The long-term associations between kindergarten bedtime and sleep duration, executive function, and academic achievement.

objectiveWe investigated whether kindergarten bedtime and later sleep duration predicted executive function (EF), behavior, and academic achievement in middle childhood, and whether associations varied by socioeconomic status (SES), race or ethnicity, and disability. By accounting for the independent effects of these factors, findings reflect the unique associations between early sleep patterns and later developmental outcomes.

methodsData were drawn from the nationally representative Early Childhood Longitudinal Study, Kindergarten Cohort of 2010-11 (N = 6945). Structural equation modeling (SEM) tested whether kindergarten bedtime (age 5, 2010-2011) predicted third-grade sleep duration (age 9), which in turn influenced fourth-grade EF and behavior (age 10), and fifth-grade academic test scores (age 11, 2015-2016). We examined whether sleep duration mediated bedtime's association with EF, behavior, and achievement; whether EF and behavior mediated sleep duration's association with achievement; and whether these associations were also moderated by SES, disability, and race or ethnicity.

resultsBedtime predicted duration, which predicted higher achievement through effects on cold EF (i.e., emotionally neutral cognitive processes like working memory and cognitive flexibility). These indirect effects were observed across racial or ethnic and SES groups but became nonsignificant after adjusting for covariates. Although cold EF was the strongest predictor of achievement, duration remained a small but significant contributor.

conclusionsDisparities in achievement by SES and race or ethnicity may be driven by structural factors beyond sleep duration or bedtime. Promoting early bedtime routines is important, but broader systemic interventions are needed to close achievement gaps.