Trends in Sleep Problems Among Japanese Adolescents: 2004 to 2017

Abstract

Background: Adolescence is a period of physical, mental, and social development. Sleep problems in adolescence, such as insomnia and short sleep duration, have been associated with physical and mental health problems. Little is known about the recent trends in sleep problems among adolescents. This study aimed to examine trends in sleep problems among Japanese adolescents. Methods: Using data from the Lifestyle Survey of Adolescents collected in 2004, 2008, 2010, 2012, 2014, and 2017, we calculated the prevalence of insomnia, short sleep duration, late bedtime, long sleep duration, and poor sleep quality. Multivariable logistic regression analysis models were used to examine the association of each sleep problem and survey years. Sampling weights were constructed based on participation rates. Findings: We analyzed data from 545,285 Japanese adolescents. Results indicated that, since 2004, the odds of insomnia decreased (AOR 0·86, 95%CI 0·84-0 ·88), as did the odds of short sleep duration (AOR 0·89, 95%CI 0·90-0·94) and poor sleep quality (AOR 0·93, 95%CI 0·92-0·95). However, the odds of late bedtime tended to increase (AOR 1·07, 95%CI 1·05-1·10) during this period. Interpretation: The prevalence of insomnia symptoms, short sleep duration, and poor sleep quality among adolescents decreased from 2004 to 2017. However, the prevalence of late bedtime increased. These changes are both relieving and concerning. Teachers, parents, and health professionals should consider educating adolescents regarding sleep hygiene, adjusting schedules of extracurricular activities, and enhancing time management to improve their sleep quality. Funding Statement: This study was supported by a grant for Comprehensive Research on Lifestyle-Related Diseases including Cardiovascular Diseases and Diabetes Mellitus by the Ministry of Health and Welfare Health Science Research Fund in Japan (grant no. 29060801). Declaration of Interests: Adam P. Spira received an honorarium from Springer Nature Switzerland AG for Guest Editing a Special Issue of Current Sleep Medicine Reports. The other authors declare no conflicts of interest associated with this manuscript. Ethics Approval Statement: Informed written consent was obtained from all study participants. Due to the new epidemiological research guidelines, informed consent was obtained from each junior high school student’s parent or guardian in the 2017 survey. Parents’ and guardians’ informed consent was not required by the guidelines governing anonymous and non-invasive research entailing students who had finished junior high school in the earlier years. The teachers explained the nature of confidentiality and voluntary participation to all the students, and completed questionnaires were returned to the working group in sealed envelopes. This protocol is in accordance with the Japanese Ethical Guidelines for Epidemiological Research announced by the Ministry of Health, Labour and Welfare and the Ministry of Education, Culture, Sports, Science and Technology of Japan. The working group used anonymized questionnaires to prevent the identification of individual participants and to safeguard their privacy. This study was approved by the ethical review board of the Nihon University School of Medicine.