Outcomes of Child Sleep Problems Over the School-Transition Period: Australian Population Longitudinal Study

BACKGROUND: Adequate sleep optimizes children's learning and behavior. However, the natural history and impact of sleep problems during school transition is unknown. OBJECTIVES: To determine (1) the natural history of sleep problems over the 2-year period spanning school entry and (2) associations of children's health-related quality of life, language, behavior, learning, and cognition at ages 6.5 to 7.5 years with (a) timing and (b) severity of sleep problems. METHODS: Data were drawn from the Longitudinal Study of Australian Children. Children were aged 4 to 5 years at wave 1 and 6 to 7 years at wave 2. Parent-reported predictors included (1) timing (none, persistent, resolved, incident) of moderate/severe sleep problems over the 2 waves and (2) severity (none, mild, moderate/severe) of sleep problems at wave 2. Outcomes included parent-reported health-related quality of life and language, parent- and teacher-reported behavior, teacher-reported learning, and directly assessed nonverbal (matrix reasoning) and verbal (receptive vocabulary) cognition. Linear regression, adjusted for child age, gender, and social demographic variables, was used to quantify associations of outcomes with sleep-problem timing and severity. RESULTS: Sleep data were available at both waves for 4460 (89.5%) children, of whom 22.6% (17.0% mild, 5.7% moderate/severe) had sleep problems at wave 2. From wave 1, 2.9% persisted and 2.8% developed a moderate/severe problem, whereas 10.1% resolved. Compared with no sleep problems, persistent and incident sleep problems predicted poorest health-related quality of life, behavior, language, and learning scores, whereas resolving problems showed intermediate outcomes. These outcomes also showed a dose-response relationship with severity at wave 2, with effect sizes for moderate/severe sleep problems ranging from -0.25 to -1.04 SDs. Cognitive outcomes were unaffected. CONCLUSIONS: Sleep problems during school transition are common and associated with poorer child outcomes. Randomized, controlled trials could determine if population-based sleep interventions can reduce the prevalence and impact of sleep problems.