Densitometry of the Peripheral Skeleton to Detect Osteopenia-Reply

Dr Bilbrey alleges that there is evidence that the distal radius provides an early indication of osteopenia useful for diagnosis of osteoporosis. He presumes that this is due to a higher trabecular content at a "5-mm" radius site used in the Beta Diagnostics clinics. The 5-mm site is located at from 5% to 10% of the

forearm length, where there is only 35% trabecular bone, not more than 50% as claimed.¹ The trabecular content is immaterial however, since even purely trabecular bone of the distal radius (1) is poorly correlated with that of the axial skeleton,^2,3 (2) has an onset of bone loss a decade after that in the spine and the femur, (3) has a low rate of aging bone loss,^3,4 and (4) does not respond to various therapies used for osteoporosis.^5,6

Peripheral measurements could be clinically useful if they predicted bone density