A Systematic Review and Revised Meta-analysis of the Effort-Reward Imbalance Model of Workplace Stress and Hypothalamic-Pituitary-Adrenal Axis Measures of Stress.

OBJECTIVE: Despite considerable research in the past 20 years into associations between the effort-reward imbalance (ERI) model and various health outcomes, the mechanisms responsible for the association remain unclear. Our meta-analysis assessed the associations of ERI and overcommitment (OC) in the workplace with measures from the hypothalamic-pituitary-adrenal (HPA) axis. METHODS: Electronic databases were searched with the phrase "effort * reward * imbalance," which yielded 319 studies leading to 56 full-text studies being screened. Thirty-two studies within 14 articles met the inclusion criteria and were meta-analyzed using mixed- and random-effects models. RESULTS: Greater ERI was associated with increased HPA axis activity (r = 0.05, p = .02, k = 14, n = 2461). The cortisol waking concentrations (r = 0.11, p = .02, k = 6, n = 493) were the only subgroup associated with ERI. Meta-regression revealed that studies that contained more men had stronger ERI to HPA marker associations. When all HPA markers were considered collectively, OC was not associated with greater HPA axis activity (r = 0.01, p = .70, k = 10, n = 1684), with only cortisol (pm) associated with OC (r = -0.24, p = .02, k = 2, n = 95). CONCLUSIONS: ERI and OC were associated with HPA responsivity. Although the cortisol waking concentrations and not the CAR were associated with ERI, this may be due to heterogeneity in the experience of stress between studies. Future studies should consider the concurrent assessment of burnout to better assist the interpretation of ERI with HPA responsivity.

Trait Mindfulness Helps Explain the Relationships Between Job Stress, Physiological Reactivity, and Self-Perceived Health.

OBJECTIVE: The aim of this study was to assess, for the first time, the associations among work stress as measured by the job-demands resources (JD-R) model, trait mindfulness, and indices of the physiological stress response. METHOD: Dairy farmers (N = 79) completed job stress (using the JD-R model), trait mindfulness, burnout, and self-reported health questionnaires and provided physiological indices of the stress response. RESULTS: Our findings suggest that those reporting higher mindfulness have better physical and mental health, and that being more mindful may buffer the effects of a large cortisol awakening response on poor physical health. CONCLUSION: Although assessments of both psychological and physiological indicators of stress and ill-health will inform the underlying mechanisms of the associations between work stress and disease, assessing the role of trait mindfulness in this relationship may prove useful.

Do workplace-based mindfulness meditation programs improve physiological indices of stress? A systematic review and meta-analysis.

OBJECTIVE: Mindfulness-based interventions (MBI) have been related with improved job satisfaction, wellbeing, health, and reduced workplace stress with employees. However, until now, synthesis of the evidence of the effect of MBIs on physiological indices associated with stress and ill-health has been lacking. Therefore the current systematic review aimed to synthesise the literature from employee samples to provide guidance for future investigations in terms of which physiological indicators and biological systems may be most impacted by MBIs. METHODS: Electronic databases were searched. Studies that conducted a mindfulness-based program with an employee sample, which targeted workplace stress or work engagement, and measured a physiological outcome were selected for inclusion. Studies using either a between-group or within-group design were included. Nine papers were found to meet the inclusion criteria for our systematic review and meta-analysis of the literature. RESULTS: MBIs were found to be effective in reducing cortisol production, as indicated by lowered high and low diurnal cortisol slopes. However, no changes were found for cortisol awakening response or concentrations for single a.m. and p.m. time-points. MBIs also improved autonomic balance, assessed by heart rate variability coherence measures, but not blood pressure. Sympathetic nervous system reactivity as measured by salivary alpha amylase was also reduced following MBI. While aspects of immune function were also improved following MBIs, specifically, increased antibody response to a viral vaccine and reduced C-reactive protein concentrations, each of these outcomes were only assessed in a single study. CONCLUSION: Taken together, the findings suggest that MBIs are a promising avenue for intervention for improving physiological indices of stress. Our findings suggest that changes in daytime cortisol secretion and HRV coherence may be particularly influenced by MBIs. Future studies should aim to assess multiple physiological indices to confirm the current findings and further improve current understanding of which biological systems (and indices within these systems) show responses indicative of reduced stress due to MBI.

The salivary alpha amylase awakening response is related to over-commitment.

We assessed the relationship between physiological and psychological measures of workplace stress as measured by the effort-reward imbalance (ERI) model, with a seldom studied sample of owner-operator dairy farmers. Dairy farmers (N = 74) self-reported ERI, over-commitment (OC), dedication, and health then provided awakening saliva samples that were used to calculate the salivary alpha amylase awakening response (sAA-AR), cortisol awakening response (CAR), and salivary immunoglobulin A (sIgA) level. ERI, OC, and dedication levels were not related with sIgA or the CAR, but more over-committed farmers had a less pronounced sAA-AR. OC was more associated than ERI with the physiological indicators of stress, potentially due to the owner-operator sample used in this investigation. The suitability of sAA as a viable physiological measure of autonomic nervous system activity has been debated, but our findings promote its inclusion in future occupational stress research.

A Systematic Review and Meta-analysis of the Effort-Reward Imbalance Model of Workplace Stress and Hypothalamic-Pituitary-Adrenal Axis Measures of Stress.

OBJECTIVE: The association between effort-reward imbalance (ERI) and various health outcomes has been well documented over the past 20 years, but the mechanisms responsible for this association remain unclear. The present meta-analysis assessed the associations of ERI and overcommitment (OC) in the workplace with hypothalamic-pituitary-adrenal (HPA) axis measures. METHODS: Electronic databases were searched with the phrase "effort*reward*imbalance," which yielded 319 studies leading to 56 full-text studies being screened. Thirty-two studies within 14 articles met inclusion criteria and were meta-analyzed using mixed and random effects models. RESULTS: Greater ERI was associated with increased HPA axis activity (r = .09, p < .001, k = 14, N = 2541). The cortisol awakening response (r = .14, p < .001, k = 9, N = 584) and cortisol waking concentrations (r = .12, p = .01, k = 6, N = 493) were the only HPA measures associated with ERI. OC was also associated with greater HPA axis activity (r = .06, p < .01, k = 10, N = 1918). Cortisol (PM) (r = .13, p = .02, k = 3, N = 295) was the only HPA measure associated with OC. CONCLUSIONS: ERI and OC were similarly related with HPA responsivity. However, because OC moderated the relationship between ERI and HPA axis markers, the importance of OC should not be overlooked. Because OC is likely more malleable than ERI to intervention, this may be a promising avenue for future research.

Associations between the effort-reward imbalance model of workplace stress and indices of cardiovascular health: A systematic review and meta-analysis.

Work stress can increase the risk of cardiovascular disease by 50%, with increasing research focusing on the underlying mechanisms responsible for these associations. Our meta-analysis assessed the associations of the effort-reward imbalance (ERI) workplace stress model with indices of cardiovascular disease. The search term 'effort*reward*imbalance' produced 22 papers (129 associations, N=93,817) meeting inclusion criteria. Greater ERI was most associated with increased hypertension (r=0.26, p<0.001, N=1180), intima media thickness (r=0.23, p<.001, N=828) and fibrinogen (r=0.13, p=0.03, N=4315). Trait over-commitment was most associated with increased hypertension (r=0.24, p=0.02, N=899) and intima media thickness (r=0.19, p=0.02, N=828). Interventions aimed at reducing the impact of ERI and over-commitment on cardiovascular disease should consider concurrently assessing changes in physiological markers of cardiovascular disease.

A systematic review and meta-analysis of the effort-reward imbalance model of workplace stress with indicators of immune function.

OBJECTIVE: Despite considerable research into associations between the effort reward imbalance (ERI) model and various health outcomes over the past 20years, the underlying mechanisms responsible for the association remain unclear. Recently, ERI investigations have examined associations with immune sub-systems (e.g., leukocytes, cytokines and immunoglobulins). Synthesis of the amalgamated research evidence will aid clarity to this field of enquiry. We conducted a meta-analysis and reviewed the associations of ERI and over-commitment (OC) in the workplace with immunity. METHOD: Electronic databases were searched with the phrase 'effort reward imbalance' which initially yielded 319 studies leading to 57 full text studies being screened. Seven studies that met inclusion criteria were combined using mixed and random effects models. RESULTS: Greater ERI was associated with lower immunity (r=-0.09, CI -0.14, -0.05, p<0.001). Sub-group analyses revealed the effect with mucosal immunity was stronger (r=-0.33, CI -0.47 to -0.18) than trends between both cytokine (r=-0.04, CI -0.07, -0.01) and leukocyte sub-groups (r=-0.02 CI -0.04, 0.01) respectively (k=7, N=9952). Over-commitment was also associated with lower immunity (r=-0.05, CI -0.09, 0.01, p=0.014); subgroup (leukocytes, cytokines, mucosal immunity) associations, however, were homogenous (Q=1.83, df=2, p=0.400, k=6, N=2358). CONCLUSIONS: Greater ERI and OC were both associated with lower immunity. The association between mucosal immunity and ERI was stronger than the cytokine and leukocyte sub-groups. OC moderated the relationship between ERI and immunity.