Screen time is more strongly associated than physical activity with overweight and obesity in 9- to 16-year-old Australians

Background: Both reduced moderate-to-vigorous physical activity (MVPA) and increased screen time have been implicated in the aetiology of childhood overweight/obesity. This study aimed to determine which behaviour had the stronger association with overweight/obesity. Method: 2200 randomly selected 9- to 16-year-old Australians provided four 24-h use-of-time recalls. Participants were classified into weight status categories and as high or low physical active, and high or low screen time according to Australian guidelines (≥60 min MVPA; ≤120 min recreational screen time daily). Multivariate logistic regression was used to calculate the odds ratios (OR) for overweight/obesity for each screen time and MVPA category. Results: Increased likelihood of overweight or obese was often associated with high screen time (ORs, 2.13-2.55 for boys and 1.47-1.72 for girls), but only sometimes and less strongly associated with low MVPA (ORs, 0.49-2.55 for boys and 1.06-1.47 for girls). Analyses conducted for combined screen time and MVPA categories showed screen time to be a stronger indicator of weight status than physical activity, especially in boys. Conclusion: Overweight and obesity were more strongly associated with screen time than physical activity. Screen time may be an important target for interventions aimed at reducing childhood overweight and obesity.