Measurements of bone mineral density by DXA total body absorptiometry in different skeletal sites in postmenopausal osteoporosis.

In order to evaluate the bone mineral density (BMD) of the entire skeleton and its major anatomical areas, total body DXA absorptiometry was performed in 330 postmenopausal women whose ages ranged from 42-85 years. Sixty-three of them were normal women and constituted the control group (Group 1). Two hundred sixty-seven were patients affected with postmenopausal osteoporosis: 107 osteoporotic patients had vertebral biconcavity deformities of grade 1 (Group 2), and the other 160 had vertebral wedge, biconcavity, and compression deformities of grade 2 (Group 3). Total body absorptiometry was assessed by a DXA system (Lunar DPX). Significant reduction in total body BMD values was observed in patients in Groups 2 and 3 (p less than 0.01): the bone loss was more intense in osteoporotic women of Group 3. The low values of the BMD in osteoporotic patients are, moreover, localized in the areas of spine, arms, and legs; the osteopenia was particularly enhanced in patients with grade 2 vertebral deformities. Multiple linear regression indicated that values of total BMD were significantly related to age and BMI. Receiver operating characteristic (ROC) analysis showed that total BMD provided high sensitivity: At 90% of specificity it was 78% for Group 2 and 89% for Group 3. DXA total body absorptiometry has demonstrated that, in postmenopausal osteoporotic women, the reduction in bone mass is not localized only in the spine, but also involves the appendicular skeleton.