title: Urinary interleukin-8 is a biomarker of stress in emergency physicians, especially with advancing age--the JOBSTRESS* randomized trial.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors: Emergency Department, University Hospital (CHU), G. Montpied Hospital, Clermont-Ferrand, France ; Department of Occupational Medicine, University Hospital (CHU), G. Montpied Hospital, Clermont-Ferrand, France ; Laboratory of Metabolic Adaptations to Exercise in Physiological and Pathological Conditions EA3533, Blaise Pascal University, Clermont-Ferrand, France ; School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia ; Department of Sport Medicine and Functional Exploration, University Hospital (CHU), G. Montpied Hospital, Clermont-Ferrand, France.
authors: Frédéric
authors: F
authors: Dutheil
authors: Marion
authors: M
authors: Trousselard
authors: Christophe
authors: C
authors: Perrier
authors: Gérard
authors: G
authors: Lac
authors: Alain
authors: A
authors: Chamoux
authors: Martine
authors: M
authors: Duclos
authors: Geraldine
authors: G
authors: Naughton
authors: George
authors: G
authors: Mnatzaganian
authors: Jeannot
authors: J
authors: Schmidt
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000652:urine*; D015415:Biomarkers / Q000652:urine; D002055:Burnout, Professional / Q000503:physiopathology / Q000652:urine*; D004636:Emergency Service, Hospital; D005221:Fatigue / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016209:Interleukin-8 / Q000652:urine*; D008297:Male; D015999:Multivariate Analysis; D010820:Physicians; D012044:Regression Analysis; D012890:Sleep; D013315:Stress, Psychological / Q000503:physiopathology / Q000652:urine*
chemical_list: D015415:Biomarkers; C508606:CXCL8 protein, human; D016209:Interleukin-8
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