Severity of Vertebral Fractures Is Associated With Alterations of Cortical Architecture in Postmenopausal Women

Patients with vertebral fractures (VFx) have trabecular architectural disruption on iliac biopsies. Because cortical bone is ail important determinant of bone strength, we assessed cortical and trabecular microarchitecture at peripheral sites in patients with VFx of varying number (N) and severity (S). Bone architecture and volumetric density (vBMD) were assessed at the distal radius and tibia with HR-pQCT (XTreme CT; Scanco Medical, Bassersdorf, Switzerland) in 100 women with VFx (age, 74 +/- 9 yr) of different S (GI, n=23 GII, n=35; GIII, n=42) and in 362 women (age 69 +/- 7 yr) without peripheral or VFx (G0) from the OFELY study. Spine areal BMD (aBMD) was assessed by DXA. Among all women, at the radius and after adjustment for age and aBMD, there were significant trends in lower vBMD, cortical thickness (Cort.Th), trabecular number (Tb.N) and thickness (Tb.Th), higher trabecular separation (Tb.Sp), and distribution of separation (Tb.Sp.SD) with greater VFx S and N. Among women with VFx, lower Cort. Th and cortical vBMD (D.Cort) were associated with severe (GIII) and multiple (n>2) VFx (p<0.05). The age-adjusted OR for each SD decrease of Cort.Th was 2.04 (95% CI, 1.02-4.00) after adjustment for aBMD. At the tibia, there were trends for lower vBMD, Tb.N,Tb.Th, and higher Tb.Sp and Tb.Sp.SD with greater VFx S and N (p<0.001). Among women with VFx, lower Cort.Th and D.Cort were associated with severe and multiple (n>3) VFx (p<0.01). In postmenopausal women, VFx are associated with low vBMD and architectural decay of trabecular and cortical bone at the radius and tibia, independently of spine aBMD. Severe and multiple VFx are associated with even more alterations of cortical bone.