Vertebral strength, load-to-strength ratio, volumetric BMD, and the ratio of vertebral strength to volumetric BMD, all plotted against total lumbar spine areal BMD (by DXA). Fracture cases are shown in solid red (n=63), no-fracture cases are shown in open black (n=243). Total lumbar spine areal BMD values of 0.82 and 0.98 g/cm2 correspond to T-scores of −2.5 and −1.0, respectively, using young male reference values.