Osteoprotegerin deficiency attenuates the dual effect of strontium on bone

Abstract

quality profile of subjects with and without non-traumatic hip fracture non-invasively. Methods: Hip fractured postmenopausal women (n=25) and ageand gender-matched normal controls (n=38) were recruited. The bone quality at the non-dominant distal radius and non-fracture (fracture group)/non-dominant (control group) of distal tibia were measured by HR-pQCT (XtremeCT, Scanco Medical AG). HR-pQCT, with 82 mm resolution, provided volumetric trabecular BMD (Dtrab), cortical BMD (Dcort), bone to tissue volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp). Independent t-test was used for between-group analysis. Results: Similar age and body weight were found in both groups. At the distal tibia, all vBMDs, including total BMD, Dtrab and Dcort, were significantly lower in the hip fracture (HF) group (−26.2 to −7.5%; all, p<0.02). For bone microarchitecture parameters, lower BV/TV (−21.2%; p=0.02) and higher Tb.Sp (+56.4%; p=0.02), were found in the HF group. Moreover, the HF group had significantly smaller cortical bone area (−30.5%; p<0.01) and cortical thickness (−32.5%; p<0.01), while bone area in the trabecular region was significantly larger (+14.5%; p=0.02) as compared with the control group. Similar findings were also found at the distal radius. Discussion and conclusion: Lower vBMDs and poor bone microarchitecture at both distal tibia and radius were found in the hip fracture group as compared with those of the control. In addition to BMD, our results suggested that poor bone microarchitecture was associated with hip fracture. Of all the parameters, trabecular separation was more sensitive in detecting patient with hip fracture. Smaller cortical bone area and cortical thickness together with larger trabecular bone area are typical structural deterioration in osteoporotic patients with significant trabecularization or osteoporosis of cortical bone. Our HR-pQCT findings may imply cortical thinning was also observed in hip fracture group. Bone structural information and BMD, measured by non-invasive HR-pQCT with low radiation, help us understand the characteristics of patients with hip fracture.