Sleep and Sibling Relationships in Middle Childhood: Potential Bidirectional Associations?

The interconnection between family contexts and sleeping patterns play a crucial role in childhood development, with disturbances in either being indicative of future health outcomes in adulthood. It is unclear whether sibling relationships and sleep would have a similar effect as there are not many studies that have examined these links by using subjective sleep and sibling relationship assessments. Given this gap in the literature, the present studied aimed to 1) examine potential bidirectional relations between sibling relationships (warmth, conflict) and sleep variables (duration, efficiency, and sleep midpoint variability) across ages 8 and 10, and 2) test whether a novel sibling interaction task with measures of sharing and competition conducted at age 8 predicts sleep variables both cross sectionally and two years later at age 10. Data are from the Arizona Twin Project which includes a racially and socioeconomically diverse representation of children in Arizona. Twins wore an actigraph watch at both age 8 and age 10 to capture sleep duration and efficiency. Primary caregivers also reported sibling relationships via a questionnaire during both waves. Twins completed a marble pulling task to measure negotiation and cooperation behaviors at age 8 only. We tested cross-lagged prospective associations between sleep and sibling contexts. My study identified a longitudinal, positive association with sibling warmth at age 8 and sleep duration at age 10 and another concurrent, positive association with sibling conflict at age 8 and sleep midpoint variability at age 8. A negative association was identified between sibling warmth and sleep efficiency at age 10. Stability over time was also identified in both sleep variables and sibling relationships. Future studies can further investigate the different ways siblings may influence sleep behaviors, or vice versa, by taking into consideration the quality of the relationship, age, gender, and overall family dynamics. Due to the complexity of sibling relationships, the relations between sleep and siblings may vary among different individuals and families. These additional factors may need to be considered when evaluating the effects of sibling relationships and sleep on child development and well-being.