Doctor: Eve Reynaud

Title: Study of nocturnal awakenings and behavior of the child aged 2 to 5 in the EDEN cohort : a developmental approach

Supervisor: Sabine Plancoulaine

Doctoral school: ED 393 Epidemiology and Biomedical Information Sciences, Université Paris Cité

Date of thesis defense: 27/09/2017

Jury: Sabine Plancoulaine, Maria Melchior, Bruno Falissard, Carmen Schröder, Karen Spruyt, Michel Lecendreux

Thesis summary:

The structure of sleep evolves greatly in the first years of life. Occasional nightwaking is thus normal in young children, but waking-up every other night or more is considered adversely frequent. The scientific literature suggests that frequent night-waking is associated with concomitant behavioral difficulties in children. Yet, little is known about the evolution of night-waking in preschool years and its longitudinal association with behavior. Objectives: To model the evolution of night-waking between the age of 2 and 5-6 years and explore the association with family and child related factors. To analyze the associations between night-waking trajectories and behavior before school entry. Population and methods: Analyses were based on the French birth-cohort study EDEN, which recruited 2 002 pregnant women between 2003 and 2006 in the maternity of Poitiers and Nancy. Information regarding night-waking and behavior were assessed using parental questionnaires at the ages of 2, 3 and 5-6 years. The « group based trajectory modeling » method allowed us to model the evolution of night-waking and of inattention/hyperactivity, describing different developmental trends between the age of 2 and 5-6 years. The associations between night-waking trajectories, family and child related factors and behavior, were analyzed using logistic regressions, adjusted on potential confounding factors. Results: Two distinct night-waking trajectories were identified in children between the age of 2 and 5-6 years. One, named « rare night-waking », represented 77% of the children. This group followed a linear trajectory, which was close to zero and slightly declining with time. The second trajectory, named « common night-waking », represented 23% of the children. It was higher than the first trajectory at each time-point, and a peak was observed at age 3. Risk factors for belonging to the « common night-waking » trajectory were life-style related factors: exposures to second hand smoking, collective care arrangement, and time spent in front of the television. Children belonging to the common night-waking trajectory had higher risk of having emotional symptoms, conduct problems and inattention/hyperactivity at age 5-6. No associations were found with prosocial behavior nor peer-relationship problems. Three trajectories of inattention/hyperactivity were identified, a low, an intermediate and a high one, all stable in time. The risk of belonging to a high inattention/hyperactivity trajectory, compared to a low one, were four time more important for children with a « common night-waking » trajectory. Conclusion: Night-waking and inattention/hyperactivity persist in preschool years. A common night-waking trajectory during this period is a risk factor of diverse behavioral difficulties: emotional symptoms, conduct problems and inattention/hyperactivity. The latter co-evolves with night-waking. Our results highlight the importance of identifying sleep problems in early years, especially in the presence of behavioral difficulties.

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