Night-shift work related problems in young female nurses in Japan

Background: The relationship of night-shift work to sleep problems and work performance was examined in young female nurses in 11 hospitals in Japan. Methods: A cross-sectional study was conducted by means of anonymous self-administered questionnaires, carried out in July 1999. Subjects were 620 female nurses (Average age: 23.9) who started their careers in April 1997 and continued working in the same hospitals for two years and three months until the time of the survey. A questionnaire consisting mainly of items concerning sleep disorders from the Japanese version of the Pittsburgh Sleep Quality Index was distributed to the subjects. Results: Significant associations were observed between working on night shift and the use of alcoholic beverages to help induce sleep, and between working on night shift and daytime drowsiness. Significant differences were also observed between two- and three-shift systems with regard to subjective sleep quality. Moreover, average hours of sleep were significantly associated with three related sleep items: subjective sleep quality, difficulty in getting to sleep, and daytime drowsiness. Conclusion: Results suggest that in Japanese shift-work systems, sufficient sleep hours are needed for nurses who work night shift to ensure good quality of sleep and consequently better services for patients.