Osteoporosis

views updated May 11 2018

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

views updated May 11 2018

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

views updated May 23 2018

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 unnoticedeither 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 radiationabout 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 exerciseswhere bones and muscles work against gravityare 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

views updated Jun 27 2018

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 radiationabout 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 (1520 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 2030 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

views updated May 23 2018

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, [email protected], 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.

Osteoporosis

views updated Jun 27 2018

Osteoporosis

Definition

Description

Demographics

Causes and symptoms

Diagnosis

Treatment

Nutrition/Dietetic concerns

Therapy

Prognosis

Prevention

Resources

Definition

Osteoporosis is a chronic disorder in which the mass of bones decreases and their internal structure degenerates to the point where bones become fragile and break easily.

Description

Bone is living material. It is constantly broken down by cells called osteoclasts and built up again by cells called osteoblasts. This process is called bone remodeling, and it continues throughout an individual’s life. Normally, more bone is built up than is broken down from birth through adolescence. In the late teens or early twenties, people reach their peak bone mass—the most bone that they will ever have. For twenty or so years, bone gain and bone loss remain approximately balanced in healthy people with good nutrition. However, when women enter menopause, usually in their mid to late forties, for the first 5to 7 years bone loss occurs at a rate of 1–5% a year. Men

tend to lose less bone, and the loss often begins later in life. Osteoporosis occurs when bone loss continues and bones become so thin and their internal structure is so damaged that they break easily.

Bone remodeling occurs because bone is made primarily of calcium and phosphorous. Calcium is critically involved in muscle contraction, nerve impulse transmission, and many metabolic activities within cells. To remain healthy, the body must keep the level of free calcium ions (Ca 2+) within a very narrow concentration range. Besides providing a framework for the body, bone acts as a calcium “bank.” When excess calcium is present in the blood, osteoblasts deposit it into bones where it is stored. When too little calcium is present, osteoblasts dissolve calcium from bones and move it into the blood. This process is controlled mainly by parathyroid hormone (PTH) secreted by the parathyroid glands in the neck. As people age, various conditions cause them to take more calcium out of the “bone bank” than they deposit, and osteoporosis (which literally means porous bones) eventually develops. Osteoporosis is a silent disorder. It usually

KEY TERMS

Anorexia nervosa —An eating disorder that involves self-imposed starvation.

Menopause —The time when women are no longer able to reproduce, the menstrual cycles stops, and physical changes occur that are often related to a decrease in the reproductive hormone estrogen.

Systemic lupus erythematosus (SLE) —A serious autoimmune disease of connective tissue that affects mainly women. It can cause joint pain, rash, and inflammation of organs such as the kidney.

shows no symptoms until bones become so weak that they fracture from a seemingly minor bump of fall. All bones in the body may be affected by osteoporosis, but spinal vertebrae, the hip, and the wrist and forearm are the bones most often broken.

Demographics

The National Osteoporosis Foundation estimates that 10 million people in the United States over age 55 have osteoporosis, and another 34 million have lost enough bone mass to put them at high risk for developing the disorder. The National Institutes of Health estimate that 25 million people in the United States have osteoporosis. Since people rarely seek treatment until they have a bone fracture, accurate estimates are difficult to obtain. However, about 1.5 million fractures are attributed to osteoporosis in the United States each year. Internationally, in Europe 1 of every 8 people over age 50 will have a spinal fracture, suggesting a high rate of osteoporosis.

Osteoporosis is a disorder of older individuals. It rarely develops before age 50. and the likelihood of developing it increases steadily with age. Eighty percent of the people who have osteoporosis are women, but there is a fair amount of variation among the rate in women of different ethnic groups. White women, especially those of northern European ancestry, are at highest risk of developing osteoporosis. Their rate is twice as high as Hispanic women and four times as high as black women. White men also are most likely to be affected, but the differences in the rate of osteoporosis among men of different races and ethnicities is smaller than among women.

Causes and symptoms

Although the immediate cause of osteoporosis is loss of bone, there are many risk factors that increase the change of developing this condition. Age, race, gender, and heredity play a role in the development of osteoporosis, but other the risk factors are related to lifestyle. These include:

  • cigarette smoking. Smoking causes the liver to destroy estrogen at a faster than normal rate .
  • heavy alcohol consumption. Alcohol can interfere with calcium absorption.
  • lack of exercise. Weight bearing exercises help increase bone mass.
  • too much strenuous exercise in women. Extreme exercise causes menstrual cycles to stop (amenorrhea), reducing estrogen levels.
  • Poor diet. Vitamin D and calcium are both necessary to build strong bones.

Medical conditions and treatments can also cause osteoporosis. These include:

  • conditions that cause low testosterone levels in men (e.g. hypogonadism)
  • cancer or treatment with certain chemotherapy drugs (e.g. cyclosporine A).
  • early hysterectomy or removal of the ovaries. This reduces the level of estrogen in the body.
  • use of anticonvulsant drugs (e.g. phenytoin, carba-mazepin). These cause vitamin D deficiency and reduce the amount of calcium absorbed from the intestine.
  • long-term use of corticosteroids drugs (e.g. cortisone, prendisone) to treat conditions such as systemic lupus erythematosus (SLE) or rheumatoid arthritis. These drugs directly inhibit bone formation.
  • Certain hormonal disorders such as Cushing syndrome where the body makes too many corticosteroids
  • spinal cord injury that results in paralysis or any other medical condition that severely limits the individual’s physical activity

Osteoporosis is a disorder that shows few obvious symptoms. Elderly individuals may begin to lose height and develop a curved upper back and what is sometimes called a dowagers hump. For most people, signs of osteoporosis only become apparent when they either fracture a bone or have a bone mineral density (BMD) test done.

Diagnosis

Diagnosis begins with a medical history to determine whether what risk factors the individual has. The physician may order blood and urine tests to rule out other disorders. The definitive test for osteoporosis is a bone mineral density (BMD) test. The most commonly used BMD is called a dual-energy x-ray absorptiometry (DXA) test. This test measures the density of bone in the hip and spine. It is similar to an x ray, only with less exposure to radiation, and it is painless. Results are given as a T-score, with negative numbers indicating low bone mass. Occasionally the physician may order a bone scan. A bone scan checks for bone inflammation, fractures, bone cancer, and other abnormalities, but it does not measure bone density.

Treatment

Osteoporosis cannot be cured but it can be treated with exercise (see Therapy), diet, and sometimes with medication. There are several types of prescription medications approved by the United States Food and Drug Administration for the treatment of osteoporosis.

  • Antiresorptive medications slow or prevent bone from being broken down. These include alendronate sodium (Fosamax), ibandronate sodium (Boniva), etidronate (Didronel), and risedronate sodium (Actonel). If drug therapy is used, these medication are often the first choice.
  • In women, estrogen therapy and hormone replacement therapy drugs increase the level of estrogen in the body and improve bone health. Because of side effects such as the increase in breast cancer, heart attacks, and stroke, these drugs are used less frequently. Most often they are used to treat other symptoms of menopause rather than specifically to treat osteoporosis.
  • Selective estrogen receptor modulators (SERMs) such as raloxifene (Evista). These drugs are being developed to replace estrogen and hormone therapy drugs. They act on estrogen receptors in bone in a way that prevents the bone from being broken down.
  • Parathyroid hormone stimulates the formation of new bone by activating more new osteoblasts. It is marketed as teriparatide (Fortéo)
  • Calcitonin (Miacalcin, Calcimar, Cibacalcin) is a hormone that slows bone breakdown by inhibiting osteoclast activity.

Nutrition/Dietetic concerns

Calcium and vitamin D are both essential to building and maintaining strong bones. Dairy products are a good source of these nutrients. Calcium supplements are recommended for many women who have difficulty getting enough calcium in their diet. Recommended dietary allowances (RDAs) and lists of foods that are high in calcium and vitamin D can be found in their individual entries. Fluoride also is needed to develop healthy bones and teeth.

People with the eating disorder anorexia nervosa are at especially high risk of developing osteoporosis later in life because they have poor, unbalanced diets. The menstrual cycle in girls with anorexia is often delayed in starting or if it has started, stops. In addition, people with anorexia almost never get enough calcium to build strong bones during adolescence and they make unusually larger amounts of cortisol, a corticosteroid made by the adrenal gland that causes bone loss. Although the effect of this eating disorder on bones will not be seen until the individual is older, failure to build strong, dense bones during the teen years substantially increases the risk of osteoporosis later.

Therapy

Physical therapy involving weight-bearing exercises an help individuals of any age, even those who are frail or have chronic illnesses slow bone loss and regain muscle mass. Physical therapy exercises that emphasize improving strength, flexibility, coordination, and balance also decrease the risk of falls and fractures in individuals who have osteoporosis.

Prognosis

Osteoporosis cannot be cured but preventive behaviors and treatment can slow its progression. Falls that result in hip and spine fractures present the greatest risk of complications. Almost one-fourth of people over age 50 who have hip fractures die within one year. Although women have two to three times more hip fractures than men, men with hip fractures die twice as often as women. One study found that six months after a hip fracture, only about 15% of individuals could walk across a room unaided. Many require long-term care. About 20% end up in nursing homes. Quality of life is greatly affected by osteoporosis.

Prevention

Prevention should begin in childhood and the teenage years with healthy diet and plenty of physical activity to build strong bones. The higher the bone mass density in early adulthood, the greater the chance of avoiding or delaying the effects of osteoporosis.

Individuals need to get the RDA for calcium and vitamin D beginning in childhood and continuing through old age. Exercise at any age is also beneficial in slowing osteoporosis. A BMD test should be done every two years in older individuals. Medicare will usually pay for a BMD test every two years. Signs of osteoporosis should be treated as soon as they appear.

Resources

BOOKS

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: Warner Books, 2003.

Gates, Ronda and Beverly Whipple. Outwitting Osteoporosis: The Smart Woman’s Guide to Bone Health. Hills-boro, OR: Beyond Words Pub., c2003.

Hodgson, Stephen F. Mayo Clinic on Osteoporosis: Keeping Bones Healthy and Strong and Reducing the Risk of Fracture. New York: Kensington Pub., 2003.

ORGANIZATIONS

National Institutes of Health Osteoporosis and Related Bone Diseases National Resource Center. 2 AMS Circle, Bethesda, MD 20892-3676. Telephone: (800) 624-2663(BONE) or (202) 223-0344. TTY: (202)466-4315. Fax: (202) 293-2356 Website: <http://www.osteo.org>

National Osteoporosis Foundation. 1232 22nd Street N.W., Washington, DC 20037-1292. Telephone: (202) 223-2226. Website: <http://www.nof.org/>

OTHER

Surgeon General of the United States “The 2004 Surgeon General’s Report on Bone Health and Osteoporosis.”<http://www.surgeongeneral.gov/library/bonehealth/docs/Osteo10sep04.pdf>

Hobar, Coburn. “Osteoporosis.” emedicine.com, December 16, 2005. <http://www.emedicine.com/med/topic1693.htm>

Medline Plus. “Osteoporosis.” U. S. National Library of Medicine, March 30, 2007. <http://www.nlm.nih/gov/medlineplus/osteoporosis.html>

Nalamachu, Srinivas R. and Shireesha Nalamasu. “Osteoporosis (Primary).” emedicine.com, December 6, 2006. <http://www.emedicine.com/pmr/topic94.htm>

National Institute of Arthritis and Musculoskeletal Disorders “Osteoporosis: The Diagnosis.” November 2005. <http://www.niams.nih.gov/bone/hi/osteoporosis_diagnosis.htm>

National Institute of Arthritis and Musculoskeletal Disorders “Other Nutrients and Bone Health at a Glance.”December 2004. <http://www.niams.nih.gov/bone/hi/other_nutrients.htm>

National Institute of Arthritis and Musculoskeletal Disorders “What People With Anorexia Nervosa Need to Know About Osteoporosis.”December 2004. <http://www.niams.nih.gov/bone/hi/other_nutrients.htm>

National Osteoporosis Foundation. “Medications to Treat & Prevent Arthritis.”2007. <http://www.nof.org/patientinfo/medications.htm>

Tish Davidson, A.M.

Osteoporosis

views updated May 14 2018

Osteoporosis

Prevalence of Osteoporosis

Types and Causes of Osteoporosis

Signs and Symptoms

Diagnosing Osteoporosis

Treatment Options

Early Prevention

Resources

Osteoporosis (os-te-o-po-RO-sis) is a disorder in which there is loss of bone density) which increases the likelihood of fracture.

KEYWORDS

for searching the Internet and other reference sources

Aging

Bones

Menopause

Skeletel System

Bone consists of two layers: a compact outer layer, called cortical bone, and a porous inner layer, called spongy (or cancellous) bone. Osteoporosis weakens mostly bones with a large percentage of spongy bone. These include the vertebrae (bones of the spine), the hips, and the wrists. Bones of this kind are more fragile and are especially prone to fracture when affected by osteoporosis.

Osteoporosis develops gradually over time, although rates vary in different individuals. It results from an imbalance in the normal process in which bone is constantly being broken down and replaced by new bone. In osteoporosis, the rate at which bone tissue is lost exceeds the rate at which it is replaced. This imbalance results in an overall loss of bone.

Prevalence of Osteoporosis

No one can say how many people have osteoporosis, because it develops gradually and merges with the natural process of aging. However, it is known that women are much more likely to develop the disorder than men, and that people of European ancestry have a higher incidence of osteoporosis than people of African ancestry.

Often, a person can have osteoporosis but not be aware of it until she fractures a bone. Typically, this happens in a fall that would not have caused the fracture to occur in a young adult. It has been estimated that in the United States osteoporosis is responsible for more than 1.2 million bone fractures each year. Among women, surveys indicate that at least 10 percent of those over age 50 have bone loss severe enough to increase the risk of fractures of the spine, hip, or long bones.

Types and Causes of Osteoporosis

Osteoporosis is classified as primary or secondary, depending on whether there is some other condition or abnormality causing the bone loss.

Primary osteoporosis

Primary osteoporosis is the most common form of the disorder. It has been divided further into age-related osteoporosis, postmenopausal osteoporosis, and idiopathic (of unknown cause) juvenile osteoporosis. Age-related (or senile) osteoporosis occurs mostly in elderly people whose bones have become significantly thinner owing to their advanced age. Postmenopausal osteoporosis results from the acceleration of bone loss in women after they have reached menopause*, when their ovaries have stopped producing estrogen, a hormone that helps maintain bone mass.

*menopause
(MEN-o-pawz) is the time of life when women stop menstruating (having their monthly period) and can no longer become pregnant.

The amount of bone mass a person has as a young adult when the skeleton is mature is believed to be related to the likelihood of developing osteoporosis after middle life. It is believed that the generally greater incidence* of osteoporosis in women than in men, and in people of European background than in those of African origin, is due largely to their lower skeletal density as young adults. Moreover, the density of bone in a persons skeleton in young adulthood is partly determined by his or her genes* (inherited), and people with lighter skeletons who develop osteoporosis in later life are likely to have relatives with the same condition.

*incidence
means rate of occurrence.
*genes
are chemicals in the body that help determine a persons characteristics, such as hair or eye color. They are inherited from a persons parents and are contained in the chromosomes found in the cells of the body

Juvenile osteoporosis is rare and occurs in boys and girls before they reach their teens. It may last 2 to 4 years until normal bone growth resumes. Another uncommon form occasionally develops in young adults.

Secondary osteoporosis

A condition is said to be secondary when it is caused by something else not functioning correctly. Secondary osteoporosis may have several causes. Immobility, as in someone with a paralytic disease, can cause the bones to thin and become brittle. This effect also has been observed in astronauts who have undergone prolonged periods of weightlessness in space. (It is difficult to get proper exercise when there is no gravity to work against.)

Additional causes of secondary osteoporosis include hormonal diseases, such as hyperthyroidism, and estrogen loss caused by failure or removal of the ovaries*. Nutritional disorders such as anorexia nervosa can also lead to osteoporosis. Smoking and heavy consumption of alcoholic beverages are thought to be strong contributing factors in some cases of osteoporosis.

*ovaries
are the sexual glands in which eggs are formed in women and the female hormone estrogen is produced.

Signs and Symptoms

Osteoporosis does not always produce obvious symptoms. That is why an older person may first learn of his or her condition after breaking a bone in a fall. An x-ray then reveals the decreased bone density.

It has been estimated that 70 percent of fractures in people age 45 and older can be attributed to osteoporosis. About one third of women older than age 65 will have fractures of the vertebrae. The ratio of women to men experiencing spinal fractures is about 8 to 1. By the time people reach very advanced age, one third of women and one sixth of men will have broken a bone in the hip. Another common site of fracture is the forearm bone (radius) just above the wrist.

The thinning vertebrae in a person with osteoporosis may collapse spontaneously. Called compression fractures, these breaks can cause severe pain, usually in the mid or lower back. Chronic, or long-lasting, pain may develop after several such fractures have occurred. The person may gradually lose inches of height, and the upper back often curves forward. These signs and symptoms typically develop in women within 20 years after menopause if osteoporosis is not treated.

Diagnosing Osteoporosis

A diagnosis of osteoporosis is usually made by noting the persons physical appearance in general and the spine in particular. X-rays can reveal that the bones are less dense than normal. Special imaging techniques, including photon densitometry (FO-ton den-si-TOM-e-tree), are also used to detect osteoporosis.

In some instances, a blood test and bone biopsy (removal of a tiny sample of bone for examination) may be used to rule out the possibility of osteomalacia (OS-te-o-ma-LAY-she-a), a closely related condition in adults that results from a lack of vitamin D.

Treatment Options

If osteoporosis is not treated, the loss of bone density may continue. The risk of fractures will increase correspondingly as the person ages. Treatment is aimed primarily at stopping the bone loss.

Medications

Calcium supplements in tablet form at recommended dosages are safe, inexpensive, and effective. Still more effective is treatment with the hormone estrogen, but this can have harmful side effects. Doctors may or may not prescribe estrogens, depending largely on other health considerations in individual patients. Other drugs such as calcitonin can prevent bone loss and may be given to women who do not take estrogen.

Certain drugs taken to treat other conditions may have the additional effect of causing bone loss. The use of such medications may have to be curtailed or adjusted for people who have osteoporosis. Cortisone, thyroid hormone, and diuretics (used for various disorders to increase the flow of urine) are examples of drugs that can cause loss of bone density.

Men who develop osteoporosis usually are not given hormone treatment but take calcium supplements and can be given some of the newer drugs available.

Lifestyle

General measures that can be taken to slow further loss of bone include undertaking a regular program of exercise (including long walks or some equivalent activity), quitting smoking, and drinking alcoholic beverages only in moderation. Good eating habits are important, and a balanced diet should include adequate calcium, vitamins, and other nutrients. Elderly people need to take precautionary measures to avoid falls.

Calcium Supplements

Calcium is essential for developing strong bones and teeth and for the proper function of heart, muscles, and the nervous system. Getting enough calcium is especially important for children, adolescent females, and pregnant women. Studies have shown that proper bone development in adolescent females can lessen the effects of osteoporosis later in life. If the diet does not provide enough calcium (for example, when someone is allergic to dairy products), calcium supplements can help make up the difference.

Calcium is usually found in foods and supplements as a saltthat is, the calcium is chemically combined with another element or compound. It is important to read the label of any calcium supplement to find out how much calcium it supplies and in what form of salt it is. Some peoples bodies have problems absorbing particular forms of calcium; such persons should avoid calcium supplements with those salts.

Pain Relief

Standard pain-relieving drugs, such as aspirin, and heat applications can be used for back pain. Posture training and special exercises for the stomach and back muscles can have long-term benefits in reducing pain and discomfort. Occasionally a back brace may be necessary to provide support.

Early Prevention

The best time to start taking steps to prevent osteoporosis is during the childhood and teen years. This is particularly so for young women with lightweight skeletons and small bones and who have close relatives with osteoporosis. As in older people, getting plenty of regular exercise is important, as is calcium in the diet. It is estimated that more than 70 percent of children and teenagers fail to consume adequate amounts of calcium in their diets. Foods rich in calcium include milk and other dairy products, green leafy vegetables, citrus fruits, fish such as sardines and mackerel, and shellfish. The aim is to achieve full, normal bone density in the skeleton at maturity

Lifestyle choices such as not smoking and limiting alcohol use are important. Also to be avoided are fad diets that promise rapid weight loss. While exercise, particularly supervised weight training, is important in the prevention of osteoporosis, excessive exercise in teenage girls and young women can have the opposite effect. Extreme amounts of exercise (especially if it is combined with dieting and weight loss) can cause the stopping of menstrual periods and decreased estrogen levels in the body. Significant bone loss can be a result.

Did You Know?

  • The thinning of bones due to osteoporosis is believed responsible for more than 1.2 million fractures in the United States each year.
  • Someone can have osteoporosis and not know it.
  • Spinal curvature in the elderly is a common sign of osteoporosis.
  • People can lose several inches of height as a result of osteoporosis.
  • The great majority of people with osteoporosis are women.
  • Young women in their teens with small bones can take important steps to avoid osteoporosis in later life.

See also

Broken Bones and Fractures

Eating Disorders

Thyroid Disease

Resources

Books

Bonnick, Sydney Lou. The Osteoporosis Handbook. Dallas, TX: Taylor Publishing Company, 1997. Provides further information on the disorder in nontechnical language and is fully illustrated.

Germano, Carl. The Osteoporosis Solution: New Therapies for Prevention and Treatment. New York: Kensington Publishing Corporation, 1999. Emphasizes nutrition as it relates to osteoporosis.

Organizations

The National Institutes of Health posts information about osteoporosis on its website.
http://www.nih.gov/niams/healthinfo/opbkgr.htm

The National Osteoporosis Foundation posts relevant information onits website.
http://www.nof.org

Osteoporosis and Related Bone DisordersNational Resource Center also maintains a website with useful information.
http://www.osteo.org

The U.S. Centers for Disease Control and Prevention (CDC), located in Atlanta, Georgia, posts information about osteoporosis at its website.
http://cdc.gov/nceh/

Osteoporosis

views updated Jun 08 2018

OSTEOPOROSIS

Osteoporosis is a bone disease that affects over ten million Americans and 1.4 million Canadians. Persons with this disease have low bone mass and structural deterioration of bone tissue. This causes the bone to become more fragile and more likely to fracture. Osteoporosis is often referred to as a "silent disease" because most people are unaware that they have the disease until they actually sustain a fracture. Although awareness of the disease is growing, many persons remain undiagnosed and undertreated.

Consequences of osteoporosis

Although osteoporosis increases the likelihood of any bone breaking, the typical sites are the wrist, hip, and vertebrae. It is estimated that at least one-half of the women and one-eighth of the men over age fifty will suffer an osteoporotic fracture in their lifetimes. Hip fractures are among the most devastating consequences of osteoporosis. Twenty percent of persons die within one year of breaking a hip and only one-third will regain their pre-fracture functional level. The morbidity from vertebral fractures is also considerable. The pain from an acute fracture can last weeks to months, and elderly persons in particular may require admission to hospital for pain management. Chronic back pain may occur, and persons with multiple vertebral fractures may lose height to the extent that their ribs rest painfully on the top of their pelvic bones. Economically, osteoporosis resulted in $13.8 billion of nursing home and hospital costs in the United States in 1995 alone.

Risks

Osteoporosis is a multifactorial disease. Although osteoporotic fractures occur most commonly in old age, risk factors can be traced back to childhood. A person's peak bone strength is established by the age of twenty. Although many people think of bone as an inert object, it is actually a living tissue, continually renewing itself to correct defects that occur from wear and tear. Cells called osteoclasts break down areas of bone and create cavities, which are then filled with new bone that is produced by the osteoblast cells. As we age, the rate of bone breakdown exceeds the rate of bone formation, and bone loss occurs at a rate of 1 percent each year. This increases to 2 to 5 percent per year during the first five years after menopause and also increases somewhat after the age of seventy-five. By the age of eighty, the average woman will have lost 30 percent of her skeleton. Thus, it can be understood that the larger the peak bone mass established in early life, the more will remain after years of progressive bone loss. A diet low in calcium and vitamin D and low physical activity in childhood decrease the peak bone mass and therefore increase the risk of osteoporosis. Premature menopause (natural or surgically induced) causes the rapid bone loss period associated with estrogen deficiency to occur earlier. Women, because of menopause, and because of a relatively lower peak bone density, are at higher risk that men. As bone loss occurs progressively through life, age itself is an important risk. Other risk factors include excessive alcohol use, caffeine consumption, race (white or Asian), a thin small frame, and a positive family history. Medical conditions such as hyperthyroidism and hyperparathyroidism, and drugs such as steroids and anticonvulsants, are also important contributors to osteoporosis.

Diagnosis

The diagnosis of osteoporosis is often not made until a typical osteoporotic fracture has occurred. However, patients can be diagnosed earlier by measuring bone density. This is most commonly done using an X-ray technique called a DEXA (dual energy X-ray absorptiometry) scan. The bone density of the person is then calculated as the number of standard deviations (SD) above or below the average value of a healthy young adult. The lower the bone density, the higher the risk of fracture. The WHO (World Health Organization) defines osteoporosis as a bone mineral density 2.5 SD below the young adult average. Other methods such as heel ultrasound and CT scans can also be used, although they have not been as extensively studied. Screening for osteoporosis is a controversial area and guidelines vary, but all recommend individual consideration of the person's risk factors and the treatment being considered.

Treatment

The best treatment for any disease is prevention. To maximize bone density, attention must be paid to ensuring adequate calcium and vitamin D intake, frequent weight-bearing exercise, and minimal alcohol and cigarette use from an early age. Estrogen and other medications such as bisphosphonates can decrease the amount of bone lost at the time of menopause. Persons requiring steroids for prolonged periods of time can be treated with bisphosphonates. Even among persons with established osteoporosis, there is much that can be done to reduce further bone loss, increase bone density, and, most importantly, prevent fractures. As many persons have a diet deficient in calcium and vitamin D, supplements are often needed to ensure a daily intake of 12001500 mg of elemental calcium and 400800 IU of vitamin D. Medications that decrease bone turnover include estrogen, SERMs (selective estrogen receptor modulators, such as raloxifene), bisphosphonates (such as etidronate, alendronate, and risedronate), and calcitonin. These have been proven to increase bone density and to reduce vertebral fractures. Estrogen, risedronate, and alendronate have also been proven to decrease the risk of hip fracture. The selection of the best medication for the individual person depends on their other illnesses and risk factors, consideration of potential side-effects, and cost. Although much attention is focused on increasing bone density, equally, if not more important, are measures to reduce the falls that lead to fractures. Exercise, especially balance and resistance training, has been proven to reduce falls. Many medications such as benzodiazepines, antidepressants, and antipsychotics increase the risk of falls and should be stopped or reduced if possible. Vision should be checked. Attention should also be paid to home safety. Throw rugs should be discarded or taped down, grab bars should be installed in the bathroom and there should be adequate lighting. The person should wear sturdy flat shoes and be encouraged to use a walking aid if required. Hip protectors, which are shorts with pads over the hip bone, can also prevent hip fracture.

Conclusion

In summary, osteoporosis is a common and underdiagnosed disease. The consequences of osteoporotic fractures are serious and include pain, functional decline, institutionalization, and death. However, today much can be done both to prevent osteoporosis and to treat established disease. Effective treatment to prevent fractures includes both medications to increase bone density and measures to prevent falls.

Janet Gordon

See also Arthritis; Balance and Mobility; Hip Fracture; Menopause; Physiological Changes; Organ Systems; Bone.

BIBLIOGRAPHY

Lauritzen, J. B.; Petersen M. M.; and Lund B. "Effect of External Hip Protectors on Hip Fractures." Lancet 341(2 January 1993): 1113.

"Osteoporosis: Review of the Evidence for Prevention, Diagnosis and Treatment and Cost Effectiveness Analysis." Osteoporosis International 8, Suppl 4. (1998): S1S88.

"Prevention and Management of Osteoporosis: Consensus Statements from the Scientific Advisory Board of the Osteoporosis Society of Canada." Canadian Medical Association Journal 155, no. 7 (1996): 921965.

Reid, I. R. "Pharmacological Management of Osteoporosis in Postmenopausal Women." Drugs & Aging 15, no. 5 (1999): 349363.

Osteoporosis

views updated May 18 2018

OSTEOPOROSIS

DEFINITION


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

DESCRIPTION


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

Osteoporosis: Words to Know

Alendronate:
A drug used to treat osteoporosis in women who have passed through menopause.
Calcitonin:
A drug used to treat osteoporosis in women who have passed through menopause.
Calcium:
An essential mineral with many important functions in the body, one of which is in the formation of bone.
Computed tomography (CT) scan:
A diagnostic technique in which a specific region of the body is X-rayed from many angles. A computer then combines the various X-ray photographs.
Computerized axial tomography (CAT) scan:
Another name for a computed tomography (CT) scan.
Densitometry:
A technique for measuring the density of bone by taking photographs with low-energy X rays from a variety of angles around the bone.
Estrogen:
A female hormone with many functions in the body, one of which is to keep bones strong.
Hormone replacement therapy (HRT):
A method of treating osteoporosis by giving supplementary doses of estrogen and/or other female hormones.
Menopause:
The period in a woman's life when she stops menstruating.
Protein:
A type of chemical compound with many essential functions in the body, one of which is to build bones.
Resorption:
The process by which the elements of bone are removed from bone and returned to the body.

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

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

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

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

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

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

CAUSES


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

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

SYMPTOMS


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

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

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

DIAGNOSIS


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

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

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

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

TREATMENT


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

Drugs

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

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

Surgery

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

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

Alternative Treatment

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

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

PROGNOSIS


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

PREVENTION


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

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

FOR MORE INFORMATION


Books

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

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

Periodicals

Bilger, Burkhard. "Bone Medicine." Health Magazine (MayJune 1996): pp. 12528.

Braun, Wendy. "Do Your Bones Pass the Test?" Saturday Evening Post (MarchApril 1997): pp. 1822+.

Organizations

Arthritis Foundation. 1330 West Peachtree Street, Atlanta, GA 30309. (404) 8727100. http://www.arthritis.org.

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

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

Osteoporosis

views updated Jun 11 2018

Osteoporosis

Definition

Osteoporosis is a disease characterized by low bone mass and deterioration of bone tissues, leading to bone fragility and, consequently, an increase in fracture risk.

Description

The term osteoporosis comes from the Greek word osteon, meaning bone, and porus, meaning pore or passage. Osteoporosis literally makes bones porous. The amount of calcium stored in bones decreases over time causing the skeleton to weaken.

In the body of early adults, both the mineral portion and the framework of bone is in constant flux. Old tissue is broken down and reabsorbed and new bone is created at approximately the same rate. In later years, this rate of renewal begins to slow behind the rate of removal. This slowing is what leaves the bones thinner and more fragile. The most typical sites of fractures related to osteoporosis are the hip, spine, wrist, and ribs, although the disease can affect any bone in the body.

The average woman acquires 98% of her skeletal mass by approximately age 20. Building strong bones during childhood and adolescence is a key defense against developing osteoporosis later. There are four main steps to preventing osteoporosis: consuming a balanced diet rich in calcium and vitamin D; participating in weight-bearing exercise; following a healthy lifestyle, including no smoking and limited alcohol intake; and testing bone density and taking medication when appropriate.

Type I, postmenopausal osteoporosis, is the most common. It is usually a consequence of reproductive hormone deficiency, and afflicts mostly women over age 50. The disorder typically appears within the first ten or twenty years after menopause. Men may also develop the disorder, usually around 50-60 years of age, as a result of:

  • Prolonged exposure to certain medications such as steroids used to treat asthma or arthritis, anticonvulsants, aluminum-containing antacids, and certain cancer treatments
  • Chronic disease that affects the kidneys, lungs, stomach, and intestines and alters hormone levels
  • Undiagnosed low levels of the sex hormone testosterone
  • Lifestyle habits such as smoking, excessive alcohol use, low calcium intake, inadequate physical exercise

Type II, senile osteoporosis, affects both men and women over the age of 70, although women are twice aslikely to develop the disorder.

In some cases, osteoporosis is secondary to another cause. It can accompany endocrine disorders such as acromegaly and Cushing syndrome. It results from excessive use of drugs such as corticosteroids. In these cases, the treatment is directed at curing the principal ailment or at not using the offending drug. Blood or urine tests will diagnose other causes of bone loss or bone density.

Genetic profile

Osteoporosis results from a complex interaction between genetic and environmental factors throughout life. Evidence suggests that peak bone mass is inherited, but current genetic markers are only able to explain a small proportion of the variation in individual bone mass or fracture risk. At this time, no specific mode of inheritance has been identified. Heritability of bone mass has been estimated to account for 60-90% of its variance. Studies have shown reduced bone mass in daughters of osteoporotic women when compared with controls; in men and women who have first-degree relatives with osteoporosis; and in perimenopausal women who have a family history of hip fracture. Body weight in infancy may be a determinant of adult bone mineral area.

Some scientists think that environmental influences during early life interact with the genome to establish the functional level of a variety of metabolic processes involved in skeletal growth.

Many candidate genes exist for osteoporosis, however relatively few have been studied. The first candidate gene to be identified was the vitamin D receptor (VDR) gene, and studies are ongoing as to how much this gene accounts for variance in bone mass. The response of bone mass to dietary supplementation with vitamin D and calcium is known to be dependent, in part, on VDR polymorphisms. Other genes may aid in establishing who would benefit from treatments like hormone replacement therapy, bisphosophonates, or exercise. Associations between bone mass and polymorphisms have also been found in the estrogen receptor gene, the interleukin-6 genes, the transforming growth factor beta, and a binding site of the collagen type I alpha1 (COLIA1) gene.

The risk of osteoporosis is greatly determined by peak bone mass, and any gene linked to fractures in the elderly may possibly be associated with low bone mass in children as well.

Environmental influences such as diet, climate, and physical exercise may have significant impact on gene expression, as well. In particular, malnutrition early in life is likely to have permanent effects resulting in lowered bone mass.

Demographics

Significant risk has been reported in people of all ethnic backgrounds. Asian and white women are at greatest risk of bone thinning because they generally have the lowest bone density. Although the risk is

smaller, African-American and Hispanic-American women should take percaution, as well. An estimated 10% of African-American women over age 50 have osteoporosis and an additional 30% have low bone density that puts them at risk of developing osteoporosis.

Women in general have a four times greater risk than men of developing osteoporosis, and 80% of those affected by osteoporosis are women. In the United States, an estimated eight million American women and two million men have osteoporosis.

An osteoporosis-related fracture will occur in one in two women and one in eight men over the age of 50.

Signs and symptoms

Often called "the silent disease" because bone loss occurs without symptoms, people may not know that they have osteoporosis until they have a fracture from a minor bump or fall, or a vertebra collapses. Physical signs of osteoporosis include back pain, loss of height over time, stooped posture, and fractures of vertebrae, wrists, or hips. Osteoporosis can be detected by a bone mineral density test or even a regular x ray.

Without preventive treatment, women can lose up to 20% of their bone mass in the first five to seven years following menopause, making them more susceptible to osteoporosis.

Over many years, a sequence of spinal compression fractures may cause kyphosis, the bent-over posture known as dowager's or widow's hump. These fractures rarely require surgery, and they can range from causing minor discomfort to severe painful episodes of backache. In either case, pain generally subsides gradually over one to two months.

Diagnosis

Since osteoporosis can develop undetected for decades until a fracture occurs, early diagnosis is important.

A bone mineral density test (BMD) is the only way to diagnose osteoporosis and determine risk for future fracture. The painless, noninvasive test measures bone density and helps determine whether medication is needed to help maintain bone mass, prevent further bone loss, and reduce fracture risk.

Several different machines measure bone density. Central machines, such as the dual energy x-ray absorptiometry (DXA or DEXA) and quantitative computed tomography (QCT), measure density in the hip, spine and total body. Peripheral machines, such as radiographic absorptiometry (RA), peripheral dual energy x-ray absorptiometry (pDXA), and peripheral quantitative computed tomography (pQCT), measure density in the finger, wrist, kneecap, shin bone, and heel.

A physician may be able to observe osteoporotic bone in a routine spinal x ray, however, BMD tests are more accurate and can measure small percentages of lost bone density. In an x ray, osteoporotic bone appears less dense and the image is less distinct, suggesting weaker bone.

There are no official guidelines for osteoporosis screening. Some physicians recommend bone density testing at menopause to begin preventive treatment if necessary. Generally, testing is recommended for postmenopausal women who have suffered a bone fracture after menopause or who have gone through menopause and have at least one risk factor for the disease. The major risk factors are low body weight, low calcium intake, poor health, and a history of osteoporosis in the family. The test is usually recommended for all women over 65.

Testing may also be recommended for elderly men with one of the following risk factors: bone fracture, poor health, or low testosterone levels.

Treatment and management

There a number of options for preventing and treating bone loss.

Therapeutic options

Various therapies have been shown to be effective in preventing bone loss and increasing bone mass. These include:

  • Estrogen. For women with postmenopausal osteoporosis, estrogen replacement therapy helps halt bone loss and exerts a modest bone-building effect. Stopping estrogen therapy restarts bone loss, so long-term treatment is usually recommended. For women entering menopause, some physicians recommend estrogen replacement therapy to replace the decreasing supply of naturally occurring estrogen in the body and enable the skeleton to slow its rate of absorption and retain calcium. Estrogen is considered the best treatment against osteoporosis. Physicians may recommend combination estrogen and progesterone replacement therapy in women who have an intact uterus in order to reduce endometrial cancer risk. Some studies indicate a relationship between estrogen use and breast cancer while other studies indicate no relationship at all; the issue is still to be determined.
  • Raloxifene. One of a class of drugs called selective estrogen receptor modulators (SERMs) that appear to prevent bone loss, raloxifene (Evista) produces small increases in bone mass. It is approved for the prevention and treatment of osteoporosis. Like estrogens, SERMs produce changes in blood lipids that may protect against heart disease, although the effects are not as potent as that of estrogen. Unlike estrogens, SERMs do not appear to stimulate uterine or breast tissue.
  • Alendronate. One of a class of medications called bisphosphonates, alendronate (Fosamax) may prevent bone loss, increase bone mass, and reduce the risk of fractures.
  • Risedronate. Also from the bisphosphonate family, risedronate (Actonel) has been shown to reduce bone loss, increase bone density, and reduce the risk of fractures.
  • Calcitonin. A hormone that regulates calcium levels in the blood, calcitonin and may prevent bone loss. It is approved for treatment of diagnosed osteoporosis.

Preventive options

Measures have been identified that improve bone strength over the life span. Physicians recommend that all adult men and women, but particularly men and women over the age of 50, take the following measures to prevent osteoporosis:

  • Consume at least 1,000 mg calcium. Foods high in calcium include dairy products, leafy green vegetables, beans, nuts and whole-grain cereals. Supplements may be taken if adequate intake cannot be achieved through diet.
  • Consume 400 IU of vitamin D to enhance calcium absorption.
  • Participate in regular weight-bearing exercise, such as walking, jogging, tennis, weight-lifting, and crosscounty skiing, to strengthen bones.
  • Stop smoking.
  • Reduce intake of caffeine to not more than three cups a day.
  • Limit alcohol to not more than two drinks per day.
  • Avoid excessive amounts of dietary fiber as it binds to calcium and may interfere with absorption.

Making the house a safer place against falls can decrease risk of fracture in people with osteoporosis. Install handrails on the stairs; remove loose throw rugs; keep rooms and hallways well-lit including night lights; install handrails beside the tub, shower and toilet; place nonskid mats in the bathtub, shower, and on tile bathroom floors.

If fractures occur, treatment may require casts, braces, physical therapy and surgery to assist bone healing.

Prognosis

When osteoporosis is untreated, it can cause serious disability. Osteoporosis can be managed with proper medical and self-care.

Osteoporosis is associated with 40,000 deaths annually, mostly from complications of surgery or immobilization after hip fractures.

Resources

BOOKS

Osteoporosis in Men: The effects of gender on skeletal health, edited by Eric S. Orwoll. Academic Press, 1999.

Osteoporosis: Diagnosis and management, edited by Pierre J. Meunier. Mosby, 1998.

PERIODICALS

Altkorn, Diane, Tamara Vokes, and Alice T. D. Hughes. "Treatment of Postmenopausal Osteoporosis." JAMA: Journal of the American Medical Association 11 (2001): 1415+.

NIH Consensus Development Panel on Osteoporosis Prevention, Diagnosis, and Therapy. "Osteoporosis Prevention, Diagnosis, and Therapy." JAMA: Journal of the American Medical Association 285 (2001): 785+.

ORGANIZATIONS

Foundation for Osteoporosis Research and Education. 300 27th St., Oakland, CA 94612. (888) 266-3015. <http://www.fore.org>.

WEBSITES

National Osteoporosis Foundation. <http://www.nof.org>.

Osteoporosis and Related Bone Diseases–National Resource Center. National Institutes of Health. <http://www.osteo.org>.

Jennifer F. Wilson, MS