Background Acute or chronic stress can lead to physical and mental disorders. Measuring cortisol can objectify the degree of stress. Cortisol is traditionally measured in serum, but recently the relevant fraction of free cortisol can be reliably measured in saliva, using the very sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The use of saliva is non-invasive and allows easy serial testing around stressful events. The main objective of this study is to investigate whether serial saliva cortisol determinations using the LC-MS/MS method can be used to assess the stress response that first responders may experience during moments of acute professional deployment in their daily work.
Methods Healthy first responders (police officers, firefighters, rapid response team, ambulance personnel, first aid and emergency medical personnel) were recruited to participate in a Euregional high-reliability simulation training (‘Be Aware’-scenario training, 19 April 2018). At three time points, simultaneous venous blood samples and saliva samples were obtained. These time points were 1 hour before, immediately after and 10 hours after the simulation training. The correlation between changes in saliva cortisol measured by LC-MS/MS and serum cortisol at all three time points was determined. Results were compared with spectators not directly participating in the simulation.
Results 70 subjects participated in the simulation. There was a strong correlation between the changes in saliva and blood cortisol at the three time points. A significant increase in blood and saliva cortisol was shown 1 hour after the experienced stress moments. The levels had almost completely returned to baseline in all healthy volunteers 10 hours later. Cortisol in spectators was unaffected.
Conclusion Serial saliva cortisol measurements using LC-MS/MS is a reliable and fast non-invasive functional stress assay, which can be easily collected in daily practice and used for investigation and monitoring of stress response in front line responders.
- first responders
- care systems
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Handling editor Caroline Leech
Collaborators Not applicable.
Contributors MS and ML designed and conceptualised the research. MS and ML wrote the first concept of the article. MS and ML coordinated all aspects of this study. PV, WD and WvM commented on the initial draft version of the manuscript and were involved in actively revising the subsequent draft and discussing them in the research until submission of the final version.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval All participants were informed on the nature of the study protocol and signed informed consent. The study was performed according to the Helsinki Declaration and was approved by the Medical Ethical Committee of the Zuyderland Medical Hospital (registration no. METCZ20180039). Data were analysed anonymously and reported results could not be traced back to individual participants.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. Data are anonymised by deidentifying the participants. The data are gathered in ResearchManager of our institute and are available on request (mail to: firstname.lastname@example.org)
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