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DOI: 10.1055/s-0033-1353329
In pre-school children, sleep objectively assessed via sleep-EEGs remains stable over 12 months and is related to psychological functioning, but not to cortisol secretion
Objectives: Cross-sectional studies provide evidence that in pre-schoolers poor sleep is already associated with both poor psychological functioning and an increased cortisol secretion. However, long-term studies on the stability of sleep in pre-schoolers are scarce. The aim of the present study was therefore to investigate objective sleep in pre-schoolers longitudinally, and to predict objective sleep, psychological functioning and cortisol secretion prospectively as a function of sleep 12 months earlier. Method: A total of 58 pre-schoolers (mean age: 5.43 years; 47% females) took part in a follow-up 12 months after initial assessment. Assessment included sleep-EEGs, psychological assessment, and cortisol secretion as a marker of the hypothalamic-pituitary-adrenocortical (HPA) axis activity under baseline and challenge conditions. Results: Longitudinally, poor objective sleep at age 5.4 years predicted poor objective sleep and psychological difficulties but not cortisol secretion 12 months later. Cross-sectionally, at the age of 6.4 years, poor sleep was associated with greater psychological difficulties and increased cortisol secretion. Conclusion: In pre-schoolers, objectively assessed poor sleep at the age of 5.4 years predicted poor sleep and psychological difficulties one year later. Data suggest that in pre-schoolers, sleep remains stable over a 12-months-period. Pre-schoolers with poor sleep appear to be at risk for developing further psychological difficulties. This study was supported by Swiss National Science Foundation.