Nonrestorative sleep is associated with somatic and depressive symptoms in Japanese junior high school students

Nonrestorative sleep (NRS) has been identified as a potential risk factor for physical and mental well-being in adults, but limited research exists for children and adolescents. This study aimed to clarify the factors associated with NRS in Japanese junior high school students.

The participants were 529 Japanese junior high school students in grades 7 through 9. Participants were asked to respond to Google Forms, and responses were obtained from 392 students. Sleep habits, history of coronavirus disease (COVID-19), physical symptoms, social isolation, and the presence of the symptoms of restless legs syndrome (RLS) were identified. NRS, insomnia symptoms, and depressive symptoms were evaluated using the Restorative Sleep Questionnaire (RSQ), Athens Insomnia Scale (AIS), and Patient Health Questionnaire (PHQ)-9, respectively. The cut-off value for NRS determination by the RSQ score was the mean of the scores that maximized the sensitivity and specificity sum for detecting participants with AIS and PHQ-9 scores of ≥ 6 and ≥ 5, respectively. NRS-associated sleep parameters and those associated with depressive symptoms were evaluated using binominal logistic regression analysis. Multinomial logistic regression (MLR) analysis was used to confirm the reproducibility of the binomial logistic regression analysis results with lower RSQ scores.

The NRS group comprised 40.1% of participants and exhibited a higher prevalence of physical and depressive symptoms compared to those with restorative sleep. Logistic regression analysis, adjusted for sex, grade, and COVID-19 history, revealed the following odds ratios (95% confidence interval) for NRS: average total sleep time < 7 h 2.44 (1.16-4.33), AIS ≥ 6 2.74 (1.51-4.95), evening chronotype 2.58 (1.49-4.47), and RLS symptoms 2.21 (1.21-4.03). The same results were obtained using MLR as those obtained via binomial logistic regression analysis. Logistic regression analysis for depressive symptoms revealed that NRS displayed the highest odds ratio (95% CI) of 3.16 (1.90-5.27) among the sleep-related variables.

These findings suggest that NRS in Japanese junior high school students is associated with physical and mental health issues. Intervention and longitudinal studies are warranted to address NRS-associated sleep-wake problems in this age group.