Sami Salo1, Ville Leinonen2, Toni Rikkonen3, Pauli Vainio4, Jarkko Marttila4, Risto Honkanen5, Marjo Tuppurainen6, Heikki Kröger7, Joonas Sirola7. 1. Bone and Cartilage Research Unit, Surgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland. Electronic address: saksalo@student.uef.fi. 2. Department of Neurosurgery, Kuopio University Hospital, Kuopio, Finland. 3. Bone and Cartilage Research Unit, Surgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland. 4. Department of Radiology, Kuopio University Hospital, Kuopio, Finland. 5. Bone and Cartilage Research Unit, Surgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Lapland Hospital District, Rovaniemi, Finland. 6. Bone and Cartilage Research Unit, Surgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Obstetrics and Gynecology, Kuopio University Hospital, Finland. 7. Bone and Cartilage Research Unit, Surgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Orthopedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
Abstract
OBJECTIVES: Higher vertebral bone mineral density (BMD) has been found to be related with lumbar disc degeneration (LDD), while relationship between femoral neck BMD and LDD remains controversial. The aim of our research was to study the relationship between LDD and BMD of the lumbar spine and femoral neck. STUDY DESIGN: The study population consisted of 168 postmenopausal women (aged 63.3-75.0 years, mean 68.6 years) from the prospective OSTPRE and OSTPRE-FPS study cohorts. The severity of LDD was graded from T2-weighted MRI images using the five-grade Pfirrmann classification. Four vertebral levels (L1-L4) were studied (total 672 discs). The association between lumbar BMD and Z-score and the severity of LDD was studied separately for each vertebral level with AN(C)OVA analysis, using potential confounders as covariates. RESULTS: Higher lumbar BMD and Z-score were associated with more severe LDD at all studied levels (L1-L4): between L4-L5 disc and L4 BMD (p=0.044) and L4 Z-score (p=0.052), between L2-L3 disc and L3 BMD (p=0.001) and at all other levels (p<0.001). The mean degeneration grade of the studied discs was associated with the mean L1-L4 BMD and Z-score (p<0.001). Statistical significance of any result did not alter after controlling for confounding factors. There was no significant association between femoral neck BMD and LDD. CONCLUSIONS: Higher lumbar BMD/Z-score were associated with more severe LDD. There was no significant association between femoral neck BMD and disc degeneration. Femoral neck BMD may be a more reliable measurement for diagnosing osteoporosis in postmenopausal women with degenerative changes in the lumbar spine.
OBJECTIVES: Higher vertebral bone mineral density (BMD) has been found to be related with lumbar disc degeneration (LDD), while relationship between femoral neck BMD and LDD remains controversial. The aim of our research was to study the relationship between LDD and BMD of the lumbar spine and femoral neck. STUDY DESIGN: The study population consisted of 168 postmenopausal women (aged 63.3-75.0 years, mean 68.6 years) from the prospective OSTPRE and OSTPRE-FPS study cohorts. The severity of LDD was graded from T2-weighted MRI images using the five-grade Pfirrmann classification. Four vertebral levels (L1-L4) were studied (total 672 discs). The association between lumbar BMD and Z-score and the severity of LDD was studied separately for each vertebral level with AN(C)OVA analysis, using potential confounders as covariates. RESULTS: Higher lumbar BMD and Z-score were associated with more severe LDD at all studied levels (L1-L4): between L4-L5 disc and L4 BMD (p=0.044) and L4 Z-score (p=0.052), between L2-L3 disc and L3 BMD (p=0.001) and at all other levels (p<0.001). The mean degeneration grade of the studied discs was associated with the mean L1-L4 BMD and Z-score (p<0.001). Statistical significance of any result did not alter after controlling for confounding factors. There was no significant association between femoral neck BMD and LDD. CONCLUSIONS: Higher lumbar BMD/Z-score were associated with more severe LDD. There was no significant association between femoral neck BMD and disc degeneration. Femoral neck BMD may be a more reliable measurement for diagnosing osteoporosis in postmenopausal women with degenerative changes in the lumbar spine.