In this next part of the ongoing discussion regarding osteoporosis I wanted to talk about diagnosis and the confusion that surrounds it.
Standard medical diagnosis of osteoporosis or osteopenia is done by a low-dose radiation x-ray of the hip and spine call a DEXA scan. Please note that plain film x-rays are not a good way to screen or establish a firm diagnosis of osteoporosis although it will often indicate some issues with bone mass that need to be followed up with the appropriate diagnostics.
The results of a DEXA scan are reported as the T score and Z score in both the hip joint and in the lower lumbar spine. A mild decrease in bone mass compared to what is considered standard will result in the diagnosis of osteopenia while a more significant decrease of bone mass will result in a diagnosis of osteoporosis. The scoring associated with a diagnosis of osteoporosis is also usually associated statistically with a certain fracture risk over the following 10 years.
As a patient you need to understand that there are some caveats and limitations associated with how you interpret your own DEXA scan results.
- The DEXA scan has a certain margin of error. If you are close to a cutoff of osteoporosis or osteopenia this could be significant.
- The margin of error can be amplified when comparing repeat scans by having the procedure performed on a different machine or by a different technician. In some instances this could be significant and make the interpretation of comparative scans difficult. If you're tracking osteoporosis response to treatment whether medical or integrative, you really should always be getting your scan on the same machine at the same facility.
- There are some issues with the spine and hips that can give you a false positive or negative readings, most commonly positive readings. This is especially true for people who have some degree of degenerative disc disease with bone spurs, more advanced degeneration, or congenital anomalies of the lumbosacral spine such as a spondylolisthesis. If this is a significant concern for false-positive, a quantitative CAT scan would be the definite testing but it involves more radiation.
- There is some question about the validity of a single scoring system applied to different ethnic groups, as well as in women with very small frames, whose bone mass may be naturally and sufficiently lower than their counterparts. It is also true that women with very high BMI may look like they have adequate bone mass but in reality the bone density may not be sufficient to protect them from fracture because of the increased demands associated with the extra weight.
- The DEXA scan measures the raw amount of bone mineral, however it does not measure the quality of the bone architecture which is very important for fracture prevention. This is not to invalidate the benefit of a DEXA scan but to realize that there is still some question about whether or not current osteoporosis drugs improve bone density without concurrently improving architecture, meaning that we may get a false sense of security against fracture risk long-term.
- Finally and possibly most importantly the DEXA scan only measures one snapshot of your bone mass in time. Unless you have comparative scans you have no idea if you are currently losing bone, are in the process of starting to lose bone, or have previously lost bone mass but have plateaued. This is why I strongly suggest that every woman has a baseline DEXA scan prior to menopause or at the onset of menopause for future comparison and good treatment decision.
- Based on the above, it can be extremely useful to couple the DEXA scan with other testing that may give you more real-time information about bone metabolism and turnover. One such test which is mostly used in integrative health practices rather than allopathic traditional medical care would be a urinary D-Pyrilink excretion test. We will talk more about it in our next segment.
