Work-related Low Back Disorders Research Articles

Risk Factors for Recurrent Episodes of Work-Related Low Back Disorders in an Industrial Population

An observational longitudinal design. To characterize the rate of and risk factors for recurrent episodes of work-related low back disorder in industrial workers. Little data exist on risk factors for recurrent episodes of work-related low back disorders in employed persons. A total of 352 active hourly union employees who were diagnosed with a recent work-related low back disorder and who had at least one follow-up visit within 12 months enrolled for participation in a rehabilitation intervention study at the workplace. Information on clinical and job factors was obtained at each study visit. Job risk for low back disorder was quantified using the Lumbar Motion Monitor. The main outcome measure, recurrence of work-related low back pain, was derived from a computerized file of administrative records of visits to the plant's medical department. The rate of repeated episodes was 24.4%; an additional episode occurred in 2.3%. Adjusting for age, gender, health status and job exposures, lower levels of physical health, increasing back pain disability, spinal deformity, high stress, and increasing number of different jobs worked at the same plant were risk factors for a recurrent episodes of low back pain. Early identification of risk factors for a work-related low back disorder may signal the need for early and intense rehabilitation to prevent recurrent episodes. Because these findings were based on jobs with medium risk of low back disorders, other factors may be significant in higher risk jobs.

Cumulative Effects of Load Frequency and Velocity on the Lumbar Spine Response during a Repetitive Lifting Task

Work—related low back disorders arise from a complex interaction of events. One aspect of interest is cyclic or repetitive tasks, which are performed on a daily basis in a variety of situations, and often for extended periods of time. The specific questions to be addressed in this study are the effects of the load frequency and time-dependent material properties on the lumbar spine component behavior. The newly developed and validated, subject specific, finite element model of lumbar spine is used in conjunction with kinematic data imported from human subjects experimental testing of repetitive sagittally-symmetric lifting and lowering tasks. Creep and energy dissipation in the lumbar spine components are used to quantify the effect of lifting frequency and velocity on the potential for injury over an eight-hour workday.

Classification of jobs with risk of low back disorders by applying data mining techniques

Work related low back disorders (LBDs) continue to pose significant occupational health problem that affects the quality of life of the industrial population. The main objective of this study was to explore the application of various data mining techniques, including neural networks, logistic regression, decision trees, memory-based reasoning, and the ensemble model, for classification of industrial jobs with respect to the risk of work-related LBDs. The results from extensive computer simulations using a 10-fold cross validation showed that memory-based reasoning and ensemble models were the best in the overall classification accuracy. The decision tree and memory-based reasoning models were the most accurate in classifying jobs with high risk of LBDs, whereas neural networks and logistic regression were the best in classifying jobs with low risk of LBDs. The decision tree model delivered the most stable results across 10 generations of different data sets randomly chosen for training, validation, and testing. The classification results generated by the decision tree were the easiest to interpret because they were given in the form of simple 'if-then' rules. These results produced by the decision tree method showed that the peak moment had the highest predictive power of LBDs.

Individual and combined impacts of biomechanical and work organization factors in work-related musculoskeletal symptoms.

Investigations of work-related low back (LB) and upper extremity (UE) disorders have increasingly utilized multivariable models that include biomechanical/physical and work organization factors. However, the nature of any interactive effects is not well understood. Using questionnaires, high and low exposure groups for biomechanical/physical factors, cognitive demands, cognitive processing, interpersonal demands, participatory management, skill discretion, and time pressure for 289 individuals (U.S. Marines) were identified. Musculoskeletal symptom status was also determined by questionnaire. Individual and biomechanical-psychosocial combinations were examined in adjusted multivariable logistic regression analyses. Time pressure was associated with both LB and UE symptoms (odds ratio(s) (OR) range = 2.13-3.09), while higher biomechanical exposures were risk factors for LB symptoms (OR = 2.07; 95% confidence intervals (CI): 1.00-4.35) and concurrent LB and UE symptoms (OR = 2.80; CI: 1.35-5.83). Greater risks for concurrent LB and UE symptoms were indicated for combinations involving higher biomechanical exposure and: time pressure (OR = 2.21; CI: 1.19-4.10); cognitive demands (OR = 2.25; CI: 1.23-4.09); cognitive processing (OR = 2.08; CI: 1.16-3.75); interpersonal demands (OR = 2.44; CI: 1.35-4.41); participatory management (OR = 2.50; CI: 1.30-4.81). Results did not suggest any interaction between biomechanical and work organization factors. While no synergism was indicated, the present findings emphasize the need to consider both biomechanical factors and specific work organization factors, particularly time pressure, in reducing musculoskeletal-related morbidity.

A survey of lifting and lowering tasks

An assessment of 1063 lifting and lowering tasks was conducted, and the individual task parameters were analyzed. The survey was conducted as part of an epidemiological study of the relationship between low-back workers’ compensation claims and the physical demands of lifting and lowering tasks. The primary objective of the study was to provide summary statistics of the parameter values of a large sample of actual lifting and lowering tasks. The 10, 25, 50, 75, and 90 percentile values of the parameters of the lifting tasks, defined in accordance with the NIOSH lifting equation, are presented. A secondary objective of the study was to compare the results to a previous survey of lifting and lowering tasks. The results showed fairly strong agreement with the previous survey with the exception of load and frequency. The median load from the current survey was approximately one half the value found previously whereas the median frequency was approximately double. The potential reasons for these differences are explored. The results are also compared to several epidemiologic studies of repetitive lifting/lowering. Relevance to industry Prevention of work-related low-back disorders continues to be a critical component of workplace health and safety programs. The parameters of lifting and lowering tasks are summarized to provide benchmarks for practitioners as well as researchers investigating lifting and lowering tasks in the laboratory.

Trends in research and prevention policies for work-related musculoskeletal disorders at the European Agency for Safety and Health at Work (EU-OSHA)

The European Agency for Safety and Health at Work (EU-OSHA) has been working on matters related to occupational health problems in 15 European Union (EU) member states. EU-OSHA established 10 topic centers on work and health research in 1998. One of the topic centers is assigned for research and information on work-related musculoskeletal disorders. The present report is written because such activities of EU-OSHA are scarcely known in Japan. Work-related musculoskeletal disorders have become a very serious problem in EU member states, i.e., 30% of workers complain of backache, and 17% complain of muscular pains in their arms and legs. The affected workers not only suffer at work but also in their home life. The economic costs of all work-related ill health range from 2.6 to 3.8% of the gross national product, and work-related musculoskeletal disorders constitute 40-50% of this. Therefore EU member states consider that prevention of work-related musculoskeletal disorders in itself is an extremely good economic policy. EU-OSHA published "Work-related neck and upper limb musculoskeletal disorders" in 1999, and "Research on work-related low back disorders" in 2000. These publications suggest various preventive methods which can be introduced in practice at work. One of the most remarkable things in EU-OSHA's activities for work-related musculoskeletal disorders is that EU-OSHA has been trying hard to introduce the results of its research into real policies for EU member states by several means, i.e., held a seminar participated in by policy makers, representatives of trade unions, and researchers from EU member states, and sent seminar resolutions to politicians who are responsible for employment and social affairs. Finally the resolution has been adopted in a new social affairs policy by the EU parliament and will be put into force during 2002. Work-related musculoskeletal disorders will remain one of the most serious occupational problems in EU member states, and EU-OSHA will continue to pay close attention to it.

Job exposures as correlates of recovery in population-based rehabilitation intervention for work-related low back disorders

PURPOSE: Evaluating the impact of population-based rehabilitation interventions for work-related low back disorders (WR-LBD) requires job exposure factors to be considered as time-varying covariates. The role of job factors in recovery has not been well-established as most studies are based upon clinic samples, not working populations. This report represents the initial exploration of variables to be included in modeling job exposures as time-varying covariates of a study of work-place based rehabilitation intervention.METHODS: The study sample consisted of 162 hourly production employees from two automotive plants with work-related low back disorder not due to external trauma. Data reported herein were collected at baseline from an on-going large randomized clinical trial of rehabilitation for WR-LBD. Low back pain as measured by the North American Spine Society Baseline Form was examined in relation to: self-reported job factors from the Job Content Questionnaire and job risk category for low back disorder determined by the Lumbar Motion Monitor (LMM), an electronic goniometer which transmits back motion signals to a computer for analysis.RESULTS: Low back pain, with and without leg pain, was not found to be associated with hours worked in the previous week, job shift, perceptions of the pace of the job, or job risk of low back disorder as measured by the LMM. Low back pain was significantly (p < 0.05) correlated with perceptions of: how hard the work was, how much physical effort was required, how hectic the job was, whether or not there was sufficient time to do the job, and how much concentration and physical effort were required for the job.CONCLUSIONS: Self-report of perceptions of job strain may be as important, if not more important, than current quantitative factors thought to influence recovery from work-related low back pain.

A Test of the LiftTrainer: An Aggressive Approach for Preventing Back Injuries Through Training

Most jobs in warehousing and distribution require a considerable amount of manual material handling. Many studies have shown that the way an individual lifts and handles objects can have a substantial impact on the resulting spine loads (Buseck, Schipplein, Andersson, & Andriacchi, 1988; de Looze, Toussaint, van Dieen, & Kemper, 1993; Dolan, Mannion, & Adams, 1994; Leskinen, Stalhammar, Kuorinka, & Troup, 1983; Toussaint, van Baar, van Langen, de Looze, & van Dieen, 1992; van Dieen, Hoozemans, & Toussaint, 1999). This suggests that training on manual material handling (lifting) techniques potentially plays a critical role in the prevention of work related low back disorders. The purpose of this study was to quantify the effectiveness of a new behavior-based approach for training workers on lifting techniques.

Association between recovery outcomes for work-related low back disorders and personal, family, and work factors.

Incident cases of work-related low back disorders were identified in an automotive metal stamping plant. Individuals were asked to recall health and work habits at the time of diagnosis of the work-related disorder and to report their current low back pain and physical functioning. To evaluate five measures of health outcomes for work-related low back disorders in an industrial population and to determine potentially modifiable correlates of recovery. The factors that influence recovery in actively working adults and how to best measure recovery outcome in this population are not well known. Eighty-eight hourly employees of a metal stamping plant who experienced a work-related low back disorder were interviewed. Health status, health habits, and family and work relations were assessed with a structured interview to determine their association with various recovery outcomes (low back pain, low back pain disability, physical functioning, general physical health, and lost workdays). Interview information was supplemented with data from the plant's Occupational Safety and Health Administration Form 200 log. The clinical measures of recovery from the work-related low back disorders examined had similar overall predictive ability. However, in multivariate analyses, different potentially modifiable prognostic variables emerged as significant among them. Poorer self-rated health status and high personal stress were correlated with low back pain disability. Higher levels of cigarette smoking were correlated with higher levels of low back pain disability, lower physical functioning, and more severe low back pain at follow-up. The choice of measure of recovery from work-related low back disorders should be made in the context of the rehabilitation intervention goal. Interventions designed to modify and promote healthful personal behavior should be given more emphasis in rehabilitation efforts for work-related low back disorders.

A Comparison of Four Methods Commonly Used to Determine Low-Back Disorder Risk in a Manufacturing Environment

Manual material lifting is a major risk factor for work-related low back disorders (LBD's). Several methods for quantifying the specific aspects of lifting which are believed to contribute to LBD's have been developed and are beginning to be used in industry for job evaluation and re-design. The optimal method for determining the risk of occupational LBD on a population basis has not been determined. This study compared four evaluation methods used to assess occupational LBD risk in manual material handling tasks. The job evaluation methods examined were: the 1993 NIOSH model, the UAW-GM Ergonomic Risk Factor Checklist, the Static Strength Prediction Model, and the Lumbar Motion Monitor (LMM) model. The four methods were selected because they represent either common practice within the automotive industry, the result of governmental efforts to protect the work force, or models thought to be the most scientifically advanced. The analysis presented here was based on a random sample of production jobs in an automotive metal fabricating plant. The study population was comprised of automotive workers who perform materials handling operations. The sixty two jobs were all performed by three or more full time employees. Inter-correlations between measures were computed. In general, the inter-correlations while statistically significant (p&lt;.05) were low (r &lt; .42). This indicates that the different measures are most likely assessing different aspects of the work process.

The influence of personal variables on work-related low-back disorders and implications for future research.

Work-related low-back disorders (LBDs) continue to be one of the single largest sources of compensation costs. The relative contributions of personal, workplace, organizational, and environmental variables to the development and severity of LBDs are not completely understood. The inclusion of personal variables in epidemiologic studies of LBDs has been inconsistent, and different authors have different opinions concerning the importance of such variables. Personal variables either known or suspected to influence outcomes are discussed to elucidate the importance of these variables with respect to understanding LBDs and conducting epidemiological studies in industry. The authors suggest that age, gender, injury history, relative strength, smoking, and psychosocial variables be studied further, and that height, weight, pathologies, genetic factors, maximum oxygen uptake, and absolute strength are unlikely to produce significant effects in industrial populations.