Association of Children's Physical Activity and Screen Time With Mental Health During the COVID-19 Pandemic.

Importance: Children's physical activity and screen time are likely suboptimal during the COVID-19 pandemic, which may influence their current and future mental health. Objective: To describe the association of physical activity and screen time with mental health among US children during the pandemic. Design, Setting, and Participants: This cross-sectional survey was conducted from October 22 to November 2, 2020, among 547 parents of children aged 6 to 10 years and 535 parent-child dyads with children and adolescents (hereinafter referred to as children) aged 11 to 17 years and matched down to 500 children per cohort using US Census-based sampling frames. Children aged 11 to 17 years self-reported physical activity, screen time, and mental health, and their parents reported other measures. Parents of children aged 6 to 10 years reported all measures. All 1000 cases were further weighted to a sampling frame corresponding to US parents with children aged 6 to 17 years using propensity scores. Exposures: Child physical activity, screen time, COVID-19 stressors, and demographics. Main Outcomes and Measures: Mental health using the Strengths and Difficulties Questionnaire for total difficulties and externalizing and internalizing symptoms. Results: Among the 1000 children included in the analysis (mean [SD] age, 10.8 [3.5] years; 517 [52.6%] boys; 293 [31.6%] American Indian/Alaska Native, Asian, or Black individuals or individuals of other race; and 233 [27.8%] Hispanic/Latino individuals), 195 (20.9%) reported at least 60 minutes of physical activity every day. Children reported a mean (SD) of 3.9 (2.2) d/wk with at least 60 minutes of physical activity and 4.4 (2.5) h/d of recreational screen time. COVID-19 stressors were significantly associated with higher total difficulties for both younger (β coefficient, 0.6; 95% CI, 0.3-0.9) and older (β coefficient, 0.4; 95% CI, 0.0-0.7) groups. After accounting for COVID-19 stressors, engaging in 7 d/wk (vs 0) of physical activity was associated with fewer externalizing symptoms in younger children (β coefficient, -2.0; 95% CI, -3.4 to -0.6). For older children, engaging in 1 to 6 and 7 d/wk (vs 0) of physical activity was associated with lower total difficulties (β coefficients, -3.5 [95% CI, -5.3 to -1.8] and -3.6 [95% CI, -5.8 to -1.4], respectively), fewer externalizing symptoms (β coefficients,  -1.5 [95% CI, -2.5 to -0.4] and -1.3 [95% CI, -2.6 to 0], respectively), and fewer internalizing symptoms (β coefficients, -2.1 [95% CI, -3.0 to -1.1] and -2.3 [95% CI, -3.5 to -1.1], respectively). More screen time was correlated with higher total difficulties among younger (β coefficient, 0.3; 95% CI, 0.1-0.5) and older (β coefficient, 0.4; 95% CI, 0.2-0.6) children. There were no significant differences by sex. Conclusions and Relevance: In this cross-sectional survey study, more physical activity and less screen time were associated with better mental health for children, accounting for pandemic stressors. Children engaged in suboptimal amounts of physical activity and screen time, making this a potentially important target for intervention.