Objective: To explore the occurrence pattern and its influencing factors of multi-site work-related musculoskeletal disorders (WMSDs) of the main affected body sites among manufacturing workers.
Methods: Musculoskeletal disorders questionnaire was adopted to investigate the prevalence of WMSDs and the influencing factors among workers from four manufacturing factories in China. The case of WMSDs was defined as the one who had symptoms such as pain, numbness, discomfort, or limitation of activities in one or more of the nine body sites, including neck, shoulder, elbow, wrist/hand, upper back, lower back, hip/thigh, knee and ankle/foot during the last year, which lasted for more than 24 hours and did not completely relieve after rest. Besides, trauma, disability, other acute injuries or sequelae were excluded. The correlation of WMSDs between different body sites was estimated by the prevalence ratio (PR) calculated by log-binominal model. The influencing factors of multi-site WMSDs of the main affected body sites were analyzed by multinomial logistic regression model.
Results: The overall prevalence rate of WMSDs was 79.7% among the manufacturing workers. The main affected body sites were lower back, neck, shoulder and upper back, of which the prevalence rates were 62.3%, 55.7%, 45.6%, and 38.7%, respectively. The PR values of WMSDs among these sites were relatively high. The prevalence of multi-site WMSDs involving these four sites at the same time was 25.2%, and that of three to four sites was 41.4%. Multinomial Logistic regression analysis suggested that influencing factors of multi-site WMSDs in 3-4 sites of neck, shoulder, upper back and lower back involved several aspects. Among these factors, females (OR=2.86, 95%CI 2.38-3.33) and individuals with job tenure of 15-19 years (OR=1.87, 95%CI 1.49-2.34) might have higher risk of disease. Biomechanical factors, such as often bending neck forward or holding neck in a forward position for long periods (OR=2.15, 95%CI 1.86-2.48), often twisting neck or holding neck in a twisted position for long periods (OR=1.64, 95%CI 1.40-1.92) and often twisting trunk heavily (OR=1.40, 95%CI 1.20-1.64) might be risk factors. In the aspect of work organization, doing the same work every day (OR=1.73, 95%CI 1.44-2.08), shortage of workers (OR=1.50, 95%CI 1.31-1.71) and often working overtime (OR=1.38, 95%CI 1.20-1.60) might increase the risk of disease. Factors, such as often standing for long periods at work (OR=0.77, 95%CI 0.65-0.91) and feeling breaks sufficient (OR=0.51, 95%CI 0.44-0.59) were suggested to be protective factors with OR<1.
Conclusion: The pre-valence rates of WMSDs in neck, shoulder, upper back, and lower back were high among manufacturing workers in this study. The correlation of WMSDs of these four sites was close in this study, and the comorbidity rate of 3-4 sites of these sites was relatively high, suggesting that there might be a multi-site occurrence pattern of WMSDs in "neck-shoulder-upper back-lower back" among manufacturing workers. The main influencing factors of this pattern included individual factors, biomechanical factors and work organization factors.
目的: 探讨制造业工人工作相关肌肉骨骼疾患(work-related musculoskeletal disorders,WMSDs)在多个部位的发生模式及其影响因素。
方法: 应用肌肉骨骼疾患调查问卷对4家制造企业工人的WMSDs患病情况及影响因素展开流行病学调查。WMSDs病例定义为过去一年内身体颈部、肩部、肘部、手腕/手、上背部、下背部、臀/大腿、膝部、踝/足9个部位中一个或多个部位出现疼痛、麻木、不适或活动受限等症状,持续时间超过24 h,经休息后症状仍未完全缓解,且排除外伤、残疾、其他急症或后遗症等。各部位WMSDs患病情况间的关联度用log-binomial模型计算出的现患比(PR值)评估,采用多分类Logistic回归模型分析WMSDs主要患病部位中多个部位共患病的影响因素。
结果: 制造业工人WMSDs总患病率达79.7%,主要患病部位为下背部、颈部、肩部和上背部,患病率依次为62.3%、55.7%、45.6%和38.7%。这4个部位患病情况间的PR值较高,4个部位共患病率为25.2%,3~4个部位共患病率为41.4%。多分类Lgistic回归分析提示,颈部、肩部、上背部和下背部中3~4个部位患WMSDs的影响因素涉及多个方面,其中女性(OR=2.86,95%CI 2.38~3.33)、工龄15~19年者(OR=1.87,95%CI 1.49~2.34)患病风险较高;颈部经常长时间或频繁前倾(OR=2.15,95%CI 1.86~2.48)、颈部经常长时间或频繁扭转(OR=1.64,95%CI 1.40~1.92)和经常大幅转身(OR=1.40,95%CI 1.20~1.64)等生物力学因素可能为疾患发生的危险因素;每天做相同的工作(OR=1.73,95%CI 1.44~2.08)、员工短缺(OR=1.50,95%CI 1.31~1.71)和经常加班(OR=1.38,95%CI 1.20~1.60)等组织管理因素可能增加疾患的发生风险;经常长时间站着工作(OR=0.77,95%CI 0.65~0.91)和感觉工间休息时间充足(OR=0.51,95%CI 0.44~0.59)等因素为保护性因素。
结论: 本研究中制造业工人颈部、肩部、上背部和下背部WMSDs患病率高,4个部位的患病情况间关联密切,其3~4部位共患病率较高,提示在制造业工人中可能存在“颈-肩-上背-下背”多个部位患病的WMSDs发生模式,这种模式的主要影响因素包括个体因素、生物力学因素和组织管理因素几个方面。
Keywords: Manufacturing industry; Musculoskeletal disorders; Risk factors.