Association between screen time and health-related quality of life: Testing the displacement and relational hypotheses in a prospective cohort study

Previous studies showed a significant association between screen time and health-related quality of life (HRQoL) in children. However, the mechanisms underlying the association are unclear. This study aimed to examine the extent to which displacement (physical activities and sleep) and relationship factors (dysfunctional parent-child interaction and peer problems) mediate such association. A population-representative sample of 1428 parents of primary school children (49.3 % female; Mage = 8.5 ± 1.9) in Hong Kong participated in the study over the course of one year (two waves). Children's screen time was reported by parents. The study outcome, children's HRQoL, was assessed using the Pediatrics Quality of Life Inventory Parent-Proxy Report (PedsQL). Mediators, including dysfunctional parent-child interaction (PCDI), peer problems (SDQ-PP), weighted daily time spent in moderate-to-vigorous physical activity (MVPA), and sleep-related quality of life (QoL), were assessed to test the displacement and relational hypotheses. Multilevel structural equation modeling showed a statistically significant total effect (β = −0.12, 95 % CI -0.16 to −0.08) of screen time on PedsQL. The association was partially mediated by sleep QoL (28.9 %; β = −0.03, 95 % CI -0.05 to −0.02), followed by PCDI (10.5 %; β = −0.01, 95 % CI -0.02 to −0.002), SDQ-PP (7.5 %; β = −0.01, 95 % CI -0.02 to −0.003), and MVPA (1.5 %; β = −0.002, 95 % CI -0.01 – 0.001). Intervention strategies that enhance children's sleep health and strengthen parent-child and peer relationships may mitigate the negative impacts of increased screen time on children's functioning. However, given the very small effect of screen time on PedsQL, it is probably not a major factor influencing children's HRQoL.