Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Institute of the Ruhr-Universität Bochum, Bochum, Germany.
Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Institute of the Ruhr-Universität Bochum, Bochum, Germany.
Psychoneuroendocrinology. 2024 Aug;166:107066. doi: 10.1016/j.psyneuen.2024.107066. Epub 2024 Apr 30.
Cortisol typically peaks in the morning after waking up and declines throughout the day, reaching its lowest levels during nighttime sleep. Shift work can cause misalignment between cortisol levels and sleep-wake timing. We analyzed this misalignment in female shift workers focusing on the timing and extent of these changes.
We conducted a cross-sectional study involving 68 shift workers (aged 37 ± 10 years) and 21 non-shift workers (aged 45 ± 10 years) from a hospital. Shift workers were monitored through two day shifts and three night shifts, whereas non-shift workers were monitored during two day shifts. Each participant collected six to eight saliva samples (depending on their shift type) and provided sleep timing information, which was recorded via polysomnography and sleep diaries. Generalized additive mixed models were used to estimate shift-specific differences in cortisol smooth curves. Summary measures calculated for the cortisol smooth curves included cortisol awakening response, peak-to-bed slope, and total output.
Between shift workers and non-shift workers, we observed similar diurnal cortisol profiles with a steep negative diurnal slope during day shifts. In shift workers on night shifts, a flattened U-shaped cortisol profile after the post-awakening maximum was observed, with a peak-to-bed slope close to zero. When comparing night to day shifts in the group of shift workers, mean cortisol levels were lower between 42 and 56 minutes and 1.8-11.9 hours after waking up, and higher between 14.9 and 22 hours after waking up.
Our findings indicate altered cortisol profiles in female hospital employees on night shifts. Specifically, cortisol levels were lower at night when higher levels would typically be necessary for work activities, and higher at bedtime after a night shift, when levels should normally be low.
皮质醇通常在醒来后早晨达到峰值，然后全天逐渐下降，在夜间睡眠时达到最低水平。轮班工作会导致皮质醇水平与睡眠-觉醒时间之间的不匹配。我们分析了女性轮班工人的这种不匹配情况，重点关注了这些变化的时间和程度。
我们进行了一项横断面研究，纳入了来自医院的 68 名轮班工人（年龄 37 ± 10 岁）和 21 名非轮班工人（年龄 45 ± 10 岁）。轮班工人在两个白班和三个夜班期间进行监测，而非轮班工人在两个白班期间进行监测。每位参与者采集了六到八个唾液样本（取决于他们的轮班类型），并提供了睡眠时间信息，该信息通过多导睡眠图和睡眠日记记录。使用广义加性混合模型来估计皮质醇平滑曲线的轮班特异性差异。为皮质醇平滑曲线计算的汇总指标包括皮质醇觉醒反应、峰值到床斜率和总输出。
在轮班工人和非轮班工人之间，我们观察到类似的日间皮质醇谱，在白班期间呈陡峭的负日间斜率。在夜班轮班工人中，在觉醒后最大峰值之后观察到平坦的 U 形皮质醇谱，峰值到床斜率接近零。在轮班工人组中比较夜间和白天的轮班时，在醒来后 42 到 56 分钟和 1.8-11.9 小时之间的平均皮质醇水平较低，在醒来后 14.9 到 22 小时之间的水平较高。
我们的研究结果表明，女性医院员工在夜班时皮质醇谱发生了改变。具体而言，夜间的皮质醇水平较低，而夜间通常需要更高的水平来进行工作活动，夜班后就寝时间的皮质醇水平较高，而正常情况下应该较低。
