Objective: To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases. Methods: The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established. Results: The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture (r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture (r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion: When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.
目的： 基于职业人群大样本流行病学调查和结构方程分析方法，探讨各类工效学危险因素与上肢工作相关肌肉骨骼疾患（WMSDs）的影响关系，为此类疾患的预防和干预提供参考依据。 方法： 于2018年6月至2023年12月，使用《中文版肌肉骨骼疾患电子问卷》在全国范围开展上肢WMSDs流行病学调查，通过不良工效学因素及其来源分类标准和验证性因子分析分别提取上肢WMSDs相关的工作组织、工作类型、上肢工作姿势、个体因素、上肢疲劳和上肢WMSDs 6个因子，对其进行结构方程分析，并建立结构方程模型。 结果： 上肢WMSDs发生率为24.44%，疲劳发生率为43.76%，调整后结构方程模型拟合指标基本达标（GFI=1.000、AGFI=1.000、RMSEA=0.043、NFI=0.808、TLI=0.784）。工作组织、工作类型、上肢工作姿势和个体因素4个外生潜变量间具有相关性。其中，工作类型和上肢工作姿势间存在较强的正相关（r=0.865），工作组织与工作类型、上肢工作姿势间存在中等程度的正相关（r=0.570，0.490），个体因素与其他三个外生潜变量存在较弱的负相关（P<0.05）。上肢工作姿势和个体因素对上肢WMSDs有直接效应，效应系数分别为0.10和0.06。上肢疲劳在工作组织、工作类型、上肢工作姿势与上肢WMSDs之间发挥中介作用，效应系数为0.46，间接效应构成比分别为100.0%、100.0%、38.3%。上肢工作姿势、个体因素与上肢WMSDs的直接路径效应强度弱于经上肢疲劳的中介路径。 结论： 开展上肢WMSDs防控工作时，应综合考虑工作组织、工作类型和上肢工作姿势因素导致劳动者上肢肌肉疲劳进而诱发上肢WMSDs的发病路径，为提高此类疾患的防控水平提供理论参考。.
Keywords: Ergonomic factors; Fatigue; Musculoskeletal system; Structural equation model; Work-related musculoskeletal disorders.