REDUCED FEMORAL-NECK BONE-DENSITY IN THE DAUGHTERS OF WOMEN WITH HIP-FRACTURES - THE ROLE OF LOW PEAK BONE-DENSITY IN THE PATHOGENESIS OF OSTEOPOROSIS

Low bone density in women with hip fractures (''senile'' osteoporosis) may be due to excessive bone loss or low peak bone density. If excess ive bone loss is responsible, then no reduction in bone density is exp ected in their daughters. If low peak bone density is responsible, the n bone density should also be reduced in their daughters because genet ic and family environmental factors influence the variability in bone density. Bone density was measured using dual-photon absorptiometry an d expressed as a standardized deviation or Z score relative to 697 con trols, adjusting for age, height, weight, and menopausal status. In 74 women with hip fractures, the Z score (mean +/- SEM) was -0.52 +/- 0. 14 (P < 0.001) at the femoral neck, -1.04 +/- 0.17 (P < 0.001) at the femoral shaft, and -0.43 +/- 0.10 (P < 0.001) at the lumbar spine. In their 41 daughters, the Z score was -0.40 +/- 0.17 (P < 0.05) at the f emoral neck, -0.41 +/- 0.19 (P < 0.001) at the femoral shaft, and 0.23 +/- 0.13 (NS) at the lumbar spine. We conclude that daughters of wome n with hip fractures are likely to be at increased risk for hip fractu res themselves because they have reduced femoral neck bone density. Fe moral neck fractures may not be entirely attributable to trauma; reduc ed bone density is likely to contribute and may be caused by the attai nment of a lower peak femoral neck bone density.