Open Access
CC BY-NC-ND 4.0 · Sleep Sci 2025; 18(S 02): S1-S40
DOI: 10.1055/s-0045-1812743
ID: 62

Effects of Night Shift Work on Diurnal Glycemic Profiles: A Field Study Among Female Hospital Employees

Authors

  • Rasmus H. Reeh

    1   The National Research Centre for the Working Environment, Denmark

  • Anders Aagaard

    1   The National Research Centre for the Working Environment, Denmark

  • Thomas Mandrup-Poulsen

    2   Univerisity Copenhagen, Copenhagen, Denmark

  • Kirsten Nabe-Nielsen

    1   The National Research Centre for the Working Environment, Denmark

  • Anne Helene Garde

    1   The National Research Centre for the Working Environment, Denmark
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Introduction: Around-the-clock work schedules disrupt the natural circadian rhythms resulting in circadian misalignment and increases risks for metabolic and cardiovascular diseases. Yet, it remains to be settled, how night shift work affects glycemic profiles in real-world settings. We hypothesized that working during the night impairs glucose profiles among female hospital employees compared with working during the day.

Methods: In the 1001 nights-cohort, 1075 female hospital employees in Denmark registered working hours, sleep, and food intake in diaries. A subgroup of 54 participants without known diabetes wore Continuous Glucose Monitors (GCM, Dexcom) for 6–8 days. The night shift and day shift were defined as working 8 hours from 23:00 to 07:00 and 07:00 to 15:00 respectively. An off night and off day were defined as working 0 hours during the same intervals, respectively. 51 participants were eligible for inclusion. They all worked at least one night and one day shift and had at least one-off night and one-off day. Daily mean and standard error of glucose levels for night and day shifts as well as off nights and days were calculated.

Results: Participants completed a total of 77-night shifts and 282 off nights, along with 74 days shifts and 252 off days. The mean glucose level was 115.2 (SEM 1.81) mg/dL during night shifts, 113.4 (SEM 0.93) mg/dL during off nights, 111.2 (SEM 1.52) mg/dL during day shifts, and 111.6 (SEM 0.95) mg/dL during off days.

Conclusion: Preliminary results indicate that night shifts modestly increase mean glucose levels at night but not during the daytime. Results of other CGM-derived outcome variables and statistical variance component modeling using a within-person design will be presented at the conference. Support: This project is supported by funding from The Danish Working Environment Research Fund (26–2020–09; 19–2022–09), The Health Foundation (22-B- 0452), The National Research Centre for the Working Environment, and The Danish Cardiovascular Academy, which is funded by the Novo Nordisk Foundation (NNF17SA0031406) and the Danish Heart Foundation.



Publication History

Article published online:
08 October 2025

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