Influence of shift type on sleep quality of female nurses working monthly rotating shifts with cortisol awakening response as mediating variable

ABSTRACT

When shift nurses change shifts, it is likely to affect the cortisol patterns of their bodies and sleep quality. The objectives of this study was to verify the influence of monthly rotating day, evening and night shifts on the sleep quality of female nurses and determine whether the cortisol awakening response (CAR) mediates this relationship. A total of 132 female shift nurses were recruited, and ultimately 128 complete questionnaires and samples were obtained (subject loss rate = 3.0%) from 45 day-shift nurses, 44 evening-shift nurses and 39 night-shift nurses at a teaching hospital in Northern Taiwan. The Pittsburgh sleep quality index served as the research instrument that nurses used to collect saliva samples at home every day after waking and 30 min after waking so as to calculate the net increases in cortisol levels (CARi). Hierarchical multiple regression was employed to examine the influence of shift type on the sleep quality of the female nurses and the mediating effect of CARi. The results of this study indicate that shift type significantly influenced CARi (F = 19.66, p < 0.001) and that the regression coefficients of evening versus day shifts and night versus day shifts are both negative. Shift type also significantly influenced sleep quality (F = 15.13, p < 0.001), and the regression coefficients of evening versus day shifts and night versus day shifts are both positive. After controlling for the influence of shift type, CARi remained significantly correlated with sleep quality (ΔF = 5.17, p = 0.025). The results show that female evening-shift or night-shift nurses display significantly lower CARi and experience significantly poorer sleep quality than day-shift nurses. A greater CARi in the female shift nurses represents better sleep quality. Furthermore, the results prove that CARi is a mediating variable influencing the sleep quality of female shiftwork nurses.

KEYWORDS:

• Monthly rotating shift
• female nurse
• cortisol awakening response
• sleep quality

Acknowledgments

I am very grateful to the Taipei Medical University-Shuang Ho Hospital, Ministry of Health and Welfare for providing the funding that facilitated this research: [Grant Number 106HCP-12].

Declaration of Interest statement

The author declares no conflict of interest regarding the publication of this study.

Additional information

Funding

This work was supported by the Taipei Medical University-Shuang Ho Hospital, Ministry of Health and Welfare: [Grant Number 106HCP-12].

Notes on contributors

Wen-Pei Chang

Wen-Pei Chang, PhD, RN: Associate Professor, School of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan; and supervisor in the Department of Nursing, Taipei Medical University-Shuang Ho Hospital, Ministry of Health and Welfare, New Taipei City, Taiwan.