Urinary interleukin-8 is a biomarker of stress in emergency physicians, especially with advancing age--the JOBSTRESS* randomized trial.

BACKGROUND: Emergency physicians are exposed to greater stress during a 24-hour shift (24 hS) than a 14-hour night shift (14 hS), with an impact lasting several days. Interleukin-8 (IL-8) is postulated to be a chronic stress biomarker. However, no studies have tracked IL-8 over several shifts or used it for monitoring short-term residual stress. The IL-8 response to the shifts may also increase with age. Conveniently, IL-8 can be measured non-intrusively from urine. METHODS: We conducted a shifts-randomized trial comparing 17 emergency physicians' urinary IL-8 levels during a 24 hS, a 14 hS, and a control day (clerical work on return from leave). Mean levels of IL-8 were compared using a Wilcoxon matched-pairs test. Independent associations of key factors including shifts, stress, and age with IL-8 levels were further assessed in a multivariable generalized estimating equations model. RESULTS: Mean urinary IL-8 levels almost doubled during and after a 24 hS compared with a 14 hS or a control day. Furthermore, IL-8 levels failed to return to control values at the end of the third day after the shift despite a rest day following the 24 hS. In the multivariable model, engaging in a 24 hS, self-reported stress, and age were independently associated with higher IL-8 levels. A 24 hS significantly increased IL-8 levels by 1.9 ng (p = .007). Similarly, for every unit increase in self-reported stress, there was a 0.11 ng increase in IL-8 levels (p = .003); and for every one year advance in age of physicians, IL-8 levels also increased by 0.11 ng (p = .018). CONCLUSION: The 24 hS generated a prolonged response of the immune system. Urinary IL-8 was a strong biomarker of stress under intensive and prolonged demands, both acutely and over time. Because elevated IL-8 levels are associated with cardiovascular disease and negative psychological consequences, we suggest that emergency physicians limit their exposure to 24 hS, especially with advancing age.

Stress assessment in acute care department nurses by measuring interleukin-8.

BACKGROUND: Cytokines, such as interleukin (IL)-8, have been shown to be related to depressive symptoms or inflammatory diseases and may be useful as stress biomarkers. AIM: This study was to assess whether urinary IL-8 levels were reliable indicators of stress among acute care department (AD) nurses. METHODS: A total of 118 nurses participated in the study. Urinary IL-8 levels of 49 AD nurses were compared with levels of a control group of 69 chronic care department (CD) nurses. RESULTS: The urinary IL-8 levels of AD nurses, who reported a higher level of professional stress, were higher than the levels of CD nurses (P < 0.01). CONCLUSION: Measurement of urinary IL-8 may be an appropriate biomarker for stress assessment in nurses.

Longitudinal changes in pituitary-adrenal hormones in South African women with burnout.

The authors' goal was to document baseline pituitary-adrenal hormonal and related metabolic variables in 16 female patients with burnout. Then, following stress management intervention, to compare the changes with an equal number of untreated control subjects. At monthly intervals for 4 mo, 24-h urine samples were obtained for determination of free cortisol excretion. In addition, fasting blood samples were analyzed for levels of cortisol, dehydroepiandrosterone sulfate (DHEAS), ACTH, aldosterone, and catecholamines. Other biochemical measurements included growth hormone, prolactin, insulin, glucose, and lipid components. The Maslach Burnout Inventory, General Health Questionnaire- 28, and Zung depression rating scale were completed on each consecutive visit. The most striking finding was the reduction of urine free-cortisol excretion in the patients compared with controls. Initial urinary free cortisol was significantly lower in the patients (mean +/- SEM = 47.2 +/- 11.0 vs 79.0 +/- 6.8 nmol/L, p = 0.02) and remained significantly reduced at 4 mo (mean +/- SEM = 44.0 +/- 6.1 vs 91.1 +/- 8.8 nmol/L, p = 0.0001). There were no significant changes in the other hormonal and biochemical data. We conclude that there is functional hypocortisolism in burnout, which is not immediately restored on stress management intervention despite clinical and psychological improvement.