Sleep duration in preschool children and impact of screen time.

Objectives: To evaluate sleep duration in a representative sample of preschoolers and examine the relationships between screen time and use of different electronic media devices with sleep duration and social jetlag.

Methods: 2903 preschoolers were included. Parent-completed questionnaire provided information on socioeconomic status, electronic media use of the children and sleep patterns of both parents and children. Preschoolers were divided according to whether they met the international screen time recommendations for their age. Comparisons between the two groups in various sleep measures and effects of different devices on sleep were evaluated.

Results: 40% of preschoolers in our cohort did not achieve the recommended sleep duration. Subjects who adhered to the screen time recommendations were from families of higher socioeconomic status, had longer sleep duration and better sleep habits. Each hour increase on portable electronic device use was associated with 11 (95%CI: -15 to -6) and 6 (95%CI: -10 to -2) minutes less of average daily sleep duration in boys and girls, respectively. Every additional hour of non-portable electronic devices use was associated with 3 min shift in social jetlag in boys. Presence of electronic devices in bedroom and their use at bedtime increased risk of social jetlag in boys with an OR of 1.40 (95%CI: 1.01 to 1.92) and 1.39 (95%CI: 1.00 to 1.95) respectively.

Conclusion: A significant proportion of preschoolers does not obtain the recommended amount of sleep. Screen time in preschoolers affects not only sleep duration but also leads to circadian discrepancy.