Context: Neuroendocrine alterations, with well-known links with health, may offer insight into why poor sleep is associated with poor health. Yet, studies testing associations between sleep and neuroendocrine activity in children are scarce.
Objective: The aim of this study was to determine whether actigraphy-based sleep pattern is associated with hypothalamic-pituitary-adrenocortical axis and sympatho-adrenal-medullary system activity in children.
Design and setting: We conducted a cross-sectional study in a birth cohort in Helsinki, Finland.
Participants: We studied 282 8-yr-old children.
Main outcome measures: We measured diurnal salivary cortisol and salivary cortisol and alpha-amylase (a sympatho-adrenal-medullary system marker) responses to the Trier Social Stress Test for Children (TSST-C).
Results: Children with short (<or=7.7 h) vs. average sleep duration (7.8-9.3 h) displayed higher cortisol awakening response and nadir (P < 0.042). Those with low (<or=77.4%) vs. average-high sleep efficiency (>77.4%) displayed higher diurnal cortisol levels across the entire day (P < 0.03), higher cortisol levels after the TSST-C stressor (P < 0.04), and higher overall alpha-amylase levels across the entire TSST-C protocol (P < 0.05). The effects were not confounded by factors that may alter sleep or hormonal patterns.
Conclusions: Poor sleep may signal altered neuroendocrine functioning in children. The findings may offer insight into the pathways linking poor sleep with poor health.