Objective  To investigate the longitudinal relationship between sleep duration (SD) and positive youth development (PYD) among primary and secondary school students in Chengdu city using a cross-lagged model, and to provide scientific evidence for enhancing sleep management practices for students.

Methods  A total of 4061 students of grades 3 through 9 from the Chengdu Child Positive Development Cohort were included in this three-wave longitudinal study. There was a one-year interval between one survey and the following round of survey, and the time points for the baseline, 12-month follow-up, and 24-month follow-up surveys were designated T0, T1, and T2. The PYD of the participants was assessed using the Chinese version of the Positive Youth Development Scale. The demographic data and the average daily SD over the past month were collected. Spearman correlation analysis was performed to examine the associations between SD and PYD, and a cross-lagged model was used to investigate the longitudinal relationship between them.

Results  The average daily SD for the 3 rounds of surveys conducted at T0, T1, and T2 was 9.00 (8.04, 10.00) hours, 10.44 (9.67, 11.11) hours, and 10.39 (9.83, 11.00) hours, respectively, while the PYD scores were 5.30 (4.73, 5.71), 5.27 (4.73, 5.73), and 5.39 (4.89, 5.77), respectively. Statistical significance was found in the differences of SD and PYD scores across the 3 rounds ( P < 0.05). Spearman correlation analysis revealed synchronous correlations between SD and PYD at all three time points ( r = 0.10 at T0, r = 0.18 at T1, and r = 0.21 at T2, P < 0.05) and significant lagged correlations (e.g., r = 0.10 for T1-PYD and T2-SD, and likewise, significant correlation was found for the 3 other cross-lagged paths). The cross-lagged model demonstrated that PYD at T0 and T1 positively predicted SD at T1 and T2, respectively (β_0-1 = 0.116 95% CI, 0.083-0.150, β_1-2 = 0.097 (95% CI, 0.067-0.127), P < 0.05), and that SD at T0 and T1 also positively predicted PYD at T1 and T2 (β_0-1 = 0.028 95% CI, 0-0.056, β_1-2 = 0.042 95% CI, 0.010-0.074, P < 0.05). According to these findings, a bidirectional predictive relationship between SD and PYD across different time points was observed in primary and secondary school students. Furthermore, PYD demonstrated better performance for predicting SD than SD did for PYD. Subgroup analysis by sex confirmed the robustness of the predictive power of PYD for SD.

Conclusion This study reveals a positive bidirectional predictive relationship between SD and PYD among primary and secondary school students, suggesting that higher levels of PYD may contribute to adequate sleep. These findings provide critical scientific evidence for schools and families to strengthen sleep management and promote the holistic development and well-being of adolescents.