Many women first start wondering about bone health right at the age when the doctor recommends a bone density scan. But from my experience, getting the results of a bone density scan can generate more questions than answers — especially if your doctor isn’t up to date in the latest thinking on bone health. Here’s what you should know about using a bone density test to predict your risk of fracture or excessive bone loss.
DEXA (Dual-energy x-ray absorptiometry) or other common bone density scans such as single-photon absorptiometry (SPA); broadband ultrasound attenuation (ultrasound); and quantitative computed tomography (QCT) help determine if you have low bone density, one important risk factor for osteoporosis. These tests measure the bone mineral content in various locations of your body (such as the hip or wrist).
The best known bone-density test is the DEXA scan. It’s a precise test and today is considered the gold standard by many conventional doctors as they evaluate bone health.
A bone density test result is generally presented in numbers as grams per cubic centimeter, and also calculated as a “T score” and a “Z score.” Your T-score compares your bone density to what’s considered the ideal density of a young woman. The Z-score compares your density with that of other people your same age and sex. As you’ll see from the chart below, there is also a big void of other information that a bone density test cannot ever tell you.
| What a bone density test does… | What a bone density test DOES NOT do… |
| Estimates the mineral content of bone at a specific time. | Doesn’t tell you if you are currently losing bone or if you have had low bone density for many years. Significant changes are rarely measurable in less than two years. Also, bone density can fluctuate based on the season. |
| Measures all body types the same way. | Doesn’t take body type into consideration, for example women who are thinner will always have a lower bone density than heavier women. |
| Measures specifically the amount of minerals in bones to determine bone loss. | Doesn’t detect either bone quality or bone strength. Many of the people who are shown to have low bone density on these tests will never suffer an osteoporotic fracture. |
| Uses a “gold standard” that compares your results to those of a “normal young woman” (your T-score) or measures against the average bone mineral density for people your age and sex (your Z-score). | Doesn’t compare your bone density to healthy, fracture-free people of your age. |
| Delivers results that can vary greatly depending on the machine used — and the technician running it! | Doesn’t provide an accurate assessment from test to test. Placement of patient on the machine is important and a 5-6% change from test to test is necessary to be sure the change was not due to errors in placement on the machine. |
As you can see, a bone density test is best used as one of many tools to evaluate your bone health!
Consider other bone health tests to get a more rounded perspective of your bone health. At our clinic we like to monitor the results of a woman’s NTx test, which is a blood or urine test that indicates the rate of bone breakdown by measuring a specific molecule, or marker, released during bone resorption. We also measure a woman’s pH level, which can help determine whether her diet and lifestyle are placing an excessive burden on her bones’ reserves of alkalizing compounds.
We know that extreme bone loss is often connected to many variables. That’s why I always recommend that my clients take advantage of the new fracture assessments tools. These tools are designed to look at multiple risk factors, with and without bone density measurement. Eleven of these key risk factors identified by the landmark Women’s Health Initiative are:
Based on the research showing that a fracture risk assessment is truly the best way to know who will experience an osteoporotic fracture, I’ve developed my own simple Better Bones Fracture Risk Assessment. By answering just a few questions, you can get a much clearer picture about your potential risk of fracture. Get started now.