost always require hospitalization and major surgery; and may lead to other serious consequences, including permanent disability and even death.

To understand osteoporosis, it is helpful to understand the basics of bone formation. Bone is living tissue

that's constantly being renewed in a two-stage process (resorption and formation) that occurs throughout life. In the resorption stage, old bone is broken down and removed by cells called osteoclasts. In the formation stage, cells called osteoblasts build new bone to replace the old. During childhood and early adulthood, more bone is produced than removed, reaching its maximum mass and strength by the mid-30s. After that, bone is lost at a faster pace than it's formed, so the amount of bone in the skeleton begins to slowly decline. Most cases of osteoporosis occur as an acceleration of this normal aging process. That is referred to as primary osteoporosis. The condition can also be caused by other disease processes or prolonged use of certain medications that result in bone loss; if so, it is called secondary osteoporosis.

Osteoporosis occurs most often in older people, especially in women after menopause . It affects nearly half of all adults, men and women, over the age of 75. Women, however, are five times more likely than men to develop the disease. They have smaller, thinner bones than men to begin with, and they lose bone mass more rapidly after menopause (usually around age 50), when they stop producing a bone-protecting hormone called estrogen. In the five to seven years following menopause, women can lose about 20% of their bone mass. By age 65 or 70, though, men and women lose bone mass at the same rate.

As an increasing number of men live longer, health professionals are increasingly aware that osteoporosis is an important health issue for men as well. In fact, men account for about 20% of all spinal fractures and up to 30% of all hip fractures due to osteoporosis.

Causes & symptoms

A number of factors increase the risk of developing osteoporosis. They include:

• Age. Osteoporosis is more likely as people grow older and their bones lose strength.
• Sex. Women are more likely to have osteoporosis because they start out with less bone. They also lose bone tissue more rapidly as they age. While women commonly lose 30%–50% of their bone mass over their lifetimes, men lose only 20%–33% of theirs.
• Race. Caucasian and Asian women are most at risk for the disease, but African American and Hispanic women can get it too.
• Body type. Women with small bones or thin frames are more liable to develop osteoporosis.
• Early menopause. Women who begin menopause early because of heredity, surgery, or lots of physical exercise may lose large amounts of bone tissue early in life. Such conditions as anorexia and bulimia may also lead to early menopause and osteoporosis.
• Lifestyle. People who smoke or drink too much, or do not get enough exercise, have an increased chance of getting osteoporosis.
• Medications. Certain prescription medications may speed up the loss of bone. These drugs include methotrexate, cimetidine, corticosteroids, and heparin.
• Diet. Adults who do not get enough calcium or protein may be more likely to have osteoporosis. People who constantly diet are more prone to the disease.

Osteoporosis is often called the silent disease, because bone loss occurs without symptoms. People often don't know they have the disease until a bone breaks, frequently in a minor fall that wouldn't normally cause a fracture. A common occurrence is compression fractures of the spine. These can happen even after a seemingly normal activity, such as bending or twisting to pick up a light object. The fractures can cause severe back pain , but sometimes they go unnoticed. Either way, the vertebrae collapse down on themselves, and the person actually loses height. The hunchback appearance of many elderly women, sometimes called dowager's hump or widow's hump, is due to the effect of osteoporosis on the vertebrae.

Diagnosis

Certain types of doctors may have more training and experience than others in diagnosing and treating people with osteoporosis. These include a geriatrician, who specializes in treating the aged; an endocrinologist, who specializes in treating diseases of the body's endocrine system (glands and hormones); and an orthopedic surgeon, who treats fractures, such as those caused by osteoporosis.

Before making a diagnosis of osteoporosis, the doctor usually takes a complete medical history, conducts a physical examination, and orders x rays, as well as blood and urine tests, to rule out other diseases that cause loss of bone mass. The doctor may also recommend a bone density test. This is the only way to know for certain if osteoporosis is present. It can also show how far the disease has progressed.

Several diagnostic tools are available to measure the density of a bone. The ordinary x ray is one, though it's the least accurate for early detection of osteoporosis, because it doesn't reveal bone loss until the disease is advanced and most of the damage has already been done. Two other tools that are more likely to catch osteoporosis at an early stage are computed tomography scans (CT scans) and machines called densitometers, which are designed specifically to measure bone density.

The CT scan, which takes a large number of x rays of the same spot from different angles, is an accurate test, but uses higher levels of radiation than other methods. The most accurate and advanced of the densitometers uses a technique called DEXA (dual energy x-ray absorptiometry). With the DEXA scan, a double x-ray beam takes pictures of the spine, hip, or entire body. It takes about 20 minutes to do, is painless, and exposes the patient to only a small amount of radiation—about 1/50 that of a chest x ray.

In late 2001, Medicare began reimbursing for a test that measures bone resorption, an important measure for tracking a patient's response to osteoporosis therapy. The relatively inexpensive test measures a baseline amount, then compares amounts from later tests to track progress. The test consists of simple urine collection.

People should talk to their doctors about their risk factors for osteoporosis and if and when to have a bone density test. Ideally, women should have bone density measured at menopause and periodically afterward, depending on the condition of their bones. Men should be tested around age 65. Men and women with additional risk factors, such as those who take certain medications, may need to be tested earlier.

Treatment

Alternative treatments for osteoporosis focus on maintaining or building strong bones. They include nutritional and herbal therapies and homeopathy .

Nutritional therapy

A healthful diet low in fats and animal products and containing whole grains, fresh fruits and vegetables, and calcium-rich foods (such as dairy products, dark-green leafy vegetables, sardines, salmon, and almonds), along with nutritional supplements (such as calcium, magnesium , and vitamin D ) are important components of nutritional approaches to treating this disease.

Women should also eat more soy products such as tofu, soy burgers, or miso. Soy beans contain a substance called isoflavones which have estrogen-like activity. Isoflavones may help to increase bone density, alleviate hot flashes and other menopausal symptoms, lower the risk of cancer , and even reduce the risk of heart attacks. Natural hormone therapy, such as the use of soy products, is a safer alternative to synthetic estrogenic hormones, which may increase the risk of breast cancer .

In addition, women should avoid foods that may accelerate bone loss. They should avoid having too much salt in their diet, not only because salt raises the blood pressure but also because it may contribute to osteoporosis. They should also cut down on coffee, caffeinated sodas, and alcohol. High consumption of these beverages, studies have shown, are associated with accelerated drop in bone density and increase risk of bone fracture in old age. Caffeinated sodas are especially bad for the bones because in addition to containing caffeine , they also have high amounts of phosphoric acid. Phosphoric acid increases bone resorption, thus decreasing bone density.

Herbal supplements

Herbal supplements for osteoporosis emphasize such calcium-containing plants as horsetail (Equisetum arvense ), oat straw (Avena sativa ), alfalfa (Medicago sativa ), licorice (Glycyrrhiza glabra ), marsh mallow (Althaea officinalis ), and sourdock (Rumex crispus ). There are, however, few data from clinical trials to support the use of these herbs.

Homeopathy

Homeopathic remedies for osteoporosis focus on treatments believed to help the body absorb calcium. These remedies may include such substances as Calcarea carbonica (calcium carbonate) or Silica (flint). Again, there are few data other than isolated case reports regarding the effectiveness of these remedies.

Allopathic treatments

There are a number of good treatments for primary osteoporosis, most of them medications. For people with secondary osteoporosis, treatment may focus on curing the underlying disease.

Drugs

For most women who've gone through menopause, the best treatment for osteoporosis is hormone replacement therapy (HRT), also called estrogen replacement therapy. In addition to alleviating hot flashes, synthetic estrogens protect women against heart disease and they help to relieve and prevent osteoporosis. HRT increases a woman's supply of estrogen, which helps build new bone while preventing further bone loss.

Some women, however, do not want to take hormones because they have been linked to an increased risk of breast or uterine cancer . Other studies suggest that the risk is due to increasing age. Whether or not a woman takes hormones is a decision she should make carefully with her doctor. Most women take estrogen along with a synthetic form of progesterone, another female hormone. The combination helps protect against cancer of the uterus.

For people who can't or decide not to take estrogen, two other medications can be good choices. These are alendronate and calcitonin. Alendronate and calcitonin both stop bone loss, help build bone, and decrease fracture risk by as much as 50%. Alendronate (sold under the name Fosamax) is the first nonhormonal medication for osteoporosis ever approved by the FDA. It attaches itself to bone that's been targeted by bone-eating osteoclasts. It protects the bone from these cells. Osteoclasts help your body break down old bone tissue.

Calcitonin is a hormone that's been used as an injection for many years. A new version is on the market as a nasal spray. It too slows down bone-eating osteoclasts. Side effects of these drugs are minimal, but calcitonin builds bone by only 1.5% a year. Fosamax (alendronic acid) has proven safe in very large multi-year studies, and is now indicated for treatment of osteoporosis in most men. Several medications under study include other biphosphonates that slow bone breakdown (like alendronate), sodium fluoride, vitamin D metabolites, and selective estrogen receptor modulators.

Surgery

Unfortunately, much of the treatment for osteoporosis is for fractures that result from advanced stages of the disease. For complicated fractures, such as broken hips, hospitalization and a surgical procedure are required. In hip replacement surgery, the broken hip is removed and replaced with a new hip made of plastic, or metal and plastic. Despite often-successful surgeries, a large percentage of those who survive are unable to return to their previous level of activity, and many end up moving from self-care to a supervised living situation or nursing home. That's why prevention, getting early treatment, and taking steps to reduce bone loss are vital.

Expected results

There is no cure for osteoporosis, but it can be controlled. Most people who have osteoporosis fare well once they get treatment. The medicines available now build bone, protect against bone loss, and halt the progress of this disease.

Prevention

Building strong bones, especially before the age of 35, and maintaining a healthy lifestyle are the best ways of preventing osteoporosis. To build as much bone mass as early as possible in life, and to help slow the rate of bone loss later in life:

Get calcium in foods

Experts recommend 1,500 milligrams (mg) of calcium per day for adolescents, pregnant or breast-feeding women, older adults (over 65), and postmenopausal women not using hormone replacement therapy. All others should get 1,000 mg per day. Foods are the best source for this important mineral. Milk, cheese, and yogurt have the highest amounts. Other foods that are high in calcium are green leafy vegetables, tofu, shellfish, Brazil nuts, sardines, and almonds.

Take calcium supplements

Many people, especially those who don't like or can't eat dairy foods, don't get enough calcium in their diets and may need to take a calcium supplement. Supplements should be taken with meals and accompanied by six to eight glasses of water a day.

Get vitamin D

Vitamin D helps the body absorb calcium. People can get vitamin D from sunshine with a quick (15–20 minute) walk each day or from foods such as liver, fish oil , and vitamin D fortified milk. During the winter months it may be necessary to take supplements. Four hundred mg daily is usually the recommended amount.

Avoid smoking and alcohol

Smoking reduces bone mass, as does heavy drinking. To reduce risk, do not smoke; and limit alcoholic drinks to no more than two per day. An alcoholic drink is 1.5 ounces of hard liquor, 12 ounces of beer, or 5 ounces of wine.

Exercise regularly

Exercising regularly builds and strengthens bones. Weight-bearing exercises, in which bones and muscles work against gravity, are best. These include aerobics, dancing, jogging, stair climbing, tennis, walking, and lifting weights. People who have osteoporosis may want to attempt gentle exercise, such as walking, rather than jogging or fast-paced aerobics, which increase the chance of falling. Try to exercise three to four times per week for 20–30 minutes each time.

Resources

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.

The Burton Goldberg Group. Alternative Medicine: The Definitive Guide. Fife, WA: Future Medicine Publishing, 1995.

Hammond, Christopher. The Complete Family Guide to Homeopathy: An Illustrated Encyclopedia of Safe and Effective Remedies. New York: Penguin Books, 1995.

Murray, Michael and Joseph Pizzorno. Encyclopedia of Natural Medicine. Rocklin, CA: Prima Health, 1998.

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.

Zand, Janet, Allan N. Spreen, and James B. LaValle. Smart Medicine for Healthier Living: A Practical A-to-Z Reference to Natural and Conventional Treatments for Adults. Garden City Park, NY: Avery Publishing Group, 1999.

PERIODICALS

"Brittle bone relief for men." Chemist and Druggist (December 15, 2001):25.

"Test Gains Mandatory National Medicare Coverage." Health and Medicine Week (December 31, 2001):29.

ORGANIZATIONS

Arthritis Foundation. 1330 W. Peachtree St. PO Box 7669. Atlanta, GA 30357-0669. (800) 283-7800. http://www.arthritis.org.

National Osteoporosis Foundation. Suite 500, 1150 17th Street, NW. Washington, DC 20036-4603. (800) 223-9994. http://www.nof.org.

Mai Tran

Teresa G. Odle

Osteoporosis

Definition

Osteoporosis is a disease in which the density and quality of bone is reduced, significantly increasing the risk of fracture.

Description

Although rigid, bones are living tissues that constantly rebuild throughout a person's life. In the

fetus and infant, there is rapid bone formation (osteogenesis). The rate of osteogenesis slows down during childhood. At adolescence, growth spurts forward, along with heightened bone formation. Adult levels of bone mass are usually achieved by age 18, with low levels added until approximately 28–30 years of age. If the body makes new bone faster than it removes old bone (bone lysis) during childhood and adolescence, throughout adult years however, bone is lost faster than it can be made.

In bones, special cells are responsible for new bone formation and old bone removal. Specialized bone cells, called osteoblasts, located on the surface of bones, produce osteoid matter which mineralizes to become bone matrix (osteoid synthesis). When they migrate into the bone matrix, these cells become osteocytes, mature bone cells. Osteoclasts are the cells responsible for bone resorption, a process by which old bone tissue is broken down and removed, and for bone reformation.

When osteoid synthesis is not sufficient enough to compensate for normal bone loss, bones become more brittle (osteopenia) with a reduced bone mineralization that is revealed on plain x ray. Osteopenia is generally considered the first step leading to osteoporosis, in which bone density is extremely low and bones become porous and vulnerable to fracture. Everyone loses some bone mass as they age, but people with osteoporosis lose as much as 25% of their bone density, making them very susceptible to breaking bones.

Demographics

Osteoporosis affects an estimated 75 million people in Europe, the United States, and Japan. According to the National Institute of Arthritis and Musculoskeletal Diseases (NIAMS), 10 million Americans have osteoporosis and 34 million more have low bone mass, which places them at increased risk for this disease. Additionally, 1 out of every 2 women and 1 in 4 men over 50 will be diagnosed with an osteoporosis-related fracture in their lifetime. Osteoporosis is responsible for more than 1.5 million fractures annually, including 300,000 hip fractures, approximately 700,000 vertebral fractures, 250,000 wrist fractures, and more than 300,000 fractures at other sites. Caucasian white and Asian people are most likely to develop osteoporosis and osteoporosis-related fractures. While African American women tend to have higher bone mineral density (BMD) than white women throughout life, they are also at significant risk of developing osteoporosis.

Causes and symptoms

According to the WHO, whether a person develops osteoporosis or not depends on bone thickness early in life and on the practice of healthy habits later in life. Genetic factors are believed to determine as much as 50–90% of bone mass, while environmental factors account for the remaining 10–50%. A factor believed to increase the risk of developing osteoporosis is less-than-optimal bone growth during childhood and adolescence, which can result in failure to reach optimal adult peak bone mass. People who reach optimal adult peak bone mass are less prone to osteoporosis when bone loss starts occurring as a result of aging and other factors.

An important contributor to reduced bone density in women during later life is the reduction in estrogen levels that occurs with menopause . Estrogen is the sex hormone that plays an important role in building and maintaining bone. Decreased estrogen production, whether occurring as a result of menopause, or chemotherapy or radiation treatments for cancer , can lead to bone loss. After menopause, the rate of bone loss increases as the amount of estrogen produced by a woman's ovaries drops significantly. Bone loss is most rapid in the first few years after menopause but continues into the postmenopausal years. In men, sex hormone levels also decline after middle age, and also contribute to bone loss after age 50. Lifestyle factors, such as a sedentary or inactive life style, bed rest exceeding three or more days, a lack of weight—carrying activities or exercise also play a role in the development of osteoporosis.

Osteoporosis has few symptoms, with some people experiencing back pain or tenderness, lower height, or a slight curving of the spine. This is why osteoporosis is often called the “silent disease,” as people unfortunately only find out that they have it after a fracture.

Diagnosis

Osteoporosis is diagnosed using “Dual Energy X-ray Absorptiometry” (DEXA), a technique that can measure bone density. A DEXA scan provides the bone mineral density (BMD), defined as the number of grams of bone per centimetre of bone. A normal BMD is equal or higher than +1. The test also compares a person's BMD to that of women in their thirties (T-score), the age at which women's bones reach peak bone mass and are strongest. Normal results range between +1 and −1. Osteopenia is diagnosed for scores ranging between −1 and −2.5 and osteoporosis for scores less than −2.5. An additional result (Z-score) compares the BMD to that of persons of the same age. X rays may also be taken to detect bone problems, especially of the spine, to determine if a person has a reduced height. Blood and urine tests also help to identify conditions that may contribute to bone loss.

Treatment

Treatment for osteoporosis seeks to influence the ratio between the work of osteoclasts (bone-removing cells) and osteoblasts (bone-building cells) and taking steps to keep the osteoporosis from worsening. This can be achieved by a combination of dietary changes, medications, and weight-bearing exercise.

Nutrition/Dietetic concerns

Calcium is the most critical mineral for a healthy bone mass and is found in milk and other dairy products, green vegetables, and calcium-enriched foods. Calcium supplements , often combined with vitamin D may also be prescribed for osteoporosis. For women, 1000mg per day of calcium are recommended before menopause and 1500mg per day after menopause. Vitamin D helps the body absorb calcium and other minerals. The skin should also be exposed to 10 minutes of sunlight per day to promote enough vitamin D formation. It is also found in eggs, salmon, sardines, swordfish, and some fish oils. Recommended levels are 400IU per day until age 60, and 600–800IU per day after age 60. Regular exercise is also important as it promotes strong bones, since bone forms in response to physical activity.

Therapy

Drug therapy for osteoporosis may include medications such as bisphosphonates, calcitonin calcitonin, hormone replacement therapy (HRT), and teriparatide.

FDA-approved bisphosphonates for the treatment of osteoporosis include Alendronate (Fosamax), risedronate (Actonel) and ibandronate (Boniva). These medications are prescribed to slow down bone loss and decrease the risk of fractures. Calcitonin (Calcimar, Miacalcin), a hormone made from the thyroid gland, has been FDA-approved for the treatment of postmenopausal osteoporosis. It has been shown to help prevent spine fractures and for controlling the pain resulting from these fractures. HRT prescribed hormones such as estrogen and progesterone can decrease the risk of osteoporosis and osteoporotic fractures in women. However, the combination of estrogen with a progestin has been shown to increase the risk for breast cancer , strokes, heart attacks and blood clots . Teriparatide is a form of parathyroid hormone used in the treatment of advanced osteoporosis to help stimulate bone formation.

QUESTIONS TO ASK YOUR DOCTOR

• What is the cause of osteoporosis?
• What factors can increase one's chances of developing osteoporosis?
• Why are women at greater risk for osteoporosis than men?
• Can some medications increase chances of developing osteoporosis?
• How can I be sure I get enough calcium and vitamin D in my diet?

Prognosis

There is no cure for osteoporosis. However, people with mild osteoporosis have good outcomes, with those who have a fracture can usually expect their bones to heal normally. If the condition is detected and treated early, bone density, even in severe osteoporosis, can generally be stabilized or improved, lowering the risk of fractures by 50% or more after several years of treatment.

Prevention

A balanced diet and regular exercise have been shown to help slow the loss of bone density, while delaying or preventing osteoporosis altogether. Adequate calcium and vitamin D must be part of the diet which should include dairy products, green leafy vegetables, and grains. Coffee and beverages containing caffeine should be taken in moderation. It is also important to keep physically active and perform aerobic exercises, such as walking, jogging, cycling for at least 30 minutes, four to five times a week. Tobacco and alcohol should be avoided. Evidence suggests that many women who sustain a fragility fracture are not appropriately diagnosed and treated for probable osteoporosis. The National Osteoporosis Foundation recommends bone density testing for all women over age 65, and for all women under the age of 65 who have one or more risk factors for osteoporosis in addition to menopause.

Caregiver concerns

A survey, conducted by the International Osteoporosis Foundation (IOF) in 11 countries, showed denial of personal risk by postmenopausal women, lack of dialogue about osteoporosis with their primary care physician, and restricted access to diagnosis and treatment before occurrence of the first fracture. The unfortunate result is that osteoporosis is too often underdiagnosed and undertreated in this population group.

KEY TERMS

Bone mineral density (BMD) —The number of grams of bone per centimeter of bone. In a DEXA test, BMD numbers equal to or higher than +1 show normal bone mineral density.

Bone lysis —The breakdown of old bone matter.

Bone resorption —The process by which old bone tissue is broken down and removed by special cells called osteoclasts.

Dual Energy X-ray Absorptiometry (DEXA) —Technique used to measure bone mineral density.

Estrogen —A hormone secreted by the ovaries which affects many aspects of the female body, including a woman's menstrual cycle and normal sexual and reproductive development.

Hormone replacement therapy —Hormones such as estrogen and progesterone, given to women after menopause to replace the hormones no longer produced by the ovaries.

IU —International Unit. A measure of strength based on an accepted international standard for dosages of Vitamins A, D and E.

Menopause —The time in a woman's life when menstrual periods permanently stop and end the female reproductive phase of life.

Mineralization —The process of adding minerals to the bone matrix.

Osteoblasts —Bone cells located on the surface of bones that produce osteoid matter.

Osteoclast —A large multi-nucleated cell located on bone surface that nibbles at and breaks down bone and is responsible for bone resorption by secreting acid and enzymes in the space close to the bone surface.

Osteocytes —A branched cell embedded in the matrix of bone tissue.

Osteogenesis —The process of bone formation.

Osteoid —Uncalcified bone matrix, the product of osteoblasts.

Osteoid synthesis —The process of producing osteoid matter.

Osteopenia —Condition in which the amounts of calcium and phosphorus are decreased in bones, causing them to be weak and brittle, and increasing the risk of fractures.

Osteoporosis —The thinning of bone tissue and loss of bone density over time.

Progestin —Any substance that has the biological effects of the female hormone progesterone.

Resources

BOOKS

Alexander, Ivy, and Karla A. Knight. 100 Questions & Answers About Osteoporosis and Osteopenia. Boston: Jones and Bartlett Publishers, 2006.

Bohme, Karine, and Frances Budden. The Silent Thief: Osteoporosis, Exercises and Strategies Prevention and Treatment. Richmond Hill, ON: Firefly Books, 2001.

Cosman, Felicia. What Your Doctor May Not Tell You About Osteoporosis: Help Prevent—and Even Reverse—the Disease that Burdens Millions of Women. New York, NY: Grand Central Publishing, 2003.

Daniels, Diane. Exercises for Osteoporosis: A Safe and Effective Way to Build Bone Density and Muscle Strength, Revised Edition. Long Island City, NY: Hatherleigh Press, 2004.

Glenville, Marilyn. Osteoporosis: The Silent Epidemic—and What Every Woman Should Know. London, UK: Kyle Cathie, 2006.

Hodgson, Stephen. Mayo Clinic on Osteoporosis: Keeping Bones Healthy and Strong and Reducing the Risk of Fractures. Rochester, MN: Mayo Clinic Trade Paper, 2003.

Nelson, Miriam E., and Sarah Wernink. Strong Women, Strong Bones: Updated Edition. New York, NY: Perigee Trade (Penguin Group), 2006.

Sparrowe, Linda. Yoga for Healthy Bones: A Woman's Guide. Boston, MA: Shambhala Publications, 2004.

Winters-Stone, Kerri. Action Plan For Osteoporosis. Champaign, IL: Human Kinetics Publishers, 2005.

PERIODICALS

Andersen, S. J. “Osteoporosis in the older woman.” Clinical Obstetrics and Gynecology 50, no. 3 (September 2007): 752–766.

Cabanillas, M. E. “Elderly patients with non-Hodgkin lymphoma who receive chemotherapy are at higher risk for osteoporosis and fractures.” Leukemia & Lymphoma 48, no. 8 (August 2007): 1514–1521.

Ersoy, F. F. “Osteoporosis in the elderly with chronic kidney disease.” International Urology and Nephrology 39, no. 1 (2007): 321–331.

Haas, M. L., and K. Moore. “Osteoporosis: an invisible, undertreated, and neglected disease of elderly men.” Journal of Elder Abuse& Neglect 19, no. 1 (2007): 61–73.

Harvard Medical School. “Standing tall. Exercises can help with the bad posture and osteoporosis that cause us to stoop and lose height as we get older.” Harvard Health Letter 31, no. 2 (December 2005): 1–3.

Korpelainen, R., et al. “Lifelong risk factors for osteoporosis and fractures in elderly women with low body mass index—a population-based study.” Bone 39, no. 2 (August 2006): 385–391.

Madureira, M. M., et al. “Balance training program is highly effective in improving functional status and reducing the risk of falls in elderly women with osteo-porosis: a randomized controlled trial.” Osteoporosis International 18, no. 4 (April 2007): 419–425.

Troen, B. R. “Osteoporosis in older people: a tale of two studies (and three treatments).” Journal of the American Geriatric Society 54, no. 5 (May 2006): 853–855.

OTHER

Calcium and Vitamin D: Important at Every Age. NIAMS, Nutrition and Bone Health Page. (March 08, 2008) http://www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition/default.asp

Exercise and Bone Health. NIAMS, Health Information Page. (March 08, 2008) http://www.niams.nih.gov/Health_Info/Bone/Bone_Health/Exercise/default.asp

Osteoporosis. NIAMS, Handout on Health. (March 08, 2008) http://www.niams.nih.gov/Health_Info/Bone/Osteoporosis/osteoporosis_hoh.asp

Osteoporosis. NIAMS, Information Page. http://www.niams.nih.gov/Health_Info/Bone/Osteoporosis/default.asp

Osteoporosis. NIH, Senior Health Page (March 08, 2008) http://nihseniorhealth.gov/osteoporosis/toc.html

Tone Your Bones. University of Alabama at Birmingham, Website. (March 08, 2008) http://www.toneyourbones.org

ORGANIZATIONS

National Institute of Arthritis and Musculoskeletal Diseases (NIAMS), 1 AMS Circle, Bethesda, MD, 20892-3675, (301)495-4484, (877)22-NIAMS, (301)718-6366, NIAMSinfo@mail.nih.gov, http://www.niams.nih.gov.

National Institutes of Health, Osteoporosis and Related Bone Diseases—National Resource Center, 2 AMS Circle, Bethesda, MD, 20892-3676, (202)223–0344, (800)624–BONE, (202)466-4315, NIAMSBo-neInfo@ mail.nih.gov, http://www.niams.nih.gov/Health_Info/Bone.

National Osteoporosis Foundation, 1232 22nd Street N.W., Washington, DC, 20037-1202, (202)223-2226, (800) 231-4222, http://www.nof.org.

Monique Laberge Ph.D.