VDT worker's posture and workload in free-address office system]

A free-address system is a new office layout in which a worker can freely sit in their favorite place with a computer and materials. Since this layout has recently been introduced in offices, we conducted a questionnaire survey which aimed to clarify the effects of the free-address system on visual display terminals (VDT) workers' posture and workload. A total of 203 male VDT workers who were system engineers aged 20 to 59 using a notebook computer were evaluated, of whom 150 used the free-address layout, and 53 used the fixed-address layout. The free-address layout was effective in the improvement of individual work space compared with the fixed-address layout. Also, in this layout the worker did not feel dissatisfaction with communication or support between workers. However, workers using the free-address layout assumed an unsuitable work posture, without adjusting the height of their chairs. Furthermore, this layout might have risk factors which increase neck/shoulder and low back stiffness and/or pain. Therefore, the free-address layout may have incipient problems, and it will be necessary to examine further the effects of this layout on VDT worker's health.     

Influence of work duration or physical symptoms on mental health among Japanese visual display terminal users

The present study examined the relationship of work duration or physical symptoms to the mental health of visual display terminal (VDT) workers in Japan. The mental health status of 2,327 VDT users at an administrative office was investigated using the 12-item General Health Questionnaire (GHQ-12). Subjects were asked about their age, sex, hours of daily VDT use, rest and breaks during VDT work, eyestrain, and musculoskeletal pain. Logistic regression analysis was used to evaluate the associations with mental health status (GHQ-12 scores). The mean age of subjects was 39.5 yr (SD=10.3). Among all subjects, 36.7% could rest during VDT work and 66.9% received breaks during VDT work. The proportion of subjects who reported eyestrain and musculoskeletal pain were 19.6% and 25.7%, respectively. Eighteen percent of subjects were classified into a GHQ-12 high score group. Logistic regression analysis showed that age less than 40 yr, not receiving breaks during VDT work, and the presence of eyestrain and musculoskeletal pain were significantly associated with poor mental health status (high GHQ-12 scores). Using a VDT for more than 5 h/d and being female were also marginally associated with high GHQ scores (p<0.1). In conclusion, the management of physical health as well as work duration is important for good mental health status among VDT users.     

Survey on subjective symptoms in VDT workers: complaint rate and years of service

A questionnaire survey was conducted on 271 workers of microelectronics company. The questionnaire included such items as age, years of service, working conditions and subjective symptoms related to visual, musculoskeletal and general status. The following results were obtained: Of these workers, approximately 80% operated visual display terminals (VDT). The years of service for most were less than 4 to 5 years with the average being about 2 years (Fig. 1). The working hours per day on the VDT for most of them was less than 90 min, although some workers operated VDT for 3 or more hours per day (Fig. 2). A high incidence of complaints of visual function, i.e. eye strain and blurring of distant objects, was observed. Some also complained of musculoskeletal and general symptoms (Table 1). The rates of these subjective symptoms increased with years of service (Figs. 4 and 5), while the complaint rates decreased with age (Fig. 3). Significant positive correlations were found between most of these complaint rates and length of service (Table 2), although correlations between the complaint rates and age were generally non-significant but negative. The complaints tended to increase with working hours per day, although the operators who worked for longer period per day did not seem to complain as much as those who did not work so long (Fig. 6). In conclusion, the results of this questionnaire suggest that the effects of visual display terminals (VDT) work accumulate gradually over months and years.     

Musculoskeletal disorders and visual strain in intensive data processing workers

BACKGROUND: This study was conducted for a UK Trade Union in response to increasing numbers of health complaints among intensive computer workers in a data processing environment. AIM: To estimate prevalence of musculoskeletal pain/discomfort and visual strain symptoms among data processing workers and to explore associations with work factors. METHODS: A self-report questionnaire was distributed to data processors (n = 175) and a control group (n = 129) in the same organization. RESULTS: Eighty-six per cent of data processors reported musculoskeletal pain/discomfort in the previous year, with the highest prevalence rate found for the neck (58%). The 12 month reported prevalence for visual strain symptoms was 47%, tired eyes (41%) was the most commonly reported symptom. In the last week, 56% reported pain/discomfort and 25% visual strain symptoms. Data processors reporting pain in the previous year were more likely to be dissatisfied with their jobs (P < 0.01), to report a lack of choice in deciding what they did at work (P < 0.02), to have insufficient time to complete work (P < 0.05) or to receive help from others when time was limited (P < 0.03). CONCLUSION: The prevalence of self-reported musculoskeletal pain/discomfort and visual strain symptoms was high among data processors. A systematic approach to risk reduction addressing organizational, psychosocial and physical work factors is required. This study has implications for reorganization of this and other intensive computer work, given the increasing requirement for intensive computing work in many industrial sectors. More research is needed to investigate interactions between job demands and support systems for these workers.     

Factors affecting subjective symptoms of VDT workers

In 1983, 285 (male: 129, female: 156) VDT workers and 60 (male: 30, female: 30) control subjects were examined in order to detect the factors affecting the subjective symptoms of VDT workers. Biological information (for example: sex, age), life histories, information about VDT work, tests (for example: visual acuity), symptoms and interferences to daily life of VDT workers and control subjects were collected. The following results were obtained. Female VDT workers experienced more fatigue from commuting to work, stiffness in shoulders, distant blurred vision complaints of visual acuity and sum of the scores of ocular complaints than female control subjects. Only among female VDT workers, the longer the daily working hours, the greater were their ocular symptoms. A remarkable relationships were observed between psychological burden factors (for example: self-control of VDT work, sensation of excessive VDT work) and subjective symptoms of the VDT workers (both sexes). In particular, VDT workers who considered VDT work to be excessive had marked by greater subjective symptoms than those who did not.     

视屏显示终端作业对骨骼肌肉系统影响的调查

目的探讨视屏显示终端（VDT）作业对骨骼肌肉系统的影响。方法采用断面流行病学方法,对337名从事VDT作业人员及203名对照组工人进行调查研究,用问卷调查、健康检查资料分析VDT作业对骨骼肌肉系统的影响。结果VDT组的骨骼肌肉酸痛不适的自觉症状的检出率为31.1%,其中以颈部（25.2%）、肩膀（19.3%）、下背部（18.1%）为主,高于对照组,差异有统计学意义（P〈0.05）;VDT组的颈椎及腰椎X线异常检出率分别为24.1%、17.3%,明显高于对照组（P〈0.05）;其中以颈曲变直（18.4%）、颈椎骨质增生（13.9%）、颈椎椎间隙变窄（9.8%）、腰椎骨质增生（13.6%）、腰椎退行性改变（11.3%）为主,分别高于对照组的相应的检出率,（均P〈0.05）;VDT组颈椎及或腰椎出现改变的平均患病年龄（34.9±7.3）岁,低于对照组,差异有统计学意义（P〈0.05）。结论VDT作业可能引起骨骼肌肉系统功能性及器质性损伤。     

Physical discomfort among visual display terminal users in a semiconductor manufacturing company: a study of prevalence and relation to psychosocial and physical/ergonomic factors

The associations among several alleged psychosocial and physical/ergonomics risk factors and the visual and musculoskeletal discomforts were assessed in a cross-sectional study of 119 video display terminal (VDT) users in a semiconductor manufacturing company. Cases of discomfort were identified using self-reported discomfort symptoms through questionnaire surveys. Data on individual, physical/ergonomic, and psychosocial aspects were obtained. Multivariate logistic regression models were developed to predict physical discomforts of 11 body areas. The prevalence of upper extremity discomfort found in this semiconductor manufacturing company was 42%, which is similar to the prevalence among VDT users in telecommunication companies and the newspaper industry. Full-time VDT users (data-entry personnel, programming engineers, and CAD engineers) had significantly higher rates of physical discomfort (66%) than part-time VDT users (fabrication engineers) (41%). Physical/ergonomic variables were found more dominant than psychosocial factors for visual and upper extremity discomforts. However, psychosocial variables were the dominant for back and lower extremity discomfort, when compared with the subjectively characterized physical/ergonomic factors. Because both physical/ergonomics variables and psychosocial factors and some of their interactions were associated with visual and musculoskeletal discomfort, integrating psychosocial prevention with physical/ergonomic design improvements is an effective approach to reducing the prevalence of discomfort.     

Association between duration of daily visual display terminal work and insomnia among local government clerks in Japan

BACKGROUND: Visual display terminal (VDT) work has become very common among office workers in developed countries; however, studies investigating the association between the duration of daily VDT work and insomnia are limited. METHODS: The aim of this study was to clarify the association between the duration of daily VDT work and sleep disturbances. We investigated 2,417 clerks (men, 2,030; women, 387) at local government offices. Sleep disturbances were evaluated using the Athens Insomnia Scale (AIS). RESULTS: VDT work of 6 hr or more per day was significantly associated with insomnia (odds ratio = 1.62, 95% confidence interval: 1.16-2.27) and, in particular, caused problems with "total sleep duration" and "sleepiness during the day" among sleep-related symptoms, even after adjusting for possible confounding factors. CONCLUSIONS: Our study suggested that VDT work of 6 hr or longer per day was related to insomnia.     

VDT作业人员肌肉骨骼疾病的工效学调查

目的了解VDT作业人员肌肉骨骼疾病的现状及病因,为VDT作业管理提供改善依据。方法采用问卷调查的方法,选取267名VDT作业人群为调查对象,然后对问卷进行数据统计,应用模糊综合评价方法对骨骼肌疲劳进行评价。结果受调查的VDT作业者总体上处于一种比较疲劳的状态,且有67%的VDT作业者处于有疲劳状态。VDT作业者的肌肉骨骼损伤与VDT作业空间、日连续作业时间,作业量等有关。结论 VDT作业导致的肌肉骨骼疲劳存在工效学问题,相关VDT作业空间设计者应根据相关人因工程学知识设计作业空间,相关VDT作业者应关注自己的作业管理,以保障VDT作业者的身心健康。     

Upper extremity musculoskeletal symptoms among female office workers: Associations with video display terminal use and occupational psychosocial stressors

The relationships between musculoskeletal symptoms and both video display terminal (VDT) use and occupational psychosocial stress were assessed among women office workers by self-administered questionnaires. Significantly increased odds ratios for neck or shoulder symptoms were observed from subjects who had ever used a VDT, had less job security, and had more stressful work during the 2 weeks prior to completion of the questionnaire. Significantly increased odds ratios for arm and hand symptoms were observed for subjects who had used a VDT for more than 6 years, reported a very crowded workplace, or reported very stressful work during the 2 weeks prior to completion of the questionnaire. Among current non-users, those who previously used VDTs were more likely to report upper extremity musculoskeletal symptoms than those who had never used VDTs. This suggests that individuals with symptoms may be more likely to reduce their VDT usage, distorting results of cross-sectional studies. © 1996 Wiley-Liss, Inc.     

Occupational physical activity and long-term risk of musculoskeletal symptoms: A national survey of post office pensioners

The objective of this work was to address the relationship between physical activity in the workplace and subsequent musculoskeletal pain syndromes. We performed a survey of 5,042 men and women aged 70–75 years, selected from the retirement population of a large national employer (the post office). Subjects were sent a short postal questionnaire enquiring about all occupations held for at least 1 year, the physical activities performed in those jobs, and about recent rheumatic symptoms. The 1-month period prevalence of rheumatic symptoms ranged from 19.9% for hip pain or stiffness in men to 50% for knee pain or stiffness in women. Symptoms were more common in women than men at all sites and there were significant (P < 0.001) associations between symptoms at different sites. Obesity was significantly (P < 0.001) associated with the risk of pain or stiffness at the knee and hip. Prolonged occupational exposure (20+ years) to heavy lifting was associated with hip pain (RR = 1.5; 95% CI = 1.2–1.8); and prolonged exposure to working with arms elevated was associated with an increased risk of shoulder pain (RR = 1.4; 95% CI = 1.2–1.6). Tall stature (P = 0.003) and heavy lifting (P < 0.001) were both associated with increased risks of low back pain among men. This survey confirms the high prevalence of musculoskeletal symptoms observed in previous population-based studies. Associations between occupational activities and musculoskeletal symptoms were specific for activity type and skeletal site involved. Our results imply that the adverse effects of these occupational activities can be found many years after cessation of exposure. Am. J. Ind. Med. 32:76-83, 1997. © 1997 Wiley-Liss, Inc.     

Association between duration of daily VDT use and subjective symptoms

BACKGROUND: Although visual display terminal (VDT) work has become a common task among office workers, surveys which would help to determine the allowable duration of daily VDT use are limited. METHODS: We investigated more than 25,000 workers three times over a 3-year period using a self-administered questionnaire. Three factors, namely mental, physical and sleep-related symptoms, were extracted by factor analysis. Adjusted means of each factor score were compared with the duration of daily VDT use by general linear model. RESULTS: Physical symptoms score became higher with increasing duration of daily VDT use without a threshold effect. Mental and sleep-related symptom scores of the workers using VDT for more 5 hr/day were significantly higher than that of the groups using VDT for >1, 1-3, and 3-5 hr/day. CONCLUSIONS: Duration of daily VDT use was linearly related to the physical symptom score, and was non-linearly related to mental and sleep-related symptom score with a threshold effect of 5 hr/day.     

大学生睡眠时间与视频显示终端综合征症状的关系

探讨西安市高校大学生睡眠时间与视频显示终端(video display terminal,VDT)综合征症状间的关系,为高校学生VDT综合征的综合防治提供参考.方法 采用多阶段分层整群抽样方法,抽取西安市5所高校1 477名在校大学生作为研究对象,采用自编问卷进行个人基本情况、睡眠时间、VDT综合征相关临床症状等资料的收集.通过探索性因子分析、秩和检验等方法,探讨睡眠时间与VDT综合征症状的关系.结果 调查对象每日睡眠时间范围为(4.013.0)h,平均睡眠时间为(7.53±1.02)h/d,其中13.4%的调查者日均睡眠时间≤6 h.随睡眠时间减少,除眼部症状外的其他症状因子得分升高;不同睡眠时间组学生视觉症状因子得分差异有统计学意义(χ2=26.09,P<0.01),且与每日睡眠时间>67 h组和≥8 h组相比,每日睡眠时间≤6 h组的视觉症状程度更为显著(Z值分别为-2.81,-4.94,P值均<0.01).结论睡眠时间与学生VDT综合征视觉症状的发生密切相关,增加睡眠时间对减缓VDT注视带来的重影、视物模糊、视力下降等不良视觉问题具有重要意义.     

Co-occurrence of musculoskeletal pain among female kitchen workers

Objectives: The co-occurrence of musculoskeletal pain symptoms in seven body sites and their combinations among women in kitchen work were studied. Methods: Data on musculoskeletal pain during the past 3 months in the neck, shoulders, forearms/hands, low back, hips, knees and ankles/feet were gathered by questionnaire from 495 female workers (mean age 45 years) in connection with an ergonomic intervention study in municipal kitchens of four cities in Finland. Altogether 122 kitchens (60% of those eligible) participated in the study. The response rate in the participating kitchens was 98%. Results: The 3-month prevalence of any musculoskeletal pain was 87%, the most common sites being the neck (71%), low back (50%) and forearms/hands (49%). About 73% of the subjects had pain in at least two, 36% in four or more, and 10% in 6–7 sites. In pair wise comparisons, e.g. neck pain was associated with pain in other sites with prevalence ratios (PR) varying from 1.3 to 1.6, and ankle or foot pain with ratios between 1.9 and 2.4. The seven pain symptoms occurred in more than 80 different combinations. When the co-occurrence of pain was studied in three larger anatomical areas, i.e. any pain in the axial (neck and low back), upper limb and lower limb areas, subjects reporting concurrent pain in all three were the largest category (36% of the respondents). Altogether 53% of the workers reported pain in at least the axial and upper limb areas, and 48% in at least the axial and lower limb areas. Conclusions: Widespread co-occurrence of musculoskeletal pain symptoms was common among female kitchen workers with slight predominance in the upper body.     

VDT作业对肌肉骨骼系统的健康影响研究

本研究采用横断面流行病学方法对４５１名ＶＤＴ作业的和４３２名普通读写对照的肌肉骨骼系统症状进行了调查，研究发现ＶＤＴ作业者肌内骨骼系统各症状现患率均显著高于对照，ＶＤＴ作业对作业者肌肉骨骼系统的主要影响部位是下背，手腕，上臂，肩部和颈部。研究结果提示：ＶＤＴ作者者肌肉骨骼系统症状现患率与作业时间长短有关，ＶＤＴ作业对肌肉骨骼系统存在着职业性影响。     

VDT作业职业性影响研究

对鞍钢计算机作业人员，采用“病例”对照配对方法进行了职业性影响研究，结果表明，计算作业人员的视觉，骨髓机、全身疲劳症状发生率显著高于对照组（P＜0．01）。     

Carpal tunnel syndrome in male visual display terminal (VDT) workers

BACKGROUND: The association between working at a video display terminal (VDT) and development of carpal tunnel syndrome (CTS) is not well-established. The study surveyed the prevalence of CTS symptoms, explored the risk factors and evaluated the clinical application of hand diagrams, physical tests and electrodiagnosis among male VDT workers. METHODS: A cross-sectional study was performed in an information and communication technology company. Three-forty questionnaires were completed and 82 volunteers participated in the physical examination and nerve conduction study. The personal and occupational risk factors for CTS were analyzed. RESULTS: The prevalence of CTS symptoms was 3.8% among 340 subjects, while prolonged median motor distal latency (>4.2 msec) was disclosed in 3.7% of a subgroup receiving examination. Classic/probable CTS symptoms was associated with high body mass index (>28 kg/m(2), odds ratio = 4.1, P = 0.029) and moderate job seniority (3-5 years, odds ratio = 4.6, P = 0.023). Prolonged median motor distal latency was associated with older age (>35 years old). We did not observe correlation between CTS symptoms, abnormal NCS, positive Tinel's sign or Phalen's test. CONCLUSION: The prevalence of CTS symptoms was not high among the group of male VDT workers studied. Job seniority, but not specific tasks, was associated with CTS symptoms. More reliable and valid methods to quantify the ergonomic exposure are needed to establish the association of VDT tasks and CTS.     

Job strain and neck-shoulder symptoms: a prevalence study of women and men white-collar workers

BACKGROUND: Neck-shoulder symptoms are frequent among workers. Psychosocial factors at work have been associated with neck-shoulder symptoms, but few studies have examined job strain, the combined effect of high psychological demands (PD) and low decision latitude (DL). AIMS: To examine the association between psychosocial factors at work and the prevalence of self-reported neck-shoulder symptoms among white-collar workers. METHODS: In a cross-sectional study of 1543 white-collar workers, PD and DL at work were measured with Karasek's questionnaire. Prevalent cases were workers for whom neck-shoulder symptoms were present for >or=3 days during the previous 7 days and for whom pain intensity was greater than half the visual analogue scale. Gender and social support at work were evaluated as potential effect modifiers. RESULTS: Workers exposed to high job strain had a higher prevalence of neck-shoulder symptoms [adjusted prevalence ratio (PR): 1.54, 95% confidence interval (CI): 1.00-2.37]. No modifying effect of gender was observed in this association. The effect of job strain was stronger in workers with low social support (adjusted PR: 1.84, 95% CI: 0.92-3.68). These associations tended to be stronger and/or more precise when using alternative exposures and case definition. Namely, a stronger job strain effect was observed when a tertile cut-off was used to classify exposure (adjusted PR: 2.47, 95% CI: 1.15-5.32). CONCLUSION: These results suggest that primary prevention of neck-shoulder symptoms among white-collar workers should consider the exposure to job strain, especially when workers are exposed to low social support at work.     

Symptoms of musculoskeletal disorders among apprentice construction workers

Musculoskeletal disorders (MSDs) are a major cause of work-related disability and lost-time illnesses for many occupational groups. This study determined the prevalence of musculoskeletal symptoms among young construction workers. A symptom and job factors survey was self-administered to 996 construction apprentices. Prevalence was determined by the percent of positive responses to musculoskeletal symptom questions. Odds ratios and 95 percent confidence intervals were the measures of association between prevalent musculoskeletal symptoms and demographic, leisure, and job factors and were determined by logistic regression. The low back was the site most commonly reported for job-related musculoskeletal symptoms (54.4%), which was also the most common reason for seeking care from a physician (16.8%) and missing work (7.3%). Number of years worked in the construction trade was significantly associated with knee (p-trend = 0.0009) and wrist/hand (p-trend < 0.04) MSD symptoms and was suggestive of an association with low back pain (p-trend = 0.05). "Working in the same position for long periods" was the job factor identified as most problematic, with 49.7 percent of all construction apprentices rating it as a moderate/major problem contributing to musculoskeletal symptoms. Musculoskeletal symptoms are a significant problem among young construction workers at the beginning of their careers. Prevention strategies are needed early in the apprentice training program to reduce the potential disability associated with work-related musculoskeletal symptom disorders.     

Work-related musculoskeletal symptoms among sheet metal workers

We report results of two pilot studies of the relationship between musculoskeletal disorders and work tasks in sheet metal workers. These two studies were undertaken as pilot investigations to determine if symptoms of carpal tunnel syndrome or other work-related musculoskeletal symptoms are present in sheet metal workers, and to determine if we could begin to identify the factors in sheet metal work that cause them. In the first study, telephone interviews were conducted with 18 disabled sheet metal workers; the second survey entailed self-administered questionnaires completed by 47 active and retired sheet metal workers. Among the disabled workers, rotator cuff cases reported the greatest percent of time spent hanging duct, an overhead task commonly carried out during field work. Carpal tunnel cases reported more hand tool use than the rotator cuff cases. The questionnaire survey of active and retired workers found the proportion of time spent in a sheet metal shop (contrasted with field work) to be positively associated with hand symptoms; sheet metal workers who spent at least 65% of their time in the shop had an odds ratio of 3.4 for symptomatic hand cumulative trauma disorder (CTD) (p = 0.12). The proportion of time spent hanging duct was positively associated with both neck and shoulder symptoms, with odds ratios of 7.9 (p = 0.08) and 2.7 (p = 0.16), respectively. The results show that symptoms of neck, arm, and hand pain are common in sheet metal workers who are actively working, that carpal tunnel syndrome or hand pain is positively associated with more time spent working in the shop, and that shoulder pain or shoulder injuries is associated with work overhead (hanging duct). Ergonomic risks and cumulative trauma disorders have not been well characterized in the construction industry; these data strongly suggest that a subset of work tasks in construction increase the risk of cumulative trauma disorders.