Ergonomic Stressors Research Articles

Health Survey of Workers Exposed to Mixed Solvent and Ergonomic Hazards in Footwear and Equipment Factory Workers in Thailand

A cross-sectional health study was performed at four footwear and one equipment factory in Thailand to evaluate the prevalence of chemical- and ergonomic-related symptoms in Thai factory workers and to investigate associations between these symptoms and exposures to organic solvents, isocyanates and ergonomic risks. A 10-page health questionnaire was administered to 1784 workers across the four footwear and equipment factories. A total of 1675 questionnaires were returned, yielding a 94% response rate. The questionnaires asked about age, gender, use of chemicals, use of personal protective equipment and health outcomes. Without exception, the percentages of workers reporting symptoms after being hired were higher than those reporting symptoms before being hired for all the factories. The highest symptom percentages were related to ergonomic stressors. Multiple logistic regression was used to calculate adjusted prevalence odds ratios and 95% confidence intervals. This study showed that adverse health effects experienced by footwear and equipment factory workers are associated with occupational exposures to chemicals (volatile organic solvents and water-based adhesives) and ergonomic hazards.

Evaluating Ergonomic Stresses in North Carolina Commercial Crab Pot and Gill Net Fishermen

There are challenges in evaluating physical demands of commercial fishing, including identifying sources of exposure variability. Low back biomechanical stresses associated with crab pot and gill net fishing were estimated; the variability was partitioned between and within fishing type, crew size, job title, and worker to improve understanding of risk factors for low back injury. The authors observed 162 person-hours of work among 25 North Carolina commercial fishermen on 16 crews. Postures and forces during fishing tasks were measured through direct and indirect observation using two methods to determine the percentage of time fishermen were exposed to high levels of low back stress. A multilevel linear model estimated exposure variability for the dependent variables by four nesting variables: fishing type, crew size, job title, and worker. Fishermen set and pulled crab pots or gill nets for 80% of the workday. Twenty-five percent of that time was spent handling gear. For both fishing types, handling heavy loads produced high peak compression values (3586 N to 5315 N) and high NIOSH lifting index values (3.3 to 5.4), but these tasks represent a small percentage of the overall work time (0 to 14%). The majority of exposure variation in non-neutral trunk posture and/or force > 9 kg, handling materials, NIOSH Lifting Index > 1, and Lumbar Motion Monitor probability of high-risk group membership > 70% was accounted for by fishing type (range 60 to 91%). Crew size was not an important source of variability for these six variables when fishing type and job title were accounted for in the model; but in the model restricted to crab pot fishing, crew size accounted for 51 to 88% of the variability in low back stress. For both models, job title comprised the majority of exposure variability for NIOSH Lifting Index > 3.0 (46 and 65%) and worker comprised the majority of variability for spine compression > 3400 N (54 and 65%). The magnitude and duration of musculoskeletal loads experienced by fishermen vary by the type of fishing and the tasks performed by the worker. Understanding this variability may help researchers target ergonomic interventions for this work population.

Musculoskeletal symptoms among young male workers and associations with exposure to hand–arm vibration and ergonomic stressors

The overall aim of this study was to explore the association between incident musculoskeletal symptoms in the neck and upper limbs and exposure to hand-arm vibration and ergonomic stressors. The study has a prospective design and data at baseline and follow-up was assessed by self-administered questionnaires. The study population consisted of students that had graduated from vocational high schools in 2001-2003 in northern and western Sweden and a total of 586 men responded to both the baseline and follow-up questionnaires. The mean age was 20.7 (range 19-27) years, and the exposure information included questions regarding hand-arm vibration, postural stress, computer work, mental stress and perception of muscular tension. Musculoskeletal symptoms in the neck and upper limbs were assessed at baseline and at follow-up. Men who reported their daily vibration exposure duration (work and leisure) as more than 1 h at baseline had an increased risk of neck pain in the preceding 7 days at follow-up, when adjusting for all the other exposure variables (PR 3.29, 95% CI 1.02-14.9). Men with a calculated 8-h weighted vibration exposure level [A(8)] above 1.7 m/s(2) had an increased risk of developing neck pain in both the unadjusted and adjusted analyses compared to those with an exposure level below 0.5 m/s(2). Men who reported their daily vibration exposure duration (work and leisure) to be more than 1 h at baseline had an increased risk of neck pain for the preceding 7 days at follow-up. An increased prevalence of neck pain was also observed in individuals with a calculated 8-h frequency weighted vibration exposure level above 1.7 m/s(2) (calculated from data assessed at follow-up) compared to those with an exposure level below 0.5 m/s(2). The increased risks remained when adjusting for postural and mental stress; however the results could still be confounded by other ergonomic and physical load factors not adjusted for in the analyses.

A prospective cohort study of manipulative dexterity in vibration-exposed workers

To investigate the relation between manipulative dexterity and vibration exposure, ergonomic risk factors, and upper limb disorders in a group of workers exposed to hand-transmitted vibration (HTV). Manipulative dexterity was investigated on 115 HTV workers (82 forestry workers and 33 stone workers) and 64 control men over 1-year follow-up period. The Purdue pegboard method was used to test manipulative dexterity which was scored for the dominant hand, non-dominant hand, and both hands. Information about individual, work and health history was obtained by means of a standardised questionnaire. Vibration exposure was assessed in terms of tool vibration magnitudes, daily and total exposure duration, and cumulative vibration dose. On the cross-sectional investigation, Purdue pegboard scores were significantly lower in the HTV workers than in the controls (0.001 < P < 0.05). Over 1-year follow-up period, Purdue pegboard scores were found to be inversely related to age, smoking and use of vibratory tools (0.001 < P < 0.05). Moreover, deterioration of some measures of manipulative dexterity was significantly associated with sensorineural and vascular symptoms in the fingers of the HTV workers. Random-intercept linear regression analysis showed that Purdue pegboard scores decreased with the increase of vibration exposure. The reduction of assembly score (i.e. number of pins, collars, and washers assembled in a 60-s period) was significantly associated with the increase in vibration exposure and ergonomic stress (neck-upper arm posture, hand-intensive work, and total ergonomic score). Purdue pegboard scores tended to improve over the follow-up period in both the controls and the HTV workers, suggesting a possible learning effect over time. The findings of this longitudinal study suggest an association between deterioration of manipulative dexterity and neurovascular symptoms in the fingers of HTV workers. There was evidence for a significant relation between loss of precise manipulation and exposures to hand-transmitted vibration and ergonomic risk factors.

ERGONOMIC RISK FACTORS AND MUSCULOSKELETAL DISORDERS (PREVALENCE &amp; COST) AMONG WORKERS IN A MULTINATIONAL CAR ASSEMBLY PLANT, EGYPT

Objectives: to define the magnitude of the ergonomic stressors related to neck and trunk posture, energy expenditure and upper extremity among workers in the studied plant, to find out the incidence rate of work injuries resulted from ergonomic causes among the studied workers and to find out the prevalence rate and cost of musculoskeletaldisorders among the studied workers. Subjects & Methods: this study was conducted inside a multinational factory in Egypt for car assembly. 553 workers were included in the study. All workers were subjected to checklists to monitor thedifferent ergonomic stressors during their daily work. Environmental measures were conducted through coordination with National Institute of Occupational Safety and Health (NIOSH), Egypt. Data about distribution and cost of MSDs were obtained from the medical recording system inside the medical department of the factory.Results: noise, ultraviolet rays, vibration and carbon monoxide in body shop while heat and thinner in paint shop were above the permissible level. 21.7%, 3.2% and 27.6% of workers were standing stationary, kneeling and knee bent respectively.Trunk posture revealed that 43.1%, 11.8% and 49.2% of workers were doing forward bending, backward bending and lateral bending respectively. Neck posture revealed that 29.7%, 13.8% and 17.2% of workers were doing forward bending, backwardconsebendingand lateral bending respectively. About 11% were doing sit/stand position.Energy expenditure assessment revealed that; 12.1 of workers in their jobs need to walk more than 30m2/M while carrying weights. Upper extremity stressors revealed that 36.7% were doing repetitive work, 14.2%, 7.1% and 13.5% were gripping on objectwith slippery surface, tip of a finger used for pressing and gloves hinder the grip respectively. 11.3% and 5.1% of workers were pushing or pulling objects weight >300gm by one hand repeatedly and hold repeatedly an object which weighs more than 200gm in one hand respectively. 7.4% and 15.6% were using pinch grip and using rotating motion of the forearm respectively. 3.9% were exposed repeatedly to vibrating tools. It was found that; incidence rate of work injuries/100 workers/one year was (1.2) and the prevalence rate of MSDs was (23.7%). About 43% of the ergonomic core requirements were fully implemented inside the studied plant. It was estimated that the cost of MSDs/person/year 2006 was about 7300 L.E.(1281$). Conclusion:MSDs of neck was strongly associated with combined neck ergonomic stressors. Hand/Arm pain was strongly associated with repetitiveness and pushing forces. Lumbosacral disorders were strongly associated with combined trunk ergonomic stressors. The prevalence rate of MSDs was 23.7% and cost of MSDs/ person/ year 2006 was about 7300 L.E. (1281$).

Health-related job loss: findings from a community-based survey

Aims: To explore the frequency, nature, determinants and outcome of health-related job loss (HRJL) in men sampled from the general population of three rural areas. Methods: Data on lifetime occupational...

호텔 요리사의 인간공학적 작업 위험성 평가

This paper summarizes the ergonomic risk assessment of hotel chef. The cooking operations were observed in order to determine sources of ergonomic stress and make recommendations to reduce the risk of work-related musculoskeletal disorders in Korean, Japanese, and western style cooking. We used interviews, document analysis, video analysis, and risk assessment to identify and quantify ergonomic risk factors. The results indicate that the cooking operations have some ergonomic problems. These findings identified in this study can be used to reduce the risk of work-related musculoskeletal disorders in food service areas.

Work routinization and implications for ergonomic exposure assessment

Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels.

Musculoskeletal pain in ragpickers in a southern city in Brazil

Ragpickers are informal workers who collect recyclable materials to earn a small wage. Their life and working conditions are extremely precarious. The ergonomic hazards and musculoskeletal pain in a sample of ragpickers in Pelotas, a city in southern Brazil are examined. Two comparison groups were available: a matched sample of non-ragpickers from the same poor neighborhoods, and a random sample of the general population of the city. The cross-sectional study gathered data by interview on 990 individuals in 2004. Musculoskeletal pain was assessed using the Standardized Nordic Questionnaire. Ragpickers reported higher prevalences for most awkward postures and ergonomic exposures compared to neighbors with other demanding manual jobs. The prevalence within the last 12 months of low back pain (LBP), lower extremity pain (LEP), and upper extremity pain (UEP) among ragpickers were 49.2%, 45.1%, and 34.9%, respectively; levels similar to those reported by neighborhood controls. Both ragpickers and non-ragpickers reported considerably higher ergonomic exposures, and more prevalent LBP, than the general population. Ragpickers experience many occupational hazards and ergonomic stressors. Their overall prevalence of musculoskeletal pain was similar to a comparison group with other physically demanding manual jobs. For LBP, this prevalence was substantially higher (49% vs. 35%) than in the general population.

The Characterization of Airborne Occupational Safety and Health Hazards in Selected Small Businesses; Manufacturing Wood Pallets

Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated occupational safety and health concerns in the small business wood pallet manufacturing industry because of an injury rate (2000) 226% greater than that for general industry. NIOSH investigators conducted walk-through evaluations at seven wood pallet manufacturing companies, and returned to four of them to take environmental measurements. Carbon monoxide (CO) levels, noise levels, and total particulate were measured, ergonomic observations made, and occupational safety practices analyzed at each of the four facilities where measurements were taken. The focus of this study is the evaluation of airborne particulate and carbon monoxide exposures for the purpose of determining areas of potentially high exposures. This knowledge can guide the plant owner or health professional to determine whether further measurements are necessary and where they might be needed. Safety factors and physical stressors (noise and ergonomic stressors) were described in a previously published companion paper. Although we did not take 8 h samples, we did find certain exposures that were potentially of concern to the small business owner. The main findings of this investigation were as follows: 1) CO levels in three plants, for the time periods measured, were less than the OSHA permissible exposure limit (PEL) of 50 parts per million (ppm) for an 8-h TWA. Three measurements, all from one plant, were due to a older and defective forklift and were above 50 ppm. 2) Total dust measures ranged from 0.86 to 1.67 mg/m3, taken adjacent to an operating machine cutting hardwood and measured up to 6 min. The American Conference of Governmental Industrial Hygienists (ACGIH) guideline for hardwood dust is 1.0 mg/m3, again for an 8-h TWA.

The Heavy Load of Lead: Ergonomic Stress Heightens Exposure-Related Neuropathy

Vol. 113, No. 12 EnvironewsOpen AccessThe Heavy Load of Lead: Ergonomic Stress Heightens Exposure-Related Neuropathyis accompanied byEffect of Lead Exposure and Ergonomic Stressors on Peripheral Nerve Function Dinesh C. Sharma Dinesh C. Sharma Search for more papers by this author Published:1 December 2005https://doi.org/10.1289/ehp.113-a838AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Long-term lead exposure among industrial workers can result in neuropathy (a disorder of the peripheral nervous system), while lower exposure levels cause muscle weakness. Until recently, however, the interaction between lead toxicity and chronic repetitive muscle use had not been investigated. Researchers from the Center for Occupational and Environmental Neurology in Baltimore now report that the impact of chronic lead exposure is augmented by concomitant ergonomic stress [EHP 113:1730–1734].The study included 80 lead smelter workers who were routinely exposed on the job to inorganic lead dust and (to a lesser extent) lead fumes. Historical blood lead records for all the workers were available from the smelter, which checked all employees’ blood lead at least quarterly. These records showed that workers had high chronic exposure in the distant past, much lower exposure in the more proximate past, and still lower exposure at the time of the study. The researchers also measured current blood and bone lead levels and used the historical records to calculate two metrics of cumulative lead exposure—working-lifetime integrated blood lead (IBL) and working-lifetime weighted-average blood lead (TWA).The team used the current perception threshold test to examine nerve fiber populations in the workers’ shoulders, arms, wrists, and hands. This test measures the amount of electrical current needed to induce a sensation. The team also created a three-tiered ergonomic stress rating based on all the different jobs the workers had ever performed, cumulated over their employment history. This was used to arrive at a time-weighted average ergonomic stressor. Sensory nerve conduction threshold was measured in large myelinated, small myelinated, and unmyelinated nerve fibers.The results showed that decrements in nerve function—a precursor to neuropathy—were limited to large and small myelinated sensory nerve fibers, with a threshold effect at a TWA of 28 micrograms per deciliter. At higher levels of lead exposure and presence of ergonomic stress, nerve fibers were more susceptible to increased damage, something that has never before been shown in human studies. The investigators suggest that nerves affected by lead are more susceptible to traction or mechanical compression, as would occur in the carpal tunnel of workers who perform activities such as heavy lifting and shoveling.Measures of chronic lead exposure may serve as strong predictors of impaired nerve function. In addition, the authors believe they have been able to separate the impact of two components of cumulative blood lead—duration and intensity—with exposure intensity appearing to have a greater influence than duration on the outcome studied. Finally, the authors point out that although TWA and IBL are associated with peripheral nerve damage, bone lead—another measure of chronic exposure—is a weak predictor of lead effects in the nervous system because it reflects only that lead stored in the bone compartment and not necessarily the cumulative blood lead to which peripheral nerves were exposed.Double jeopardy.Ergonomic stress may heighten the threat posed by on-the-job lead exposure.FiguresReferencesRelatedDetailsRelated articlesEffect of Lead Exposure and Ergonomic Stressors on Peripheral Nerve Function8 August 2005Environmental Health Perspectives Vol. 113, No. 12 December 2005Metrics About Article Metrics Publication History Originally published1 December 2005Published in print1 December 2005 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Estimating the global burden of low back pain attributable to combined occupational exposures

There is little information about the global burden of non-traumatic low back pain (LBP) attributable to the effects of physical and psychosocial occupational stressors. Based on a review of the epidemiological evidence, occupation-specific relative risks were used to compute attributable proportions by age, gender, and geographical sub-region for the economically active population aged 15 and older. The reference group was professional/administrative workers; other risk categories were Low, clerical and sales; Moderate, operators (production workers) and service; and High, farmers. Worldwide, 37% of LBP was attributed to occupation, with twofold variation across regions. The attributable proportion was higher for men than women, because of higher participation in the labor force and in occupations with heavy lifting or whole-body vibration. Work-related LBP was estimated to cause 818,000 disability-adjusted life years lost annually. Occupational exposures to ergonomic stressors represent a substantial source of preventable back pain. Specific research on children is needed to quantify the global burden of disease due to child labor.

The cost effectiveness of occupational health interventions: Preventing occupational back pain

Occupational back pain exacts a toll on society with concomitant economic losses; it is imperative to evaluate the cost-effectiveness of interventions to reduce the relevant ergonomic stressors at work. This study estimates and evaluates the average and incremental cost-effectiveness ratios (CERs) of specific interventions for the prevention of occupationally induced back pain for the World Health Organization (WHO) defined subregions of the world. Four back-pain interventions were selected from the literature: training (T), engineering controls (EC), engineering controls and training (EC&T), and a comprehensive full ergonomics program (EP) for evaluation. A simulation model for a 100-year time horizon, developed by the WHO CHOICE initiative project was used to estimate the effectiveness of the interventions in healthy year equivalents. The intervention costs were adjusted for all WHO subregions. In all of the subregions, training was the most cost-effective with CERs varying from 74 dollars per healthy life years gained in the subregion comprising of Egypt, Iraq, Morocco, Yemen (EMROD) to approximately 567 dollars in the subregion covering Canada and the United States (AMROA). Training is considered to be very cost-effective and would be the first choice option where resources are scarce. However, the overall effectiveness of training is low. Although other interventions such as engineering controls and total ergonomic interventions are relatively more expensive, the addition to health outcome through these interventions is much higher. The difference in the CERs for training and other engineering controls and full ergonomic interventions is relatively small for most of the industrialized regions of the world. It is clear from the ranked CERs and incremental CERs over the different subregions that in most of the industrialized regions of the world additional resources, if they become available, should go straight to the full ergonomics program. The model results based on CERs show that worker training is a low cost, feasible first step toward reducing back pain/injury incidence. However, all of the average CERs for the different interventions, for each of the regions, fall well within their GDP per capita estimates [World Bank, 2001]. According to the WHO Commission on Macroeconomics and Health any intervention that costs less than three times GDP per capita for saving a healthy year equivalent should be considered worthwhile and good value for money [WHO, 2002]. Given this criterion, the engineering controls interventions as well as the full ergonomics program look very cost effective for all of the WHO subregions.

Automation of a Multiplexed Competitive Luminex Immunoassay for Measuring Antibodies to Human Papillomavirus Types 6, 11, 16, and 18

Serum specimen pipetting is a labor-intensive process that can be a source of laboratory error, ergonomic stress, and a potential source of accidental exposure to infectious pathogens. Automated solutions for sample preparation reduce time spent on sample handling, minimize exposure to infectious pathogens, reduce laboratory error, reduce ergonomic stress, and save money. A fully automated method was developed for a custom-designed competitive Luminex immunoassay (cLIA) on a TECAN Genesis Workstation that measures antibodies to human papillomavirus (HPV) virus-like particles (VLPs). The automated program generated statistically similar data to assays performed manually. Overall, HPV 6, 11, 16, and 18 antibody titers obtained from samples prepared with the automated program were 3.2%, 6.6%, 3.6%, and 2.0% higher, respectively, than antibody titers from samples prepared manually. The agreement rates between methods for HPV positive and negative samples for HPV 6, 11, 16, and 18 were 100%, 96.8%, 98.4%, and 97.3%, respectively. An overview of the basic workflow of the automated HPV cLIA used to support our HPV vaccine Phase III clinical trials is described.

Integrating Decision Support Systems and Ergonomics: A Case Study of Software Designed for Evaluating and Controlling Ergonomic Stresses

The study examines the use of a computerized decision support system developed for evaluating and controlling ergonomic stresses in an automobile assembly plant. The decision support system is based on a database of job videos, standardized work information, upper-extremity physical stress ratings for over 400 jobs, and historical job data that could be used in the job evaluation and improvement process. The study showed the software was useful to the extent that it had a user-friendly design, provided a significant amount of job information in one centralized location, and facilitated a more detailed analysis during injury investigation.

Effect of Lead Exposure and Ergonomic Stressors on Peripheral Nerve Function

In this study we investigated the effect of recent and chronic lead exposure, and its interaction with ergonomic stressors, on peripheral nerve function. In a cross-sectional design, we used retrospective exposure data on 74 primary lead smelter workers. We measured blood and bone lead levels and, from historical records, calculated lead dose metrics reflecting cumulative lead exposure: working-lifetime integrated blood lead (IBL) and working-lifetime weighted-average blood lead (TWA). We additionally created five metrics related to IBL that cumulated exposure only above increasing blood lead levels ranging from 20 to 60 μg/dL (IBL20–IBL60). Current perception threshold (CPT) assessed large myelinated (CPT2000), small myelinated (CPT250), and unmyelinated (CPT5) sensory nerve fibers. Using multiple linear regression, we modeled CPT on the different measures of lead dose after adjusting for relevant covariates. CPT had a curvilinear relationship with TWA, with a minimum at a TWA of 28 μg/dL. Both TWA and IBL accounted for a significant percentage of the variance of CPT2000 (ΔR2 = 8.7% and 3.9%, respectively). As the criterion blood lead level increased from IBL20 through IBL60, so did the percentage of CPT2000 variance explained, with ΔR2 ranging from 5.8% (p < 0.03) for IBL20 to 23.3% (p < 0.00) for IBL60. IBL60 also significantly contributed to the explanation of variance of CPT250 and significantly interacted with ergonomic stressors. Measures of chronic blood lead exposure are associated with impairment of large and small myelinated sensory nerve fibers. This effect is enhanced at the highest doses by ergonomic stressors.

Work-related disorders of the upper limb in female workers using orbital sanders

To investigate the prevalence of vascular, neurological and musculoskeletal disorders of the upper limb in a group of female workers performing either mechanical or hand sanding in the furniture industry (n=100) and in a control group of female office workers (n=100). A further aim was to study the possible adverse effects of exposure to a combination of vibration and ergonomic risk factors in female workers. All female workers underwent a medical interview and a complete physical investigation. The clinical diagnoses of Raynaud's phenomenon and carpal tunnel syndrome (CTS) were made according to international consensus criteria. Hand-transmitted vibration from orbital sanders was measured according to International Organization for Standardization (ISO) recommendations. Daily vibration exposure was assessed in terms of 8-h energy-equivalent frequency-weighted acceleration [A(8)] according to the European Directive on physical agents. Ergonomic load on the upper limbs was estimated by means of strain index methodology. There was no significant difference in the prevalence of Raynaud's phenomenon between the furniture workers (4%) and the controls (8%). The prevalence of CTS, peripheral sensorineural disturbances (after exclusion of CTS cases) and upper-limb musculoskeletal complaints was significantly greater in the furniture workers than in the controls. CTS was clinically diagnosed in 19% of the furniture workers and 8% of the controls. A log-binomial regression analysis showed that the occurrence of soft-tissue disorders of the upper limb increased significantly with the increase of both daily vibration exposure and the strain index score. It was estimated that the risk for CTS increased by a factor of 1.30 (95% CI 1.11-1.53) for each unit of increase in A(8) (ms(-2)), and by 1.09 (95% CI 1.02-1.15) for each unit of increase in the strain index score. Even though the cross-sectional design of this epidemiological study does not allow aetiological considerations, our findings suggest a significant association between occupational use of vibratory tools and soft-tissue disorders in the upper limbs of female workers. Quantitative estimation of vibration exposure and ergonomic stress showed that these physical risk factors seem to contribute in a multiplicative way to the occurrence of chronic nerve and musculoskeletal disorders in female workers operating hand-held vibrating tools in the furniture industry.

A Longitudinal Study of Industrial and Clerical Workers: Incidence of Carpal Tunnel Syndrome and Assessment of Risk Factors

This study followed workers over an extended period of time to identify factors which may influence the onset of Carpal Tunnel Syndrome (CTS). The purpose was to evaluate incidence of CTS and to create a predictive model of factors that play a role in the development of CTS. This prospective study followed 432 industrial and clerical workers over 5.4 years. Incident cases were defined as workers who had no prior history of CTS at baseline testing and were diagnosed with CTS during the follow-up period or at the follow-up screening. On the basis of logistic regression, significant predictors for CTS include baseline median-ulnar peak latency difference, a history of wrist/hand/finger tendonitis, a history of numbness, tingling, burning, and/or pain in the hand, and work above the action level of the peak force and hand activity level threshold limit value. This longitudinal study supports findings from previous cross-sectional studies identifying both work related ergonomic stressors and physical factors as independent risk factors for CTS.

Digital vibration threshold testing and ergonomic stressors in automobile manufacturing workers: a cross-sectional assessment

Upper extremity musculoskeletal disorders (UEMSDs) comprise a large proportion of work-related illnesses in the USA. Physical risk factors including manual force and segmental vibration have been associated with UEMSDs. Reduced sensitivity to vibration in the fingertips (a function of nerve integrity) has been found in those exposed to segmental vibration, to hand force, and in office workers. The objective of this study was to determine whether an association exists between digital vibration thresholds (VTs) and exposure to ergonomic stressors in automobile manufacturing. Interviews and physical examinations were conducted in a cross-sectional survey of workers (n=1174). In multivariable robust regression modelling, associations with workers' estimates of ergonomic stressors stratified on tool use were determined. VTs were separately associated with hand force, vibration as felt through the floor (whole body vibration), and with an index of multiple exposures in both tool users and non-tool users. Additional associations with contact stress and awkward upper extremity postures were found in tool users. Segmental vibration was not associated with VTs. Further epidemiologic and laboratory studies are needed to confirm the associations found. The association with self-reported whole body vibration exposure suggests a possible sympathetic nervous system effect, which remains to be explored.

Ergonomic Concerns of Pregnant Workers: An Exploration of Existing Research

Pregnant women, though typically numbering one million a year in the United States workforce, are often neglected by the ergonomic community. This claim is supported by considering available literature from a variety of sources including peer reviewed ergonomic journals, ergonomics text books, general web searches, cites pulled from seminal research articles, and reviews of the NIOSH and OSHA WebPages. Results show that only a few researchers have attempted to go beyond back pain and carpal tunnel syndrome concerns to consider other ergonomic factors affecting pregnant women. More information concerning the health of the fetus is available than the health and well-being of the pregnant women. Much of the research that focuses on pregnant women separate from their fetuses is nearly a decade old, leaving a tremendous gap in current research. Clearly additional and varied research considering both long and short term effects of ergonomic stressors on pregnant women are warranted.