Ultrasound and X-ray-based bone densitometry in patients with anorexia nervosa

In 20 patients (mean age 23+/-5 years) with anorexia nervosa (AN), bone mass was evaluated by broadband ultrasound attenuation (BUA) of the calcaneus, peripheral quantitative computed tomography (pQCT) of the distal radius, and dual X-ray absorptiometry (DXA) of the lumbar spine and the hip. Compared with 20 age- and sex- matched healthy controls, patients with AN showed marked osteopenia at all measuring sites. Values of BUA (33.0+/-9 dB/MHz vs. 51.0+/-5.7 dB/MHz; P<0.0001) and of BMD of all regions of the hip (e.g., femoral neck: 0.71+/-0.13 g/cm(2) versus 0.89+/-0.07 g/cm(2); P<0.001), lumbar spine (0.82+/-0.15 g/cm(2) versus 1.24+/-0.06 g/cm(2); P<0.003) and total BMD of the peripheral radius (303.2+/-75 g/cm(3) versus 369.4+/-53.2 g/cm(3), P<0.001) were significantly reduced. Calculating a Z-score we found the most prominent differences between AN and controls by BUA of the calcaneus (-3.2+/-1.6), followed by DXA at the lumbar spine (-2.9+/-2.2) and the hip (femoral neck -2.1+/-1.7) and by pQCT at the distal radius (total BMD -1.2+/-2.0). There were highly significant correlations between BUA of the calcaneus and BMD of the femoral neck (r = 0.78, P<0.0001) and lumbar spine (r = 0.75, P<0.0001) as well as between BMD values of the femoral neck and lumbar spine (r = 0.95; P<0.0001). In addition, there were significant correlations (P<0.001) between body mass index (BMI) and the three different measuring sites and between the duration of the disease and BUA (r = 0.5, P<0.05). Our data suggest that BUA of the calcaneus is a valuable tool in the management of osteoporosis. Being a fast, radiation-free investigation method of good acceptance, it may be well suited for an assessment of the skeletal status in patients with AN.