【作者】 徐建国；

【导师】 杜亚平；

【作者基本信息】 浙江大学 ， 社会医学与卫生事业管理， 2007， 硕士

【摘要】 腰背痛是最常见的肌肉骨骼疾患,居骨、外科就诊原因的首位和手术治疗的第三位。腰背痛是一组疾病的总称,按病因分损伤性、炎症性、退变性、发育异常、肿瘤及其它,但与职业有关的以损伤性和退变性两类为主,主要特征为疼痛和功能受限,由此导致工作能力和生活质量下降、甚至失能残疾,并耗费巨额。铸造工业是数个世纪以来的基础工业,也被认为是作业环境最差的行业,尽管随着工业机械化和自动化的发展,作业方式有所改善,但工人的安全和健康仍很突出,特别以重体力手工作业为主,存在多种肌肉骨骼疾患的危险因素。研究表明,腰背痛与重体力作业、搬举和过度用力、弯腰和扭转、全身振动及静态作业姿势等不良工效学因素的暴露密切相关。然而,既往铸造行业的卫生研究主要集中于物理、化学危害的评估,或仅限于肌肉骨骼不良症状的调查,而存在综合因素的情况下,其肌肉骨骼疾患患病率的分布及其相关的危险因素和影响因素等均有待研究。研究目的通过流行病学调查描述和分析铸造工人腰背痛及有关效应的分布特征,并对整个工作系统进行各种不良工效学因素的识别,从而评价体力负荷暴露与腰背痛的接触效应关系,判断铸造工人产生腰背损伤的高危作业。为改善铸造工人作业条件和预防腰背损伤提供依据。对象与方法1调查对象随机抽查慈溪市的三家铸造厂为调查现场,调查对象要在现岗位工作超过12个月及没有已诊断为严重的内科疾病和外伤的工人。2007年4-6月组织了本次调查,共调查铸造工人617人,按其所从事工种分为后勤组、车床组、清理组和造型组。2工人健康体检由一名专业骨科医师进行,体检内容包括触诊、运动功能、感觉功能和神经反射。3问卷调查以NORDIC问卷(北欧骨骼肌肉症状分析标准问卷)为基础,增加了腰背痛发作特点、时间和诱因等项目,由统一培训的调查员逐一询问。4疼痛强度测量采用三种不同方法对近一年有腰背痛发作的工人进行疼痛强度的测量,即视觉模拟评分法、口述描绘评分法和六点行为评分法。5作业场所工效学分析以工作场所工效学分析方法对铸造作业的四个工种的不良工效学因素进行全面的识别,共分14个项目,包括作业空间、体力劳动、搬举、作业姿势和动作、事故危险性、作业内容、劳动受限程度、交流程度、决策程度、劳动重复性、注意力程度、光线、热环境和噪声。6铸造工人姿势与负荷分析采样方法采用多瞬间点观察法对造型组、车床组、清理组、后勤组人员活动进行观察,姿势分析采用修订的芬兰职业安全中心和职业健康机构推荐方法OWAS劳动姿势与负荷分析系统,并细化了背部姿势,增加了劳动相和工具的编码,完成编码后,计算各项目的单一姿势构成比,最后确定单一和复合姿势分级。7个体体力负荷暴露估计根据对铸造工人的姿势、负荷和劳动相分析结果确定各个工种的姿势系数、负荷系数和手工操作系数,分别以工龄乘各种系数,计算出个体暴露的各种体力负荷,再求和作为每个工人所暴露体力负荷的相对估计量,称为体力负荷暴露指数,它综合考虑了姿势、负荷和手工操作各种不良因素的权重。研究结果1腰背痛患病率骨科体检结果,受检工人感觉、肌力均正常,直腿抬高和加强试验仅有3例阳性,主要阳性体征是颈部和背部压痛,机体各部位在近一年的疼痛患病率腰背部最高,为29.2%,其次是肩、颈和手腕部,各工种趋势一致。职业性腰背痛总患病率为23.3%,造型工最高,为29.9%。清理和造型工种腰背压痛的粗OR值分别是6.16和11.90,职业性腰背痛的粗OR值分别是2.13和2.56,而曾有腰背痛的OR值各组没有差异。以Mantel-Haenzel方法消除混杂因素,按性别分层,趋势不变;按年龄、工龄分层,清理和造型组OR值加大。2腰背痛强度三种方法所测疼痛强度结果一致,均在中等强度以下。3腰背痛的诱发和危险因素以过度用力、重复劳动和不良姿势居前三位,占总诱因的80%以上。进入职业性腰背痛回归模型的危险因素有吸烟、搬举和使用振动工具因素。4工作系统和姿势分析结果造型作业不良因素最多,存在过度体力劳动、过度搬举、不良作业姿势和动作、重复劳动与噪声。造型和清理工分别存在需要尽快纠正的3级单一姿势,3级以上的复合姿势以清理组最高(52.6%),其次是造型(30.3%)和车床(11.1%),后勤人员则很少(3.3%)。5体力负荷暴露指数造型组最高,平均为296.4,是后勤组的10倍,车床、清理工种的2倍。职业性腰背痛的患病率随个体的体力负荷暴露指数的增高而上升。结论1铸造工人以清理和造型工种腰背痛患病情况最严重,诱发因素是过度用力、重复劳动和不良姿势,危险因素有吸烟、搬举、使用振动工具。2造型作业存在的不良工效学因素最多,有过度体力劳动、过度搬举、不良作业姿势与动作、重复劳动与噪声,其非自然姿势占85%以上。3职业性腰背痛患病率随个体体力负荷暴露指数的增大而上升,造型工体力负荷暴露最大。综合流行病学调查和工效学评价两方面结果,造型工是铸造工人中腰背损伤的高危作业工种。更多还原

【Abstract】 Low back pain is a common musculoskeletal disorder. It is the first most common reason for visits to orthopedics, and third most common reason for surgery. Low back pain can be caused by injury, infection, degeneration, dysplasia, tumors and others. But occupational related low back pain are mainly caused by injury and degeneration, and the main features are pains and function restrictiveness, which lead to weakened work ability and downgraded daily life quality, even disability and cost a lot of money.Foundry has been one of the basic industries for centuries. It is regarded as an occupation with worst working environment. Although the working environment has improved for some degree with the development of industrial mechanization and automation, the problem of the safety and health of workers are still serious, especially for those with heavy work, who face many risk factors of musculoskeletal disorder.The current study revealed that the low back pain is highly related with exposure to ergonomic work place factors such as heavy work, lifting and overexert ion, bending and twisting, whole body vibration and static work postures. The health studies in foundry industry in the past, however, are mainly focused on the assessment of the physical and chemical hazards, or are limited to the investigation of musculoskeletal symptoms. Given that those factors have a composite effect, the distribution of the prevalence of the musculoskeletal disorder and its risk and contributing factors need to be explored.ObjectiveUsing cross-sectional epidemiology to examine and analyze the characteristics of the low back pain and its related consequences in foundry workers; conducting ergonomic audit of the work place factors, and then use work posture analysis to measure the different factors observed during physical work activities when completing the work tasks. Those results can then be used to assess the relationship between the physical load exposure effects and the low back pain, and further to reveal the high-risk occupations leading to low back pain in foundry, and thus to provide guidelines for improving working conditions of foundry workers and for preventing from low back pain. Subjects and Methods1 Subjects under investigation: Randomly sample three foundry factories in the Cixi city as on-site examination places, the qualified workers need to be employed for more than 12 months without any serious internal diseases and trauma. The total sample size is 617 workers, which are divided into four groups of auxiliary workers, lathe operators, cleaners and molders.2 Physical examination of the workers: Examined by an orthopedic surgeon, examination including palpation, sports function, sensory function and neural reflection.3 Questionnaire: Based on Nordic Questionnaire (Northern European standard questionnaire for the analysis of musculoskeletal symptoms), with additional questions such as the main features, timing, and contributing factors of the low back pain, the questionnaire is conducted by trained examiners.4 Measurements of the intensity of the pain: Using 3 different methods, i.e., visual analogue scales (VAS), verbal rating scales (VRS), and 6-point behavioral rating scales (BRS-S) to measure the intensity of the pain in workers with low back pain within past one year.5 Ergonomic work place analysis: systematic ergonomic audit of work place factors for the 4 groups in foundry using ergonomic work place analysis according to 14 different items including: working site, general physical activity, lifting, work posture and movement, accident risk, job content, job restrictiveness, worker communication, decision making, repetitiveness of work, attentiveness, lighting, thermal environment and noise.6 Method for the evaluation of postural load in foundry workers: using split-second observations to reveal the subject’s posture in auxiliary workers, lathe operators, cleaners and molders. The OWAS analysis system, recommended by Finnish Institute of Occupational Health, with additional fine back postures, is used to analyze the work postures. Additional work phase and work tool related codes are added. The weight of each individual posture component is then calculated, and finally the individual posture and composite posture levels are determined.7 Assessment of the individual physical loads exposure: The posture index, loading index and manual operation index are determined based on foundry workers’ work postures, loads and work phases. Those indexes are then multiplied by employment years to give the different kinds of physical loads of an individual, which are summed up to get the relative estimate of the physical loads of each worker. It is called physical load exposure index, which is a weighted index taking into consideration of postures, loads and manual operation factors.Results1 The prevalence of the low back pain: Results from orthopedic examination show that the workers have normal sensory and normal muscle strength. Only 3 positive cases are identified in straight leg lifting and extra-intense tests. The main features in positive cases are point tenderness in neck and back, with the highest prevalence of 29.2% of low back pain among all kinds of pains of the body parts in past year, followed by the pains in shoulders, neck and wrist. It shows the same trend in all kinds of workers. The overall prevalence in occupational low back pain is 23.3%, with the highest 29.9% in molders.The OR value of low back point tenderness in cleaners and molders are 6.16 and 11.90 respectively, and the OR value in their occupational low back pain are 2.13 and 2.56 respectively. There is no difference in the OR value of low back pain in all workers. After removing noise with Mantel-Haenzel method, the trend doesn’t change among different sex groups; the OR value increases with the age or employment years.2 Intensity of the low back pain: the intensities measured from 3 different methods are all below medium level.3 Contributing and risk factors of low back pain: Overexertion, repetition and awkward posture are the top 3 contributing factors with a percentage of above 80% over all other factors. The risk factors that show up in the regressive model include smoking, lifting and use of vibration tools.4 Work place and postural analysis results: Molders have the most exposure to workplace factors including overexertion, heavy lifting, awkward work postures and movement, repetition and noise. Molders and cleaners need to correct the 3rd-level single posture as soon as possible. Cleaners have the highest percentage (52.6%) of 3rd-level+ composite posture, followed by molders (30.3%) and lathe operators (11.1%), and auxiliary workers the least (3.3%).5 Physical load exposure index: Molders have the highest with an average of 296.4, which is 10 times of that in auxiliary workers, and 2 times of that in lathe operators and cleaners. The prevalence of the occupational low back pain increases with individual physical load exposure index. Conclusion1 Cleaners and molders have the most serious low back pain symptoms among all foundry workers. The contributing factors include overexertion, repetition and awkward work postures. Risk factors include smoking, lifting, and use of vibration tools.2 Molders have the most exposure to ergonomic workplace factors, including overexertion, heavy lifting, awkward work posture, repetition and noise, over 85% work postures are unnatural postures.3 The prevalence of occupational low back pain increases with the individual physical load exposure index. Molders have the largest physical load exposure.Based on the results from the epidemiology investigation and the ergonomic evaluation, the group of molders has the highest risk of low back pain in foundry.更多还原