DNC News

Tests for Osteoporosis: prevention and treatment monitoring

Urinary Screening for Bone Loss: Two important tests to screen for osteoporosis and to monitor treatment Practical Guidelines for Screening and Monitoring of Bone Loss By Michael T. Murray, N.D.

[most of this article were copied from the magazine Natural Medicine Online that is produced by Phytopharmica. I was writing essentially the same article so thought it easier to send out this one. Keep in mind that Phytopharmica produces this magazine to help promote their products and that Dr. Murray works for them. We run both the urine tests mentioned in the article. Information on the tests is at the end.]

For women, knowing their bone density and rate of bone loss is just as important as knowing their cholesterol level, blood pressure, and the results from a yearly Pap smear.
Why? Because osteoporosis is just as serious a risk to their long-term health as heart disease, stroke, and cancer. Early detection of bone loss by measuring bone density leads to more effective intervention. Monitoring the rate of bone loss using recently developed biochemical assessments provides assurance in the success of the treatment and maintenance program. The importance of these measures cannot be overstated, especially in women at high risk for osteoporosis.

There are several different techniques for determining bone density, but the one with the greatest support and popularity is dual energy x-ray absorptiometry (DEXA). Some newer techniques being used in research, such as some of the computerized tomography (CT) scans, are promising because they not only indicate bone density but also bone quality and structure. DEXA, however, is currently considered the gold standard.
[1] In addition to providing the most reliable measurement of bone density, the DEXA test requires less radiation exposure than other x-ray procedures for measuring bone density. Exposure amounts to roughly the amount of daily exposure to background radiation. Usually the DEXA exam measures both the hip and the lumbar spine density. It is often recommended that women of high risk get a baseline bone density measurement before the age of 50 and then monitor the rate of bone loss by urine tests that measure breakdown products of bone such as cross-linked N-telopeptide of type I collagen or deoxypyridinium (discussed below).
However, since we now know that the earlier intervention and prevention is started the better the long-term bone health, I recommend that all women over the age of 25 get bone-density measurements whether it is reimbursed by insurance or not.

Urine tests of bone resorption

There are two readily available urine tests of bone resorption that can be used to monitor the rate of bone loss and success (or failure) of therapy. One test measures the level of cross-linked N-telopeptide of type I collagen (NTX), the other test measures free deoxypyridinium (F-Dypr).
Both compounds are linked to bone breakdown. These compounds function in bone in the crosslinking of collagen-the main protein of bone that provides the organic mesh upon which calcium and other minerals are deposited.
Increased levels of F-Dypr or NTX in the urine signify loss of both the organic (protein) and inorganic (mineral) phases of bone. The higher the level, the greater the rate of bone loss.[2-5] These urinary tests provide quicker feedback compared to DEXA, which can take up to two years to detect a therapeutic response.
The DEXA test is best used to measure bone density, while urinary bone resorption assessments can be used to measure the rate of bone loss. Reducing urinary levels of these markers of bone breakdown over a two-year period has produced increases in bone density measurements.[6] I tell my patients that bone density determination indicates how much they have in their "bone bank" and the urine tests tells them how fast they are withdrawing from their bank. Together these two tests can help preserve or improve bone density.

Recommendations:
Here are my typical recommendations based upon the results of these tests.

Normal Initial F-Dypr or NTX with Average or Above-Average DEXA Assessment:
Add a yearly F-Dypr as part of their annual check-up. Be sure to have the patient follow all of the general guidelines given in the feature article and have them use at least Level 1 Support (see below).

Normal First Time F-Dypr or NTX with Below Average DEXA Assessment:
Perform another F-Dypr in 3 months. This first test result tells you that the patient is on the right track, but you need to make sure that they stay on course.

Moderately or Severely Elevated First Time F-Dypr or NTX with Average or Above-Average DEXA Assessment:
No need to panic. The patient will have to be much more aggressive about their bone health and you should repeat the F-Dypr in 3 months.

Tests for Osteoporosis: prevention and treatment monitoring
(continued)

If they were doing nothing to support their bone health, start out with Level 2 Support along with trying to get them to walk as much as possible. If they were being aggressive, switch to Level 3 Support.

Moderately or Severely Elevated First Time F-Dypr with Below Average DEXA Assessment:
This patient does not have the luxury of high reserves, go immediately to Level 3 Support and repeat the F-Dypr in 3 months. If it is still elevated, they will need Level 4 Support.

Repeat Test Interpretations Normal Repeat F-Dypr or NTX with Below Average DEXA Assessment:
The patient is definitely on the right track. Repeat the F-Dypr yearly and the DEXA every two years.

Moderately or Severely Elevated Repeat F-Dypr or NTX:
Have the patient move up a level. If they were at Level 2 Support, previously, go to Level 3 Support. If they have already been at Level 3, then determine the appropriateness of Level 4 Support.

Supplement Recommendations
Level 1 Support: A high potency multiple vitamin and mineral formula such as Clinical Nutrients for Women 45+ (PhytoPharmica).

Level 2 Support: Clinical Nutrients for Women 45+ and Clinical Nutrients for Bone Health.
If other products are being used make sure they provide the following levels of key nutrients:
Calcium 1,000-1,500 mg.
Vitamin D 400 IU
Vitamin C (Ascorbic Acid) 500 mg.
Magnesium 500 mg.
Boron (Sodium Tetraborate Decahydrate) 6 mg.
Vitamin K (Phytonadione) 300 mcg.

Level 3 Support: Level 2 plus ipriflavone (e.g., Ostivone(r)): 200 mg three times daily. Ipriflavone, in combination with 1,000 mg of calcium, has been shown to halt bone loss and in cases of osteoporosis improve bone density.[7]

Level 4 Support: Level 3 plus either intranasal calcitonin, hormone replacement therapy, or Fosamax.

Tests for Osteoporosis: prevention and treatment monitoring
(continued)

Although these measures have some side effects, the benefits (prevention of hip fracture) usually outweigh these side effects in severe cases.[8,9]

Caveat
While a high bone density is great news for bone health, it is important to consider the fact that bone mass in women appears to be a very sensitive indicator of cumulative exposure to estrogen. Therefore, a higher bone density may also mean a greater risk for breast cancer. There is evidence to support this hypothesis. Results from the Framingham Study indicated that after adjustments for age and other potential confounding factors, the rate ratios for the risk of breast cancer were 1.0, 1.3, 1.3, and 3.5 from the lowest to the highest bone density measurements.

[10] These results indicate that while a high bone density signifies protection against osteoporosis it may also signify cumulative estrogen exposure and, therefore, be associated with an increased risk of breast cancer.

An addendum from the Denver Naturopathic Clinic:
The two different urine tests for bone loss described in this article can be ordered through our office:

Clinical Labs of Colorado Test Code # 121550 NTX:
Bone resorption rate
Price $85.00 This is a local lab. We give you a requisition and you collect a urine sample as directed by the lab and drop it off at one of their collection sites. Fee for the lab is billed to our account and you pay us.

Great Smokies Diagnostic Laboratory Bone Resorption Assessment [measurement of pyridinium (Pyd) and Deoxypyridinium (D-pyd)] Price: $ 66.00 This is an out of state lab which we use frequently.
You pick up a test kit from our office. You collect the sample at home, put it in the package and call Airborne Express. You give the lab your credit card number and they bill you directly. A little cheaper, a little less hassle, and just as accurate.

It is important to note that once you use one test, you'll need to stick with that test for accurate comparisons.

References:
1. Kanis J: Bone density measurements and osteoporosis. J Int Med 241:173-5, 1997.
2. de la Piedra C, et al: New biochemical markers of bone resorption in the study of postmenopausal osteoporosis. Clinica Chimica Acta 265:225-34, 1997.
3. Russell RGG: The assessment of bone metabolism in vivo using biochemical approaches. Horm Met Res 29:138-44, 1997.
4. Eyre DR: Bone biomarkers as tools in osteoporosis management. Spine 22:17S-24S, 1997.
5. Ross PD and Knowlton W: Rapid bone loss is associated with increased levels of biochemical markers. J Bone Min Res 13:297-302, 1998.
6. Chestnut CH, et al.: Hormone replacement therapy in postmenopausal women: Urinary N-telopeptide of type I collagen monitors therapeutic effect and predicts response of bone mineral density. Am J Med 102:29-37, 1997.
7. Zhang Y, et al.: Bone mass and the risk of breast cancer among postmenopausal women. N Engl J Med 336:611-7, 1997.
8. Zhang Y, et al.: Bone mass and the risk of breast cancer among postmenopausal women. N Engl J Med 336:611-7, 1997.
9. Liberman UA, et al.: Effect of oral endronate on bone mineral density and the incidence of fractures in postmenopausal osteoporosis. New Engl J Med 333:1437-43, 1995
10. Reginster JY: Calcitonin for prevention and treatment of osteoporosis. Am J Med 95(Suppl.5A):44S-7S, 1993


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