The test-retest reliability of a new occupational risk factor questionnaire for outcome studies of low back pain

Prevalence and Biopsychosocial Factors Associated With a Current Episode of Low Back Pain Among Adults With a Previous History of Low Back Pain: A Cross-sectional Study of Market Traders in an African Population

Low back pain (LBP) is the leading cause of years lived with disability globally, with Nigeria having one of the greatest burdens. A current episode of LBP is important in Nigeria, but the associated factors are unknown. This cross-sectional study investigated the prevalence, biomechanical, and psychosocial factors associated with a current episode of LBP among 700 adult market traders with previous LBP in an urban Nigerian population. Descriptive, bivariate, and multivariate analyses were conducted. The prevalence of a current episode of LBP was 76.4%. Factors associated with an increased risk of a current episode of LBP in a decreasing order of importance were exposure to biomechanical factors (aggregate [total] score) (odds ratio [OR] = 1.535; 95% confidence interval [CI] = 1.398-1.685); anxiety (OR = 1.182; 95% CI = 1.089-1.282); fear-avoidance beliefs (physical activity) (OR = 1.139; 95% CI = 1.029-1.261); fear-avoidance beliefs (work) (OR = 1.105; 95% CI = 1.047-1.165); while factors associated with a reduced risk of a current episode of LBP were ability to take breaks in the job in addition to scheduled breaks (OR = .430; 95% CI = .240-.773) and ability to control the order and pace of tasks (OR = .477; 95% CI = .236-.965). Occupational biomechanical and psychosocial factors were associated with a current episode of LBP in logistic regression models explaining 52.7% and 73.1% of the variation in a current episode of LBP. Occupational biomechanical factors, particularly handling large and bulky objects at arm's length and kneeling and squatting, produced the greatest risk of a current episode of LBP. PERSPECTIVE: Occupational biomechanical factors, occupational psychosocial factors, and personal psychosocial factors such as anxiety and fear-avoidance beliefs are associated with a current episode of LBP in Nigeria. Pragmatic public health and occupational health initiatives that modify exposure to these factors may be required in Nigeria.

Occupational biopsychosocial factors associated with neck pain intensity, neck-disability, and sick leave: A cross-sectional study of construction labourers in an African population

INTRODUCTION

The burden and impact of neck pain is high in African countries including Nigeria. This study investigated the occupational biomechanical and occupational psychosocial factors associated with neck pain intensity, neck disability and sick leave amongst construction labourers in an urban Nigerian population.

METHODS

This cross-sectional study measured clinical neck pain outcomes, occupational biomechanical factors, and occupational psychosocial factors. Descriptive, and univariate/multivariate inferential statistical analyses were conducted.

RESULTS

Significant independent factors associated with neck pain intensity were order and pace of tasks being dependent on others (β = 0.35; p<0.0001); inability to take breaks in addition to scheduled breaks (β = 0.25; p<0.0001); inability to work because of unexpected events (β = 0.21; p<0.0001); inability to control the order and pace of tasks (β = 0.20; p<0.0001); and weight of load (β = 0.17; p<0.0001); accounting for 53% of the variance in neck pain intensity. Significant independent factors associated with neck disability were weight of load (β = 0.30; p<0.0001); duration of load carriage (β = 0.16; p = 0.01); working under time pressure/deadlines (β = 0.16; p = 0.02); and accounting for 20% of the variance in neck disability. Significant independent factor associated with sick leave was duration of load carriage (β = 0.15; p = 0.04), in a non-significant regression model explaining -4% of the variance in sick leave. Addition of pain intensity significantly explained more variance in neck disability (31.0%) but less variance in sick leave (-5%), which was not statistically significant (F (10, 190) = 0.902, p = 0.533).

CONCLUSIONS

Occupational biomechanical factors may be more important than occupational psychosocial factors in explaining neck disability and sick leave. In contrast, occupational psychosocial factors may be more important than occupational biomechanical factors in explaining neck pain intensity in this population in Nigeria.

Challenges of Measuring Self-Reported Exposure to Occupational Biomechanical Risk Factors Amongst People with Low Literacy Engaged in Manual Labour: Findings from a Cross-Cultural Adaptation and Psychometric Investigation in an African Population with Chronic Low Back Pain

PURPOSE

Occupational biomechanical factors are implicated in the aetiology and progression of low back pain (LBP). This study cross-culturally adapted and psychometrically investigated the Occupational Risk Factor Questionnaire (ORFQ) in a low literate Nigerian Igbo population with chronic LBP.

METHODS

Forward and back translation of the original ORFQ by clinical and non-clinical translators was followed by an expert committee review. The adapted ORFQ was pre-tested amongst rural Nigerian adults with chronic LBP using cognitive think-aloud interviewing. Internal consistency (Cronbach's alpha) and test-retest reliability (unweighted and linear weighted k statistic for item-by-item agreement, and intra-class correlation coefficient-ICC) were investigated amongst 50 rural and urban Nigerian dwellers with chronic LBP. Spearman's correlation and regression analyses were conducted with the Igbo-ORFQ, and measures of disability [World Health Organisation Disability Assessment Schedule (WHODAS 2.0), Roland Morris Disability Questionnaire (RMDQ), Back performance scale (BPS)], pain intensity [Eleven-point box scale (BS-11)] and social support [Multidimensional Scale of Perceived Social Support (MSPSS)], to test construct validity with 200 rural Nigerian dwellers with chronic LBP.

RESULTS

Cross-cultural adaptation highlighted difficulty conceptualising and concretising exposure to biomechanical risk factors. Item-by-item agreement, internal consistency (α = 0.84) and intraclass correlation coefficient (ICC = 0.83) were good. Some unexpected direction of associations between the biomechanical components of the Igbo-ORFQ, and disability, pain intensity, and social support prohibits establishment of construct validity.

CONCLUSION

Prospective studies comparing the Igbo-ORFQ to other measures of exposure to occupational biomechanical risk factors are required to establish the construct validity of the Igbo-ORFQ.

Agreement between observed and interview-based exposure to ergonomics factors for the upper extremities in employees of a package sorting plant

Aim of the study was to estimate agreement between observational and interview-based exposure to ergonomic factors at work. Thirty-two male workers employed in a logistics hub were interviewed through the OCRA check-list on exposure to ergonomic factors in one of six work tasks. Observations of workers in each work task, based on the same OCRA check-list, were used to assess exposure in that task. Agreement between observed and interview-based scores of the check-list OCRA index, as well as of frequency and posture, was estimated both at individual and task group level through the Intraclass Correlation Coefficient (ICC). At work task level, high concordance was found between observed and interview-based scores for all the exposures examined, while at the individual level agreement was moderate. These results suggest that exposure assessment through interviews based on the OCRA check-list is a valid method, which could be used as a workstation screening tool. Practitioner summary: The study aimed to evaluate agreement between observational and interview-based exposure to ergonomic factors at work, assessed through the OCRA check-list on 32 male workers. Agreement was found at least moderate, suggesting that interview-based exposure assessed through the OCRA check-list could be used as a proxy of observations for workstation screening. Abbreviations: ART: assessment of repetitive tasks; CI: confidence intervals; EAWS: European assembly worksheet; ICC: intraclass correlation coefficient; ISO: International Standards Organization; OCRA: occupational repetitive actions; ULRA: upper limb risk assessment; WUEMSDs: work-related upper extremity musculoskeletal disorders.

Upper-extremity musculoskeletal disorders: how many cases can be prevented? Estimates from the COSALI cohort

Objective:

This study aimed to estimate the proportion and number of incident upper-extremity musculoskeletal disorders (UEMSD) cases attributable to occupational risk factors in a working population.

Methods:

Between 2002−2005, occupational physicians randomly selected 3710 workers, aged 20–59, from the Pays de la Loire (PdL) region. All participants underwent a standardized clinical examination. Between 2007−2010, 1611 workers were re-examined. This study included 1246 workers who were free of six main clinically diagnosed UEMSD at baseline but were diagnosed with at least one of these UEMSD at follow-up [59% of men, mean age: 38 (standard deviation 8.6) years]. Relative risks and population-attributable fractions (PAF) were calculated using Cox multivariable models with equal follow-up time and robust variance. The total number of incident UEMSD in the PdL region was estimated after adjustment of the sample weights using 2007 census data. The estimated number of potentially avoidable UEMSD was calculated by multiplying PAF by the total number of incident UEMSD in PdL.

Results:

At follow-up, 139 new cases of UEMSD (11% of the study sample) were diagnosed. This represented an estimated 129 320 incident cases in the PdL in 2007. Following adjustment for personal factors, 26 381 (20.4% of all incident UEMSD) were attributable to high physical exertion, 16 682 (12.9%) to low social support, and 8535 (6.6%) to working with arms above shoulder level.

Conclusions:

A large number and important proportion of incident UEMSD may be preventable by reducing work exposures to physical exertion and working with arms above shoulder level as well as improving social support from co-workers/supervisors.

[Measuring work-related physical demand: factorial structure and reliability of items on posture, handling of loads and repetitiveness]

This study sought to analyze the dimensionality of a set of items that measure work-related physical demand, their internal consistency and their test-retest reliability. We carried out an exploratory factorial analysis of ten physical demand items in two populations, totaling 1,070 workers from the footwear industry and from urban cleaning, using weighted least squares means and adjusted variance with Promax oblique rotation. We measure internal consistency using Cronbach's alpha. The test-retest used a subsample of 121 workers, using quadratic weighted kappa. We identified two dimensions in urban cleaning and three in the footwear industry: (1) dynamic work with anomalous postures; (2) work that requires handling material; and (3) work that demands repetitive motions. Reliability was excellent for upright work posture, good for walking, moderate for lifting loads, squatting, rotated trunk and only regular for repetitive motions and arms above shoulders. The dimensions we identified through factorial analysis are compatible with the physical demands of urban cleaning and the footwear industry and, in general, showed good internal consistency. The 10 items' reliability was compatible with the literature, showing excellent to good reliability for general posture, moderate for specific body segment posture and regular for repetitiveness. Results reveal the specificity of each occupational group, which suggests a dimensionality of physical demand items, supporting their use for measuring physical exposure.

Methodology and cohort profile for the Hangzhou Lumbar Spine Study: a study focusing on back health in a Chinese population

Back pain is a worldwide health problem, adding a tremendous burden to modern societies. However, little information on back health is available in China, even though a quarter of the world's population is Chinese. To enhance knowledge in this area, we designed and initiated the Hangzhou Lumbar Spine Study, which is a cross-sectional study of a general sample of mainland Chinese with focusing on disc degeneration, Modic changes, endplate lesions, and back pain. The study consists of a structured questionnaire to measure back pain history and lifetime exposure to suspected risk factors, magnetic resonance imaging of the lumbar spine, bone mineral density study of the spine and hip, and DNA sample analysis. Here we briefly introduce the study methodology, report the test-retest reliability of the questionnaire, and describe the cohort profile to date. Since May 2014, 301 randomly selected subjects (male/female, 122/179; mean age, 51.0 years; range, 20-87 years) have been recruited. Tests-retests of the questionnaire, completed by 40 participants, revealed good reliability. To our knowledge, the Hangzhou Lumbar Spine Study is the first population-based epidemiological study conducted to characterize lumbar spinal phenotypes and back pain, their interaction, and their associations with lifetime environmental exposure, in mainland Chinese. Epidemiological information obtained from a reliable questionnaire, magnetic resonance (MR) imaging data, dual energy X-ray absorptiometry (DXA) measurements, and DNA analysis may serve as a valuable reference for future studies on back health, particularly for mainland Chinese.

Biopsychosocial factors associated with chronic low back pain disability in rural Nigeria: a population-based cross-sectional study

Introduction

Many people in Nigeria are living with disability due to chronic low back pain (CLBP), with the greatest burden accounted for by people living in rural Nigeria. However, factors associated with disability in rural Nigeria have not yet been established. We investigated the biomechanical and psychosocial predictors of CLBP disability in a rural Nigerian population.

Methods

A cross-sectional study of adults with non-specific CLBP recruited from rural communities in Enugu State, South-eastern Nigeria. Measures of self-reported and performance-based disability, pain intensity, anxiety and depression, coping strategies, social support, occupational biomechanical factors, illness perceptions and fear avoidance beliefs were collected by trained community health workers. We used univariate and multivariate analyses.

Results

200 individuals were recruited. Psychosocial factors were the most important factors associated with CLBP disability, and accounted for 62.5% and 49.1% of the variance in self-reported and performance-based disability, respectively. The significant predictors of self-reported disability were: illness perceptions (β=0.289; p<0.0005), pain intensity (β=0.230; p<0.0005), catastrophising (β=0.210; p=0.001), fear avoidance beliefs (β=0.198; p=0.001) and anxiety (β=0.154; p=0.023). The significant predictors of performance-based disability were: illness perceptions (β=0.366; p<0.0005), social support (β=0.290; p<0.0005), fear avoidance beliefs (β=0.189; p<0.01) and female gender (β=0.184; p<0.01). Illness concern was the most salient dimension of illness perceptions predicting self-reported and performance-based disability.

Conclusions

These results provide evidence which can be used to inform the development of interventions to reduce CLBP disability in rural Nigeria, and may have relevance in other rural African contexts.

Assessing agreement of self-reported and observed physical exposures of the upper extremity

Assessment of workplace physical exposures by self-reported questionnaires has logistical advantages in population studies, but is subject to exposure misclassification. This study measured agreement between eight self-reported and observer-rated physical exposures to the hands and wrists, and evaluated predictors of intermethod agreement. Workers (n = 341) from three occupational categories (clerical/technical, construction, and service) completed self-administered questionnaires and worksite assessments. Analyses compared self-reported and observed ratings using a weighted kappa coefficient. Personal and psychosocial factors, presence of upper extremity symptoms, andjob type were evaluated as predictors of agreement. Weighted kappa values were substantial for lifting (0.67) and holding vibrating tools (0.61), moderate for forceful grip (0.58), and fair to poor for all other exposures. Upper extremity symptoms did not predict greater disagreement between self-reported and observed exposures. Occupational category was the only significant predictor of inter-method agreement. Self-reported exposures may provide a useful estimate of some work exposures for population studies.

Perioperating nurses and technicians' perceptions of ergonomic risk factors in the surgical environment

The aim of this study was to identify the magnitude and characteristics of work-related musculoskeletal complaints among perioperative nurses and technicians (PNT) and determine the associated ergonomic risk factors in the operating room (OR) environment based on self-report and focus group discussion. The 50 PNTs who participated in the study completed a self-report survey for musculoskeletal symptoms, Job Description Questionnaire, and Psychometric Evaluation Questionnaire, and participated in focus groups to discuss potential OR ergonomic risk factors. The results of the study demonstrated a high prevalence of work-related musculoskeletal disorders (WMSD) among PNTs, with lower back pain the most prevalent (84%) complaint, followed by ankle/foot (74%) and shoulder (74%) pain. In addition, lower back pain (31%), followed by ankle/knee (24%) pain were found to be the main causes of absenteeism from work. Participants suggested simple ergonomic and engineering solutions can be adopted to improve the work environment of PNTs.

A review and critique of assessment instruments for patients with persistent pain

BACKGROUND

Early identification of individuals at risk of developing persistent pain is important to decrease unnecessary treatment costs and disability. However there is scant comprehensive information readily available to assist clinicians to choose appropriate assessment instruments with sound psychometric and clinical properties.

OBJECTIVE

A national insurer commissioned the development of a compendium of assessment instruments to identify adults with, or at-risk of developing, persistent pain. This paper reports on the instrument identification and review process.

METHODS

A comprehensive systematic literature review was undertaken of assessment instruments for persistent pain of noncancer origin, and their developmental literature. Only assessment instruments which were developed for patients with pain, or tested on them, were included. A purpose-built 'Ready Reckoner' scored psychometric properties and clinical utility.

RESULTS

One hundred sixteen potentially useful instruments were identified, measuring severity, psychological, functional and/or quality of life constructs of persistent pain. Forty-five instruments were short-listed, with convincing psychometric properties and clinical utility. There were no standard tests for psychometric properties, and considerable overlap of instrument purpose, item construct, wording, and scoring.

CONCLUSION

No one assessment instrument captured all the constructs of persistent pain. While the compendium focuses clinicians' choices, multiple instruments are required for comprehensive assessment of adults with persistent pain.

Work-related musculoskeletal disorders in physical therapists: a prospective cohort study with 1-year follow-up

BACKGROUND

Work-related musculoskeletal disorders (WMSDs) have a significant impact on physical therapists, but few studies have addressed the issue. Research is needed to determine the scope of the problem and the effects of specific risk factors.

OBJECTIVES

The objectives of this study were: (1) to determine the 1-year incidence rate of WMSDs in physical therapists and (2) to determine the effects of specific risk factors.

DESIGN

This was a prospective cohort study with 1-year follow-up.

METHODS

Subjects were randomly selected American Physical Therapy Association members (N=882). Exposure assessment included demographic data, physical risk factors, job strain, and specific physical therapy tasks. The primary outcome was WMSDs, with a severity rating of at least 4/10 and present at least once a month or lasting longer than a week.

RESULTS

The response rate to the baseline questionnaire was 67%. Ninety-three percent of the subjects who responded to the baseline questionnaire responded to the follow-up questionnaire. The 1-year incidence rate of WMSDs was 20.7%. Factors that increased the risk for WMSDs included patient transfers, patient repositioning, bent or twisted postures, joint mobilization, soft tissue work, and job strain.

LIMITATIONS

The primary limitation of this study was the number of therapists who had a change in their job situation during the follow-up year.

CONCLUSIONS

Work-related musculoskeletal disorders are prevalent in physical therapists. Physical therapy exposures, patient handling, and manual therapy, in particular, increase the risk for WMSDs.

Work and family support systems and the prevalence of lower back problems in a South African steel industry

INTRODUCTION

Back complaints are a common in society.

METHODS

An analytical cross-sectional epidemiological study was carried out among 366 steel plant workers to examine the prevalence and association between lower back problems (LBP) and family and workplace related psychosocial risk factors.

RESULTS

Using inclusive and stringent definitions for LBP, point prevalence was 35.8% and 15.3%, respectively. Logistic regression analyses indicated significant adjusted odd ratios (OR) for negative perceptions of workplace support (2.32; CI 1.09-4.92), unexpected events (2.58; CI 1.19-5.59) and working under time pressures and deadlines (2.83; CI 1.24-6.48). A significant protective association was found for control over the order and pace of working tasks (OR 0.30; CI 0.14-0.63). A significant univariate association was further found between LBP and negative perceptions of family (1.97; CI 1.06-3.68) support.

CONCLUSION

These findings suggest that workers who feel more in control on the job and who have good family and workplace support systems in tact are less likely to experience LBP. Supervisors are therefore encouraged to develop appropriate support and organizational systems which may be an inexpensive, but potentially beneficial, means of reducing worker stress and LBP.

Lower back problems and work-related risks in a South African manganese factory

An analytical cross-sectional epidemiological study carried out among 109 manganese plant workers aimed to examine the prevalence and association between lower back problems (LBP) and occupational risk factors. Outcome was defined using a guided questionnaire and a functional rating index. Exposure to occupational risk factors was determined using self-reported questionnaires and workstation analyses. Multivariate logistic regression analyses indicated significant adjusted odds ratios (OR) for prolonged 90 degrees trunk flexion (OR 2.16; CI 1.15-4.05); manual handling (1.89; 1.17-3.08); load carriage (1.54; 1.08-2.19); and lifting (4.61; 1.37-15.47). The findings illustrate regional and occupational specifics of risk for LBP, and indicate that self-selection or adaptation to task-specific demands could possibly lead to observations of ergonomically relevant risk factors, which do not necessarily yield statistically significant associations with LBP. The findings further support multi-modal preventative approaches.

Medium- and long-term reproducibility of self-reported exposure to physical ergonomics factors at work

INTRODUCTION

The literature is sparse on reproducibility of self-reported exposure to physical ergonomics risk factors for musculoskeletal disorders (MSDs). Aims of this study were to evaluate, in a cohort of workers interviewed up to three times: 1-year test-retest reliability; and 5- and 6-year recall of physical exposures. We also examined whether reproducibility was influenced by the presence of UE MSD or by technological changes introduced between the last two surveys.

METHODS

A cohort of automobile manufacturing employees was interviewed at baseline, one and six years later about work history, physical and psychosocial exposures at work, upper limb symptoms, injury and medical history, and demographics. Agreement between interviews was evaluated by intraclass correlation and Spearman coefficients. Differences in exposure between 1- and 6-year follow-up were analyzed by Wilcoxon matched-pairs signed-ranks test.

RESULTS

Large and significant decreases in work pace and physical effort were observed from baseline, although an upper extremity composite index was quite stable in the total population. One-year test-retest reliability was fair to good for the composite exposure index (ICC=0.58), whole-body vibration, handling parts, and tool use, but poor for the other variables considered. Long-term reproducibility, from baseline or 1-year follow-up to 6-year follow-up, was poor for the composite index and almost all single items. UE MSD case status influenced 1-year test-retest reliability, with subjects who changed case status from baseline displaying higher reliability, but not reproducibility of recalled exposures. A strong regression to the mean effect was observed on exposures reported at follow-up surveys.

CONCLUSIONS

Recalled ergonomics exposures could be employed in retrospective cohort studies as a somewhat reliable and unbiased estimate of the self-reported exposures that would have been obtained up to one year earlier, but not over a longer period (5-6 years). These longer-term results may have been limited by difficulty in matching jobs between interviews; also the regression to the mean effect likely contributed to reduce agreement. Changes in production technology and work organization produced a decrease in physical workload intensity and job pace, but did not have a substantial impact on an exposure index for the upper limb.

Perceptions of work and family assistance and the prevalence of lower back problems in a South African manganese factory

An analytical cross-sectional epidemiological study was carried out among 109 manganese plant workers to examine the prevalence and association between lower back problems (LBP) and family and workplace related psychosocial risk factors. Outcome (LBP) was defined using a guided questionnaire and a functional rating index. Exposure to family and workplace related psychosocial risk was determined using the Occupational Risk Factor (ORFQ) and APGAR questionnaires for work and family support. Using inclusive and stringent definitions for perceived LBP, point prevalence was 37.6% and 29.4%, respectively. Only 8 cases of LBP were, however recorded officially over a 7-yr period (1996-2003). Multivariate analyses indicated a high, but non-significant odds ratio (OR) for negative perceptions of workplace support OR 3.29 (CI 0.95-11.30). A positive, non-significant, association for negative perceptions of family support (2.56; CI 0.69-9.52) and a protective, but non-significant, association for control over the order and pace of working tasks (OR 0.40; CI 0.12-1.35) was found. These findings together with the under-reporting, leads one to conclude that work hardening and a cultural ethos of non-complaining among manual labourers, moderates the association between LBP and the aetiological factors studied.

The prevalence of and risk factors for back pain among home care nursing personnel in Hong Kong

BACKGROUND

There is a large gap in research with regard to back pain (BP) among home care nursing personnel (HCNP); only seven studies have been conducted worldwide. There is a need to identify the magnitude of and risk factors for BP that are unique to Hong Kong (HK) HCNP.

METHODS

A total population sampling technique was employed in this cross-sectional questionnaire-based study. Hierarchical multiple logistic regression analyses were used to control for potentially confounding variables.

RESULTS

The 12-month prevalence of upper and lower BP was 71.2% (n=265). Three predictors were identified: physical risk factors in the office (OR=3.57, 95% CI=1.55-8.24), static postures (OR=1.41, 95% CI=1.04-1.90), and psychological job demands (OR=1.11, 95% CI=1.01-1.22).

CONCLUSION

HCNP in HK have a high prevalence of BP. BP in HK HCNP is independently attributable to physical work factors in the office, static postures, and psychological job demands, and is not primarily associated with patient lifting and transferring which are traditionally identified as risk factors for BP in hospital nursing personnel. Am. J. Ind. Med. 49:14-22, 2006. (c) 2005 Wiley-Liss, Inc.

Epidemiologic surveillance of upper-extremity musculoskeletal disorders in the working population

OBJECTIVE

Since 2002, an epidemiologic surveillance system of work-related, upper-limb musculoskeletal disorders (MSDs) has been implemented in France's Pays de la Loire region to assess the prevalence of MSDs and their risk factors in the working population.

METHODS

The surveillance was based on a network of occupational physicians (OPs) and used the recommendations of a group of European experts (criteria document consensus). In 2002-2003, 80 of 400 OPs volunteered to participate. All underwent a training program to standardize the physical examination. Health status was assessed by self-administered questionnaire and physical examination. Occupational risk factors were assessed by self-administered questionnaire. Exposure scores were computed for each anatomic zone by summing the risk factors taken into account by the criteria document.

RESULTS

More than 50% of the 2,685 men and women randomly included in 2002-2003 experienced nonspecific musculoskeletal symptoms during the preceeding 12 months and approximately 30% experienced them in the preceeding week. The prevalence of clinically diagnosed MSDs was high: approximately 13% of workers experienced at least 1 of the MSDs. The most frequent disorder was rotator cuff syndrome followed by carpal tunnel syndrome and lateral epicondylitis. The prevalence of MSDs increased with age and varied widely across economic sectors and occupations. More than half of the workers were exposed to at least 2 risk factors of MSDs. Exposure varied according to industrial activity and occupation. According to the criteria document, a high percentage of MSD cases could be classified as probably work related (95% in men and 89% in women age <50, and 87% in men and 69% in women age >50).

CONCLUSION

Nonspecific upper-limb symptoms and specific upper-limb MSDs are common in the working population. These results show the need to implement prevention programs in most sectors to reduce the prevalence of MSDs.

Lower back problems and occupational risk factors in a South African steel industry

BACKGROUND

The etiology of work-related back disorders is often population specific. The objective of this study was to identify and establish the association of occupational risk factors with the prevalence of low back (LB) problems in a semi-automated South African Steel industry.

METHODS

The design entailed an analytical cross-sectional epidemiological study among a group of 366 steel plant workers. Outcome of LB problems was defined using a guided questionnaire and a functional rating index. Exposure to occupational risk factors was determined using self-reported questionnaires.

RESULTS

Multivariate logistic regression analyses indicated significant adjusted odds ratios (OR) for twisting and bending (OR 2.81; CI 1.02-7.73); bulky manual handling (5.58; 1.16-26.71); load carriage (7.20; 1.60-32.37); prolonged sitting (2.33; 1.01-5.37); kneeling and squatting (4.62; 1.28-16.60); and working on slippery and uneven surfaces (3.63; 1.20-10.90).

CONCLUSIONS

This study supports the current view of a multifactorial etiology in idiopathic LB problems, and emphasizes the importance of multiple intervention strategies in industrial settings.

Interrelationships between pain, disability, general health, and quality of life and associations with work-related and individual factors: a study among workers on sickness absence for 2 to 6 weeks for musculoskeletal complaints

STUDY DESIGN

A cross-sectional study.

OBJECTIVES

To measure interrelationships among pain, functional disability, general health, and overall quality of life for workers on sickness absence for 2 to 6 weeks due to musculoskeletal complaints, and to assess the impact of work-related and individual characteristics on these different health dimensions. The results of this study will contribute to a better understanding of the relationship between health and functional disability.

SUMMARY OF BACKGROUND DATA

When choosing a patient-based outcome measure, different health dimensions must be considered. For musculoskeletal complaints, four health dimensions are important: pain, disability, general health, and overall quality of life. Improvement at one dimension does not necessarily correlate with better health on another dimension. Moreover, correlations between different dimensions may be influenced by individual and environmental factors. However, it is not known whether these factors influence different health dimensions differently.

METHODS

A total of 218 workers on sickness absence for 2 to 6 weeks due to musculoskeletal complaints completed a questionnaire on four different health dimensions and work-related and environmental factors.

RESULTS

Moderate correlations (r < 0.50) among measures of pain, disability, general health, and quality of life were found. These health dimensions were not influenced by work-related physical and psychosocial workload, suggesting no impact of recall bias in studies for work-related musculoskeletal complaints. Self-perceived ability to return to work within 6 weeks explained 21% to 26% of the outcomes on pain and disability and contributed less to the generic measures of health.

CONCLUSION

Within a population of workers on sickness absence for 2 to 6 weeks, specific dimensions of pain and disability seem to be more appropriate measures of health than generic instruments of general health and quality of life.

Self-assessed and directly measured occupational physical activities--influence of musculoskeletal complaints, age and gender

This study compares questionnaire assessed physical activity with direct technical measurements among cleaners and office workers, stratified regarding age, gender and self-reported neck/shoulder complaints. During two full working days number of steps was recorded by a pedometer, sitting/standing positions by a posimeter and heart rate by a Sport-Tester. In addition the subjects kept a work task diary for 10 days. There were high intra-individual variations in exposure between the days. Subjects with complaints rated their exposure higher than those without, although they in fact showed lower direct measured exposure. This may imply underestimation of exposure-effect relationships. Rate of perceived exertion showed low correlation with heart rate ratio within the two occupational groups, but high, 0.64 when the two groups were combined. Age and complaints explained 31% of the variance for the cleaners.

A participatory approach to the study of lifting demands and musculoskeletal symptoms among Hong Kong workers

AIMS

To investigate the use of a worker based methodology to assess the physical stresses of lifting tasks on effort expended, and to associate this loading with musculoskeletal outcomes (MO).

METHODS

A cross sectional study was conducted on 217 male manual handling workers from the Hong Kong area. The effects of four lifting variables (weight of load, horizontal distance, twisting angle, and vertical travel distance) on effort were examined using a linguistic approach (that is, characterising variables in descriptors such as "heavy" for weight of load). The numerical interpretations of linguistic descriptors were established. In addition, the associations between on the job effort and MO were investigated for 10 body regions including the spine, and both upper and lower extremities.

RESULTS

MO were prevalent in multiple body regions (range 12-58%); effort was significantly associated with MO in 8 of 10 body regions (odds ratios with age adjusted ranged from 1.31 for low back to 1.71 for elbows and forearm). The lifting task variables had significant effects on effort, with the weight of load having twice the effect of other variables; each linguistic descriptor was better described by a range of numerical values rather than a single numerical value.

CONCLUSIONS

The participatory worker based approach on musculoskeletal outcomes is a promising methodology. Further testing of this approach is recommended.

What is a demanding lifting job for manual handling workers in Hong Kong?

Although lifting tasks are traditionally evaluated by researchers, through the use of methods which depend on one or more approaches (i.e., psychophysical, biomechanical and physiological methods), none of these approaches makes use of expert workers in the evaluation of lifting activities. Given that 97% of lower back symptoms are aches, pains and discomfort and rely on self-reports, it is intuitive to use expert workers in evaluating the stressfulness of lifting activities. In this investigation, 217 workers from three industries in the Hong Kong area were surveyed to determine what constitutes a demanding lifting job from a worker standpoint. This was achieved by asking workers to map, in numerical terms, the level of lifting task parameter described in linguistic values. For example, the weight of load was described in three linguistic descriptors, namely, 'light', 'moderate' and 'heavy'. Then, each worker was asked to assess the meaning of these linguistic descriptors in numerical terms, based on their perception and experience with manual handling work. In this study, workers were asked to map the physical analogue of linguistic descriptors for seven lifting task parameters which are utilized in the NIOSH lifting equation, that is, weight of load, horizontal distance, vertical travel distance, vertical origin of lift, angle of asymmetry, frequency of handling and task duration. The data obtained from the workers were then subjected to validity testing in relation to norms and values reported in the published literature. On a preliminary basis, it appears that workers' assessments are logical and valid. The results suggest that the worker-based methodology is a promising approach and that it is worthwhile to pursue this approach further in the evaluation of industrial lifting activities.

Biopsychosocial multivariate predictive model of occupational low back disability

STUDY DESIGN

To establish outcome, 253 workers with subacute and chronic low back conditions were assessed with a comprehensive multimethod biopsychosocial protocol at baseline, 3 days after the initial examination, and 3 months later.

OBJECTIVE

To validate empirically a biopsychosocial model for prediction of occupational low back disability.

SUMMARY OF BACKGROUND DATA

Costs of low back occupational disability continue to spiral despite stabilization of low back injury rates. An empirically based model to predict occupational disability in workers with low back injuries is required.

METHODS

Workers with subacute low back injuries (4-6 weeks after injury, n = 192) and those with chronic back pain (6-12 months after injury, n = 61) were the study participants. The biopsychosocial protocol included five groups of variables: 1) sociodemographic, 2) medical, 3) psychosocial, 4) pain behavior, and 5) workplace-related factors. Predictive validity was investigated through a 3-month follow-up assessment, at which time the return to work outcome was determined. Stepwise logistic regression models were developed to predict work status.

RESULTS

The final integrated model consisted of variables from a wide biopsychosocial spectrum: vitality, health transition, feeling that job is threatened due to injury, expectations of recovery, guarding behavior, perception of severity of disability, time to complete walk, and right leg typical sciatica.

CONCLUSIONS

The "winning" variables identified in the integrated model are dominated by cognitions, which are accompanied by disability behaviors. A cognitive-behavioral model with an adaptation-oriented rather than a pathology-oriented focus is favored for early intervention with high-risk workers since cognitions are amenable to change.

Validity of a self-administered questionnaire for assessing physical work loads in a general population

The aim of the study was to evaluate eight questions concerning physical loads, used in public health questionnaires. Working women and men (203) completed a self-administered questionnaire twice, following a test-retest method. The questions were also validated with a structured interview. Response agreement was calculated with Cohen's kappa statistics with quadratic weights (kappa w). Test-retest agreement varied from 0.74 to 0.92, and inter-method agreement from 0.38 to 0.81. The lowest coefficients were for the questions concerning bent/twisted work postures (kappa w 0.38) and repetitive movements (kappa w 0.39). The results did not indicate any substantial influence of gender, type of work or musculoskeletal complaint. The questions concerning general physical activity and sitting work postures, and physical exercise/sports during leisure times, had good validity. The questions concerning bent/twisted work posture and repetitive movements need to be re-designed.