American Journal of Industrial Medicine
January 2009 Volume 52, Issue 1
Impact of implementing the washington state ergonomics rule on employer reported risk factors and hazard reduction activityMichael Foley, MA 1 *, Barbara Silverstein, PhD, MPH, CPE 1, Nayak Polissar, PhD 2, Blazej Neradilek, MS 2
1Safety and Health Assessment and Research for Prevention (SHARP) Program, Washington State Department of Labor and Industries, Olympia, Washington
2The Mountain-Whisper-Light-Statistical Consulting, Seattle, Washington
email: Michael Foley ()
Abstract
Background
In Washington State an ergonomics rule was adopted in 2000 that focused on primary prevention. The implementation process followed a 6-year phase-in schedule where employers came into compliance based upon their size and industry. In late 2003 the rule was repealed by an industry-funded voter initiative. Evaluating the implementation of this rule offers a unique opportunity to observe the general deterrent effect of a new public health regulation and to study how employers and workers responded to new requirements.
Methods
Weighted survey regression methods were used to analyze the results from three employer surveys covering more than 5,000 workplaces administered in 2001, 2003, and 2005. These were compared to a baseline employer survey conducted in 1998 before the rule was promulgated. Questions covered the following topics: WMSDs experienced at the workplace; levels of employee exposure to musculoskeletal hazards; steps being taken, if any, to address these hazards; results of these steps; and sources of ergonomic information/assistance used.
Results
From 1998 to 2003 there was a reduction in reported exposures among workplaces in the highest hazard industries. Following the rule's repeal, however, hazard exposures increased. While more workplaces reported taking steps to reduce exposures between 1998 and 2001, this gain was reversed in 2003 and 2005. Employers who took steps reported positive results in injury and absenteeism reduction. Large workplaces in the high hazard industries were more active in taking steps and used a wide variety of resources to address ergonomics issues. Small employers relied more on trade associations and the state. Am. J. Ind. Med. 52:1-16, 2009. © 2008 Wiley-Liss, Inc.
American Journal of Industrial Medicine, January 2009
Psychosocial factors and shoulder symptom development among workersCaroline K. Smith, MPH 1 *, Barbara A. Silverstein, PhD, MPH, CPE 1, Z. Joyce Fan, PhD 1, Stephen Bao, PhD, CPE 1, Peter W. Johnson, PhD 2
Abstract
Background
Shoulder injuries are a common cause of pain and discomfort. Many work-related factors have been associated with the onset of shoulder symptoms. The psychosocial concepts in the demand-control model have been studied in association with musculoskeletal symptoms but with heterogeneous findings. The purpose of this study was to assess the relationship between the psychosocial concepts of the demand-control model and the incidence of shoulder symptoms in a working population.
Methods
After following 424 subjects for approximately 1 year, 85 incident cases were identified from self-reported data. Cox proportional hazards modeling was used to assess the associations between shoulder symptoms and demand-control model quadrants.
Results
Cases were more likely to be female and report other upper extremity symptoms at baseline (P0.05). From the hazard models, being in either a passive or high strain job quadrant was associated with the incidence of shoulder symptoms. Hazard ratios were 2.17, 95% CI 1.02-4.66 and 2.19, 95% CI 1.08-4.42, respectively.
Conclusions
Using self-reporting to determine demand-control quadrants was successful in identifying subjects at risk of developing work-related shoulder symptoms. Research is needed to determine if this relationship holds with clinically diagnosed shoulder and other upper extremity musculoskeletal disorders. This may be part of a simple tool for assessing risk of developing these UEMSDs. Am. J. Ind. Med. 52:57-68, 2009. © 2008 Wiley-Liss, Inc.
American Journal of Industrial Medicine, December 2008
December 2008 Volume 51, Issue 12
Predictors of upper extremity symptoms and functional impairment among workers employed for 6 months in a new jobBethany T. Gardner, OTD, OTR 1, Ann Marie Dale, MS, OTR/L 2, Linda VanDillen, PT, PhD 3, Alfred Franzblau, MD 4, Bradley A. Evanoff, MD, MPH 2 *
Abstract
Background
We sought to identify personal and work-related predictors of upper extremity symptoms and related functional impairment among 1,108 workers employed for 6 months in a new job.
Methods
We collected data at baseline and 6-month follow-up using self-administered questionnaires. Multivariate logistic regression models were created for each outcome variable. Predictors included personal risk factors, physical work exposures and psychosocial factors.
Results
Independent predictors for upper extremity symptoms at 6-month follow-up were age, Caucasian race, female gender, baseline history of UE symptoms, and job tasks involving wrist bending or forceful gripping. Independent predictors for functional impairment were baseline history and severity of UE symptoms, wrist bending, and social support.
Conclusions
Both personal and work-related factors were independent predictors of upper extremity symptoms and functional impairment in this working population. We found different risk factors for symptoms than for functional impairment related to symptoms. Am. J. Ind. Med. 51:932-940, 2008. © 2008 Wiley-Liss, Inc.
January 2009 (Volume 40, Issue 1)
National occupational research agenda (NORA) future directions in occupational musculoskeletal disorder health research
William S. Marras, Robert G. Cutlip, Susan E. Burt, Thomas R. Waters
Abstract
Musculoskeletal disorders are among the most costly health care problems facing society today. The scientific literature has indicated that psychosocial factors, individual factors, workplace physical requirements, and workplace organizational factors have been associated with risk. Since musculoskeletal risk is multi-dimensional, the magnitude of risk attributable to various factors can be of importance to scientists and policy makers in designing countermeasures to reduce injury incidence. Traditionally, the disciplines of biomechanics, physiology, and psychophysics have dominated the body of knowledge that has defined exposure limitations to work. However, recent research has explored the association of psychosocial and work organization factors with musculoskeletal problems. Advances have been made to better quantify the levels of occupational exposure by improved exposure metrics, quantification of three-dimensional loads experienced by certain joints (e.g. the spine), identification of tissue tolerance limits and tissue response to mechanical stresses, and the impact of psychosocial stresses. However, efforts to quantitatively link epidemiological, biomechanical loading, soft tissue tolerance, and psychosocial studies should be pursued to establish a better understanding of the pathways of injury and resultant preventive strategies. Although we are beginning to understand how the major risk factors influence the load–tolerance relationship of human tissue, how these risk factors interact is virtually unexplored. Since the impact of the interactions may be far greater than that of any individual factor, the impact of the interactions between risk factors must be delineated so that work-related risk can be better quantified. Efforts to quantitatively link epidemiological, biomechanical loading, soft tissue tolerance, and psychosocial studies should be pursued to establish a better understanding of the pathways of injury and resultant preventive strategies.
January 2009
A visual ergonomic evaluation of different screen types and screen technologies with respect to discrimination performance
Sophie Oetjen, Martina Ziefle
Abstract
An increasing demand to work with electronic displays and to use mobile computers emphasises the need to compare visual performance while working with different screen types. In the present study, a cathode ray tube (CRT) was compared to an external liquid crystal display (LCD) and a Notebook-LCD. The influence of screen type and viewing angle on discrimination performance was studied. Physical measurements revealed that luminance and contrast values change with varying viewing angles (anisotropy). This is most pronounced in Notebook-LCDs, followed by external LCDs and CRTs. Performance data showed that LCD's anisotropy has negative impacts on completing time critical visual tasks. The best results were achieved when a CRT was used. The largest deterioration of performance resulted when participants worked with a Notebook-LCD. When it is necessary to react quickly and accurately, LCD screens have disadvantages. The anisotropy of LCD-TFTs is therefore considered to be as a limiting factor deteriorating visual performance.
The effects of an office ergonomics training and chair intervention on worker knowledge, behavior and musculoskeletal risk
Michelle Robertson, Benjamin C. Amick III, Kelly DeRango, Ted Rooney, Lianna Bazzani, Ron Harrist, Anne Moore
Abstract
A large-scale field intervention study was undertaken to examine the effects of office ergonomics training coupled with a highly adjustable chair on office workers’ knowledge and musculoskeletal risks. Office workers were assigned to one of three study groups: a group receiving the training and adjustable chair (n=96), a training-only group (n=63), and a control group (n=57). The office ergonomics training program was created using an instructional systems design model. A pre/post-training knowledge test was administered to all those who attended the training. Body postures and workstation set-ups were observed before and after the intervention. Perceived control over the physical work environment was higher for both intervention groups as compared to workers in the control group. A significant increase in overall ergonomic knowledge was observed for the intervention groups. Both intervention groups exhibited higher level behavioral translation and had lower musculoskeletal risk than the control group.
January 2009
Rater reliability and concurrent validity of the Keyboard Personal Computer Style instrument (K-PeCS)
Nancy A. Baker, James R. Cook, Mark S. Redfern
Abstract
This paper describes the inter-rater and intra-rater reliability, and the concurrent validity of an observational instrument, the Keyboard Personal Computer Style instrument (K-PeCS), which assesses stereotypical postures and movements associated with computer keyboard use. Three trained raters independently rated the video clips of 45 computer keyboard users to ascertain inter-rater reliability, and then re-rated a sub-sample of 15 video clips to ascertain intra-rater reliability. Concurrent validity was assessed by comparing the ratings obtained using the K-PeCS to scores developed from a 3D motion analysis system. The overall K-PeCS had excellent reliability [inter-rater: intra-class correlation coefficients (ICC)=.90; intra-rater: ICC=.92]. Most individual items on the K-PeCS had from good to excellent reliability, although six items fell below ICC=.75. Those K-PeCS items that were assessed for concurrent validity compared favorably to the motion analysis data for all but two items. These results suggest that most items on the K-PeCS can be used to reliably document computer keyboarding style.
Applied Ergonomics November 2008 (Volume 39, Issue 6)
Usability of pointing devices for office applications in a moving off-road environment
Thorsten Baldus, Patrick Patterson
Abstract
Three pointing devices (mouse, touch pad, touch screen) were evaluated for usability with a Windows™-style menu selection task while in a moving off-road environment. A pilot study determined which commercially available devices had the potential to promote good performance in the environment. Eighteen subjects performed a series of complex pointing tasks that simulated the use of a standard application in a moving tractor. The devices were also rated for subjective usability. The mouse and the touch screen produced the best performances, with the mouse receiving the best subjective usability ratings. The participants had a significantly lower performance with the touch pad, which also received lower ratings in the subjective usability ratings.
November 2008
Test–retest reliability and concurrent validity of a web-based questionnaire measuring workstation and individual correlates of work postures during computer work
Stefan IJmker, Janneke Mikkers, Birgitte M. Blatter, Allard J. van der Beek, Willem van Mechelen, Paulien M. Bongers
Abstract
Introduction: “Ergonomic” questionnaires are widely used in epidemiological field studies to study the association between workstation characteristics, work posture and musculoskeletal disorders among office workers. Findings have been inconsistent regarding the putative adverse effect of work postures. Underestimation of the true association might be present in studies due to misclassification of subjects to risk (i.e. exposed to non-neutral working postures) and no-risk categories (i.e. not exposed to non-neutral working postures) based on questionnaire responses. The objective of this study was to estimate the amount of misclassification resulting from the use of questionnaires.
Methods: Test–retest reliability and concurrent validity of a newly developed questionnaire was assessed. This questionnaire collects data on workstation characteristics and on individual characteristics during computer work (i.e. work postures, movements and habits). Pictures were added where possible to provide visual guidance. The study population consisted of 84 office workers of a research department. They filled out the questionnaire on the Internet twice, with an in-between period of 2 weeks. For a subgroup of workers (n=38), additional on-site observations and multiple manual goniometer measurements were performed.
Results: Percentage agreement ranged between 71% and 100% for the test–retest analysis, between 31% and 100% for the comparison between questionnaire and on-site observation, and between 26% and 71% for the comparison between questionnaire and manual goniometer measurements. For 9 out of 12 tested items, the percentage agreement between questionnaire and manual goniometer measurements was below 50%.
Conclusions: The questionnaire collects reliable data on workstation characteristics and some individual characteristics during computer work (i.e. work movements and habits), but does not seem to be useful to collect data on work postures during computer work in epidemiological field studies among office workers.
November 2008
Effects of variable lighting intensities and colour temperatures on sulphatoxymelatonin and subjective mood in an experimental office workplace
Georg Hoffmann, Veronika Gufler, Andrea Griesmacher, Christian Bartenbach, Markus Canazei, Siegmund Staggl, Wolfgang Schobersberger
Abstract
Workplace illumination is of paramount importance in determining the employee's productivity and well-being. Moreover, light exerts non-visual effects with respect to biological rhythms. In this study, we investigated the impact of different lighting conditions (500–1800lx, 6500K; 500lx, 4000K) on sulphatoxymelatonin (aMT6-s) and subjective mood in an experimental office accommodation. Urinary aMT6-s concentrations were significantly decreased at all days of the experiment in both lights. On day 3, differences between aMT6-s concentrations in specimen collected at 05:00p.m. and at 09:00a.m. were significantly higher under variable lighting conditions. Analyses of a mood rating inventory revealed a benefit of variable light with respect to the dimensions of “Activity”, while “Deactivation” and “Fatigue” were increased in regular light on day 1. “Activity”, “Concentration”, and “Deactivation” changed in opposite directions when comparing variable with regular illumination on two consecutive days. In conclusion, variable light exerts a potential advantage in indoor office accommodations with respect to subjective mood, although no unequivocal