Risk factors analysis of low back pain among workers in a foundry factory of the automobile company / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the main risk factors of low back pain of workers ina foundry factory of the automobile company using cross sectional epidemiological investigation, and to provide scientific base for preventing the disorder.</p><p><b>METHODS</b>The low back pain and work loads of 1340 workers in a foundry factory of the automobile company were investigated using questionnaire, and logistic regression analysis was used to analyze the risk factors.</p><p><b>RESULTS</b>The one-year morbidity of low back pain in workers was 58.9% the morbidities of low back pain in workers engaged in foundry, transportation and modeling were 64.6%, 64.6% and 62.5%, respectively. The lifting with squat postures, bending trunk heavily, bending trunk with twisting and moving the heavy objects were found to be the most dominant risk factors for low-back pain, the OR values were 2.085, 1.961, 1.967 and 1.956, respectively. The distributions of risk factors were different among the different jobs. The logistic regression analysis showed that moving the heavy objects, lifting with squat postures, bending trunk heavily, bending trunk with twisting existed simultaneously, also the work years and gender were the risk factors.</p><p><b>CONCLUSION</b>The manual moving heavy objects, awkward working posture or both were the most important risk factors for low-back pain. The intervene ergonomic study should be performed in future to reduce the morbidity of low-back pain.</p>

A field assessment on the risk factors of musculoskeletal disorders / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the usability of quick exposure check (Quick Exposure Check, QEC) for the field assessment of occupational musculoskeletal disorder risk factors.</p><p><b>METHOD</b>In the shipyard and automobile manufacturing plants, QEC was used to observe the operations among workers with different jobs and to assess the work loads of workers. On the basis of results, the reliability of QEC was evaluated, and the correlation between QEC scores and morbidities of musculoskeletal disorders in workers was analyzed.</p><p><b>RESULTS</b>The inter-observer reliability (ICC) was in the range from 0.737 to 1.000, and intra-observer reliability (Spearman coefficient) was from 0.605 to 1.000. The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the shipyard factory was plumbers > assemblers > welders; The order of exposure levels to risk factors of workers engaged in different jobs (QEC scores) in the automobile factory was welders > punching workers > machinists > casters > assemblers. In different body parts, the exposure level at back and neck parts was the highest and the exposure level at the shoulder and wrist parts was the second. The regression analysis between QEC scores of body parts and the morbidities of musculoskeletal disorders showed that there was a good correlation between exposure levels and morbidities, the coefficients (r(2)) at the shoulder, wrist, and back (static work) were 0.670, 0.740 and 0.958, respectively (P < 0.05).</p><p><b>CONCLUSION</b>The QEC method is suitable and reliable as demonstrated by the field assessment on the exposure to risk factors in shipyard and automobile workers, and its results is correlated closely to the disease prevalence.</p>

Experimental simulated study on the break for manual lifting task by surface electromyography and electrocardiogram / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the recovery duration of manual lifting tasks.</p><p><b>METHODS</b>30 college student volunteers with gender equally distributed were involved in the simulated stoop-, squart- and semi squart-lifting tasks in the laboratory. Signals of electromyography (EMG) at the back muscles (left and right thorax m. erector spinae, LT(10) and RT(10); left and right lumbar m. erector spinae, LL(3) and RL(3)) and electrocardiography (ECG) were recorded during the rest intervals. The percentage of maximum voluntary electrical activation (MVE%), EMG median frequency (MF), and heart rate (HR) were analyzed to predict the recovery time required.</p><p><b>RESULTS</b>During the break, MVE% at 4 back muscles of all the male subjects were recovered to resting level within 5 minutes and 91.8% were within 2 minutes. Except for RL(3) after squat- and stoop-lifting task, the MVE% of female subjects went back to resting level within 3 minutes and 67.8% were within 2 minutes. The MF of male subjects were recovered in 10 minutes and 74.9% within 2 minutes, with the exception of RL(3) after stoop- and squat-lifting tasks. All the female MF were recovered in 8 minutes and 83.4% were within 2 minutes. However, during the last 20 minute break after the lifting tasks, the MVE% and MF of all male and female subjects were recovered, while HR came back to resting level within 14 and 5 minutes, respectively.</p><p><b>CONCLUSIONS</b>For the three manual lifting tasks with 25% MVC workload lasting for 4.5 min, a break of 15 minutes is sufficient for most erectors spinae to recover from local muscle load. However, in terms of the HR, a break of 15 minutes is enough for the recovery of systematic load.</p>

Survey on prevalence of occupational musculoskeletal disorders among workers in a shipyard / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the prevalence of occupational musculoskeletal disorders (OMSDs) in a shipyard and explore the relationship between type of work, age, length of service and OMSDs by cross sectional epidemiological survey.</p><p><b>METHODS</b>1570 workers from a shipyard were selected as survey objects, and a revised Northern Europe Standardized Questionnaire was used to investigate OMSDs. 253 technicians and clerks in the shipyard were selected as controls.</p><p><b>RESULTS</b>OMSDs in these workers primarily located in waist, neck and shoulder, prevalence were 58.0%, 54.6% and 44.3% respectively; There were significant differences among workers of different types of work (P < 0.05) in prevalence and the cumulative parts number of OMSDs. The control group in this study also showed a higher prevalence of neck, shoulder and waist OMSDs. Female workers had higher prevalence of OMSDs in neck and shoulder compared with male workers (P < 0.05). As well there was significant correlation between age and OMSDs prevalence except the wrist and ankle disorders (P < 0.05), OMSDs prevalence increased with years. In addition, there was correlation between length of service and OMSDs prevalence, the group of ≤ 5 years had the lowest prevalence and the prevalence of low-back, neck and shoulder increased with service years.</p><p><b>CONCLUSION</b>The OMSDs in workers engaged in shipyard are serious, the length of service, age, gender and type of work seem to be the risk factors, and it seems reasonable that the ergonomics intervention in the above aspects should be necessary for the prevention of OMSDs.</p>