Night sleep duration trajectories and associated factors among preschool children from the EDEN cohort

Objective. Sleep duration may vary inter-individually and intra-individually over time. We aimed at both identifying night-sleep duration (NSD) trajectories among preschoolers and studying associated factors. Methods. NSD were collected within the French birth-cohort study EDEN at ages 2, 3 and 5-6 years through parental questionnaires, and were used to model NSD trajectories among 1205 children. Familial socioeconomic factors, maternal sociodemographic, health and lifestyle characteristics as well as child health, lifestyle, and sleep characteristics at birth and/or at age 2 years were investigated in association with NSD using multinomial logistic regressions. Results. Five distinct NSD trajectories were identified: short (SS, <10h, 4.9%), medium-low (MLS, <11h, 47.8%), medium-high (MHS, $\approx$11h30, 37.2%), long (LS, $\ge$11h30, 4.5%) and changing (CS, i.e. $\ge$11h30 then <11h, 5.6%) NSD trajectories. Multivariable analyses showed in particular that, compared to the MHS trajectory, factors associated with increased risk for belonging to SS trajectory were male gender, first child, maternal age and working status, night-waking, parental presence when falling asleep, television-viewing duration and both the `Processed and fast foods' and the `Baby food' dietary patterns at age 2 years. Factors positively associated with the CS trajectory were maternal smoking, bottle-feeding at night and the `Processed and fast foods' dietary pattern at age 2 years whereas child's activity and emotionality scores at age 1 year were negatively associated. Conclusion. We identified distinct NSD trajectories among preschoolers and associated early life factors. Some of them may reflect less healthy lifestyle, providing cues for early multi-behavioral prevention interventions