Bone structure in patients with low bone mineral density with or without vertebral fractures

Vertebral fractures (VFX) are caused by low bone mass and microstructural d eterioration of bone tissue, The latter is not well defined, We investigate d bone structure in transiliac biopsy specimens from 88 volunteers. Biopsy specimens were obtained at baseline in the Multiple Outcomes of Raloxifene Evaluation trial, a prospective study in osteoporotic (BMD less than or equ al to -2.5 T score) postmenopausal women without or with VFX on standardize d lateral spinal radiographs. Bone biopsy specimens were embedded in methyl methacrylate (MMA), Histomorphometry was done in 8 mu m (U.S.A.) or 5 mu m (Europe) Goldner stained sections, Vertebral fracture status (yes/no) was t he outcome variable in logistic regression models adjusted for age and biop sy specimen origin (U.S.A. vs. Europe), Patients with and without VFX (26/6 2) were similar regarding age (69.2 +/- 5.2 years vs. 67.3 +/- 6.7 years), bone volume (BV/TV; 17.7 +/- 4.7% vs. 19.0 +/- 5.8%), and bone surface (BS/ TV; 2.7 +/- 0.6 mm(2)/mm(3) vs. 2.8 +/- 0.6 mm(2)/mm(3)). A lower cortical thickness (C.Th; 652 +/- 267 mu m vs. 822 +/- 325 mu m), total strut length (TSL; 826 +/- 226 mu m/mm(2) vs. 922 +/- 256 mu m/mm(2)), node-to-loop (Nd -Lp) strut length (10.1 +/- 10.3% vs. 15.0 +/- 13.6%), together with a high er node-to-terminus (Nd-Tm) strut length (45.6 +/- 9.7% vs. 39.1 +/- 9.3%) were each associated with prevalent VFX (0.01 < p < 0.10), Differences in B V/TV did not explain these associations. In conclusion, cortical thinning a nd disruption of trabecular lattice are possible pathogenic mechanisms in p atients with VFX.