Cross-sectional associations between physical activity pattern, sports participation, screen time and mental health in Swedish adolescents

Objectives To investigate the associations between physical activity pattern, sports participation, screen time and mental health in Swedish adolescents. Design, setting and participants A total of 1139 Swedish adolescents (mean age 13.4) from 34 schools participated in the cross-sectional study 'Physical Activity for Healthy Brain Functions in School Youth' in 2019. Methods Time spent sedentary and in moderate-to-vigorous physical activity (MVPA) was measured using accelerometers for seven consecutive days. Screen time and sports participation were self-reported. Anxiety and health-related quality of life (HRQoL) were assessed using a Short version of the Spence Children's Anxiety Scale and Kidscreen-10. Results MVPA was positively associated (95% CI 0.01 to 0.05 in girls and 0.02 to 0.07 in boys) whereas screen time on weekdays was inversely associated with HRQoL (-4.79 to -2.22 in girls and -2.66 to -0.41 in boys). The largest effect sizes were observed between the high/low MVPA group in boys (Cohen's d=0.51) and screen time groups in girls (Cohen's d=0.59 on weekdays). With regards to anxiety, high compared with lower time spent in MVPA during leisure time on weekdays was associated with lower anxiety scores (95% CI -0.13 to -0.05 in girls and -0.07 to -0.01 in boys). Gender differences were observed, boys who participated in organised sports had low anxiety scores (95% CI -3.49 to -0.13) whereas girls who reported 5 hours or more of screen time had high scores (95% CI 1.94 to 6.18 on weekdays and 1.39 to 5.29 on weekend days). Conclusions This study showed that MVPA was associated with better mental health, whereas the opposite was seen for screen time. These associations were not consistently significant throughout all time domains, between the genders and mental health outcomes. Our results could create a paradigm for future studies to decide which types of PA patterns and time domains to target in intervention studies with the aim improve mental health among adolescents.