Bone mineral density at distal forearm can identify patients with osteoporosis at spine or femoral neck

Forearm bone mineral density (BMD) was investigated in women to identifyosteoporosis at the spine or femoral neck (or both) defined by WHO criteria(T score -2.5) without requirement for fracture. BMD was measured bysingle-energy X-ray absorptiometry (DTX100) and by dual- energy X-rayabsorptiometry (DXA) in the lumbar spine and femoral neck in 422 subjectsaged 22-90 yr. A total of 62% of subjects with osteoporosis (at the spine,femoral neck, or both sites) were detected with 89% specificity [receiveroperating characteristics (ROC) analysis] and included all subjects belowforearm BMD 0.34 g/cm2. Conversely, above 0.419 g/cm2, only 10% of patientshad osteoporosis. A total of 71.8% of women could be assigned either tothose who warranted therapy (<0.34 g/cm2) or to those who did not(>0.419 g/cm2) with 90% certainty. Subjects with forearm BMD between0.34 and 0.419 g/cm2, who constituted 28.2% of the total group and included31% of subjects with osteoporosis, had a 40% chance of having osteoporosis.This leads to a high identification rate on subsequent DXA scanning, whichis thus used efficiently.