Associations between a novel measure of sleep health and cognitive functioning in middle childhood: a crosssectional Environmental Influences on Child Health Outcomes cohort study.

Study Objectives: Research linking children's sleep to cognitive outcomes is inconsistent and has largely focused on one aspect of sleep, such as duration, rather than measuring multiple dimensions of sleep health. We hypothesized that children's sleep health would be positively associated with inhibitory control and cognitive functioning.

Method: We cross-sectionally assessed 1595 participants (ages 7-11) from the Environmental influences on Child Health Outcomes cohort using the NIH Toolbox Cognition Battery, Environmental influences on Child Health Outcomes Sleep Health of Children and Adolescents questionnaire, and Patient Reported Outcome Measurement Information System Sleep Disturbance/Sleep-related Impairment instruments. We created a novel scale measuring sleep health using dichotomous "good-bad" cutoffs for sleep duration, timing, latency, satisfaction, and alertness. We used generalized estimating equations and random forest models to examine associations between sleep health and inhibitory control, working memory, processing speed, cognitive flexibility, episodic memory, reading decoding, and receptive vocabulary.

Results: Sleep health did not have statistically significant associations with any aspect of cognitive functioning. Notably, over 75 per cent of our sample had good sleep health.

Conclusions: This study assessed sleep health as a multi-faceted construct, distinguishing between "good" and "poor" sleep health across several domains. The absence of statistically significant associations between sleep health and cognitive functioning suggests children's cognitive functioning may not be cross-sectionally related to multidimensional sleep health measures. Experimentally manipulating key sleep domains such as duration or timing (as done in prior research) may be more robust. Future research might benefit from examining the cumulative impact of poor sleep health over time.