To track the health of its population, the federal government undertakes a massive health survey of the U.S. population every two years, known as the National Health and Nutrition Examination Survey (NHANES). Beginning in 2005, the survey has included bone mineral density measurements — and the most recent report shows a generalized decline in bone density.
Between 2005 and 2010, NHANES data showed bone mineral density to be fairly stable, which seemed to correlate with the slight decrease in hip fracture incidence reported by other researchers. But when they measured bone mineral density in 2014, they found a significant and generalized decrease in bone density.
Survey Cycles – Bone Mineral Density
2005-2006 – Generalized stability of bone density
2007-2008 – Generalized stability of bone density
2009-2010 – Generalized stability of bone density
2010-2014 – Generalized significant decline in bone density
Take a look at what else happened to us as a population between 2005 and 2014
The percentage of people with a sedentary lifestyle more than tripled — in women, 9.59% reported being physically inactive in 2005 compared to 31.82% in 2014, while in men, 87% reported being physically inactive in 2014 compared to 22.83% in 2005.
Not surprisingly, the percentage of people with hypertension also increased, from 35.4% to 45.08% from 2005 to 2014.
Equally predictably, the percentage of self-reported diabetes increased 6% for both men and women
Our ever-increasing lack of physical activity is catching up with our bones and our body, resulting in declining bone density. As I have shared many times, physical activity, even in small amounts, is known to positively affect inflammation, stress, cardiovascular health, and, of course, our bones. It stands to reasons that all of these would suffer if we spent too much time sitting.
Want to know more about your bone health?
In the past, you would have relied on an expensive DEXA bone scan to tell you bone density. But fortunately, bone resorption testing is now available and accepted as an accurate and inexpensive way to measure the rate of bone loss. Assessments such as urine NTX and serum CTX test, are now considered invaluable in evaluating osteoporosis, since they can identify excessive bone loss before too much damage has occurred. They also allow for more regular and more frequent assessment of bone health status than do bone density scans. This means that changes can be started to slow or reverse bone loss before it becomes more of an issue. In addition, results can be monitored more frequently and thus adjusted for maximum effectiveness.
There are multiple bone resorption tests to choose from; at least four different markers of bone resorption can be measured in the blood, and at least seven can be measured in urine and while each has advantages, let’s take a deeper look into the most commonly used bone resorption tests, urine NTX, serum CTX test and Pyrilinks-D.
What Are “CTX” Test and Urine “NTX”?
CTX and NTX are acronyms for carboxy-terminal (CTX) and amino-terminal (NTX) telopeptides of type 1 collagen. Don’t let this mouthful scare you off from learning about these important tests. These short proteins (peptides) make up certain regions of bones’ collagen. Collagen, specifically type 1 collagen, is the substance that makes up the majority of the non-mineral tissue of bone.
Collagen forms the matrix upon which the mineral portion of bone accumulates. This collagen is strengthened by cross-linked proteins such as DPD, which is measured by the Pyrlinks-D test. CTX and NTX are found in the region of type 1 collagen where the crosslinks such as DPD attach. They are produced during bone resorption and can be measured in blood or urine. Currently CTX is most commonly measured in blood (serum) while NTX is most often measured in urine.
What Do High Urine NTX or Serum CTX Test Levels Indicate?
High serum CTX test levels have been found to correlate with low bone mineral density and to predict fracture risk. Serum CTX test levels are higher in people with osteoporosis compared to those without the disease. In a Swedish study, 1,040 women aged 75 years were randomly selected and followed for ten years. High serum CTX test levels were associated with increased fracture risk for up to a decade. The urine NTX test is also commonly used and recommended as a good bone resorption marker. A study of 2,305 women found that higher urine NTX levels in the urine before menopause and across menopause is associated with a higher risk of fracture.
What Are the Normal Ranges for the Urine NTX and Serum CTX Tests?
The serum CTX test and urine NTX test are offered through LabCorp, Quest Diagnostics, and other major national labs. As with the other bone resorption tests, the various measurement techniques for CTX and NTX lead to reference ranges that may vary from lab to lab.
For urine NTX measured through LabCorp, for example, a baseline urine NTX value greater than 38 indicates significantly increased risk for decreased bone mineral density after one year. As the baseline NTX goes up from 38, the probability of a decrease in bone mineral density increases significantly. For those being treated for osteoporosis, the probability that treatment is effective after three months is significantly increased if the NTX falls below 38 or drops by 30 percent from its baseline. The retail cost for the urine NTX (N-telopeptide) test is between about $60 and $80 making assessments easy and affordable to perform every 3 to 4 months.
For a serum CTX test through Quest Diagnostics, the normal range for women aged 18-49 ranges from 40-650 pg/ml. For people being treated for osteoporosis, a serum CTX decrease of at least 25% from baseline 3 to 6 months after the start of therapy indicates the therapy is working. The serum CTX cost is significantly higher at around $300.
Which Is Better?
Different research studies have used different markers, and experts vary regarding which markers they recommend. For these reasons, most traditional doctors have been reluctant to begin regularly using bone resorption tests in clinical practice. The serum CTX test, also called C-telopeptide, is the test that some experts are currently recommending becomes the primary bone resorption test used worldwide so that international reference ranges can be set, research can be more standardized, and the test can be more useful to doctors and patients.
The main reason the serum CTX test is being recommended over the other bone resorption markers is that not all markers respond by the same amount for a given degree of bone resorption; for instance serum CTX tends to change more than urine NTX. Nevertheless, both are useful and currently in use along with Pyrilinks-D.
I recommend the bone resorption assessment from Genova Labs, it assess Pyrilinks-D and another marker of collagen loss via urine. You can be purchase the kit without a prescription
from this site, collect the urine and mail it directly to the lab.
How to Best Take Advantage of Bone Resorption Testing Using Pyrilinks-D, Urine NTX, or the Serum CTX Test
Like most lab tests this day in age, bone resorption tests can be ordered without a doctor’s recommendation or guidance through various online companies that offer direct-to-consumer access to lab tests. DirectLabs or Life Extension are examples. However, given the complexity of bone resorption testing, it is recommended that you work with a healthcare practitioner experienced using and interpreting Pyrilinks-D, urine NTX, or the serum CTX test.
Osteoporosis is a silent disease that causes major loss of mobility and even death. Fracture risk depends on much more than just bone mineral density as measured by a DEXA scan. If you’re already at risk for fractures, or if you want to know whether you’re at risk, testing for bone resorption is emerging as an integral way to help assess and treat poor bone health. No matter what your current state of bone health, if you want to start tracking your bone loss rate, it is important to establish a baseline.
The best way to take advantage of a urine NTX or serum CTX test is to find out your initial level of bone resorption and then plan to re-test 3 to 6 months later using the same test at the same laboratory. This can help you determine whether you are currently losing too much bone. It may provide an early warning before a bone density scan reveals a problem. Or you can use the testing to determine how well your current bone building plan is working. If your bone resorption levels have not improved on the follow up test, those results will serve as a great motivator for you to be more vigilant with your weight bearing exercise and other natural treatments such as whole foods diet, vitamin D3, K2, magnesium and trace minerals.
In addition, it is important to remember that bone health does not exist in a vacuum. If you are losing bone it means there is a serious imbalance in your lifestyle, physical activity, diet and nutritional status that are leading to advanced aging and playing a role in other metabolic issues.