Coronary Heart Disease (CHD) remains a global health concern, responsible for significant morbidity and mortality. While traditional risk factors like smoking, hypertension, and high cholesterol levels are well-established contributors, emerging research has shed light on the influence of psychosocial stressors at work.
Specifically, the concepts of job strain and effort-reward imbalance (ERI) have gained attention as potential risk factors for CHD. Job strain, characterized by high demands and low control, and ERI, denoting an imbalance between work effort and received rewards, have individually been linked to increased CHD risk.
However, the scarcity of evidence regarding the combined impact of these two stressors on CHD risk prompted an extensive prospective cohort study conducted among white-collar workers in Quebec, Canada. The study aimed to discern the separate and synergistic effects of job strain and ERI exposure on CHD incidence, with a particular focus on internal validity and gender differences.
The study, conducted from 2000 to 2018, involved 6,465 white-collar workers without pre-existing cardiovascular disease, with a mean age of 45.3±6.7 years. Psychosocial stressors were assessed using validated questionnaires. CHD events were identified through medico-administrative databases utilizing validated algorithms. To ensure the robustness of the findings, multiple imputation and inverse probability weights were employed to mitigate potential threats to internal validity.
Among the 3,118 men in the study, 571 experienced a first CHD event. The study revealed that exposure to either job strain or ERI individually was associated with a 49% increase in CHD risk, as indicated by an adjusted hazard ratio (HR) of 1.49 (95% CI, 1.07–2.09). Notably, combined exposure to both job strain and ERI significantly amplified the risk, with an adjusted HR of 2.03 (95% CI, 1.38–2.97), translating to a 103% increase in CHD risk. Importantly, the results remained consistent even after excluding early CHD cases and censoring at retirement.
In contrast, the findings for the 3,347 women in the study were less definitive. The HRs for various exposures, including passive job (HR 1.24, 95% CI 0.80–1.91), active job (HR 1.16, 95% CI 0.70–1.94), job strain (HR 1.08, 95% CI 0.66–1.77), and ERI (HR 1.02, 95% CI 0.72–1.45), yielded inconclusive results.
Comparison with Previous Studies
This study contributes to an ongoing debate within the scientific community by providing compelling evidence regarding the combined impact of job strain and ERI on CHD risk. Previous studies have yielded inconsistent results, often employing binary definitions of job strain and ERI that may have led to misclassification and underestimated effects.
In contrast, the present study utilized a more nuanced approach, considering all components of job strain and utilizing the quadrant measure. This approach allowed for a reference category that aligned with the theoretical minimum risk level.
Implications and Mechanisms
The observed effect sizes of job strain and ERI on CHD incidence among men are comparable to those of several well-established biomedical and lifestyle CHD risk factors. This finding highlights the substantial role that psychosocial stressors at work play in contributing to CHD risk.
The underlying pathophysiological mechanisms linking psychosocial stressors at work to CHD are multifaceted. Over the course of a professional career, exposure to these stressors can trigger the activation of various physiological systems, including the sympathetic nervous system, the renin-angiotensin-aldosterone system, and the hypothalamo-pituitary-adrenal axis.
This activation, in turn, can lead to the occurrence and progression of coronary atherosclerosis. Additionally, psychosocial stressors can precipitate cardiovascular events through sympathetic nervous system activation, potentially resulting in atherosclerotic plaque disruption and platelet activation.
Addressing Early CHD Cases
The study also addressed the potential influence of early CHD cases on the findings. Some previous research has suggested that early cases might introduce reverse causation or effect underestimation due to a possible induction period. However, the study’s results demonstrated marginally strengthened associations after removing early CHD cases. This observation suggests that the effects of psychosocial stressors at work can persist beyond the end of exposure, aligning with the natural progression of atherosclerosis over many decades.
Gender Disparities and Future Research
While this study provides valuable insights into CHD risk among men exposed to job strain and ERI, the findings for women remain inconclusive. Gender-specific differences in CHD pathophysiology, case numbers, and disease onset present unique challenges in studying the impact of psychosocial stressors at work. Future research, potentially in the form of meta-analyses specifically focusing on women, may help elucidate the role of these stressors in CHD among females.
This pioneering prospective cohort study provides compelling evidence of the adverse impact of psychosocial stressors at work on CHD incidence, particularly among men. The findings underscore the significance of job strain and ERI as independent risk factors for CHD. Moreover, the study reveals that the combined exposure to both stressors significantly heightens CHD risk, emphasizing the need for comprehensive interventions targeting these psychosocial stressors in the workplace.
For men, early interventions that address job strain and ERI could be pivotal in reducing the burden of CHD. These findings hold great promise for public health strategies aimed at reducing the incidence of CHD in male white-collar workers.
However, the study’s findings among women are inconclusive, necessitating further investigation. The complexities of gender-specific psychosocial stressors and their impact on CHD risk warrant a more nuanced exploration in future research.
In summary, this study represents a crucial contribution to our understanding of the relationship between psychosocial stressors at work and CHD risk. The implications are profound, highlighting the potential benefits of tailored interventions to mitigate these stressors, particularly among men, and offering new avenues for research and prevention in the field of cardiovascular health.
reference link : https://dx.doi.org/10.1161/CIRCOUTCOMES.122.009700