Bone diminution of osteoporotic females at different skeletal sites

Summary

The bone mineral density (BMD) of the radius and spine was determined by photo absorptiometry in a large number of controls (radius: n=111; spine: n=85; age range: 50–79 years) and osteoporotic women (radius: n=98; spine n=140; age range: 50–79 years) with at least one “atraumatic” vertebral compression fracture. Compared to age-matched controls, the BMD of the osteoporotic women showed the following diminutions: sixth decade: radius:−9.1%; spine:−25%; femur: −33%; seventh decade: radius:−16%; spine: −19%; femur:−23%; eighth decade: radius: −21%; spine:−20%; femur:−24%. The BMD was significantly diminished at all sites in all decades but in contrast to the radius, the difference from controls was bigger in the spine and femur in the sixth decade than in the seventh and eighth decade. In the osteoporotic women there was a significant correlation between radius BMD and age (4=−0.56;P<0.01) but not between spine or femoral BMD and age. The femoral neck BMD was also determined in a subset group of female controls (n=68), patients with crush fractures of the spine without a fracture of the hip (n=46), and in patients with fractures of the proximal femur (n=21). There was no difference among these groups in mean age (64±7, range: 50–79 years). Patients with hip fracture and spine fracture showed bone diminution in all three regions that was significantly below controls (P<0.001). The Ward's triangle region was specially diminished (−35%) and as a consequence the neck BMD was low (−26%). Trochanteric density was lower (−25%) in spine fracture cases than in hip fracture (−16%). The difference between the two groups of osteoporotic women was significant (P<0.05). In the hip fractures cases, spine BMD was reduced only moderately compared to controls (−14%,P<0.01) and slightly elevated compared to spinal osteoporosis where the diminution was greater (−24%,P<0.001). Again, the difference between the two osteoporotic groups was significant (P<0.05). It appeared that spinal osteoporosis involved loss of bone from both the spine and hip, whereas femoral osteoporosis showed a preferential loss of bone from the femur neck region, and a lesser loss from the trochanter or the spine.