AUTHOR=Bjorvatn Bjørn , Axelsson John , Pallesen Ståle , Waage Siri , Vedaa Øystein , Blytt Kjersti M. , Buchvold Hogne V. , Moen Bente E. , Thun Eirunn 

TITLE=The Association Between Shift Work and Immunological Biomarkers in Nurses

JOURNAL=Frontiers in Public Health

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2020.00415

DOI=10.3389/fpubh.2020.00415

ISSN=2296-2565

ABSTRACT=Objectives: Shift work is associated with several negative health effects. The underlying pathophysiological mechanisms are unclear, but low-grade inflammation has been suggested to play a role. This project aimed to determine whether levels of immunological biomarkers differ depending on work schedule, self-reported sleep duration, self-reported sleep quality, and presence of shift work disorder (study 1). Furthermore, we aimed to determine whether these biomarkers differ after a night of sleep versus at the end of a night or a day shift (study 2). 
Methods: In study 1, 390 nurses provided blood samples after a night of sleep with the dried blood spot method. In study 2, a subset of 55 nurses also provided blood samples after a day shift and after a night shift. The following biomarkers were measured: interleukin-1alpha, interleukin-1beta, interleukin-4, interleukin-6, interleukin-8, interleukin-10, interleukin-13, monocyte chemoattractant protein-1, interferon-gamma, and tumor necrosis factor-alpha. 
Results: In study 1, neither work schedule, number of night shifts, number of quick returns (less than 11 hours between consecutive shifts), short sleep duration, poor sleep quality, nor shift work disorder were clearly associated with the levels of these biomarkers. The only significant finding was that levels of interleukin-10 were higher among day-evening workers compared with day only and three-shift rotation workers. In study 2, the only significant finding was that levels of monocyte chemoattractant protein-1 were lower after a day shift and after a night shift compared with after night sleep. 
Conclusions: We found no clear indications of shift workers to have higher levels of a multitude of inflammatory biomarkers. However, results should be interpreted with caution due to limitations, e.g. related to the sampling procedure and to low levels of biomarkers in the blood samples.