Within-child associations between sleep quality and emotional self-regulation over 6 months among preschool-aged (3- to 5-year-old) children.

Objective: We leveraged an observational, repeated-measures study to examine the within-child associations between sleep quality and emotional self-regulation, controlling for between-child effects. Methods: Children aged 3-5 years and one parent each were recruited from the community in northern New England between 2019 and 2022. Parents completed online surveys at baseline and 2, 4, and 6 months post-baseline. Child sleep quality was measured with the validated Children's Sleep Habits Questionnaire modified for preschoolers; higher scores indicate worse sleep quality (range 32-96). Child emotional self-regulation was measured with the validated Child Social Behavior Questionnaire; higher scores indicate better emotional self-regulation (range 1-7). Adjusted mixed-effects linear regression was used to model the associations between nighttime sleep quality (exposure) and emotional self-regulation (outcome) measured at each of the four study time points while disaggregating the between- and within-child effects. Results: Children ( Conclusions: The findings support a causal, within-child association between sleep quality and emotional self-regulation in preschool-aged children, with effects evident over 6 months.