Prevalence of Modic changes in the lumbar vertebrae and their associations with workload, smoking and weight in northern China

The distribution of Modic changes (MCs) in the lumbar endplates and the evaluation of the relationships between MCs and risk factors are vital for research into MCs. The T1-weighted and T2-weighted sagittal MRI scans of 210 patients who exhibited lumbar intervertebral disc degeneration were retrospectively reviewed. The patients’ weights, genders, smoking statuses, physical activity levels and specific types of MC were recorded. The associations between MCs and risk factors, such as physical work, smoking and body mass index, were also analysed. MCs were observed in 47 patients (22.4%), including 16 males and 31 females. Among all patients, the L5/S1 lumbar level was most likely to suffer MCs. The MCs were predominantly type II. MCs occurred more often in obese patients than in normal and overweight patients (P < 0.05). Patients whose jobs required heavy labour were more likely to develop MCs (P < 0.05). Heavy work and obesity were related to type III MCs more strongly than the other types (P > 0.05). Smoking seemed not to be correlated with the incidence of MCs (P > 0.05). Gender, obesity and heavy work were strongly associated with MCs. Biomechanical factors may play a critical role in the development of MCs.