Occupational tasks associated with shoulder pain and upper extremity disability: a cross-sectional study in the Johnston County Osteoarthritis Project

BACKGROUND

Shoulder pain is a leading cause of disability. Occupations requiring high upper extremity demands may put workers at greater risk of shoulder injury and resulting pain. We examined associations of occupation with shoulder pain and upper extremity disability in the Johnston County Osteoarthritis Project.

METHODS

Work industry and occupational tasks for the longest job held were collected from participants. At follow-up ranging from 4-10 years later, participants were asked about shoulder symptoms (pain, aching, or stiffness occurring most days of 1 month in the last year) and given a 9-item, modified Disabilities Arm Shoulder and Hand (DASH) questionnaire to categorize disability from 0-4 (none-worst). Logistic regression and cumulative logit regression models were used to estimate associations with prevalent shoulder symptoms and with worse disability category, respectively. Models were adjusted for cohort, age, sex, race, education and time to follow-up. Sex- and race-stratified associations were evaluated.

RESULTS

Among 1560 included participants, mean age was 62 years (standard deviation ± 9 years); 32% were men, and 31% were Black. Compared to the managerial/professional industry, higher odds of both shoulder symptoms and worse upper extremity disability were seen for most industrial groups with physically demanding jobs, particularly the service industry. Work that often or always required lifting/moving > 10 lbs. was associated with higher odds of shoulder symptoms. Work that sometimes or always required heavy work while standing was associated with higher odds of shoulder symptoms, and this association was stronger among men and White workers.

CONCLUSION

Physically demanding occupations were associated with increased occurrence of shoulder pain and disability. Mitigating specific physical work demands may reduce shoulder-related disability.

Tip of the iceberg: unveiling the impact on back disorders from cumulative physical job exposure and evaluating bias from the healthy worker effect using a nationwide longitudinal cohort study

PURPOSE

Longitudinal studies across various sectors with physically demanding jobs are notably absent in back disorder risk research. This study aimed to investigate the relationship between cumulative physical job exposure (PJE) and hospital-diagnosed back disorders among individuals in Denmark. To assess the healthy worker effect, we compared the cumulative risk estimate with results from a naive cross-sectional model ignoring PJE history.

METHODS

A nationwide longitudinal cohort study was conducted using Danish registers, encompassing individuals born between 1975 and 1978 and working in 1996. Cumulative PJE was measured with a 10-year look-back period for each year 2006-2017. PJE consisted of lower-body occupational exposures, including the total weight lifted, stand/sit ratio, and the frequency of lifting more than 20 kg per day from a job exposure matrix. Odds ratio for back disorders was estimated for each year and all years combined.

RESULTS

The results unveiled a significant 31% increase in the risk of hospital-diagnosed back disorders after 4 years of cumulative PJE. The lowest risk (7%) was observed for incident back disorders with 1 year of exposure, suggesting a healthy worker effect. Nevertheless, this risk is still significantly elevated. This cumulative estimate is fourfold the estimate from the 2006 naive cross section model.

CONCLUSION

Our study clearly demonstrates an 31% increase in the risk of hospital-diagnosed back disorders with just 4 years of PJE over a 10-year period. Further, we find that cross-sectional studies strongly underestimate the risk of back disorders due to the healthy worker effect.

Is low-back pain a limiting factor for senior workers with high physical work demands? A cross-sectional study

BACKGROUND

Low-back pain (LBP) is highly prevalent among senior workers and may affect work ability, especially among those with hard physical work. This study determined the joint association of LBP intensity and physical work demands with work limitiations due to pain in senior workers.

METHODS

In the SeniorWorkingLife study (2018), 11,738 senior workers (≥50 years) replied to questions about physical work demands, LBP intensity, and work limitations due to pain. Using logistic regression analyses and controlling for potential confounders, associations between the physical work demands and LBP intensity (interaction) with work limitiations due to pain (outcome) was modeled.

RESULTS

Higher LBP intensity, as well as higher physical work demands, significantly increased the odds of experiencing work limitiations due to pain, and these two factors interacted with each other (p < 0.0001). In analyses stratified for LBP intensity, higher physical work demands gradually increased the odds of experiencing work limitiations due to pain.

CONCLUSIONS

Senior workers with a combination of physically demanding work and LBP are more affected by their pain during everyday work tasks compared to workers with similar LBP-intensity in sedentary occupations. Accommodation of work demands seems especially relevant for this group of workers.

Joint association of physical and psychosocial working conditions with risk of long-term sickness absence: Prospective cohort study with register follow-up

Aims: The interplay between physical and psychosocial working conditions for the risk of developing poor health is not well understood. This study aimed to determine the joint association of physical and psychosocial working conditions with risk of long-term sickness absence (LTSA) in the general working population. Methods: Based on questionnaire responses about physical working conditions and psychosocial working conditions (influence at work, emotional demands, support from colleagues and support from managers) and two-year prospective follow-up in a national register on social transfer payments, we estimated the risk of incident LTSA of >30 days among 9544 employees without previous LTSA from the Danish Work Environment Cohort Study. The analyses were censored for all events of permanent labour market drop-out (retirement, disability pension, immigration or death) and controlled for potential confounders. Results: In the total cohort, more demanding physical working conditions were associated with risk of LTSA in a dose-response fashion (trend test, p<0.0001). The combination of poor overall psychosocial working conditions (index measure of influence at work, emotional demands, support from managers and support from colleagues) and hard physical working conditions showed the highest risk of LTSA. However, poor overall psychosocial working conditions did not interact with physical working conditions in the risk of LTSA (p=0.9677). Conclusions: The results of this study suggest that workplaces should strive to improve both psychosocial and physical work factors in order to ensure the health of workers.

High physical work demands and working life expectancy in Denmark

Objective

In most European countries, political reforms gradually increase the statutory retirement age to counter the economic costs of a growing elderly population. However, working to a high age may be difficult for people with hard physical labour. We aim to study the impact of high physical work demands on working life expectancy (WLE).

Methods

We combined physical work demands assessed by job exposure matrix (JEM) and longitudinal high-quality national registers (outcome) in 1.6 million Danish workers to estimate WLE and years of sickness absence, unemployment and disability pension. The JEM value for physical work demand is a summarised score of eight ergonomic exposures for 317 occupations groups, sex and age. The WLE was estimated using a multistate proportional hazards model in a 4-year follow-up period.

Results

Individuals with high physical work demands had a significantly lower WLE, than those with low physical work demands, with largest differences seen among women. At age 30 years, women with high physical work demands can expect 3.1 years less working, 11 months more of sickness absence and 16 months more of unemployment than low-exposed women. For 30-year-old men, the corresponding results were 2.0 years, 12 months and 8 months, respectively.

Conclusion

Our findings show that high physical work demands are a marked risk factor for a shortened working life and increased years of sickness absence and unemployment. The results are important when selecting high-risk occupations, and expand the knowledge base for informed political decision making concerning statutory retirement age.

Association between physical work demands and work ability in workers with musculoskeletal pain: cross-sectional study

Background

Musculoskeletal pain is common in the working population and may affect the work ability, especially among those with high physical work demands. This study investigated the association between physical work demands and work ability in workers with musculoskeletal pain.

Methods

Workers with physically demanding jobs (n = 5377) participated in the Danish Work Environment Cohort Study in 2010. Associations between physical work ability and various physical work demands were modeled using cumulative logistic regression analyses while controlling for possible confounders.

Results

In the fully adjusted model, bending and twisting/turning of the back more than a quarter of the workday (reference: less than a quarter of the workday) was associated with higher odds of lower work ability in workers with low-back pain (OR: 1.38, 95% CI: 1.09–1.74) and neck-shoulder pain (OR: 1.29, 95% CI: 1.01–1.64). When adding up the different types of demands, being exposed to two or more physical work demands for more than a quarter of the workday was consistently associated with lower work ability.

Conclusions

Work that involves high demands of the lower back seems especially problematic in relation to work ability among physical workers with musculoskeletal pain. Regardless of the specific type of physical work demand, being exposed to multiple physical work demands for more than a quarter of the workday was also associated with lower work ability.

Physical working conditions and subsequent disability retirement due to any cause, mental disorders and musculoskeletal diseases: does the risk vary by common mental disorders?

PURPOSE

Physical work exposures and common mental disorders (CMD) have been linked to increased risk of work disability, but their joint associations with disability retirement due to any cause, mental disorders or musculoskeletal diseases have not been examined.

METHODS

The data for exposures and covariates were from the Finnish Helsinki Health Study occupational cohort surveys in 2000-2002, 2007 and 2012. We used 12,458 observations from 6159 employees, who were 40-60 years old at baseline. CMD were measured by the General Health Questionnaire (GHQ-12, cut-off point 3+). Four self-reported work exposures (hazardous exposures, physical workload, computer and shift work) were combined with CMD and categorized as "neither", "work exposure only", "CMD only", and "both". Associations with register-based disability retirement were assessed with Cox proportional hazards models for sample survey data adjusting for confounders over 5-year follow-up. Additionally, synergy indices were calculated for the combined effects.

RESULTS

Those reporting CMD and high physical workload had a greater risk of disability retirement due to any cause (HR 4.26, 95% CI 3.60-5.03), mental disorders (HR 5.41, 95% CI 3.87-7.56), and musculoskeletal diseases (HR 4.46, 95% CI 3.49-5.71) when compared to those with neither. Synergy indices indicated that these associations were synergistic. Similar associations were observed for CMD and hazardous exposures, but not for combined exposures to CMD and computer or shift work.

CONCLUSIONS

Identification of mental health problems among employees in physically demanding jobs is important to support work ability and reduce the risk of premature exit from work due to disability.

Inter-individual variability in load carriage economy and comparisons between different load conditions

Equivocal findings exist for the economy associated with load carried close to the body's centre of mass. Individual variation could explain some of the equivocal findings. This research aimed to examine the extent of individual variation in loaded walking economy. Eighteen females carried load on the back, head and split between the front and back. Individual variation in relative load carriage economy (ELI) was primarily assessed using standard deviation, coefficients of variation (CV) and intraclass correlation coefficients (ICC). There was large inter-individual variation in ELI values with highest mean CV's of 16%, 12% and 10% for head-, back- and combined front and back-loading. Mean ELI values were not significantly different between methods. The large amount of individual variation found here suggests future load carriage research should account for individual variation, particularly when considering sample size and when making inferences on the economy associated with different types of load carriage using group mean data.

Interaction effects of physical and psychosocial working conditions on the risk of disability pension among nursing professionals and care assistants in Sweden: A prospective study

BACKGROUND

Nursing professionals and care assistants are often subject to a combination of negative physical and psychosocial work environment factors, but most disability pension studies on such occupations have focused on one or the other of these factors. As they often coexist, there are reasons to assume that simultaneously being exposed to both types of exposures will increase the risk of disability more than being exposed to either.

OBJECTIVES

The study examined combinations of physical and psychosocial work conditions as predictors of future disability pension among nursing professionals and care assistants in Sweden.

PARTICIPANTS

The study was based on a random and representative sample of 79,004 participants in any of the Swedish Work Environment Surveys from 1993 to 2013. A total of 2576 nursing professionals, 10,175 care assistants, and 66,253 workers in other occupations were included.

METHODS

Information on background factors and disability pension was obtained from population registers. Cox proportional hazard regressions with 95% confidence intervals (CI) were performed to study if pairs of combinations of physical and psychosocial factors were related to an increased risk of disability pension. Additionally, measures of synergistic effects were estimated. The analyses were stratified on occupation group, with adjustment for selected confounders.

RESULTS

The results indicated increased hazard ratios (HR) for disability pension for most combinations of physical and psychosocial working conditions. The hazard ratios for joint exposure to high demands and heavy physical work were high among both nursing professionals (HR 1.91; CI 1.06-3.44) and care assistants (HR 2.09; CI 1.63-2.69). Also, the combination of high demands and strenuous postures resulted in significantly elevated risks of disability pension among nursing professionals (HR 1.95; CI 1.20-3.16) and care assistants (HR 2.18; CI 1.71-2.77). The HRs for joint exposure to low control and both heavy physical work and strenuous postures were significant among all other occupations (HR 2.30; CI 2.05-2.58 and HR 2.24; CI 2.01-2.51), and among care assistants (HR 1.52; CI 1.26-1.85 and HR 1.61; CI 1.34-1.93), but not significant among nursing professionals. The synergistic effects on disability pension from combined exposures were generally positive among all three occupational groups.

CONCLUSION

Nursing professionals and care assistants exposed to both negative physical and psychosocial conditions had an increased risk of disability pension. A synergistic effect with respect to disability pension was found among care assistants who reported low control and strenuous postures at work.

Effectiveness of workplace interventions in rehabilitating musculoskeletal disorders and preventing its consequences among workers with physical and sedentary employment: systematic review protocol

BACKGROUND

Musculoskeletal disorders (MSDs) are the leading cause of work disability and sickness absence worldwide. The prevalence of MSDs increases with age, consequently challenging sustainable employability among the growing ageing workforce. Knowledge of feasible and efficient workplace-based interventions to rehabilitate MSD or prevent its consequences is therefore warranted. This systematic review will evaluate the effectiveness of workplace-based interventions on MSDs and its consequences among adult workers with physical and sedentary work tasks, respectively.

METHODS

We will search the following bibliographic databases: PubMed (including the database 'MEDLINE') and Web of Science Core Collection (including the databases 'Science Citation Index Expanded', 'Social Sciences Citation Index' and 'Arts & Humanities Citation Index'). Manual searches will also be performed. We will include randomised controlled trials (RCTs) and non-RCTs reported in English in which (1) participants are adult workers with MSD, (2) interventions are aiming at rehabilitating pain symptoms of MSD or preventing the consequences of MSD and (3) interventions are initiated and/or carried out at the workplace. The review will adhere to the 'Preferred Reporting Items for Systematic reviews and Meta-Analyses' (PRISMA) guidelines for reporting systematic reviews and the Institute for Work and Health (IWH) guidelines for workplace-based interventions. For the primary evaluation of the review, the quality assessment and evidence synthesis will conform to the IWH guidelines. Secondary evaluation will include a meta-analysis (unless the included studies do not allow this due to heterogeneity) and employ the risk of bias domains recommended by Cochrane along with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach on the studies with pain intensity as an outcome.

DISCUSSION

This systematic review will provide knowledge on effective workplace-based interventions among physical and sedentary workers with MSD. RCTs are considered the most powerful experimental design in clinical trials, but solely including these may be too restrictive to understand effective workplace-based interventions where randomised and carefully controlled trials (RCTs) are not always possible. In order to maximize practical relevance, the selection process will, therefore, include both RCTs and non-RCTs and the quality assessment and evidence synthesis will conform to IWH guidelines focusing on developing practical guidelines for stakeholders. The result of this work will form the basis for industry-specific evidence-based recommendations on effective workplace-based interventions for rehabilitation of MSDs and its consequences that will later be operationalised into concrete and user-friendly practical tools for workplaces.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) number CRD42018116752 .

Is prolonged sitting at work associated with the time course of neck-shoulder pain? A prospective study in Danish blue-collar workers

OBJECTIVES

This study aimed to determine the extent to which objectively measured sitting time at work is associated with the course of neck-shoulder pain across 1 year in blue-collar workers.

METHODS

Data were analysed from 625 blue-collar workers in the Danish PHysical ACTivity cohort with Objective measurements (DPHACTO) cohort study (2012-2013). Objective data on sitting time were collected at baseline using accelerometry. Self-reported pain intensity (numeric rating scale 0-10) in the neck-shoulder region was registered for 1 year using repeated text messages (14 in total). Linear mixed models were used to determine the relationship between per cent time in sitting at work and trajectories of neck-shoulder pain, with and without adjustment for demographic, occupational and lifestyle factors, and baseline pain intensity.

RESULTS

More sitting time at work was associated with a faster decline in pain intensity over 12 months, as indicated by a statistically significant effect of sitting on pain trajectories in the crude (p=0.020) and fully adjusted models (p=0.027).

CONCLUSIONS

In blue-collar workers, more sitting time at work was associated with a favourable development of pain intensity over time. The relationship between sitting at work and pain needs further investigation before explicit recommendations and guidelines on sedentary behaviour among blue-collar workers can be developed.

The impact of sleep restriction while performing simulated physical firefighting work on cortisol and heart rate responses

PURPOSE

Physical work and sleep restriction are two stressors faced by firefighters, yet the combined impact these demands have on firefighters' acute stress responses is poorly understood. The purpose of the present study was to assess the effect firefighting work and sleep restriction have on firefighters' acute cortisol and heart rate (HR) responses during a simulated 3-day and 2-night fire-ground deployment.

METHODS

Firefighters completed multiple days of simulated physical work separated by either an 8-h (control condition; n = 18) or 4-h sleep opportunity (sleep restriction condition; n = 17). Salivary cortisol was sampled every 2 h, and HR was measured continuously each day.

RESULTS

On day 2 and day 3 of the deployment, the sleep restriction condition exhibited a significantly higher daily area under the curve cortisol level and an elevated cortisol profile in the afternoon and evening when compared with the control condition. Firefighters' HR decreased across the simulation, but there were no significant differences found between conditions.

CONCLUSION

Findings highlight the protective role an 8-h sleep opportunity between shifts of firefighting work has on preserving normal cortisol levels when compared to a 4-h sleep opportunity which resulted in elevated afternoon and evening cortisol. Given the adverse health outcomes associated with chronically high cortisol, especially later in the day, future research should examine how prolonged exposure to firefighting work (including restricted sleep) affects firefighters' cortisol levels long term. Furthermore, monitoring cortisol levels post-deployment will determine the minimum recovery time firefighters need to safely return to the fire-ground.