Validation of a questionnaire for assessing physical work load

Comparison of two self-reported measures of physical work demands in hospital personnel: a cross-sectional study

Background

Low back pain (LBP) is a frequent health complaint among health care personnel. Several work tasks and working postures are associated with an increased risk of LBP. The aim of this study was to compare two self-reported measures of physical demands and their association with LBP (the daily number of patient handling tasks and Hollmann's physical load index).

Methods

A questionnaire was distributed to 535 hospital employees in a psychiatric and an orthopedic ward in a Danish hospital. Of these 411 (77%) filled in and returned the questionnaire. Only the 373 respondents who had non-missing values on both measures of physical demands were included in the analyses. The distribution of physical demands in different job groups and wards are presented, variance analysis models are employed, and logistic regression analysis is used to analyze the association between measures of physical demands and LBP.

Results

In combination, hospital ward and job category explained 56.6% and 23.3% of the variance in the self-reported physical demands measured as the daily number of patient handling tasks and as the score on the physical load index, respectively. When comparing the 6% with the highest exposure the prevalence odds ratio (POR) for LBP was 5.38 (95% CI 2.03–14.29) in the group performing more than 10 patient handling tasks per day and 2.29 (95% CI 0.93–5.66) in the group with the highest score on the physical load index.

Conclusion

In specialized hospital wards the daily number of patient handling tasks seems to be a more feasible measure of exposure when assessing the risk of LBP compared to more advanced measures of physical load on the lower lumbar spine.

Measuring the physical demands of work in hospital settings: design and implementation of an ergonomics assessment

BACKGROUND

Assessing the physical demands of the heterogeneous jobs in hospitals requires appropriate and validated assessment methodologies.

METHODS

As part of an integrated assessment, we adapted Rapid Entire Body Assessment (REBA), using it in a work sampling mode facilitated by a hand-held personal digital assistant, expanding it with selected items from the UC Computer Use Checklist, and developed a scoring algorithm for ergonomics risk factors for the upper (UB) and lower body (LB).

RESULTS

The inter-rater reliability kappa was 0.54 for UB and 0.66 for LB. The scoring algorithm demonstrated significant variation (ANOVA p<0.05) by occupation in anticipated directions (administrators ranked lowest; support staff ranked highest on both scores). A supplemental self-assessment measure of spinal loading correlated with high strain LB scores (r=0.30; p<0.001).

CONCLUSION

We developed and validated a scoring algorithm incorporating a revised REBA schema adding computer use items, appropriate for ergonomics assessment across a range of hospital jobs.

Validation of a self-administered questionnaire for assessing exposure to back pain mechanical risk factors

OBJECTIVE

To validate a self-administered questionnaire assessing exposure to mechanical risk factors, developed for a cohort study aiming at assessing the influence of physical and psycho-social factors on the incidence of low back pain (LBP).

METHODS

The study first involved a criterion validity test. A sample of the cohort workers (n=152) was observed at the workplace during four 30 min periods randomly distributed along the shift. At the end of the work shift, the questionnaire was filled in both by the worker and the observer. Agreements were tested between self-reports and observations, and between self-reports and observer opinion. Secondly, a comparison of exposure-effect relationships based on self-reports to those based on observations was carried out on the whole study cohort (n=716). Both sets of Relative Risks of being an incident case (LBP lasting at least 7 consecutive days in the follow-up year) were tested for heterogeneity.

RESULTS

Self-reports agreement levels were better with observer opinion than with observational data and were higher for answers at a dichotomous level. Vehicle driving, manual handling without estimation of weight and frequencies, or trunk bending without rotation showed a fair to good agreement with the external criteria. Limits in the validation procedure did not allow validating the sitting and standing durations. As regards the health outcome comparison, questionnaire and observations led to homogeneous Relative Risks for the variables tested.

CONCLUSIONS

Results show that self-reports provide a limited accuracy to assess actual frequencies and durations of work activities. Using a questionnaire, classifying the workers into exposure categories is rather relative, but questionnaire and observations seem similar in their relationships to outcome.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Internal consistency and validity of a new physical workload questionnaire

AIMS

To examine the dimensionality, internal consistency, and construct validity of a new physical workload questionnaire in employees with musculoskeletal complaints.

METHODS

Factor analysis was applied to the responses in three study populations with musculoskeletal disorders (n = 406, 300, and 557) on 26 items related to physical workload. The internal consistency of the resulting subscales was examined. It was hypothesised that physical workload would vary among different occupational groups. The occupations of all subjects were classified into four groups on the basis of expected workload (heavy physical load; long lasting postures and repetitive movements; both; no physical load). Construct validity of the subscales created was tested by comparing the subscale scores among these occupational groups.

RESULTS

The pattern of the factor loadings of items was almost identical for the three study populations. Two interpretable factors were found: items related to heavy physical workload loaded highly on the first factor, and items related to static postures or repetitive work loaded highly on the second factor. The first constructed subscale "heavy physical work" had a Cronbach's alpha of 0.92 to 0.93 and the second subscale "long lasting postures and repetitive movements", of 0.86 to 0.87. Six of eight hypotheses regarding the construct validity of the subscales were confirmed.

CONCLUSIONS

The results support the internal structure, internal consistency, and validity of the new physical workload questionnaire. Testing this questionnaire in non-symptomatic employees and comparing its performance with objective assessments of physical workload are important next steps in the validation process.

A participatory ergonomics intervention to reduce risk factors for low-back disorders in concrete laborers

Construction laborers rank high among occupational groups with work-related musculoskeletal injuries involving time way from work. The goals of this project were to: (1) introduce an ergonomic innovation to decrease the risk of low-back disorder (LBD) group membership, (2) quantitatively assess exposure, and (3) apply a participatory intervention approach in construction. Laborers manually moving a hose delivering concrete to a placement site were evaluated. The hypothesis tested was that skid plates would prevent hose joints from catching on rebar matting, and the hose would slide more easily. This would decrease the need for repetitive bending and use of excessive force. Four laborers were evaluated wearing the Lumbar Motion Monitor (LMM), a tri-axial electrogoniometer that records position, velocity and acceleration. Workers were measured during three comparable concrete pours. Worker perceptions of the innovation utility and exertion were surveyed. During initial use of skid plates, flexion increased significantly (p < 0.001) while velocity, acceleration and moments did not change. After implementing a worker modification, low back velocity, acceleration and moments were significantly reduced (p < 0.05). Reductions in these factors have been associated with decreased risk of belonging to an occupational group with LBDs. Use of secured skid plates during horizontal concrete hose movement may in part decrease the risk of LBD group membership among concrete laborers. Crew participation resulted in skid plates being a more effective intervention. The LMM is a promising tool for quantitative assessment in construction.

The psychosocial work environment and musculoskeletal disorders: design of a comprehensive interviewer-administered questionnaire

BACKGROUND

Psychosocial working conditions are likely to contribute to work-related musculoskeletal disorders (WRMSDs), but a lack of standardized measurement tools reflects both the theoretical and methodological limitations of current research.

METHODS

An interdisciplinary team including biomedical, behavioral, and social science researchers used an iterative process to adapt existing instruments for an interviewer-administered questionnaire assessing psychosocial workplace exposure related to musculoskeletal disorders.

RESULTS

The resulting questionnaire included measures of psychosocial workplace factors based on two theoretical models (the demand-control-support and the effort-reward imbalance models), supplemented by the additional constructs of "emotional demands," and "experiences of discrimination." Other psychosocial and physical measures selected for questionnaire inclusion address physical workload, sociodemographic and anthropometric characteristics, social relations and life events, health behaviors, and physical and psychological health.

CONCLUSION

Using an interdisciplinary approach facilitated the development of a comprehensive questionnaire inclusive of key measures of psychosocial factors that may play a role in the complex mechanisms leading to WRMSDs.

Psychosocial risk factors for musculoskeletal symptoms among women working in geriatric care

BACKGROUND

Nursing is a stressful, physically demanding occupation and a rush setting for musculoskeletal problems. The aim of this study is to explore the extent of the association between psychosocial work characteristics and musculoskeletal symptoms among women working in geriatric care.

METHODS

The participants were female employees of all geriatric nursing homes and geriatric hospital wards in Iceland having a staff of 10 or more. A total of 1,886 questionnaires were distributed. The response rate was 80%.

RESULTS

Finding the job mentally difficult, mental exhaustion after one's shift, dissatisfaction with supervisors or the flow of information, insufficient influence at work, dissatisfaction with the hierarchy, intense time pressure, lack of solidarity, dissatisfaction with the job, harassment, violence or threats at work; all of the aforementioned gave crude odds ratios (OR) two or above for one or more musculoskeletal symptoms. Mental exhaustion and harassment, violence, and threats were the factors connected with symptoms from all the body regions studied.

CONCLUSIONS

The extent of the association of work-related psychosocial factors and musculoskeletal symptoms among the geriatric female nursing staff is substantial and needs to be taken into account by occupational health services and others involved in preventive work. Am. J. Ind. Med. 44:679-684, 2003.

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.

Perceived physical demands and reported musculoskeletal problems in registered nurses

BACKGROUND

Nursing is physically demanding, and nurses have higher rates of musculoskeletal disorders (MSDs) than most other occupational groups. The physical demands of nursing may lead some nurses to leave the profession, contributing to the shortage of registered nurses in many workplaces that is a major concern today. As a first step toward reducing MSDs and their consequences, this study was designed to examine the relationship between perceived physical demands and reported neck, shoulder, and back MSDs in nurses.

METHODS

Data were collected anonymously from 1163 randomly selected working nurses (74% response rate) using a cross-sectional survey. The 12-item survey scale (internal reliability coefficient=0.89), rated perceived physical demands such as force, awkward postures, and heavy lifting. Nurses with a presumed MSD case reported relevant past-year symptoms in the neck, shoulder, and/or back lasting >or=1 weeks, or at least monthly, with moderate or more pain, on average.

RESULTS

Moderate and high perceived physical demands were significantly associated with reported neck, shoulder, and back MSD cases, even after adjustments for demographic and lifestyle-related covariates. Adjusted odds ratios for highly demanding work (vs low) ranged from 4.98 to 6.13 depending on body site. When analyses were restricted to staff nurses only, the odds ranged from 9.05 to 11.99.

CONCLUSIONS

Perceived physical demands are associated with reported MSD in registered nurses, and the association is stronger in staff nurses.

Work correlates of back problems and activity restriction due to musculoskeletal disorders in the Canadian national population health survey (NPHS) 1994-5 data

OBJECTIVES

To describe the prevalence of musculoskeletal problems in the Canadian working population and to determine cross sectional associations between such problems and work factors, particularly job strain and physical demand variables.

METHODS

The Canadian 1994 national population health survey (NPHS) sampled 4230 working men and 4043 working women (ages 18-64) who answered an abbreviated version of the job content questionnaire. Workers were classified into four strain categories: high, passive, active, and low. Outcomes were restricted activity due to musculoskeletal disorders and the diagnosis of a back problem (both yes or no). Survey weights were incorporated to allow for different probabilities of selection. Logistic regression analyses were carried out separately for women and men, controlling for sociodemographic factors.

RESULTS

Prevalence of chronic back problems diagnosed by a health practitioner was 14.5% among men and 12.5% among women. Men had a 6.6% prevalence of restricted activity due to musculoskeletal disorders, whereas the corresponding figure for women was 5.3%. Women, but not men, in high strain jobs were more likely to report both back problems (odds ratio (OR) 1.60, 95% confidence interval (95% CI) 1.14 to 2.28) and restricted activity (OR 1.98, 95% CI 1.16 to 3.48) compared with those in low strain jobs. High physical exertion was an independent predictor of back problems in both sexes. For both men and women, low social support at work and high job insecurity were independent predictors of restricted activity due to musculoskeletal disorders. Conversely, chronic back problems contributed to explanation of high job strain among women (OR 1.76, 95% CI 1.30 to 2.39) and high physical exertion among men (OR 1.39, 95% CI 1.09 to 1.77), whereas restricted activity due to musculoskeletal disorders contributed to explanation of high job insecurity in both sexes.

CONCLUSIONS

Associations of interest between work stressors and musculoskeletal problems in this cross sectional study provide evidence for physical and psychosocial factors both affecting disability and being affected by disability in a working population.

Physically demanding work and inadequate sleep, pain medication use, and absenteeism in registered nurses

Pain and fatigue are early indicators of musculoskeletal strain. This study examined associations among eight physical demands and inadequate sleep, pain medication use, and absenteeism in 3727 working registered nurses (RNs). Among the demands, awkward head/arm postures were associated with each outcome (inadequate sleep: odds ratio [OR], 1.96; 95% confidence interval [CI], 1.41 to 2.72; pain medication: OR, 1.65; CI, 1.12 to 2.24; absenteeism: OR, 1.60; CI, 1.26 to 2.04). A dose-response relationship was present; as the number of demands increased, the likelihood of each outcome increased. Odds ratios for eight demands versus no demands were as follows: inadequate sleep (OR, 5.88; CI, 2.30 to 15.50), pain medication (OR, 3.30; CI, 1.34 to 8.11), and absenteeism (OR, 2.13; CI, 1.15 to 3.94). Adjustment using multiple logistic regression for lifestyle, demographics, and work schedule did little to alter the findings. Interventions to promote nurses' health should limit the physical demands of the work.