Why does trabecular bone mineral density assessment using DXA sometimes underestimate fracture risk in older adults with sarcopenia?

💡 Explanation

DXA measures areal bone mineral density, but fat infiltration of bone marrow in sarcopenic individuals can falsely elevate the measured density, masking true bone fragility, because fat has a different X-ray attenuation coefficient than bone. Therefore, fracture risk may be underestimated, rather than other compensatory bone changes.

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