Circadian adaptation of melatonin and cortisol in police officers working rotating shifts

Auteurs

Anastasi Kosmadopoulos, Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada, Appleton Institute for Behavioural Sciences, Central Queensland University, Adelaide, SA, Australia
Philippe Boudreau, Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada
Laura Kervezee, Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada, Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
Diane B. Boivin, Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, QC, Canada

Type de document

Études primaires

Année de publication

2024

Langue

Anglais

Titre de la revue

Journal of Biological Rhythms

Première page

49

Dernière page

67

Résumé

Misalignment of behavior and circadian rhythms due to night work can impair sleep and waking function. While both simulated and field-based studies suggest that circadian adaptation to a nocturnal schedule is slow, the rates of adaptation in real-world shift-work conditions are still largely unknown. The aim of this study was to evaluate the extent of adaptation of 24-h rhythms with 6-sulfatoxymelatonin (aMT6s) and cortisol in police officers working rotating shifts, with a special attention to night shifts. A total of 76 police officers (20 women; aged 32 ± 5.4 years, mean ± SD) from the province of Quebec, Canada, participated in a field study during their 28- or 35-day work cycle. Urine samples were collected for ~32 h before a series of day, evening, and night shifts to assess circadian phase. Before day, evening, and night shifts, 60%-89% of officers were adapted to a day schedule based on aMT6 rhythms, and 71%-78% were adapted based on cortisol rhythms. To further quantify the rate of circadian adaptation to night shifts, initial and final phases were determined in a subset of 37 officers with suitable rhythms for both hormones before and after 3-8 consecutive shifts (median = 7). Data were analyzed with circular and linear mixed-effects models. After night shifts, 30% and 24% of officers were adapted to a night-oriented schedule for aMT6s and cortisol, respectively. Significantly larger phase-delay shifts (aMT6s: −7.3 ± 0.9 h; cortisol: −6.3 ± 0.8 h) were observed in police officers who adapted to night shifts than in non-adapted officers (aMT6s: 0.8 ± 0.9 h; cortisol: 0.2 ± 1.1 h). Consistent with prior research, our results from both urinary aMT6s and cortisol midpoints indicate that a large proportion of police officers remained in a state of circadian misalignment following a series of night shifts in dim-light working environments. © 2023 The Author(s).

Mots-clés

Rythme circadien, Circadian rhythm, Travail par postes, Shift work, Police, Police force, Travail de nuit, Night work, Québec

Numéro de projet IRSST

n/a

Citation recommandée

Kosmadopoulos, A., Boudreau, P., Kervezee, L. et Boivin, D. B. (2023). Circadian adaptation of melatonin and cortisol in police officers working rotating shifts. Journal of Biological Rhythms, 39(1), 49-67. https://doi.org/10.1177/07487304231196280