Potential association of metabolic and musculoskeletal disorders with lumbar intervertebral disc degeneration: Cross-sectional study using medical checkup data

Background: The pathogenesis of intervertebral disc (IVD) degeneration is complex and involves the interaction of multiple factors. However, few systemic studies have explored the associations of metabolic disorders and age-related musculoskeletal disorders with the development of IVD degeneration. Methods: We analyzed clinical data obtained from healthy individuals who had undergone a musculoskeletal checkup. In total, 276 subjects comprising 142 males and 134 females were enrolled. The subjects were divided into two groups based on the degree of IVD degeneration according to Pfirrmann grading: those with grades 1–3, the group with non-degenerative discs; and grades 4 and 5, the group with degenerative discs. The subjects underwent examinations including abdominal circumference, blood pressure, bilateral hand grip strength, abdominal computed tomography, magnetic resonance imaging of the lumbar spine, and dual X-ray absorptiometry. To examine the independent association with IVD degeneration at L3/4, L4/5, and L5/S levels, we constructed a Poisson regression model and estimated relative risks (RRs) and 95% confidence intervals (CIs) of IVD degeneration. Results: Multivariable analysis showed that advanced age was markedly associated with IVD degeneration at all levels and that men had an inverse association with the IVD degeneration, particularly at the L4/5 level (RR = 0.7, 95% CI = 0.6–0.9). In addition, metabolic syndrome was significantly associated with IVD degeneration at the L5/S level (RR = 1.4, 95% CI = 1.1–1.8). Meanwhile, sarcopenia showed no significant association with IVD degeneration at any level. Osteoporosis was inversely associated with IVD degeneration, particularly at the L4/5 level (RR = 0.7, 95% CI = 0.6–0.9). Conclusions: Our data suggest that advanced age, female sex, and metabolic syndrome are associated with IVD degeneration. In addition, osteoporosis showed an inverse association with IVD degeneration. Our data should promote understanding of the etiology of lumbar IVD degeneration.