Physical Activity, Screen Time, and Neurobehavioural Function at Age 7 Years: The Italian PHIME-NAC-II Cohort

Objective: To investigate the cross-sectional associations of physical activity (PA) and interactive and passive screen-time (ST) exposure with behavioural and cognitive development at age 7 years within the PHIME-NAC-II prospective birth cohort. Methods: At age 7 years, 482 children from Trieste, North-eastern Italy underwent assessment of behavioural and emotional problems (CBCL) and general cognitive functioning (WISC-IV FSIQ). Parents reported PA (days/wk with ≥1 h of sports or active play), interactive ST exposure (hr/day playing video games, computers, tablets) and passive ST (television watching). Socio-demographic and lifestyle information was collected from gestation to age 7 years. Multiple linear regression models examined the associations between PA and ST variables and internalizing (IntP), externalizing (ExtP), total (TotP) behavioural problems and FSIQ. Results: PA showed quadratic associations consistent with a U-shaped pattern for IntP (B_PA = -0.77, p = 0.048; B_PA^2 = 0.32, p = 0.029), and TotP (B_PA = -0.59, p = 0.100; B_PA^2 = 0.30, p = 0.022), and predicted score minima ≈ 3.5-3.8 days/wk, while no clear association was detected with ExtP and FSIQ. Higher passive ST was associated with worse IntP, ExtP and TotP. Interactive ST was not associated with outcomes. Conclusions: engaging during school age in regular PA-with the lowest predicted behavioral problem scores observed around 3-4 days/week-was associated with lower problem scores, independent of passive screen-time exposure.