This includes the questions you might be asked as part of a detailed medical history, the types of tests you might have such as a DXA scan, ultrasound and blood tests. There is also an explanation of what a T-score from the DXA scan means.
To assess your bone density and risk of developing osteoporosis, your doctor may ask you questions linked to the causes of osteoporosis including the following:
Are you taking, or have you ever had to take, a course of:
How much exercise do you do in an average week?
Is there anyone in your immediate family (mother, father, sibling) who has had osteoporosis or fractures, and at what age were they diagnosed?
Have you suffered any fractures?
Have you ever had any thyroid problems?
What medications do you take?
Have you noticed a change in your posture or loss of height?
If you want to discuss a bone health assessment, it is worth booking a longer consultation time.
If your doctor finds you have significant risk factors for osteoporosis, then your doctor may arrange tests as outlined below.
A dual energy X-ray absorptiometry scan (DXA, previously DEXA) is a specialised X-ray used to measure bone mineral density.
A DXA scan may be used to:
X-ray beams with differing energy levels are aimed at the bones and the bone mineral density is determined from the level of absorption of each beam by bone. The scan produces high resolution pictures which provide the most accurate way to assess bone mineral density.
Having a DXA scan is a similar process to having a normal 'X-ray'. It does not hurt, is fast and has a lower radiation dose compared to other X-ray methods.
Usually only the bones in the lower back (lumbar spine) and hip region (proximal femur) are measured. In special cases the bones in your forearm (radius) may be measured.
The result of a DXA scan is presented as a T-score.
Your T-score reflects how much your bone density differs from that of a healthy young woman (when peak bone mass is at its best), measured in 'standard deviations' (the average distance from the average). A negative T-score means you have reduced bone density which will happen as you age. It is the extent of the negative score that is important to consider.
There are stages and progression of bone mineral density loss from normal to osteopenia to osteoporosis:
|-1.0 to 0||Normal bone density|
|-1.0 to -2.5||Bone density for osteopenia (thinning of the bones is present but there is no increased risk of fracture)|
|-2.5 or less||Bone density for osteoporosis (thinning of the bones is present and there is an increased risk of fracture)|
A low bone mineral density measure is associated with an increased risk of fractures. For every reduction in T-score, the risk of fracture doubles so someone with a T-score of -2 faces twice the risk of fracture compared with someone whose T-score is -1.
Other factors influence the likelihood of fracture, not just the bone mineral density reading on a DXA scan (see causes of osteoporosis).
Generally your doctor will arrange for you to have a repeat DXA scan every two years to monitor the status of your bones and/or assess the effects of therapy.
The cost of a DXA scan in Australia is generally less than $100. The cost may vary depending on where the test is performed. There are specific reasons that allow for a Medicare rebate in Australia (i.e. you may be eligible for Medicare funding for part or all of your scan costs). These include:
A plain X-ray of your upper and lower spinal column (thoraco-lumbar spine) may be ordered to determine whether there are already features of osteoporosis affecting the spinal column. Up to one third of women with osteoporosis may have had a fracture of the spine without knowing it.
It may also be necessary to have blood and urine tests to look for any contributing causes for osteoporosis. This may include assessment of vitamin D levels, calcium levels and thyroid function.
Currently ultrasound tests are available at many pharmacies. These involve an ultrasound measurement of the heel. Ultrasound tests are not as accurate in assessing for osteoporosis as a DXA scan and are not recommended by doctors.
** Currently under review **
This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at December 2013.