Approximately 10 million Americans have osteoporosis, a condition causing weak bones that break easily, and another 34 million are at risk, according to the National Osteoporosis Foundation. A medical evaluation and bone strength tests can help determine whether you have the disease or whether you're at risk for broken bones, but they can't prevent osteoporosis from occurring.
Identification
It's important to diagnose the presence of osteoporosis as soon as possible so you can start treatments to prevent bone loss that may lead to fractures, decreases in height, a hunched posture and pain. Bone density tests not only detect the presence of osteoporosis, they can determine your rate of bone loss and the effectiveness of treatment. Density measurements don't tell the complete story, since some people have bones with a low mineral density that aren't necessarily at risk for a fracture. Bone tests also won't tell you the cause of your osteoporosis, and you may need a nuclear bone scan, CT can, MRI or blood and urine laboratory tests to determine whether there is a secondary underlying reason for your condition.
Types of Tests
The gold standard for measuring bone strength is the bone density test, also called densitometry or a DXA scan. It uses an x-ray machine to image your hips and spine and tell how many grams of calcium and other bone minerals are packed into a segment of bone. The results are reported in two numbers, your T-score and Z-score. If your T-score is below -2.5, you have osteoporosis. The Z-score takes other factors into consideration, such as age, sex, weight, and ethnic or racial origin, which can affect your overall risk. If the DXA shows you have low bone density, then you may also be given a FRAX test to estimate your 10-year fracture risk.
Diagnostics Potential
Researchers at the University of Texas Medical Branch in Galveston have devised a "male osteoporosis risk estimation score," which they claim can identify more than 90 percent of men at risk who might benefit from DEXA testing. A company founded by two University of Cincinnati professors is using a test based on the concept of "Bone Shock Absorbance," which measures how the energy from a heel strike is absorbed and dissipated, to develop a diagnostic tool that will test a patient's risk of bone fracture. Scientists from NASA and Stanford University have also developed an instrument for direct, noninvasive measurement of bone mineral content, called a Mechanical Response Tissue Analyzer. It determines the bending stiffness of bone, an element related to bone strength and to its mineral density.
Considerations
Bone density testing has certain limitations that can affect your diagnosis. These include differences in testing methods, such as using a central device to test the spine and hips that is more accurate -- but more expensive -- than peripheral devices that measure bone density in your forearm or heel. Not all health insurance plans cover bone strength tests, and many won't do so for women until after menopause.
References
- U.S. News and World Report Health; For Men, a Simple New Test of Bone Strength; Avery Comarow; November 2007
- NASA.gov: Weak in the Knees - The Quest for a Cure
- National Osteoporosis Foundation: Diagnosing Osteoporois
- MayoClinic.com: Bone Density Test
- Soap Box Media: Two UC Professors Found Company to Test Bone Strength
