How healthy are your bones?
What’s the cause of your osteoporosis? Diagnostic tests and what they mean
By Dr. Susan E. Brown, PhD
Information on these common osteoporosis and bone health tests:
One of the basic principles of the Better
Bones Program® is that all osteoporosis, all excessive bone loss, or all
real increased risk of low-trauma fracture has a cause. To better understand
any undetected causes of bone loss,
it is important to obtain a medical work-up — that is, further tests that
can help find the causes of osteoporosis.
In addition to the standard DEXA bone density test, we suggest that our clients
discuss the following tests with their doctor to see which ones are appropriate.
Below are examples of tests that could be helpful and the basics of what the test results
mean so that you can better discuss your personal situation with your doctor.
Tests to help reveal what causes osteoporosis
Vitamin D 25(OH)D blood test
This test determines your blood level of vitamin
D. The results tell you the amount of vitamin D supplementation needed to
reach a therapeutic blood level of vitamin D, which is important for adequate calcium
absorption and basic bone support.
What your results tell you: The reported “normal” range
is very wide, often from 30 to 100 ng/mL. We now know that anything less than 32
ng/mL is likely to seriously limit calcium absorption and lead to bone loss. At
the Center for Better Bones, we strive for a 50-70 ng/mL blood level of 25(OH)D.
Ionized calcium test
This is a simple blood test to measure the level of free calcium — that is, the
metabolically active portion of calcium not bound to proteins in the blood. This
test isn’t meant to assess the appropriateness of your calcium intake as much as
it is meant as an indirect test of parathyroid functioning (see below). It can also
indirectly tell us some things about vitamin D status.
What your results tell you: The body controls free calcium
in the blood very tightly, with a normal laboratory range between 4.8 and 5.2 mg/dL
(between 1.2 and 1.3 mmol/L) as reported by the Merck Index. When thinking of bone
health, we look for high ionized calcium as a possible indirect indicator of excessive
parathyroid hormone activity. A low ionized calcium level might be related to low
albumin and low protein status.
Intact parathyroid hormone blood test (iPTH)
High parathyroid hormone levels are associated with excessive bone loss, as an overactive
parathyroid gland draws calcium from bone. The medical reasons for this overactivity
need to be addressed to halt the excessive bone loss. Also, a normal parathyroid
reading in the face of vitamin D deficiency can indicate magnesium inadequacy
What your results tell you: At the Center for Better Bones,
we look for an intact parathyroid hormone level within the normal range established
by the particular testing laboratory. Two common causes of an excessively high parathyroid
hormone level are vitamin D deficiency (which is easily corrected with proper vitamin
D3 supplementation and monitoring); and an overactive parathyroid, which is most
often due to benign tumors on the parathyroid glands. Correction of this situation
often requires surgery to remove the overactive glands.
Excessively high parathyroid hormone levels cause the body to release too much calcium
from the bone contributing to bone loss, and more importantly, high blood calcium.
A high parathyroid condition is best treated by an endocrinologist.
24-hour urine calcium excretion test
This test looks at how much calcium is being excreted in the urine. For this test,
you collect all your urine over 24 hours in a large container for laboratory analysis
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.
What your results tell you: The normal laboratory range
for a person eating an average diet is around 100 to 250 mg of calcium lost in the
urine each day. I consider a calcium loss of more than 250 mg to be a concern. In
such cases, the first step is to stop all calcium supplements for 4 to 5 days and
then retest the 24-hour urine calcium. If the urine calcium loss is still high,
then steps should be taken to reduce this loss of calcium in the urine, as it can
cause bone loss. Nutritional, lifestyle, and medical approaches can help.
Thyroid hormone function test (TSH)
TSH is a hormone produced in the pituitary gland that signals the thyroid to produce
more of its hormones. If TSH is high, it usually means that the thyroid isn’t producing
enough T3 and T4, so checking your TSH level is a simple way of screening for an
underactive thyroid. Thyroid hormone levels that are too high or too low can contribute
to osteoporosis, as can a dose of thyroid medication that is too high. To screen
for overactive thyroid, or to make sure your dose of thyroid medications isn't too
high if you're already being treated for hypothyroidism, you'll need tests for free
T3 and free T4.
What your results tell you: The common laboratory range
for all adults is 0.35 to 5.50 and a more ideal level is 0.35 to 2.0.
Markers of bone resorption tests
Bone resorption (or breakdown) tests measure the amount of one specific bone protein
in the urine or blood. As one loses bone this bone protein fragment shows up in
the urine and blood in increased amounts. At the Center for Better Bones, we generally
use the N-telopeptides crosslinks (NTx) urine test, but there are several others
available. One commonly used test is the urine Dpd test (deoxypyridinium crosslinks
test). There is also an NTx serum test and the CTX serum test..
As there can be a great deal of day-to-day variation in urine bone breakdown markers,
we’ve developed a two-day collection procedure for bone resorption testing for greater
accuracy. These instructions can be used for either the urine NTx or the Dpd test.
N-telopeptides crosslinks (NTx) urine marker of bone resorption test
What your results tell you: The test result “normal” range
often listed on the test report is very broad. For example, test reports from our
local lab list the premenopausal normal range for women as 17-94 nM BCE/mM creatinine
and the postmenopausal range as 26-124 nM BCE/mM creatinine. The male range is 3-51.
These ranges are far too wide to be useful.
Ideally, a woman would like to have an NTx level near that of the average premenopausal
woman, which in the urine is around 35, but levels often soar into the 60s to 80s
or higher in and around menopause. For adult men, the mean NTx is 27, which is a
more ideal value than the higher numbers. Also, these markers can get very high
in rare diseases such as Paget’s Disease and bone cancer. These situations are unusual
and understood by a knowledgeable physician familiar with bone resorption testing.
We use the NTx urine test from Osteomark to judge the success of our bone building
program. We look to bring the urine NTx level down to the 40’s, which in most cases
indicates that bone breakdown has normalized. There are some cases, however, where
bone breakdown is very low, but bone build-up is even lower. This condition, known
as “low turnover osteoporosis,” is detected when a person has a low NTx, but is
still losing significant bone (5-6%) as seen on bone density testing.
N-telopeptides crosslinks (NTx) serum marker of bone resorption test results
What your results tell you: The NTx bone-breakdown marker
can also be measured in the blood. The female range listed by the manufacturer is
6.2-19.0 nM BCE/L, with a mean of 12.6. The male range is often listed as 5.4-24.2
nM BCE/L, with a mean of 14.8. Again, this range is too wide to be useful for us
at the Center for Better Bones. We look for a result of 12 or somewhat lower in
women, and 14 or somewhat lower in men.
Dpd urine marker of bone resorption test (deoxypyridinium crosslinks test)
What your results tell you: This bone resorption test
also lists a broad range of normal values — for women, 3.0 to 7.4 nM/mM and for
men 2.3 to 5.4 nM/mM. Clinically, adult women should strive for a Dpd test score
in the 4’s, and in men an ideal level would likely be somewhat lower.
Vertebral deformity assessment
This is another x-ray test for bone that images each vertebral body of the spine
and looks to see if there are deformities or fractures. The Vertebral Deformity
Assessment can be done on newer bone density testing machines, with special software
that takes a “lateral” view of the spine.
What your results tell you: The radiologist will give
a full report of what he or she sees for each vertebral body, reporting any abnormalities,
deformities, or fractures.
Free cortisol test (blood or saliva)
Cortisol is a corticosteroid hormone produced by the adrenal cortex, which is part
of the adrenal glands. It is usually referred to as the “stress hormone” as it is
involved in response to anxiety and stress. Abnormally high cortisol levels are
damaging to bone and as such represent a major risk factor for osteoporosis and
low-trauma fractures. This test can be done with blood or saliva.
What your results tell you: Cortisol is the “get up and
go” hormone that should rise in the early morning and decline during the day. Thus,
test results vary by what time of day the test was taken. Testing labs will give
their normal range readings and the timing of the test should be taken into account
when interpreting test results.
DHEA test (blood or saliva)
Dehydroepiandrosterone (DHEA) is a hormone produced by both the adrenal glands and
the ovaries. DHEA helps to neutralize the effects of cortisol. DHEA helps to protect
and increase bone density. Stress reduction activities like yoga and meditation
can help maintain youthful DHEA level as we age. Low levels of DHEA are a risk factor
for osteoporosis. This test also can be done with blood or saliva.
What your results tell you: In saliva testing, the results
are often correlated with the results of the cortisol testing. It is also often
measured as DHEA-S, that is, DHEA in its sulfated form. Again, each lab will offer
its normal range depending on the test used.
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. It is a known risk factor for heart disease because heart disease
is largely an inflammatory disorder. Osteoporosis is also inflammatory in nature
and this test is helpful in detecting unwanted inflammation, which may contribute
to bone health problems.
What your results tell you: Generally, in the C-reactive
protein (or CRP) test, the lower the score the less inflammation and thus the better
reading. I look for a high sensitivity CRP level less than 1.0mg/dL.
Homocysteine test (plasma or serum)
Homocysteine is a non-dietary amino acid, a product of the metabolism of a dietary
amino acid, methionine. In the absence of adequate B vitamins, homocysteine can
accumulate in the body. High levels of this substance damage collagen and represent
powerful risk factors for both cardiovascular disease and for osteoporotic fractures.
What your results tell you: Normal levels of homocysteine
in the blood range from 5 to 15 mM/L. At the Center for Better Bones we like to
see a homocysteine level of 8 or below.
Celiac disease and gluten sensitivity test
Celiac disease, or even just sensitivity to gluten, can lead to inflammation of
the gut. This inflammation is related to a complex inflammatory cascade which can
increase bone loss. Also, those with celiac disease suffer from weak indigestion
and malabsorption of many nutrients including vitamins A, K, and D. These deficiencies
in turn damage bone. If there is any suggestion of gluten sensitivity or celiac
disease, appropriate testing should be considered
What your results tell you: There are varied tests used
to help determine if one is suffering from the autoimmune disease known as celiac
disease, or if there exists the intolerance of gluten sensitivity. Talk with your
healthcare practitioner about what might be right for you.
Sex hormone test results
Post-Menopausal Females: Progesterone, Estrogen
Female sex hormones drop naturally at menopause among all women, so I don’t generally
suggest testing of these hormones. Those interested in this type of hormone testing,
or those taking hormone replacement medications, should be tested for hormone levels
by their physician.
Pre-Menopausal Females (reproductive years hormone testing): Progesterone, Estrogen
For women from their teens to menopause, proper levels of sex hormones are very
important to bone health. Low levels of either estrogen or progesterone can limit
development of optimum peak bone mass. Irregular, or frequently missed, periods
should be studied by a knowledgeable physician.
According to noted progesterone researcher, endocrinologist Dr. Jerilynn Prior,
some 25% of young women in the US and Canada fail to develop optimum peak bone mass
due to undetected ovulatory disturbances which result in low progesterone levels.
Testing of estrogen and progesterone can be helpful in pre-menopausal women with
a bone health concern.
Both blood and saliva testing are available for pre-menopause sex hormone testing.
Each testing laboratory will have its range of normal sex hormone test results.
Sex Hormone Testing in Males: Testosterone and, at times, Estrogen
A common cause of osteoporosis in men is low testosterone; thus a medical work-up
for osteoporosis in men almost always includes a test for testosterone. Interestingly
enough, estrogen also plays a role in male bone health and at times the physicians
will test for estrogen in men with osteoporosis.
Both blood and saliva testing are available for sex hormone tests in men. Each testing
laboratory will have its range of normal sex hormone test results.
Everyone deserves the full story on their health
It seems like healthcare has become a knee-jerk reaction of “see a symptom, take
a pill,” but we believe that everyone deserves better than that. Your bone loss
is a symptom of something that’s just not right in your body — and rather than treating
the symptom with medications (and living with the side effects involved, some of
which are plain frightening!), I encourage everyone to dig deeper and find out the
source of the problem.
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Dr. Susan E. Brown, PhD
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Original Publication Date: 09/11/2015
Principal Author: Dr. Susan E. Brown, PhD