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Best Tests for Osteoporosis (for Women and Men)

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What you don’t know could lead to a life-threatening bone fracture

By now, most people know that osteoporosis isn’t just a female disorder. While one in two women over age 50 will experience a fracture related to the bone-thinning disease, as many as one in four men in this age group will as well.

This potentially debilitating disease is preventable and treatable—yet few people know all they should about the most effective screening methods for the disease.

Key facts for women and men…

SHOULD YOU BE SCREENED?

In women and men, bone loss occurs with age. In women, bone loss is accelerated by menopause (due to declines in estrogen levels).

The National Osteoporosis Foundation recommends that average-risk women be screened by age 65 and men by age 70. But due to a number of factors that hasten bone loss, earlier testing is advisable (at menopause for women and age 50 for men)…

Broken bones. Screening is recommended when a fracture occurs for any reason—fractures that occur from falls are often misinterpreted as being related to trauma, when osteoporosis may play a role.

Medical history. Diseases that can accelerate bone loss include diabetes, rheumatoid arthritis, inflammatory bowel disease, celiac disease and neurologic disorders (such as stroke or Parkinson’s disease). These diseases may lead to the release of certain hormones, poor nutrition (low calcium and vitamin D) or a sedentary lifestyle, all of which promote bone loss.

Use of certain medications. Oral corticosteroids, such as prednisolone, and androgen deprivation drugs used by prostate cancer patients may lower bone mass substantially. Other medications that may cause bone loss include certain aromatase inhibitor drugs taken for breast cancer, such as anastrozole (Arimidex)…and some antidepressants, such as fluoxetine (Prozac).

People who are age 50 or older and are taking—or about to start taking—any of these medications should have a bone density test.

Low body weight or recent weight loss. This is generally defined as a body mass index (weight to height ratio) of less than 20 or weight loss of 10% or more from healthy adult body weight over a period of months or years.*

Vitamin D insufficiency. Only recently have doctors come to appreciate that vitamin D is at least as important as calcium in maintaining bone health. A blood test is used to measure vitamin D levels. For adults age 50 and older, the National Osteoporosis Foundation recommends 1,200 mg of calcium and 800 international units (IU) to 1,000 IU of vitamin D daily.

Lifestyle factors. Smoking and excessive alcohol intake (more than two drinks a day for men and one for women) also cause bone loss.

MOST ACCURATE TESTING

The best bone test is dual-energy X-ray absorptiometry (DEXA or DXA), which uses minute amounts of radiation to measure bone density. The standard procedure, central DXA (cDXA), measures the lower spine, hip and narrowest part of the hip bone (the femoral neck).

What it involves: While you are clothed and lying on your back on a table, a machine takes images of your spine, hip and femoral neck. The test lasts about five minutes, costs about $80 and is virtually risk-free.

If you have osteoporosis or are at risk: Get tested every one to two years. If an initial screening shows that your bones are well-preserved, get tested every two to four years. Most insurers cover the cost of cDXA when it is ordered by a doctor.

Results of cDXA testing give an accurate estimate of how likely you are to sustain a fracture of the hip or spine (the most common sites) or elsewhere in the body. Hip fractures, in particular, can be life-threatening—long-term immobility that occurs during recovery can allow pneumonia to develop or blood clots to form in the leg veins or lungs.

OTHER TESTS TO CONSIDER

When cDXA isn’t readily available (the equipment is expensive), other options include…

Peripheral DXA (pDXA). This test uses the same technology to examine bone density in the heel, wrist or finger. These measures are useful, but hip measurements are better—hip fracture is the most important fracture to try to prevent.

Quantitative ultrasound densitometry (QUD). With this test, sound waves are used to estimate bone density in the heel, kneecap or shin. No radiation is used.

If either of these tests shows possible deficiencies, the results should be confirmed with cDXA, which is more accurate and reliable.

WHAT YOUR NUMBERS MEAN

Bone test results are usually expressed as a T-score, which compares your bone mineral density (BMD) to someone with optimal bone density.

What the results mean…

A score of -2.50 or lower means bone density is substantially below optimal (osteoporosis). The risk for fracture is sufficiently high to require some sort of therapy, such as osteoporosis medication, including alendronate (Fosamax) or risedronate (Actonel). These drugs have been linked to an unusual thighbone fracture when used for an average of seven years. However, the drugs’ benefits outweigh their risks for most osteoporosis patients.

BMD of -1.0 or higher is considered normal.

Between -1.0 and -2.5 means “low bone mass” or osteopenia, which indicates high risk for osteoporosis. How likely you are to suffer a fracture and whether you need treatment to prevent osteoporosis will depend on such factors as your personal medical history, family history, age and weight.

WHEN YOU’RE AT VERY HIGH RISK

If you’re likely to have already had a spinal fracture due to certain other risk factors (such as advanced age—70 and older for women, and 80 and older for men…loss of height—1.6 inches from past height for women, and 2.4 inches from past height for men…and/or long-term steroid treatment—three or more months), your doctor may add a vertebral fracture assessment test.

This test identifies fractures in the spine (which often cause no symptoms). The test involves a closer examination of DXA pictures of the spine. Even small and previously unnoticed spinal fractures greatly increase the risk for additional fractures—in the spine and elsewhere.

*To calculate your body mass index, go to the Web site of the National Heart, Lung and Blood Institute.

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Source: Felicia Cosman, MD, clinical director of the National Osteoporosis Foundation, and professor of clinical medicine at Helen Hayes Hospital in West Haverstraw, New York, an affiliate of Columbia University College of Physicians and Surgeons in New York City. She is the author of What Your Doctor May Not Tell You About Osteoporosis (Grand Central). Date: May 1, 2010 Publication: Bottom Line Health
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