Background: The aims of this study were 1) to clarify the prevalence of sleep problems (insomnia, insufficient sleep, and delayed sleep-wake phase) among Japanese university students; 2) to examine sociodemographic characteristics, lifestyle, and sleep-related symptoms in each sleep problem; and 3) to evaluate the association between the above-mentioned sleep problems and daytime dysfunction in school life. Methods: Self-report questionnaire surveys were conducted at eight universities in Japan, and we received 1034 valid answers (78% female). The questionnaire consisted of socio-demographic characteristics, information on lifestyle, sleep pattern, sleep-related symptoms, and daytime dysfunction in school life. Groups with insomnia, behaviorally induced insufficient sleep syndrome (BIISS), delayed sleep-wake phase (DSWP), and BIISS + DSWP were defined. To identify the association between sleep problems and daytime dysfunction in school life, the generalized linear mixed effect model was conducted. Results: Sleep duration on weekdays was 5.9 ± 1.2 h, and 38.2% of the students had a sleep duration < 6.0 h. About 16% of the students were categorized as evening-type individuals. More than half of the students (56.1%) had excessive daytime sleepiness. Insomnia was associated with tardiness (aOR: 0.8, 95%CI: 0.7-0.9) and falling asleep during class (aOR: 1.6: 95%CI: 1.4-2.0). BIISS was associated with tardiness (aOR: 1.5, 95%CI: 1.1-2.2) and interference with academic achievement (aOR: 1.9, 95%CI: 1.3-2.6). DSWP and BIISS + DSWP were associated with absence (aOR: 3.4, 95%CI: 2.2-5.1 / aOR: 4.2, 95%CI: 3.2-5.6), tardiness (aOR: 2.7, 95%CI: 1.8-4.

Background Young adults are likely to have activities and go to bed late at night due to their age-dependent delayed endogenous circadian clock. The purpose of the present study was to clarify sleep–wake rhythm and its association with lifestyle, health-related quality of life, and academic performance among nursing students. Methods Self-reported questionnaires were distributed to undergraduate nursing students at six universities in Japan. Sleep–wake rhythm was assessed using the morningness-eveningness questionnaire. A quantitative design using the generalized linear mixed effect model was utilized to identify the factors related to the evening type among female nursing students (n = 447). Results About 18% of the participants were identified as the evening type. Evening type was associated with living alone, part-time job, and club activity. Sleep duration on weekdays was shorter, meal time duration was the shortest, and the percentages of students who skipped meals and those who gained body weight were higher in the evening type than in the morning type and intermediate type. Mental health-related quality of life was lower in the intermediate type and evening type than in the morning type, while there was no difference in physical health-related quality of life among these groups. The percentages of the nursing students who have experienced absence, tardiness, falling asleep during class, and/or interference with academic achievement were higher in the evening type than in other groups. Conclusions The present study has important implications for nursing students’ biological characteristics and lifestyle, which are associated with their health-related quality of life and academic performance.

Background: Generally, nursing university students struggle with academic work, that consequently bring about delayed bed time, insufficient sleep and worsened daytime functioning. The purpose of the present study is to clarify chronotype and its association with lifestyle, health-related quality of life and academic performance among nursing students.Methods: Self-reported questionnaires were distributed to undergraduate nursing students at six universities. Chronotype was assessed using the morningness-eveningness questionnaire. The generalized linear mixed effect model was utilized to identify the related factors with evening type among female nursing students (n = 447).Results: About 18% of Japanese female nursing students were identified as evening type. Evening type was associated with living alone, part-time job and club activity. Sleep duration on weekdays was shorter, meal time duration was the shortest, and the percentages of students who skipped meals and those who gained body weight were higher in the evening type than in the morning type and intermediate type. Mental health-related quality of life was lower in the intermediate type and evening type than in the morning type, while there was no difference in physical health-related quality of life among chronotype groups. The percentages of the nursing students who have experienced absence, tardiness, falling asleep during class and/or interference with academic achievement were higher in the evening type than in other chronotypes.Conclusions: Education of sleep hygiene and a healthy lifestyle to prevent late sleep-wake rhythm would contribute to improve nursing students’ health-related quality of life / academic performance.

Background: Young adults are likely to have activities and go to bed late at night due to their age-dependent delayed endogenous circadian clock. The purpose of the present study was to clarify sleep/wake rhythm and its association with lifestyle, health-related quality of life, and academic performance among nursing students.Methods: Self-reported questionnaires were distributed to undergraduate nursing students at six universities in Japan. Sleep/wake rhythm was assessed using the morningness-eveningness questionnaire. A quantitative design using the generalized linear mixed effect model was utilized to identify the factors related to the evening type among female nursing students (n=447). Results: About 18% of the participants were identified as the evening type. Evening type was associated with living alone, part-time job, and club activity. Sleep duration on weekdays was shorter, meal time duration was the shortest, and the percentages of students who skipped meals and those who gained body weight were higher in the evening type than in the morning type and intermediate type. Mental health-related quality of life was lower in the intermediate type and evening type than in the morning type, while there was no difference in physical health-related quality of life among these groups. The percentages of the nursing students who have experienced absence, tardiness, falling asleep during class, and/or interference with academic achievement were higher in the evening type than in other groups.Conclusions: The present study has important implications for nursing students’ biological characteristics and lifestyle, which are associated with their health-related quality of life and academic performance.