Osteoporosis T-Scores And Bone Mineral Density (BMD) Tests
Osteoporosis T-scores provide a measure of bone mineral density through a test that uses x-rays to scan the spine and hips. Stomach acidity and vitamin D tests also provide guidance when developing an osteoporosis treatment program.
It is recommended that women have a baseline bone density test when they reach perimenopause (menstrual irregularity occurring usually between 45 and 55) or earlier if they are at risk from the use of certain medications.
Men should request a bone density test at age 70 or earlier if using corticosteroids or prostate cancer drugs.
Osteoporosis T-scores indicate the standard deviations below the mean bone mineral density (BMD) of a young adult female. The accepted guidelines for T-scores are as follows:
- Osteopenia: -1 and -2.5
- Osteoporosis: lower than -2.5
Bone density tests focus on bones that are most likely to break because of osteoporosis, including:
- lower spine bones (lumbar vertebrae L1-L3)
- the narrow neck of your thigh bone (femur) that adjoins your hip
- the femur itself (thigh bone)
...and sometimes the bones in your wrist and forearm. Bone loss does not occur equally among these sites, so a doctor may prescribe osteoporosis medication that targets one area more effectively than another.
Low osteoporosis T-scores are important warning signs when assessing the risk of fracture. The existence of previous low-impact fractures, certain medical conditions, a family history of osteoporosis and a person's risk of falling are also important considerations before designing a treatment program.
As an effective bone building program will take 1.5-2 years to improve bone density, most health insurance plans will only pay for tests every two years... and some are moving to three-year intervals.
Bone Health Tests
Bone Mineral Density Test (BMD, DEXA, DXA)
The most common test used to get osteoporosis T-scores is called by several names including a bone mineral density (BMD) test, a dual energy x-ray absorptiometry (DEXA) test or simply a DXA test.
This test involves lying on a table for several minutes while a small x-ray detector scans your spine, one hip, or both. The test is safe and painless and does not require any injections or other discomfort.
You receive a very small amount of radiation from a DXA test, approximately the amount you are exposed to flying from coast to coast in North America.
Like any other diagnostic test, you must be referred to a diagnostic facility by a physician.
If you are monitoring your bone density over a period of years, it is best to re-test on the same BMD machine for a more accurate comparison of your osteoporosis T-scores.
Readers may be interested in the "Myth of Osteoporosis" which argues that osteoporosis T-scores may create undue alarm (and over medication) by ignoring bone quality and the natural aging process.
Bone Turnover Tests
There are also blood/urine tests that that will allow you to measure how much your bone is building up and breaking down.
As a bone density test will not pick up a problem until a significant amount of bone has been lost, some doctors recommend these tests prior to perimenopause to assess the future risk of osteoporosis.
They may also be used to assess the effectiveness of a bone-building program when you compare future osteoporosis T-scores. (Most health programs now cover DXA tests every two or three years.)
The NTX (n-telepeptide), PYD (pyridinium) and DPD (deoxypyridin) urine tests can indicate an increased or decreased rate of bone-breakdown.
High levels of NTX, PYD or DPD in the urine have been found to accurately indicate an accelerated rate of bone loss. CTX (c-telopeptides) Osteomark tests are most commonly conducted through a blood sample.
Calcium levels in the urine and blood can vary significantly in response to food intake and time of day. There is also some overlap in the CTX levels associated with normal bone density and those associated with osteoporosis.
For these reasons, experts disagree on the value of using urine and blood tests to predict future bone loss and bone turnover markers are not yet included in any official fracture risk models. The osteoporosis T-score is still considered the best indicator of osteoporosis risk.
Stomach Acid Test
Sufficient stomach acid is important for breaking down and absorbing calcium. But for most people, stomach acid decreases with age. A simple pH test strip will help you to assess and monitor your stomach acid.
Vitamin D Test
Although vitamin D is essential for calcium absorption, research shows that over 60% of North Americans are vitamin D deficient.
When assessing the results of a vitamin D blood test, Canadian labs use 75-200 nmol/L (30-80 ng/ml) as the acceptable range. However, the Vitamin D Council recommends that vitamin D levels of 125 nmol/L (50 ng/ml) be maintained year-round to support optimal health.
Calcium Excretion (24-Hour Urine Test)
This test looks at how much calcium is being excreted in the urine over a 24-hour period. (An entire day's urine is brought to a laboratory to measure the amount of calcium in the total volume of urine.) Excessive urinary calcium excretion is a common cause of bone loss and osteoporosis.
Vertebral Deformity Assessment
Similar to a bone density test, this test also uses x-rays but images each vertebra to search for deformities or fractures. The Vertebral Deformity Assessment is usually performed on newer bone density testing machines with special software that takes a lateral view of the spine.
This new spine x-ray can also be done and interpreted by knowledgeable radiologists using other x-ray technology.
C-Reactive Protein Test (High Sensitivity If Possible)
C-reactive protein is a plasma protein that is held to be a marker of general inflammation within the body. Although it is a known risk factor for heart disease because it detects inflammation, it is occasionally used to detect inflammation that may contribute to bone health problems.
Homocysteine (Plasma Or Serum Test)
A vitamin B deficiency can cause homocysteine to accumulate in the body and damage collagen. This can be a risk factor for both cardiovascular disease and osteoporotic fractures.
Celiac Disease And Gluten Sensitivity
Celiac disease and sensitivity to gluten can lead to the inflammation of the gut. This inflammation can increase bone loss as well as malabsorption of calcium and vitamins K and D needed for bone health.
If there is any suggestion of gluten sensitivity or celiac disease, appropriate testing should be considered.
An excellent source of information on gluten sensitivity as a cause of bone loss is "The Whole-Body Approach to Osteoporosis" by R. Keith McCormick.
As life expectancy increases and people seek to optimize their health during their retirement years, there is growing interest in the use of bioidentical hormones to protect bone health.
Hormone tests are frequently used to design a program that promises the benefits of prescription hormone replacement therapy (HRT) without the risk of breast cancer and heart disease.
Mechanical Response Tissue Analyzer (MRTA)
Researchers at NASA and Stanford University have developed an instrument for measuring bone strength and mineral density. At present the instrument can only measure two bones, one in the arm (the ulna) and one in the leg (the tibia).
A company called GAITSCAN Inc. of Ridgewood, New Jersey has adopted the technology for commercial marketing.
The technology now remains with the inventor of the software (Dr. Charles R. Steele) in the academic environment of Stanford's School of Engineering, Division of Applied Mechanics and in the Life Sciences Division at Ames Research Center.