[Structural equation analysis and modeling of adverse ergonomic factors for lower back pain]

Objective: To establish a structural equation model of lower back pain and its risk factors in occupational population in China based on a large-sample occupational epidemiological survey and structural equation analysis, so as to lay the foundation for the prevention of this disease. Methods: A total of 73497 occupational epidemiological cases were selected from June 2018 to December 2023 using the Chinese version of the Musculoskeletal Disorders Electronic Questionnaire. The results were analyzed using ergonomic hazard factors and their risk source classification criteria. Confirmatory factor analysis was then applied to extract individual factors, work organization, working postures, work types, muscle fatigue, and lower back pain. These factors were subsequently classified into six categories and structural equation model was established. Results: The main structural reliability and validity indexes of the structural equation model of lower back pain and its adverse ergonomic factors after adjustment were basically up to standard[goodness of fit index (GFI) was 0.956, the adjusted goodness of fit index (AGFI) was 0.944, the root mean square error of approximation (RMSEA) was 0.043, the normed fit index (NFI) was 0.922, the comparative fit index (CFI) was 0.923, and the Tucker-Lewis index (TLI) was 0.908], and the model fit was good. There were correlations among four exogenous latent variables: individual factors, work organization, working postures and work types. Among them, individual factors had a weak negative correlation with the three exogenous potential variables of work organization, working postures and work types (r=-0.30, -0.11, -0.18), and work organization had a moderate positive correlation with working postures and work types (r=0.49, 0.55). There was a strong positive correlation between work types and working postures (r=0.72). The direct path coefficients of individual factors, working postures and muscle fatigue were 0.07, 0.11 and 0.40, respectively. The direct path coefficients of work types were -0.07. There was an indirect path mediated by muscle fatigue between work types, working postures and work organization and lower back pain, and the indirect path coefficients were: work types-muscle fatigue-lower back pain (0.15), working postures-muscle fatigue-lower back pain (-0.04) and work organization-muscle fatigue-lower back pain (0.27) . Conclusion: When carrying out the prevention and control of lower back pain, the pathogenesis of lower back pain induced by workers' muscle fatigue caused by work organization, working postures, and work types factors should be comprehensively considered, so as to provide a theoretical reference for improving the prevention and control level of lower back pain.