Prospective associations between screen-based sedentary behaviors and cognitive performance among children aged 5–7 years

Background: The 5- to 7-year shift is a critical period for cognitive development and is particularly sensitive to lifestyle factors such as sedentary behavior (SB). Screen-based activities can be classified into two types: mentally active SB requires higher cognitive engagement (e.g., computer use, electronic gaming), and mentally passive SB involves less cognitive engagement (e.g., TV-watching). Although there has been a growing interest in understanding the role of such forms of SB on cognitive development in recent years, is associated with cognitive development trajectories, considering the moderating role of the SB duration, SB type, and sex. Methods: Data from 12,257 children (6178 boys; 6079 girls) in the UK Millennium Cohort Study (MCS), a longitudinal and nationally representative birth cohort study in the UK, were analyzed. The MCS includes children born between September 2000 and January 2002. For this study, we used data from wave 3 (at the age of 5 years) to assess the association between computer use/e-gaming and TV-watching time with cognitive performance assessed in wave 4 (at the age of 7 years). Cognitive performance was assessed using the British Ability Scales II (BAS II), including word reading and pattern construction tests, and an adapted National Foundation for Educational Research (NFER) Progress in Maths test. Statistical analyses were performed via a Generalized Linear Model (GLM) adjusted for confounders and stratified by sex. Results: For boys, computer use/e-gaming at the age of 5 years was associated with better word reading performance at the age of 7 years for those who engaged in it for less than 1 h (β = 0.148, 95% CI: 0.081 to 0.215, p < 0.001) and 1–3 h (β = 0.209, 95% CI: 0.128 to 0.290, p < 0.001) per day. Regarding maths performance, computer use/e-gaming for less than 1 h (β = 0.179, 95% CI: 0.120 to 0.237, p < 0.001) and 1–3 h (β = 0.181, 95% CI: 0.101 to 0.261, p < 0.001) per day at the age of 5 years were associated with better maths performance at the age of 7 years, whereas 7 h or more per day were negatively associated with maths performance when considering the same observation period (β = −0.356, 95% CI: −0.698 to −0.134, p = 0.041). For girls, TV-watching of 1–3 h (β = −0.224, 95% CI: −0.383 to −0.065, p = 0.006), 3–5 h (β = −0.211, 95% CI: −0.385 to −0.038, p = 0.017), and 7 h or more (β = −0.257, 95% CI: −0.461 to −0.053, p = 0.014) per day at the age of 5 years were were associated with worse maths performance at the age of 7 years. No statistically significant prospective associations were found between daily time spent on screen-based SB and spatial construction performance. Conclusions: Our study extends the literature in demonstrating that the prospective associations of screen-based SB and cognitive performance are moderated by SB type, daily exposure duration, and biological sex. The observation that for boys, spending an age-appropriate amount of time in early stages of childhood (i.e., at 5 years) on mentally active SB positively predicts aspects of cognitive development assessed in a later stage (i.e., at 7 years), while for girls of the same age, a deterimental association was observed for mentally passive SB, implying that interventions and policies promoting children's optimal cognitive development should (i) consider sex differences and (ii) focus on limiting the time spent on mentally passive SB.