Trochanteric hip fracture: strong association with spinal trabecular bone mineral density measured with quantitative CT

PURPOSE: To determine the discriminatory capability for hip fracture of trabecular and integral bone mineral density (BMD) measured with quantitative computed tomography (CT) of the spine. MATERIALS AND METHODS: Fifty-six women who had sustained hip fractures and 59 control subjects underwent volumetric quantitative CT of L1 and L2 and dual x-ray absorptiometry of the hip. BMD was measured in vertebral regions of interest that encompassed trabecular, cortical, and integral bone. Logistic regression analysis was applied to each BMD measure to derive age-, weight-, and height-adjusted relative risk (RR) factors for overall hip fracture and for trochanteric fracture and cervical fracture separately. RESULTS: Spinal trabecular BMD was modestly related to overall hip fracture (RR, 1.4-1.7; P < .05) and strongly associated with trochanteric fracture (RR, 4.2-4.5; P < .005). Spinal integral BMD related similarly to overall hip fracture (RR, 1.7-1.8; P < .05) but more weakly to trochanteric fracture (RR, 2.3-3.2; P < .01). No spinal BMD measures were significantly related to cervical fracture. BMD at the hip was strongly related to overall hip fracture (RR, 3.3-4.3; P < .001), cervical fracture (RR, 2.7-5.3; P < .001), and trochanteric fracture (RR, 2.9-7.2; P < .001). CONCLUSION: Spinal trabecular BMD is strongly associated with both trochanteric and vertebral fractures.