金属加工作业的工效学负荷与肌肉骨骼疾患的关系

目的　了解金属加工行业的肌肉骨骼疾患情况 ,分析其危险因素 ,初步探讨提举系数(LI)在中国应用的有效性和实用性。方法　选择 6 9名从事手工操作的金属加工工人作为提举作业组 (JobA) ,另选同一企业机械化程度较高的 5 1名工人作为对照组 (JobB)。采用问卷调查、Ovako劳动姿势分析系统 (OvakoWorkingPostureAnalysingSystem ,OWAS)、提举参数测量及日提举负荷量计算等方法分析负荷与下背痛的关系。结果　JobA组的下背痛患病率明显高于JobB组 ,在过去 12个月内 ,下背痛持续 2 4h以上的分别为 6 3.77%、37.2 5 % ,持续 1周以上的分别为 2 6 .0 9%、5 .88% ;JobA组的背部姿势异常率 (6 6 % )高于JobB组 (6 3% ) ,差异有显著性 (P <0 .0 5 )。JobA的提举指数为 2 .4 ,高于 1.0的限值 (JobB为 0

Study on lifting-related musculoskeletal disorders among workers in metal processing

OBJECTIVE: To investigate lifting-related musculoskeletal disorders in metal processing, to analyze the risk factors, and to study the validity and feasibility of using NIOSH lifting equation in China. METHODS: The questionnaires of semi-structured interview, the Ovako Working Posture Analysing System (OWAS) postural analysis and variables of the NIOSH equation were applied to the study. The study population consisted of 69 workers mainly involved in manual materials handling (MMH), categorized as Job A; and 51 machinery workers, served as controls, that were less MMH task involved, as Job B. RESULTS: The prevalence of low back pain (LBP), which was defined at least one episode lasting for more than 24 hours in the past 12 months, were 63.8% and 37.3% for Job A and Job B, respectively. However, the prevalence of LBP lasting for more than a week due to lifting were 26.09% and 5.88% for Job A and B, respectively. The proportion of awkward back postures were found higher in Job A than that of Job B (66% vs 63%, P < 0.05). The NIOSH Lifting Index (LI) was estimated to be 2.4 for Job A, and 0 < LI < 1 for Job B. The analysis of multiple regressions revealed that the repetitiveness of lifting and length of service had greatly attributed to the occurrence of LBP. The "composite load" (object weight x activity repetitiveness) had a significant adverse effect on lower back meaning that the objective weight remains an ingredient part of the risk. CONCLUSION: The occurrence of LBP is not only related to the force load, but the repetitiveness of lifting and awkward postures. The method of OWAS observation and US-NIOSH equation are important tools in assessing characteristics and risk factors of LBP for MMH tasks. Further study aimed at developing an integral scheme for the assessment system is needed.