Immunological effects of shift work in healthcare workers

Bette Loef,Allard J Van Der Beek,Chantal Van De Ven,Rob Mariman,Ronald H J Jacobi,Nening M Nanlohy,Karin I Proper,Debbie Van Baarle

doi:10.1038/s41598-019-54816-5

Abstract

The immune system potentially plays an important mechanistic role in the relation between shift work and adverse health effects. To better understand the immunological effects of shift work, we compared numbers and functionality of immune cells between night-shift and non-shift workers. Blood samples were collected from 254 night-shift and 57 non-shift workers employed in hospitals. Absolute numbers of monocytes, granulocytes, lymphocytes, and T cell subsets were assessed. As read out of immune function, monocyte cytokine production and proliferative capacity of CD4 and CD8 T cells in response to various stimuli were analysed. The mean number of monocytes was 1.15 (95%-CI = 1.05–1.26) times higher in night-shift than in non-shift workers. Furthermore, night-shift workers who worked night shifts in the past three days had a higher mean number of lymphocytes (B = 1.12 (95%-CI = 1.01–1.26)), T cells (B = 1.16 (95%-CI = 1.03–1.31)), and CD8 T cells (B = 1.23 (95%-CI = 1.05–1.45)) compared to non-shift workers. No differences in functional parameters of monocytes and lymphocytes were observed. The differences in numbers of monocytes and T cells suggest that chronic exposure to night-shift work as well as recent night-shift work may influence the immune status of healthcare workers. This knowledge could be relevant for preventive initiatives in night-shift workers, such as timing of vaccination.

Highlights

The immune system potentially plays an important mechanistic role in the relation between shift work and adverse health effects
Night-shift workers had a higher number of monocytes than non-shift workers
With respect to function of immune cells, the results indicated no large differences in monocyte functionality and T cell proliferative responses to various stimuli between night-shift and non-shift workers

Summary

Introduction

The immune system potentially plays an important mechanistic role in the relation between shift work and adverse health effects. The differences in numbers of monocytes and T cells suggest that chronic exposure to nightshift work as well as recent night-shift work may influence the immune status of healthcare workers. Some studies have reported a higher number of lymphocytes or leukocytes in shift workers[16,17,18,19,20,21], which has been suggested to reflect enhanced inflammation and to be associated with increased disease risk[16,17,18,19,20,21], while other studies did not find these differences[11,22,23]. As a read out of immune function, we compared monocyte cytokine production and proliferative T cell responses to different stimuli between night-shift and non-shift workers

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