Associations between onset of effort-reward imbalance at work and onset of musculoskeletal pain: analyzing observational longitudinal data as pseudo-trials

Sleep quality and nighttime sleep duration mediated the association between occupational stress and work-related musculoskeletal disorders among bus drivers

BACKGROUND

Work-related musculoskeletal disorders (WMSDs) significantly affect bus drivers' health and warrant adequate attention. Previous studies had reported associations between occupational stress exposure and WMSDs, but the underlying mechanisms remain unclear. This study aimed to evaluate the associations of occupational stress with WMSDs and the mediated effect of sleep quality and nighttime sleep duration.

METHODS

A total of 1,792 bus drivers with the available information from 5 subsidiaries of Shenzhen Bus Group were included by the convenience sampling method. Logistic regression model was used to estimate the associations of occupational stress, sleep quality and nighttime sleep duration with WMSDs. Mediation analysis was performed to explore the role of sleep quality and nighttime sleep duration in the association between occupational stress and WMSDs.

RESULTS

The prevalence rate of single-site, multiple-site, and overall WMSDs among bus drivers were 10.04%, 59.26%, and 69.31%, respectively. We found that occupational stress was significantly associated with an increased risk of both multiple-site WMSDs and overall WMSDs [OR (95% CI) = 1.92 (1.56, 2.36) and 2.03 (1.63, 2.55), respectively]. Compared to those with high sleep quality, bus drivers with poor sleep quality exhibited a higher risk of multiple-site WMSDs and overall WMSDs [OR (95% CI) = 3.73 (2.89, 4.84) and 4.82 (3.53, 6.71), respectively]. Each 1-hour increment in nighttime sleep duration was linked to a 36% declined risk of multiple-site WMSDs and a 37% reduced risk of overall WMSDs [OR (95% CI) = 0.64 (0.58, 0.71) and 0.63 (0.57, 0.70), respectively]. Moreover, mediation analysis showed that sleep quality mediated 48.94% and 48.70%, and nighttime sleep duration mediated 19.63% and 18.64%, of the associations between occupational stress and multiple-site WMSDs and overall WMSDs, respectively.

CONCLUSION

Occupational stress and poor sleep quality significantly elevated the risk of both multiple-site and overall WMSDs, while increased nighttime sleep duration was associated with a reduced risk of multiple-site and overall WMSDs. Sleep quality and nighttime sleep duration emerged as potential mediators in multiple-site and overall WMSDs induced by occupational stress. Highlighting the importance of reducing occupational stress, maintaining good sleep quality and sufficient nighttime sleep duration for WMSDs prevention.

Job stress and chronic low back pain: incidence, number of episodes, and severity in a 4-year follow-up of the ELSA-Brasil Musculoskeletal cohort

ABSTRACT

We investigated the association between job stress, as assessed by the effort-reward imbalance model, and the incidence of chronic low back pain (CLBP) over a 4-year period. A total of 1733 participants from the ELSA-Brasil Musculoskeletal cohort, who were free from LBP at baseline (2012-2014), were included. Episodes of LBP in the past 30 days, intensity, and the presence of disability were investigated in annual telephone follow-ups (2015-2018). Chronic LBP was defined as episodes of LBP lasting >3 months with at least moderate intensity. We analyzed the incidence of at least one episode of CLBP (yes/no), the number of CLBP episodes (0, 1, ≥2), and CLBP severity/disability (absent, nondisabling, severe/disabling). The association between these outcomes and tertiles of the effort-to-reward ratio, as well as each dimension of the effort-reward imbalance model, was investigated using multinomial logistic and Poisson regression models adjusting for sociodemographic and occupational variables. The cumulative incidence of CLBP over 4 years was 24.8%. High effort-reward imbalance increased the chances of experiencing multiple CLBP episodes and severe/disabling CLBP by 67% (95% confidence interval [CI]: 1.12-2.47) and 70% (95% CI: 1.14-2.53), respectively. High overcommitment increased the incidence of CLBP by 23% (95% CI: 1.01-1.50) and the chances of multiple CLBP episodes and severe/disabling CLBP by 67% (95% CI: 1.11-2.50) and 57% (95% CI: 1.05-2.34), respectively. These results indicate that exposure to job stress is associated with a higher incidence, a greater number of episodes, and increased severity of CLBP over a 4-year period. If this association is causal, measures aimed at reducing exposure to job stress are likely to alleviate the burden of CLBP.

Workplace Psychosocial Factors and Their Association With Musculoskeletal Disorders: A Systematic Review of Longitudinal Studies

This systematic review examines literature regarding the relationship between workplace psychosocial factors and musculoskeletal disorders (MSDs). Musculoskeletal disorders are the leading cause of work disability, resulting in billions of dollars of financial losses. Evidence suggests that workplace psychosocial factors can lead to the development and progression of MSDs. A data search was conducted in MEDLINE, EMBASE, PsychINFO, Scopus, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) from August 2009 to May 2020 inclusive. Other eligibility criteria included studies published in English, conducted on adults within a workplace setting, conducted in developed economies, and were stability-control longitudinal observational studies. Studies were independently screened for eligibility, using COVIDENCE (software for managing and streamlining systematic reviews) and assessed for quality by multiple authors, using the JBI Evidence synthesis tool. From 6,812 studies, 47 articles were included in the final analysis. The most common MSDs investigated were lower back pain, neck and shoulder pain, and upper extremity symptoms and disorders. Included articles identified that psychosocial workplace factors of support, collaboration, job control, and job demands were statistically significantly associated with risk and progression of MSDs. Review of the articles included in this article supports the theory that MSDs have a multifactorial, complex etiology that includes psychosocial factors. Interventions to enhance psychosocial work environment provide opportunities to reduce the risk of MSDs.

Job stress and chronic and widespread musculoskeletal pain: a cross-sectional analysis from the Brazilian Longitudinal Study of Adult Health Musculoskeletal

ABSTRACT

Musculoskeletal pain is a global health concern, and work-related psychosocial stress might be a potential contributing factor. This cross-sectional study investigates whether job stress is associated with chronic and widespread musculoskeletal pain in 2051 Brazilian active civil servants included in the Brazilian Longitudinal Study of Adult Health Musculoskeletal (ELSA-Brasil MSK). Job stress was assessed using the Effort-Reward Imbalance (ERI) questionnaire. Associations between ERI domains, categorized into tertiles, and chronic musculoskeletal pain (CMP) at any site and per number of affected sites (0, 1-2, ≥3-multisite pain) and body regions (0, 1-2, 3-generalized pain), were investigated using binary and multinomial logistic regression, adjusted for sociodemographic, occupational, and health covariates. The prevalence of CMP at any site, multisites, and generalized regions was 52.9%, 18.2%, and 9.5%, respectively. After adjustments, the lower the reward and the greater the overcommitment, the higher the odds of CMP at any site. The ERI domains were more strongly associated with multisite and generalized CMP than with CMP at any site. Multisite CMP was associated with lower reward and with greater effort, overcommitment, and effort-reward imbalance ratio. Chronic musculoskeletal pain according to body regions, especially generalized pain, was also associated with ERI domains effort (OR = 2.06; 95%CI = 1.33-3.21), overcommitment (OR = 3.44; 95%CI = 2.20-5.39), and effort-reward imbalance ratio (OR = 2.06; 95%CI = 1.30-3.27). Results reveal an association between job stress not only with CMP at any site but notably with the pain spread to other body sites or regions. Our findings suggest that lowering stress at work and discouraging overcommitment may help reduce the CMP burden, including reduction of CMP spread from one site or region of the body to another.

Interrelationships between job demands, low back pain and depression: A four-way decomposition analysis of direct and indirect effects of job demands through mediation and/or interaction

BACKGROUND

Psychosocial work stressors may lead to low back pain (LBP) through depressive symptoms or to depression through LBP. Depressive symptoms or LBP may also modify these associations.

METHODS

We examined prospective interrelationships between job demands, LBP and depressive symptoms. We used comparable data from three consecutive biennial surveys in 2010-2016, from the Swedish Longitudinal Occupational Survey of Health (SLOSH) and the Work Environment and Health in Denmark (WEHD) cohorts, broadly representative of the working populations in Sweden and Denmark. We conducted multivariate counterfactual based mediation analyses allowing for four-way decomposition of the total effect of job demands, on incident LBP (N=2813, 2701) and incident major depression (N=3707, 5496). The four components estimated direct and indirect effects through mediation and/or interaction.

RESULTS

We observed no association between job demands and incident LBP four years later, but job demands was associated with later major depression (relative risks=1.88, 95% confidence interval=1.45-2.31 in SLOSH and 1.64, 1.18-2.11 in WEHD, adjusted for age, sex, panel (SLOSH data), education, cohabitation, physically strenuous work and chronic diseases. About 37% of the association was attributed to interaction between job demands and LBP in SLOSH. No interaction was found in WEHD. LBP partly mediated the relationship, by 14% in SLOSH and 2%, while statistically insignificant in WEHD.

LIMITATIONS

Possible limitations include lack of comparable data on disabling low back pain, different scales for depressive symptoms, misclassification and residual confounding.

CONCLUSIONS

This suggests mainly a direct effect of job demands on major depression, or through other pathways than LBP.

Effort-reward imbalance at work and weight changes in a nationwide cohort of workers in Denmark

Objective

To investigate the relation between effort‐reward imbalance (ERI) at work and subsequent weight changes.

Methods

We included participants from a population‐based cohort of workers in Denmark (mean age = 47 years, 54% women) with two (n = 9005) or three repeated measurements (n = 5710). We investigated the association between (a) ERI (ie, the mismatch between high efforts spent and low rewards received at work) at baseline and weight changes after a 2‐year follow‐up (defined as ≥5% increase or decrease in body mass index (BMI) vs stable), and (b) onset and remission of ERI and subsequent changes in BMI. Using multinomial logistic regression we calculated risk ratios (RR) and 95% confidence intervals (CI), adjusted for sex, age, education, cohabitation, migration background, and follow‐up time.

Results

After 2 years, 15% had an increase and 13% a decrease in BMI. Exposure to ERI at baseline yielded RRs of 1.09 (95% CI: 0.95‐1.25) and 1.04 (95% CI: 0.90‐1.20) for the increase and decrease in BMI, respectively. There were no differences between sex and baseline BMI in stratified analyses. The onset of ERI yielded RRs of 1.04 (95% CI: 0.82‐1.31) and 1.15 (95% CI: 0.84‐1.57) for subsequent increase and decrease in BMI. The RRs for the remission of ERI and subsequent increase and decrease in BMI were 0.92 (95% CI: 0.71‐1.20) and 0.78 (95% CI: 0.53‐1.13), respectively. Of the ERI components, high rewards were associated with a lower risk of BMI increase.

Conclusion

ERI was not a risk factor for weight changes. Future studies may investigate whether this result is generalizable to other occupational cohorts and settings.

Factors Affecting Psychological Stress in Healthcare Workers with and without Chronic Pain: A Cross-Sectional Study Using Multiple Regression Analysis

Background and Objectives: Pain affects psychological stress and general health in the working population. However, the factors affecting psychological job stress related to chronic pain are unclear. This study aimed to clarify the structural differences among factors affecting psychological job stress in workers with chronic pain and those without pain. Materials and Methods: A stepwise multiple regression analysis revealed the differences in structure between the psychological stress of workers with chronic pain and those with no pain. Psychological job stress by the Brief Job Stress Questionnaire was used as the dependent variable, with psychological state (depression and anxiety), specifically that characteristic of chronic pain (pain catastrophizing); information on the nature of the pain (intensity and duration); and number of years of service as independent variables. Selected independent variables were evaluated for collinearity. Results: In the model with psychological stress as a dependent variable (chronic pain: r² = 0.57, F = 41.7, p < 0.0001; no-pain: r² = 0.63, F = 26.3, p < 0.0001), the difference between the experiences of workers with chronic pain and those with no pain was that chronic pain was associated with depression (Beta = 0.43, p < 0.0001) and no pain with anxiety (Beta = 0.34, p < 0.0001). In the model with chronic pain-related depression as a dependent variable (r² = 0.62, F = 41.7, p < 0.0001), job-life satisfaction (Beta = −0.18, p = 0.0017) and magnification (a dimension of pain catastrophizing; Beta = 0.16, p < 0.0001) were significant. Conclusions: The results of this study suggest that the psychological characteristics of chronic pain, such as depression and magnification, should be considered when evaluating and intervening in the job stress of workers with chronic pain.

Risk and Prognostic Factors of Low Back Pain: Repeated Population-based Cohort Study in Sweden

STUDY DESIGN

Prospective longitudinal cohort study.

OBJECTIVE

To determine the associations for workload and health-related factors with incident and recurrent low back pain (LBP), and to determine the mediating role of health-related factors in associations between physical workload factors and incident LBP.

SUMMARY OF BACKGROUND DATA

It is not known whether the risk factors for the development of LBP are also prognostic factors for recurrence of LBP and whether the associations between physical workload and incident LBP are mediated by health-related factors. We used data from the Swedish Longitudinal Occupational Survey of Health study. Those responding to any two subsequent surveys in 2010 to 2016 were included for the main analyses (N = 17,962). Information on occupational lifting, working in twisted positions, weight/height, smoking, physical activity, depressive symptoms, and sleep problems were self-reported. Incident LBP was defined as pain limiting daily activities in the preceding three months in participants free from LBP at baseline. Recurrent LBP was defined as having LBP both at baseline and follow-up. For the mediation analyses, those responding to three subsequent surveys were included (N = 3516).

METHODS

Main associations were determined using generalized estimating equation models for repeated measures data. Mediation was examined with counterfactual mediation analysis.

RESULTS

All risk factors at baseline but smoking and physical activity were associated with incident LBP after adjustment for confounders. The strongest associations were observed for working in twisted positions (risk ratio  = 1.52, 95% CI 1.37, 1.70) and occupational lifting (risk ratio  = 1.52, 95% CI 1.32, 1.74). These associations were not mediated by health-related factors. The studied factors did not have meaningful effects on recurrent LBP.

CONCLUSION

The findings suggest that workload and health-related factors have stronger effects on the development than on the recurrence or progression of LBP, and that health-related factors do not mediate associations between workload factors and incident LBP.

LEVEL OF EVIDENCE

3.