Biochemical Manifestations of Occupational Stress: Effort–Reward Imbalance and Its Association with Cortisol/DHEA Ratio, Oxidative Stress, and Inflammatory Markers in Healthcare Professionals

Abstract

Occupational stress is a critical factor impacting the psychological and physical well-being of healthcare professionals. While the Effort--Reward Imbalance (ERI) model effectively captures psychosocial stress at work, its specific biochemical correlates remain insufficiently understood. This study aimed to evaluate the association between ERI and key neuroendocrine, oxidative, and inflammatory biomarkers among healthcare staff. A prospective observational study was conducted involving 180 healthcare professionals. Psychosocial work stress was measured using the validated ERI questionnaire. Salivary diurnal cortisol and dehydroepiandrosterone (DHEA) levels were quantified to calculate the cortisol/DHEA ratio. Serum markers of oxidative stress, including malondialdehyde (MDA) and total antioxidant capacity (TAC), and systemic inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6), were analyzed using standard assay techniques. Multivariable regression models were used to examine the associations while adjusting for demographic and lifestyle covariates. High ERI scores (ERI > 1.0) were significantly associated with an elevated cortisol/DHEA ratio (p < 0.001), indicating neuroendocrine dysregulation. Furthermore, high ERI was linked to increased oxidative damage, demonstrated by higher MDA levels (β = 0.34, p < 0.01) and reduced TAC (β = −0.28, p < 0.01). Inflammatory markers also showed strong positive associations, with significantly elevated hs-CRP (p = 0.002) and IL-6 (p = 0.005) levels observed in the high-stress group. Chronic work stress under the ERI framework manifests directly in biochemical dysregulation, marked by neuroendocrine strain, elevated oxidative stress, and heightened systemic inflammation. These findings highlight the potential for biochemical markers to serve as early physiological indicators of occupational burnout and cardiovascular risk in healthcare settings.