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miércoles, 19 de enero de 2011

Osteoporosis

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

Times Essentials

Recent findings and perspectives on medical research.

PERSONAL HEALTH

Options for Bone Loss, but No Magic Pill

By JANE E. BRODY

Medications can help treat osteoporosis, but there is no guaranteed cure or a sure way to prevent all fractures.

See All »NEWS & FEATURES

REFERENCE FROM A.D.A.M.

Back to TopAlternative Names

Thin bones

Back to Top Causes »

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 anti-seizure drugs
Hyperparathyroidism

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

In-Depth Causes »

Back to Top 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"

In-Depth Symptoms »

Back to Top Exams 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 preduct 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.

In-Depth Diagnosis »

Back to TopTreatment

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 vertebra 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.)

Back to TopOutlook (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.

Back to TopPossible 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

Back to TopWhen to Contact a Medical Professional

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

Back to TopPrevention

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.

Back to TopReferences

Cranney A, Papaioannou A, Zytaruk N, et al. Clinical Guidelines Committee of Osteoporosis Canada. Parathyroid hormone for the treatment of osteoporosis: a systematic review. CMAJ . 2006 Jul 4;175(1):52-9.

Gass M, Dawson-Hughes B. Preventing osteoporosis-related fractures: an overview. Am J Med . 2006 Apr;119(4 Suppl 1):S3-S11. Review.

Estrogen and progestogen use in postmenopausal women: July 2008 position statement of The North American Menopause Society. Menopause. July/August 2008;15(4)584-602.

Management of osteoporosis in postmenopausal women: 2006 position statement of The North American Menopause Society.Menopause . 2006 May-Jun;13(3):340-67.

National Osteoporosis Foundation. Clinician's Guide to Prevention and Treatment of Osteoporosis. Feb. 2008. Accessed July 23, 2008. Available online athttp://www.nof.org/professionals/Clinicians_Guide.htm

Purée of Winter Vegetable Soup

RECIPES FOR HEALTH

Purée of Winter Vegetable Soup

Andrew Scrivani for The New York Times

By MARTHA ROSE SHULMAN

Published: January 18, 2011

REPRINTS

Living in France, I was always impressed by the bags of mixed vegetables, called soupe, sold in farmers’ markets and supermarkets alike. The bags usually included an onion, carrots and celery, a leek, a turnip or two and a bouquet garni consisting of a bay leaf, a sprig of thyme and another of parsley. I’ve added root vegetables this ginger-scented soup, which is inspired by the many simple suppers I enjoyed in the homes of French friends.

Recipes for Health

Martha Rose Shulman presents food that is vibrant and light, full of nutrients but by no means ascetic, fun to cook and to eat.

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Recipes for Health: Winter Root Vegetables (January 17, 2011)
Recipes for Health: Grated Carrot, Kohlrabi and Radish Salad (January 19, 2011)
Recipes for Health: Root Vegetable Gratin (January 20, 2011)
Recipes for Health: Celery Root, Potato and Apple Purée(January 21, 2011)

1 tablespoon extra virgin olive oil

1 medium onion, chopped

1/2 pound leeks (1 large or 2 small), white and light green parts only, cleaned well and sliced

1/2 pound carrots (2 large), peeled and sliced

1/2 pound kohlrabi, trimmed, peeled and diced

1/2 pound turnips, peeled and diced

6 ounces potatoes (2 medium), peeled and diced

1 1/2 quarts water, chicken stock or vegetable stock (see note)

2 fat slices ginger, peeled

1 bay leaf

A couple of sprigs each thyme and parsley

12 peppercorns

Salt and freshly ground pepper to taste

1. Heat the olive oil over medium heat in a large, heavy soup pot or Dutch oven. Add the onion. Cook, stirring, until it begins to soften, about three minutes. Add the leeks and a generous pinch of salt. Cook, stirring often, until tender but not browned, about five more minutes. Add the carrots, kohlrabi, turnips, potatoes and water or stock. Bring to a boil.

2. Meanwhile, wrap the ginger, bay leaf, thyme, parsley and peppercorns in cheesecloth. Tie them up to make a bouquet garni, and add to the pot. Add salt to taste (about 2 teaspoons), reduce the heat, cover and simmer one hour. Remove the cheesecloth bag, and discard.

3. Blend the soup until smooth with an immersion blender or in batches in a regular blender. (Do not put the top on tight; cover the top with a towel to prevent hot splashes.) Pour the soup through a strainer into a bowl; press the soup through the strainer with the back of a ladle or with a pestle. Return to the pot and heat through. Add lots of freshly ground pepper, taste and adjust salt, and serve.

Note: To make a quick vegetable stock, cut away the dark green outer leaves of the leeks, wash thoroughly, and simmer in a pot of water with the peelings from the carrots while you prepare your other vegetables. Strain, and use for the soup.

Yield: Serves six.

Advance preparation: The finished soup will keep for three or four days in the refrigerator. Whisk before reheating.

Nutritional information per serving: 109 calories; 3 grams fat; 0 grams saturated fat; 0 milligrams cholesterol; 21 grams carbohydrates; 5 grams dietary fiber; 76 milligrams sodium (does not include salt to taste); 3 grams protein

Martha Rose Shulman is the author of "The Very Best of Recipes for Health."

Two Tests Could Aid in Risk Assessment and Early Diagnosis of Alzheimer’s

By GINA KOLATA

Published: January 18, 2011

REPRINTS

Researchers are reporting major advances toward resolving two underlying problems involving Alzheimer’s disease: How do you know if someone who is demented has it? And how can you screen the general population to see who is at risk?

New Old Age

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One study, reported in The New York Times in June, evaluated a new type of brain scan that can detect plaques that are uniquely characteristic of Alzheimer’s disease.

On Thursday, an advisory committee to the Food and Drug Administration, which requested the study, will review it and make a recommendation on whether to approve the test for marketing.

The second study asked whether a blood test could detect beta amyloid, the protein fragment that makes up Alzheimer’s plaque, and whether blood levels of beta amyloid were associated with a risk of memory problems. The answer was yes, but the test is not ready to be used for screening.

Both studies are to published in The Journal of the American Medical Association on Wednesday.

“These are two very important papers, and I don’t always say that,” said Neil S. Buckholtz, chief of the Dementias of Aging Branch of the National Institute on Aging.

The new brain scan involved a dye developed by Avid Radiopharmaceuticals, now owned by Eli Lilly. The dye attaches to plaque in patients’ brains, making it visible on PET scans.

The study by Avid involved 152 people nearing the end of life who agreed to have a brain scan and a brain autopsy after they died. The investigators wanted to know whether the scans would show the same plaques as the autopsies.

Twenty-nine of the patients in the study died and had brain autopsies. In 28 of them, the scan matched the autopsy results. Alzheimer’s had been diagnosed in half of the 29 patients; the others had received other diagnoses.

One subject who was thought to have had Alzheimer’s did not have plaques on the scans or on the autopsy — the diagnosis was incorrect. Two other patients with dementia turned out to have had Alzheimer’s although they had received diagnoses of other diseases.

The study also included 74 younger and healthier people who underwent the scans. They were not expected to have plaques, and in fact they did not.

If the F.D.A. approves the scan, medical experts said they would use it to help determine whether a patient with dementia had Alzheimer’s. If no plaques were found, they would have to consider other diagnoses.

The Avid scan will also be used — and is being used — by companies that are testing drugs to remove amyloid from the brain. The scans can show if the drugs are working. And a large study sponsored in part by the National Institute on Aging is scanning healthy people and following them to see if the scans predict the risk of developing Alzheimer’s disease.

The other study, on a blood test for Alzheimer’s, indicates that such a test may work. But researchers agree that it is not ready for clinical use.

The study, by Dr. Kristine Yaffe of the University of California, San Francisco, and the San Francisco Veterans Affairs Medical Center, included 997 subjects whose average age was 74 when the study began. They were followed for nine years and given memory tests and a blood test looking for beta amyloid.

Beta amyloid is in the brain and flows into the spinal fluid. From there, it can enter the bloodstream. When amyloid accumulates in plaque, its levels in spinal fluid go down. That indicates risk for Alzheimer’s disease.

Dr. Yaffe and her colleagues asked whether they could show similar Alzheimer’s risk by measuring beta amyloid levels in blood. It is difficult; amyloid levels in blood are much lower than in spinal fluid. And there appear to be other sources of amyloid in blood, confounding the test results.

“I was interested in the blood test because I think it’s been given a bit of a write-off,” Dr. Yaffe said. Some studies concluded that it worked, but just as many said that it did not. She wanted to try again with a large study following people for a long period and using a sensitive test for amyloid.

She divided the subjects into groups and found that those with the most amyloid had the lowest risk of a decline in their mental abilities, and those with the least had the greatest risk. But other factors also played a role. Low levels of the protein were not as useful in predicting mental decline in people who had more education and were more literate. People with a gene, APO e4, that is associated with an increased risk of Alzheimer’s, seemed to be at a greater risk of a mental decline even if their blood levels of amyloid were high.

That does not necessarily mean that the more people use their minds the more they will be protected from Alzheimer’s disease, researchers note. But, Dr. Yaffe said, that idea needs more study.

The test’s precision, said Dr. Clifford Jack of the Mayo Clinic, was “not crisp enough” to accurately predict whether an individual was likely to show an intellectual decline over the decade after the test was given.

Still, said Dr. Ronald C. Petersen, chairman of the medical and scientific advisory council of the Alzheimer’s Association, there is an increasing need for such a test. If treatments are developed to slow or stop the disease, it will be important to start them before irreversible damage is done.

Current tests of Alzheimer’s risk — spinal taps and MRI and PET scans — are not suitable to screen large numbers of people. “They are either expensive or invasive, or both,” Dr. Petersen said. “We need a cheap and safe population screening tool, like cholesterol for cardiology.”

A blood test could be ideal, and this study is an encouraging step forward, he said. The idea might be to screen with such a test and then follow up with those who test positive, giving them a PET scan, for example.

But, Dr. Petersen said, “this study is not sufficiently convincing that this is the answer.”