Pittsburgh Sleep Quality Indexを用いた大学生の睡眠問題調査  [in Japanese] A Study of Sleep Problems in Undergraduates using Pittsburgh Sleep Quality Index  [in Japanese]

本研究の目的は,Pittsburgh Sleep Quality Index(PSQI)を用いて,大学生の睡眠問題を把握することであった.質問紙に回答した大学生1,323名のうち,有効回答は1,118名(有効回答率84.50%)であり,睡眠薬の服用があった26名(全体の23%)を除外した1,092名を分析対象とした.記述統計量の検討では,大学生の睡眠不足・睡眠覚醒リズムの乱れが示唆された.性別による違いの検討では,女性の睡眠不足傾向・男性の睡眠相後退傾向が示唆された.学年差の検討では,1・2年生と比較して3・4年生における睡眠相の後退が確認された.クラスター分析を行ったところ,大学生の睡眠問題は(1)短時間睡眠・中途覚醒型,(2)長時間睡眠・中途覚醒型,(3)睡眠状態良好型,(4)入眠困難型,(5)短時間睡眠・熟眠型の5類型に分類された.睡眠問題の中でも,入眠困難症状の保有が全体的な睡眠の質の低下に寄与していた.睡眠不足・睡眠覚醒リズムの乱れに関する啓発活動・入眠困難の早期発見・援助が重要である.

Objective: The purpose of this study was to investigate sleep problems in undergraduates using Pittsburgh Sleep Quality Index (PSQI). Method: One thousand and one hundred eighteen undergraduates (Valid response rate: 84.50%) completed PSQI Japanese version. We analyzed 1092 undergraduates' PSQI data except for those who are using of sleeping medication (n=26: 2.3% of valid responder). Results: (a) Characteristics of PSQI data: As for undergraduates of the current study, C3 (sleep duration), C5 (sleep disturbance) and C7 (daytime dysfunction) and Global PSQI Score were higher and C4 (habitual sleep efficiency) was lower than those of participants at development and validation point in time of PSQI. (b) Sex differences: Compared with female, sleep onset time [t (1083.10)=2.27, p<0.01] and wake time [t (1068.71)=5.82, p<0.01] in male were more delayed. Similarly, total sleep time [t (1090)=4.10, p<0.01] and sleep onset latency [t (1090)=1.70, p<0.10] in male were longer than that in female. As for each PSQI component score, PSQI C2 score of men was significantly higher than that of women [t (1090)=2.19, p<0.05], however C5 [t (1075.10)=-1.83, p<0.10] and C7 [t (1075.10)=-3.72, p<0.01] scores were lower. (c) School grade differences: As a result of one-way ANOVA and post-hoc Scheffe, significant grade differences in sleep onset time [F (3,1088)=7.53, p<0.01, 1st<2nd, 3rd<4th] and wake time [F (3,1088)=7.46, p<0.01, 1st<2nd<3rd,4th] were confirmed. (d) Classification of sleep problems: Hierarchical cluster analysis (ward method) revealed five types of sleep problems: cluster 1 "Short Sleep & Sleep Maintaining Insomnia" (n=238, 21.79%); cluster 2 "Long Sleep & Sleep Maintaining Insomnia" (n=335: 30.68%); cluster 3 "Good Sleep" (n=127, 11.63%); cluster 4 "Sleep Onset Insomnia" (n=156, 14.29%) cluster 5 "Short Sleep Only" (n=236, 21.61%). As a result of one-way ANOVA [F (4,1087)=296.71, p<0.01] and post-hoc Scheffe, "Sleep Onset Insomnia" was the highest global PSQI score of these 5 clusters. Conclusion: Most of undergraduates are poor sleepers, and they have a tendency to insufficient sleep syndrome or circadian sleep rhythm disorder, especially delayed sleep phase syndrome. The sleep phase of juniors and seniors is more delayed than that of freshmen and sophomores. And the symptom of sleep onset insomnia contributes to multidimensional sleep quality in university students. Therefore it is needed to (a) widely inform undergraduates about the importance of regularized sleep-wake rhythms and prolonged sleep time and (b) perform screening test and support students with sleep onset insomnia.