Night-waking trajectories and associated factors in French preschoolers from the EDEN birth-cohort.

Night waking in preschoolers has been associated with adverse health outcomes in cross-sectional studies, but has rarely been analyzed in a longitudinal setting. Therefore, little is known about the evolution of night waking in early childhood. The objectives of the present study were: to identify night-waking trajectories in preschoolers, and to examine the risk factors associated with those trajectories. Analyses were based on the French birth-cohort study EDEN, which recruited 2002 pregnant women between 2003 and 2006. Data on a child's night waking at the ages of two, three, and five, six years, and potential confounders, were collected through parental self-reported questionnaires. Night-waking trajectories were computerized using group-based trajectory modeling on 1346 children. Two distinct developmental patterns were identified: the "2-5 rare night-waking" (77% of the children) and the "2-5 common night-waking" pattern. Logistic regressions were performed to identify the factors associated with the trajectories. Risk factors for belonging to the "2-5 common night-waking" trajectory were: exposure to passive smoking at home, daycare in a collective setting, watching television for extended periods, bottle feeding at night, high emotionality, and low shyness. This approach allowed identification of risk factors associated with night waking during a critical age window, and laid the groundwork for identifying children at higher risk of deleterious sleep patterns. Those risk factors were mainly living habits, which indicated that prevention and intervention programs could be highly beneficial in this population.