Screen time, physical activity and mental health among urban adolescents in China

Objective. To test the association between screen time (ST), physical activity (PA) and self-reported psychological problems among urban adolescents aged 11 to 16 years. Methods. In 2010, total 5003 boys and girls were analyzed from 4 junior high schools in Bengbu city of China. The Depression Self-rating Scale for Children. Screen for Child Anxiety Related Emotional Disorders and School Life Satisfaction Rating Questionnaire were administered to obtain information on current mental health. Self-reported ST, PA and dietary intake were also assessed. Logistic regression analyses were used to explore the effects of ST and PA on psychological problems. Results. Approximately 26.1% of adolescents were exposed to ST for more than 2 h/day. High ST was a risk factor for depressive symptoms (odds ratio (OR) = 1.52, 95% confidence interval (CI): 1.31-1.76), anxiety symptoms (OR= 1.36, 95%CI: 1.18-1.57) and school life dissatisfaction (OR = 2.07, 95%CI: 1.79-2.38). Sufficient vigorous PA (VPA) was a protective factor for depressive symptoms (OR = 0.78, 95%CI: 0.67-0.91) and school life dissatisfaction (OR= 0.73, 95%CI: 0.62-0.85). The combination of high ST and insufficient VPA was associated with the highest prevalence of various psychological problems. Conclusions. High ST and insufficient VPA interact to increase depressive, anxiety symptoms and school life dissatisfaction among Chinese adolescents. (C) 2011 Elsevier Inc. All rights reserved.