The age-dependent relationship between childcare attendance and children's daily napping frequency.

BACKGROUND: The majority of children in developed economies attend childcare services during the first five years of life-a period coinciding with their developmental transition from regular napping to consolidated nighttime sleep. Whether childcare attendance affects this transition is not well understood. Previous studies have relied primarily on cross-sectional designs or widely spaced longitudinal observations, limiting their ability to distinguish childcare effects from differences between children and families. METHODS: To provide greater clarity, we draw on data from the Sleep Transitions and Regularities Study (STARs), a longitudinal study of sleep behaviours among Australian children aged 1-4.5 years (N = 188; 45.74% female). We fit hybrid mixed-effects models over multiply imputed data to estimate associations between daily childcare attendance and napping frequency at both the within- and between-child levels. We test interaction effects to determine whether these associations are moderated by child age. RESULTS: Attending childcare was associated with a 4% within-child reduction in same-day napping frequency (IRR = 0.96, 95% CI [0.93, 0.98]). This association was moderated by age (IRR = 1.07, 95% CI [1.03, 1.11]), such that the association was negative before children were ∼2.18 years and became positive after ∼4.32 years. CONCLUSION: These findings may reflect the impacts of nap-scheduling practices that are standard in many childcare services, and direct future attention to the effects of such practices on children's sleep health. Our results also underscore the importance of longitudinal designs for capturing within-child change and the effects of children's social environments on their sleep and development.