Lumbar Disc Degeneration and Vertebral Fracture at the Thoracolumbar Junction Are Risk Factors for Chronic Low Back Pain With Disability: Seven Years’ Follow-Up of the Wakayama Spine Study

Introduction Low back pain (LBP) is the leading cause of disability worldwide, with its burden increasing in aging societies such as Japan. Although degenerative spinal changes like lumbar disc degeneration (DD), vertebral fractures, and lumbar spinal stenosis (LSS) are frequently identified on MRI, their combined longitudinal impact on disabling chronic low back pain (DCLBP) remains unclear. The aim of this study was to identify baseline MRI-detected lumbar spinal changes that independently predict disabling chronic low back pain in a general Japanese population. Methods This population-based longitudinal study included 663 community-dwelling Japanese adults from the Wakayama Spine Study, a sub-cohort of the nationwide Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study. Baseline whole-spine MRI and clinical assessments were conducted between 2008 and 2009, with a seven-year follow-up from 2015 to 2016. MRI findings included Pfirrmann-graded lumbar DD, Genant-graded vertebral fractures at T11-L1, and Suri-graded LSS. The primary outcome was DCLBP, defined as LBP lasting more than three months and an Oswestry Disability Index (ODI) score ≥21%. Multivariate logistic regression was used to identify independent predictors of DCLBP. Results Of 653 participants who completed follow-up with valid ODI responses, 91 (13.9%) had DCLBP. Older age (OR: 1.07 per year, p < 0.0001), female sex (OR: 3.69, p < 0.0001), higher BMI (OR: 1.11 per kg/m², p < 0.0001), greater vertebral fracture burden (OR: 1.32 per grade point, p = 0.0024), and more severe lumbar DD (OR: 1.14 per grade point, p = 0.0305) were independently associated with DCLBP. Conclusion Lumbar DD, vertebral fractures at T11-L1, and LSS are independent risk factors for disabling chronic LBP in the general population. These findings underscore the importance of comprehensive MRI-based spinal assessment in identifying high-risk individuals for early intervention in aging societies.