Can a DXA Scan Predict Fracture?

Can a DXA scan predict fracture? The need for researchers to modify what is currently done with DXA scans to increase accuracy.

 

English: bone density femur female

English: bone density femur female (Photo credit: Wikipedia)

As bone density declines, many other functions of the body suffer. Bone stores and manages the most vital mineral to, being calcium, and also generates our red and white blood cells. For the past 50 years DXA scan technology has been the gold standard for measuring bone density, and bone health in general, but that has been called to question as certain individuals have DXA numbers that would indicate healthy bone, but fractures are still occurring.

Variables Not Accounted For

In a previous article by the Osteoporosis Institute, DXA Scanning technology was discussed in reference to the inclusion of variables for race and ethnicity. The simple explanation of this is, the gauge/diameter of bone is different based on race, however not part of the bone density analysis in a DXA scan. From an engineering perspective a larger diameter bone/supporting structure with less density may have equal or greater strength than a denser thinner bone/supporting structure. With bisphosphonate drugs, (Osteoporosis treatment drugs) The potential density that is created is only in the outer cortex (outer shell) of the bone. People who take bisphosphonates have been known to have irregular fractures, making some researchers question if fracture rates are really reduced, or do DXA scans just look better? Ultimately the function of bisphosphonates is to keep older bone material from metabolizing into the body in the outer shell of the bone, but does not allow for increases in density from inside the bone, so the problem may be getting worse, physicians just can’t see it. A recent study in 2010 acknowledged this (Black, Kelly, Genant). So the new question for researchers to answer: can a DXA scan predict fracture?

Until the race/ethnicity variables are accounted for, as well as the uneven development of bone mass with bisphosphonate use, the current DXA scanning Is the best and proper indication of fracture risk or diagnosis of osteoporosis. Researchers need to move towards using DXA scan technology, and adding variables to increase accuracy of fracture prediction. The future may show us adjusted DXA scan numbers that account for the uneven bone density seen bisphosphonate users, as well as adjustments for bone diameters. Until this happens, people should be responsible with their bone health. Eating a proper diet, putting large forces on bone mass, proper sleep, and the least amount of alcohol and tobacco as possible: all key elements that should be attended to.

Reference:

Dennis M. Black, Ph.D., Michael P. Kelly, M.D., Harry K. Genant, M.D. (2010). Bisphosphonates and Fractures of the Subtrochanteric or Diaphyseal Femur. New England Journal of Medicine; 362:1761-1771

 

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