Do differences in chronotypes affect sleep and health-related quality of life of nursing students? A cross-sectional study

Nursing students experience higher levels of stress and more sleep-related problems than other students; however, the relationship of chronotype to nursing students' sleep status and health-related quality of life (HRQOL) is unclear. This cross-sectional, observational study investigated whether chronotype affected Japanese nursing college students' sleep and HRQOL. Nursing students completed the Attribute Questionnaire about Subject Background, Japanese Version Morningness-Eveningness Questionnaire (MEQ), Munich Chrono-Type Questionnaire-Japanese Version (MCTQ), Japanese Version of the Pittsburgh Sleep Quality Index (PSQI), SF-12v2 Standard, Japanese Version 2.0 (SF-12), Japanese Translation of Profile of Mood States 2nd Edition-Adult Short (POMS2). Of the 241 students (mean age 20.16 +/- 1.80 years; 80.9% female), 80 (33.2%) had evening, 142 (58.9%) had intermediate, and 19 (7.9%) had morning chronotype. The overall total PSQI score was 6.86 +/- 2.97. Additionally, 141 students (64.1%) scored >= 6, suggesting disturbed sleep. Approximately 80% of the evening chronotype students had a total PSQI score of 8.34 +/- 3.11, clearly indicating disturbed sleep. Sleep-related parameters (total PSQI score, bedtime, sleep latency, wake-up time, sleep duration, social jetlag) were worse in evening than in other chronotypes. SF-12 and POMS2 did not differ among chronotypes. Thus, evening chronotype nursing students require sleep-related support from early on.