Bone Density scanning (DEXA)
Bone density scanning (DEXA)
Dual energy x-ray absorptiometry (DEXA) scans are a way for your doctor to examine the density of your bones. IBD can cause a thinning of the bones (osteoporosis), which can weaken them. This can be caused by corticosteroids prescribed to treat IBD (e.g., prednisolone) or deficiencies caused by IBD-related malnutrition (e.g., vitamin D, calcium).
The scan is quick (i.e., around 10–30 minutes), painless, and involves a dose of X-ray radiation that is significantly less than a conventional X-ray scan. You will be asked to lie flat on the X-ray table and to hold still while the scan is conducted. The results of the test are presented as t-scores and z-scores:
- T-score: this is a score that is based on how your bone density compares with that of young adults with peak bone mass and of the same sex. Scores are interpreted as:
- -1 and above: normal bone density
- -1.1 to -2.4: low bone density (i.e., osteopenia)
- -2.5 and below: osteoporosis
- Z-score: indicates how your bone density compares with other people of the same sex and same age.
What can you do?
Active IBD is associated with nutritional deficiencies and often requires the use of corticosteroid medications. Both factors are associated with loss of bone density. As such, it is important to reduce disease activity by carefully following your prescribed treatment (i.e., not missing or delaying oral medication doses/biologic infusions) and having regular consultation with your specialist. Doing so may reduce the occurrence of avoidable or prolonged flare-ups. Other steps you can take include:
- Exercise: regular exercise and activities that are weight-bearing stimulate bone formation.
- Diet: check that you are getting enough calcium (700 mg/day). Consider modifying your diet if your calcium intake is insufficient. Calcium supplementation can help with this. If you are taking corticosteroids, then increase calcium intake to 1000-1500 mg/day
- Vitamin D: check that you are getting enough sun exposure to produce enough vitamin D (400IU/day). Those on corticosteroids may need to increase this to 800IU/day) Be careful not to overexpose yourself to sunlight, as this poses a risk of skin cancer—which is exacerbated by some IBD medications (i.e., azathioprine, mercaptopurine).Vitamin D supplements may also assist in avoiding deficiencies.