Osteoporosis

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Osteoporosis is the thinning of bone tissue and loss of bone density over time.

Causes, incidence, and risk factors

Osteoporosis is the most common type of bone disease.

Researchers estimate that about 1 out of 5 American women over the age of 50 have osteoporosis. About half of all women over the age of 50 will have a fracture of the hip, wrist, or vertebra (bones of the spine).

Osteoporosis occurs when the body fails to form enough new bone, when too much old bone is reabsorbed by the body, or both.

Calcium and phosphate are two minerals that are essential for normal bone formation. Throughout youth, your body uses these minerals to produce bones. If you do not get enough calcium, or if your body does not absorb enough calcium from the diet, bone production and bone tissues may suffer.

As you age, calcium and phosphate may be reabsorbed back into the body from the bones, which makes the bone tissue weaker. This can result in brittle, fragile bones that are more prone to fractures, even without injury.

Usually, the loss occurs gradually over years. Many times, a person will have a fracture before becoming aware that the disease is present. By the time a fracture occurs, the disease is in its advanced stages and damage is severe.

The leading causes of osteoporosis are a drop in estrogen in women at the time of menopause and a drop in testosterone in men. Women over age 50 and men over age 70 have a higher risk for osteoporosis.

Other causes include:

    Being confined to a bed

    Chronic rheumatoid arthritis, chronic kidney disease, eating disorders

    Taking corticosteroid medications (prednisone, methylprednisolone) every day for more than 3 months, or taking some antiseizure drugs

    Hyperparathyroidism

    Vitamin D deficiency

White women, especially those with a family history of osteoporosis, have a greater than average risk of developing osteoporosis. Other risk factors include:

    Absence of menstrual periods (amenorrhea) for long periods of time

    Drinking a large amount of alcohol

    Family history of osteoporosis

    History of hormone treatment for prostate cancer or breast cancer

    Low body weight

    Smoking

    Too little calcium in the diet

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Symptoms

There are no symptoms in the early stages of the disease.

Symptoms occurring late in the disease include:

    Bone pain or tenderness

    Fractures with little or no trauma

    Loss of height (as much as 6 inches) over time

    Low back pain due to fractures of the spinal bones

    Neck pain due to fractures of the spinal bones

    Stooped posture or kyphosis, also called a "dowager's hump"

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Signs and tests

Bone mineral density testing (specifically a densitometry or DEXA scan) measures how much bone you have. Your health care provider uses this test to predict your risk for bone fractures in the future. For information about when testing should be done, see bone density test.

A special type of spine CT that can show loss of bone mineral density, quantitative computed tomography (QCT), may be used in rare cases.

In severe cases, a spine or hip x-ray may show fracture or collapse of the spinal bones. However, simple x-rays of bones are not very accurate in predicting whether someone is likely to have osteoporosis.

You may need other blood and urine tests if your osteoporosis is thought to be due to a medical condition, rather than simply the usual bone loss seen with older age.

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Treatment

The goals of osteoporosis treatment are to:

    Control pain from the disease

    Slow down or stop bone loss

    Prevent bone fractures with medicines that strengthen bone

    Minimize the risk of falls that might cause fractures

There are several different treatments for osteoporosis, including lifestyle changes and a variety of medications.

Medications are used to strengthen bones when:

    Osteoporosis has been diagnosed by a bone density study.

    Osteopenia (thin bones, but not osteoporosis) has been diagnosed by a bone density study, if a bone fracture has occurred.

BISPHOSPHONATES

Bisphosphonates are the primary drugs used to both prevent and treat osteoporosis in postmenopausal women.

    Bisphosphonates taken by mouth include alendronate (Fosamax), ibandronate (Boniva), and risedronate (Actonel). Most are taken by mouth, usually once a week or once a month.

    Bisphosphonates given through a vein (intravenously) are taken less often.

CALCITONIN

Calcitonin is a medicine that slows the rate of bone loss and relieves bone pain. It comes as a nasal spray or injection. The main side effects are nasal irritation from the spray form and nausea from the injectable form.

Calcitonin appears to be less effective than bisphosphonates.

HORMONE REPLACEMENT THERAPY

Estrogens or hormone replacement therapy (HRT) is rarely used anymore to prevent osteoporosis and are not approved to treat a woman who has already been diagnosed with the condition.

Sometimes, if estrogen has helped a woman, and she cannot take other options for preventing or treating osteoporosis, the doctor may recommend that she continue using hormone therapy. If you are considering taking hormone therapy to prevent osteoporosis, discuss the risks with your doctor.

PARATHYROID HORMONE

Teriparatide (Forteo) is approved for the treatment of postmenopausal women who have severe osteoporosis and are considered at high risk for fractures. The medicine is given through daily shots underneath the skin. You can give yourself the shots at home.

RALOXIFENE

Raloxifene (Evista) is used for the prevention and treatment of osteoporosis. Raloxifene is similar to the breast cancer drug tamoxifen. Raloxifene can reduce the risk of spinal fractures by almost 50%. However, it does not appear to prevent other fractures, including those in the hip. It may have protective effects against heart disease and breast cancer, though more studies are needed.

The most serious side effect of raloxifene is a very small risk of blood clots in the leg veins (deep venous thrombosis) or in the lungs (pulmonary embolus).

EXERCISE

Regular exercise can reduce the likelihood of bone fractures in people with osteoporosis. Some of the recommended exercises include:

    Weight-bearing exercises -- walking, jogging, playing tennis, dancing

    Resistance exercises -- free weights, weight machines, stretch bands

    Balance exercises -- tai chi, yoga

    Riding a stationary bicycle

    Using rowing machines

Avoid any exercise that presents a risk of falling, or high-impact exercises that may cause fractures.

DIET

Get at least 1,200 milligrams per day of calcium and 800 - 1,000 international units of vitamin D3. Vitamin D helps your body absorb calcium.Your doctor may recommend a supplement to give you the calcium and vitamin D you need.

Follow a diet that provides the proper amount of calcium, vitamin D, and protein. While this will not completely stop bone loss, it will guarantee that a supply of the materials the body uses to form and maintain bones is available.

High-calcium foods include:

    Cheese

    Ice cream

    Leafy green vegetables, such as spinach and collard greens

    Low-fat milk

    Salmon

    Sardines (with the bones)

    Tofu

    Yogurt

STOP UNHEALTHY HABITS

Quit smoking, if you smoke. Also limit alcohol intake. Too much alcohol can damage your bones, as well as put you at risk for falling and breaking a bone.

PREVENT FALLS

It is critical to prevent falls. Avoid sedating medications and remove household hazards to reduce the risk of fractures. Make sure your vision is good. Other ways to prevent falling include:

    Avoiding walking alone on icy days

    Using bars in the bathtub, when needed

    Wearing well-fitting shoes

MONITORING

Your response to treatment can be monitored with a series of bone mineral density measurements taken every 1 - 2 years.

Women taking estrogen should have routine mammograms, pelvic exams, and Pap smears.

RELATED SURGERIES

There are no surgeries for treating osteoporosis itself. However, a procedure called vertebroplasty can be used to treat any small fractures in your spinal column due to osteoporosis. It can also help prevent weak vertebrae from becoming fractured by strengthening the bones in your spinal column.

The procedure involves injecting a fast-hardening glue into the areas that are fractured or weak. A similar procedure, called kyphoplasty, uses balloons to widen the spaces that need the glue. (The balloons are removed during the procedure.)
Expectations (prognosis)

Medications to treat osteoporosis can help prevent fractures, but vertebrae that have already collapsed cannot be reversed.

Some persons with osteoporosis become severely disabled as a result of weakened bones. Hip fractures leave about half of patients unable to walk independently. This is one of the major reasons people are admitted to nursing homes.

Although osteoporosis is debilitating, it does not affect life expectancy.
Complications

    Compression fractures of the spine

    Disability caused by severely weakened bones

    Hip and wrist fractures

    Loss of ability to walk due to hip fractures

Calling your health care provider

Call your health care provider if you have symptoms of osteoporosis or if you wish to be screened for the condition.
Prevention

Calcium is essential for building and maintaining healthy bone. Vitamin D is also needed because it helps your body absorb calcium. Following a healthy, well-balanced diet can help you get these and other important nutrients throughout life.

Other tips for prevention:

    Avoid drinking excess alcohol

    Don't smoke

    Get regular exercise

A number of medications are approved for the prevention of osteoporosis.

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What are osteoporosis symptoms and signs?

Osteoporosis can be present without any symptoms for decades because osteoporosis doesn't cause symptoms until bone fractures. Moreover, some osteoporotic fractures may escape detection for years when they do not cause symptoms. Therefore, patients may not be aware of their osteoporosis until they suffer a painful fracture. The symptom associated with osteoporotic fractures usually is pain; the location of the pain depends on the location of the fracture. The symptoms of osteoporosis in men are similar to the symptoms of osteoporosis in women.

Fractures of the spine (vertebra) can cause severe "band-like" pain that radiates from the back to the sides of the body. Over the years, repeated spinal fractures can lead to chronic lower back pain as well as loss of height and/or curving of the spine due to collapse of the vertebrae. The collapse gives individuals a hunched-back appearance of the upper back, often called a "dowager hump" because it commonly is seen in elderly women.

A fracture that occurs during the course of normal activity is called a minimal trauma, or stress fracture. For example, some patients with osteoporosis develop stress fractures of the feet while walking or stepping off a curb.

Hip fractures typically occur as a result of a fall. With osteoporosis, hip fractures can occur as a result of trivial accidents. Hip fractures also may heal slowly or poorly after surgical repair because of poor healing of the bone.

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What are osteoporosis risk factors and causes?

The following are factors that will increase the risk of developing osteoporosis:

    Female gender


    Caucasian or Asian race


    Thin and small body frame


    Family history of osteoporosis (for example, having a mother with an osteoporotic hip fracture doubles your risk of hip fracture)


    Personal history of fracture as an adult


    Cigarette smoking


    Excessive alcohol consumption


    Lack of exercise


    Diet low in calcium


    Poor nutrition and poor general health


    Malabsorption (nutrients are not properly absorbed from the gastrointestinal system) from conditions such as celiac sprue


    Low estrogen levels in women (such as occur in menopause or with early surgical removal of both ovaries)


    Low testosterone levels in men (hypogonadism)


    Chemotherapy that can cause early menopause due to its toxic effects on the ovaries


    Amenorrhea (loss of the menstrual period) in young women associated with low estrogen and osteoporosis; amenorrhea can occur in women who undergo extremely vigorous exercise training and in women with very low body fat, for example, women with anorexia nervosa


    Chronic inflammation, due to chronic diseases such as rheumatoid arthritis or liver diseases


    Immobility, such as after a stroke, or from any condition that interferes with walking


    Hyperthyroidism, a condition wherein too much thyroid hormone is produced by the thyroid gland (as in Grave's disease) or is ingested as thyroid hormone medication


    Hyperparathyroidism is a disease wherein there is excessive parathyroid hormone production by the parathyroid gland, a small gland located near or within the thyroid gland. Normally, parathyroid hormone maintains blood calcium levels by, in part, removing calcium from the bone. In untreated hyperparathyroidism, excessive parathyroid hormone causes too much calcium to be removed from the bone, which can lead to osteoporosis.


    When vitamin D is lacking, the body cannot absorb adequate amounts of calcium from the diet to prevent osteoporosis. Vitamin D deficiency can result from lack of intestinal absorption of the vitamin such as occurs in celiac sprue and primary biliary cirrhosis.

    Certain medications can cause osteoporosis. These include long-term use of heparin (a blood thinner), antiseizure medications such as phenytoin (Dilantin) and phenobarbital, and long-term use of oral corticosteroids (such as prednisone).

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Who should have bone density testing?

The National Osteoporosis Foundation guidelines state that there are several groups of people who should consider DXA testing:

    All postmenopausal women below age 65 who have risk factors for osteoporosis


    All women aged 65 and older


    Postmenopausal women with fractures, although this is not mandatory because treatment may well be started regardless of bone density


    Women with any of more than 50 medical conditions associated with osteoporosis; a primary-care physician can scan a patient's list of medical illnesses to determine if one of these conditions is present


    Women whose decision to begin treatment for osteoporosis might be aided by bone density testing to determine the presence or absence of osteoporosis or osteopenia

The National Osteoporosis Foundation guidelines state that bone density testing does not need to be performed if a person has a known osteoporotic fracture because the patient will be treated for osteoporosis with or without a bone density study. In addition, bone density testing is not appropriate if the person undergoing the test is not willing to take treatment based on the results. Therefore, if bone density testing is done, it should be performed on people willing to take some specific action based on the results.

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The goal of treatment of osteoporosis is the prevention of bone fractures by reducing bone loss or, preferably, by increasing bone density and strength. Although early detection and timely treatment of osteoporosis can substantially decrease the risk of future fractures, none of the available treatments for osteoporosis are complete cures. In other words, it is difficult to completely rebuild bone that has been weakened by osteoporosis. Therefore, prevention of osteoporosis is as important as treatment. The following are osteoporosis treatment and prevention measures:

    Lifestyle changes, including quitting cigarette smoking, curtailing excessive alcohol intake, exercising regularly, and consuming a balanced diet with adequate calcium and vitamin D

    Medications that stop bone loss and increase bone strength, such as alendronate (Fosamax), risedronate (Actonel), raloxifene (Evista), ibandronate (Boniva), calcitonin (Calcimar), zoledronate (Reclast), and denosumab (Prolia)

    Medications that increase bone formation such as teriparatide (Forteo)

Lifestyle changes

Exercise, quitting cigarettes, and curtailing alcohol

Exercise has a wide variety of beneficial health effects. However, exercise does not bring about substantial increases in bone density. The benefit of exercise for osteoporosis has mostly to do with decreasing the risk of falls, probably because balance is improved and/or muscle strength is increased. Research has not yet determined what type of exercise is best for osteoporosis or for how long it should be continued. Until research has answered these questions, most doctors recommend weight-bearing exercise, such as walking, preferably daily.

A word of caution about exercise: It is important to avoid exercises that can injure already weakened bones. In patients over 40 and those with heart disease, obesity, diabetes mellitus, and high blood pressure, exercise should be prescribed and monitored by physicians. Extreme levels of exercise (such as marathon running) may not be healthy for the bones. Marathon running in young women that leads to weight loss and loss of menstrual periods can actually promote osteoporosis.

Smoking one pack of cigarettes per day throughout adult life can itself lead to loss of 5%-10% of bone mass. Smoking cigarettes decreases estrogen levels and can lead to bone loss in women before menopause. Smoking cigarettes also can lead to earlier menopause. In postmenopausal women, smoking is linked with increased risk of osteoporosis. Data on the effect of regular consumption of alcohol and caffeine on osteoporosis is not as clear as with exercise and cigarettes. In fact, research regarding alcohol and caffeine as risk factors for osteoporosis shows widely varying results and is controversial. Certainly, their effects are not as great as other factors. Nevertheless, moderation of both alcohol and caffeine is prudent.