Abstract
BACKGROUND: Children with abdominal pain-related disorders of gut-brain interaction (AP-DGBI) often experience sleep disturbances which may be linked to the autonomic nervous system. Heart rate variability (HRV) is a non-invasive measure of autonomic nervous system activity. Our aim was to examine if HRV was associated with characteristics of disturbed sleep in children with AP-DGBI in order to elucidate the underlying physiological mechanisms of disturbed sleep. METHODS: This analysis used baseline data from a randomized control trial of 156 children ages 7-12 years with AP-DGBI. HRV was measured after dinner using a Polar monitor. Sleep disturbances were evaluated using the Children's Sleep Habits Questionnaire. Associations between HRV indices and sleep characteristics were determined using partial correlations controlling for age and stratified by sex. KEY RESULTS: Among girls, higher parasympathetic activity (Ln RMSSD and Ln pNN50) was associated with longer sleep onset delay while lower heart rate was correlated with increased sleep anxiety. Among boys, lower autonomic balance (Ln LF/HF ratio) was associated with increased daytime sleepiness. In both sexes, lower low frequency HRV was associated with greater sleep-disordered breathing. Post hoc analysis of multiple indices revealed that children with sleep-disordered breathing had significantly lower HRV vs. those without disordered breathing. CONCLUSIONS & INFERENCES: The autonomic nervous system may be a potential mechanism which impacts sleep among children with AP-DGBI. Future longitudinal studies are needed to confirm this relationship.