Lumbar disc degeneration was not related to spine and hip bone mineral densities in Chinese: facet joint osteoarthritis may confound the association

• Published in: Archives of osteoporosis Vol. 12; no. 1; p. 20
• Main Authors: Pan, Jianjiang, Lu, Xuan, Yang, Ge, Han, Yongmei, Tong, Xiang, Wang, Yue
• Format: Journal Article
• Language: English
• Published: London Springer London 01.12.2017
• Subjects: Absorptiometry, Photon - methods; Adult; Aged; Bone Density; China - epidemiology; Endocrinology; Female; Humans; Intervertebral Disc - diagnostic imaging; Intervertebral Disc - pathology; Intervertebral Disc Degeneration - diagnosis; Intervertebral Disc Degeneration - epidemiology; Intervertebral Disc Degeneration - pathology; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - pathology; Magnetic Resonance Imaging - methods; Male; Medicine; Medicine & Public Health; Middle Aged; Original Article; Orthopedics; Osteoarthritis - diagnosis; Osteoarthritis - epidemiology; Osteoarthritis - pathology; Pelvic Bones - diagnostic imaging; Pelvic Bones - pathology; Radiography - methods; Regression Analysis; Zygapophyseal Joint - diagnostic imaging; Zygapophyseal Joint - pathology; Facet joint osteoarthritis; Bone mineral density; Lumbar spine; Disc degeneration
• DOI: 10.1007/s11657-017-0315-6
• ISSN: 1862-3522; 1862-3514

Summary A sample of 512 Chinese was studied and we observed that greater disc degeneration on MRI was associated with greater spine DXA BMD. Yet, this association may be confounded by facet joint osteoarthritis. BMD may not be a risk factor for lumbar disc degeneration in Chinese. Purpose Evidence suggested that lumbar vertebral bone and intervertebral disc interact with each other in multiple ways. The current paper aims to determine the association between bone mineral density (BMD) and lumbar disc degeneration using a sample of Chinese. Methods We studied 165 patients with back disorders and 347 general subjects from China. All subjects had lumbar spine magnetic resonance (MR) imaging and dual- energy X-ray absorptiometry (DXA) spine BMD studies, and a subset of general subjects had additional hip BMD measurements. On T2-weighted MR images, Pfirrmann score was used to evaluate the degree of lumbar disc degeneration and facet joint osteoarthritis was assessed as none, slight-moderate, and severe. Regression analyses were used to examine the associations between lumbar and hip BMD and disc degeneration, adjusting for age, gender, body mass index (BMI), lumbar region, and facet joint osteoarthritis. Results Greater facet joint osteoarthritis was associated with greater spine BMD ( P  < 0.01) in both patients and general subjects. For general subjects, greater spine BMD was associated with severe disc degeneration, controlling for age, gender, BMI, and lumbar region. When facet joint osteoarthritis entered the regression model, however, greater spine BMD was associated with greater facet joint osteoarthritis ( P  < 0.01) but not greater disc degeneration ( P > 0.05). No statistical association was observed between spine BMD and lumbar disc degeneration in patients with back disorders ( P  > 0.05), and between hip BMD and disc degeneration in general subjects ( P  > 0.05). Conclusion BMD may not be a risk factor for lumbar disc degeneration in Chinese. Facet joint osteoarthritis inflates DXA spine BMD measurements and therefore, may confound the association between spine BMD and disc degeneration.