Sex-specific associations between sleep problems and hypothalamic-pituitary-adrenocortical axis activity in children

Study objectives: Sleep problems are associated with reduced physical and mental health. Altered function of the hypothalamic pituitary adrenocortical axis (HPAA) may be one underlying mechanism. We studied the associations between sleep problems and HPAA activity in children. Design: A cross-sectional epidemiological cohort study. Setting: Salivary cortisol was sampled throughout one day at home and during the Trier Social Stress Test for Children (TSST-C) in clinic. Sleep disorders were measured with a parent-rated Sleep Disturbance Scale for Children, and sleep duration measured by actigraphy for one week. Participants: 284 (51% girls) 8-year-old children. Results: Boys with sleep problems (>= 85th percentile in any of the sleep-wake transition, arousal, excessive daytime somnolence or sleep hyperhydrosis subscales) had lower diurnal salivarycortisol levels and salivary cortisol responses to TSST-C stress in comparison to boys without sleep problems. Girls with sleep problems (>= 85th percentile in disorders of initiating and maintaining sleep) displayed a higher overall level of salivary cortisol during the TSST-C. Salivary cortisol responses to stress were lower in boys and higher in girls with more than one sleep problem. Conclusions: Sleep problems in children are associated with altered HPAA function, after controlling for actual sleep quantity measured by actigraphy. Boys with sleep problems had lower HPAA activity and girls with sleep problems had higher HPAA activity, compared to children without sleep problems. (C) 2011 Elsevier Ltd. All rights reserved.