Association of sleep habits with behavior problems and resilience of 6- to 7-year-old children: results from the A-CHILD study.

Background: Childhood sleep habits are associated with mental health development; however, little is known about the impact of irregular bedtimes on the mental health of early school-aged children. The aims of this study were to examine the effect of weekday sleep habits (varying bedtimes depending on the night of the week and later than 22:00 h bedtime) on behavior problems, prosocial behavior, and resilience of children aged 6-7 years.

Methods: Data were taken from the Adachi Child Health Impact of Living Difficulty (A-CHILD) study, which involved the participation of 4291 caregivers of first-grade children (6-7 years old) living in Adachi City, Tokyo. Resilience (using the Children's Resilient Coping Scale), behavior problems (using the Strength and Difficulties Questionnaire), both modified to range 0-100, and sleep habits were measured via a questionnaire filled out by caregivers. Propensity-score matching was used to determine the associations between irregular and late bedtime, behavior problems, prosocial behavior, and resilience.

Results: A total of 320 (7.5%) children showed irregular bedtime on school nights and 540 (13.6%) children went to bed later than 22:00 h. Children with irregular bedtimes on weekdays showed lower resilience (β = -3.50, 95% confidence interval (CI) = -5.90 to -1.10) and higher levels of behavior problems (β = 3.29, 95% CI = 1.13-5.46), especially hyperactivity/inattention (β = 5.76, 95% CI = 2.03 to 9.49) and peer relationship problems (β = 3.79, 95% CI = 1.02-6.55). On the other hand, no association between bedtime after 22:00 h and resilience or behavior problems was found.

Conclusion: Among early school-aged children, irregular bedtime on weekdays may be a risk factor for lower resilience and behavior problems.