Osteoporosis is a condition in which the bones in the body become weak and brittle, and along with low bone mass is currently estimated to be a major public health threat for nearly 44 million U.S. women and men aged 50 and older.1 In addition, it is well understood that many people have no symptoms until they have a bone fracture, leaving many people unaware of their current or developing osteoporosis. Unfortunately for many, the laboratory tests commonly given to diagnose, monitor and treat this condition are insufficient in determining bone health and developing an effective treatment plan for increasing bone strength and resiliency. The following information is absolutely critical for anyone with or at risk of developing osteoporosis.
In order to understand the importance of the following information, we need to take a quick look at what osteoporosis is. Fundamentally, osteoporosis is a condition in which the body’s ability to remove bone (osteoclasts) exceeds the body’s ability to create bone (osteoblasts). The coordinated function of the breakdown, or resorption, of bone and the renewal of bone is an extremely important process in the body called remodeling, and a long-term imbalance in this process becomes problematic.
Why On Earth Does My Body Break Down Bone?
If you’re wondering why the body even breaks down bone in the first place, you are asking a common question. Though many people view bones simply as hard, stiff structures, they are much more complex. Our bones perform many functions in the body, such as support, movement, mineral storage, red blood cell production and more. In fact, bones are living tissues that grow, multiply and die just as all of the other cells in the body. Simply put, bone cells begin making bone by secreting a cartilaginous matrix made up primarily of collagen, and then signal minerals to form around this matrix. The cartilaginous matrix is soft, and the mineralization around the matrix is hard. Because our bone cells are constantly undergoing this process, old bone must be removed before new, healthy bone is laid down so that we are not left with weak, ineffective bone.
Bone Quality vs. Bone Quantity
Now, the distinction between bone matrix and bone mineralization is important. To distinguish between the two, we can refer the matrix material as constituting bone quality, and the mineral material (calcium, phosphorous, etc.) as constituting bone quantity. The reason this is so important is that both bone quantity and bone quality must be taken into account when examining bone health and effectively treating bone-related disorders. Unfortunately, the standard procedure for the diagnosis, monitoring and treatment of bone-related disorders focuses solely on bone quantity without regard to bone quality. With this kind of procedure, even the most effective treatments for bone loss only lead to increased mineralization of bone, which will increase the score on a bone mineral density test (BMD), but alone will not reduce the risk for fracture, and may even increase the risk of fracture. This is commonly seen in older individuals who continue to fracture despite taking bisphosphonates to harden their bones.
Evaluating Your Fracture Risk
In reality, no one can ever actually tell you your actual risk of fracturing a bone. It’s really a guessing game. However, with the right kind of information, you can make this speculation based on facts. When assessing your risk of fracture, you must consider three things: BMD, osteoporosis risk factors, and your chances of falling. You can then use the combination of these factors to estimate your risk. Most fractures result from a fall. Muscular weakness and poor balance resulting from a less than optimal nervous system can make a crack in the floor or a false step hazardous. This is why the main benefit of exercise as you age is not to add bone density (quantity), but to maintain bone strength, balance and coordination, all of which decrease your chances of falling.
Measuring Bone Quantity
One of the first tests your doctor will order if you are at risk of osteoporosis is a bone mineral density (BMD) test. Skeletal health is quantified by a procedure called a dual-energy X-ray absorptiometry (DXA) examination, and effectively measures BMD. Using the DXA report, two separate scores are used to compare your bone density to others. T scores are a value of measurement that compares your BMD to the BMD of a healthy young woman, while Z scores compare your BMD to the average BMD of people your same age and sex. Because this article focuses on the largely ignored assessment of bone quality, we will stop talking about the assessment of bone quantity here.
Measuring Bone Quality
Both bone quality and bone quantity can be compromised when there is increased bone resorption (breakdown) by osteoclasts, and or not enough bone formation by osteoclasts. The quantity of bone can be measured relatively easily and accurately through DXA testing, but the only way to directly assess bone quality is to bore a piece of bone from the pelvis and examine it under a microscope. This is both extremely painful and costly. Fortunately, there are laboratory tests called bone turnover markers which measure the degree at which bone remodeling is occurring, the extent to which we are making (osteoblastic activity) and breaking (osteoclastic activity) bone. The two kinds of markers fall under this kind of testing are called resorption markers and bone formation markers.
Bone Resorption Markers
By using bone resorption markers, you are able to effectively measure the level of osteoclastic activity of your bones. Usually examined in the urine, these tests look at small pieces of collagen released into circulation and then excreted in the urine. The amount of collagen detected is directly correlated to how much bone the osteoclasts are destroying. Research has both validated and encouraged the use of these markers in helping to determine bone health. For instance, it has been shown that when resorption markers are high, there is a greater risk of fracture regardless of your BMD2.
There are three resorption markers that your doctor can order, though he/she only needs to order one of them. These markers all look at the resorption process, but use different technology to do so. The three kinds of resorption markers are:
- Deoxypyridinoline (DPD)
- C-telopeptide (CTX)
- N-telopeptide (NTX)
Note* If you are currently using a bisphosphonate medication but have not had baseline tests for resorption markers checked prior to your use of the medication, these results will not be useful to you.
Bone Formation Markers
The level at which osteoblasts are forming bone can be measured through three different tests-serum osteocalcin, serum bone-specific alkaline phosphatase, and serum P1NP. Unlike the resorption markers, each of these tests is used in different situations specific to the patient.
Osteocalcin is a protein made by osteoblasts that is important for activating the mineralization of bone. For this reason it can be effectively used as a biomarker for osteoblastic activity and bone formation. Note that this is a biomarker, as opposed to the kind of marker you get from simply measuring the density of bone. By looking at the living, functioning capacity of bones, you can use this test as a measure of bone quality.
Bone-Specific Alkaline Phosphatase
This test is essential for anyone taking a bisphosphonate medication. Bone-specific alkaline phosphatase (bsALP) detects earlier signs of osteoblastic activity and is useful for assessing the oversuppression of osteoclastic activity caused by bisphosphonate treatment. This is another living marker, and is therefore a measure of bone quality.
If you are currently taking or are considering treatment through teriparatide (Forteo), you should consult your doctor about the P1NP test. The P1NP test measures the amount of collagen in your blood serum and is a direct reflection of your osteoblasatic activity3.
Putting It All Together
Overall, it is important to understand that the issue of bone loss requires a whole body approach for treatment. Inflammation, gut dysbiosis, adrenal health, blood sugar issues and a host of other things can all play a hand in the progression of osteoporosis. Therefore, diet, neurological care, and exercise alongside proper supplementation all become necessary components in effectively treating osteoporosis. Understanding the importance of assessing bone quality and bone quantity is critical for anyone at risk for or currently suffering from osteoporosis, and this, like every aspect of health, requires your proactive research and work to finding treatment and health-based approaches that will best suit your needs.