Saturday 19 September 2009

Australian study of sleep in primary school children.

It has long been recognised that adequate sleep optimizes children's learning and behavior. However, the natural history and impact of sleep problems during school transition is unknown.

This study was set up 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.

To acheive this data was 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.

Sleep data was 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 incidental 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.

The final conclusion was that sleep problems during school transition are common and associated with poorer child outcomes.

(QUACH J, HISCOCK H, CANTERFORD L, WAKE M.
Pediatrics 2009;123(5):1287-1292.)