Combinations of physical activity and screen time recommendations and their association with overweight/obesity in adolescents.

To examine the four possible combinations of adherence to physical activity and screen time recommendations in adolescents and how the combinations relate to overweight and obesity. A total of 9913 students in grades 7-12 were included in the present cross-sectional analyses. Moderate-to-vigorous physical activity (MVPA), screen time, and body mass index were self-reported. Multivariate logistic regression analysis was used to test the associations between combinations of MVPA (≥ 60 min/day [active] or < 60 min/day [inactive]) and screen time (≤ 2 h/day [not sedentary] or > 2 h/day [sedentary]) recommendations with overweight/obesity. We found that 53.1% of students in Ontario were considered "inactive+sedentary", 23.7% were considered "inactive+not sedentary", 12.1% were considered "active+sedentary", and 11.1% were considered "active+not sedentary". Some characteristics of "active+not sedentary" students (optimal category) included younger age, male gender, white ethnicity, higher socio-economic status, optimal sleep duration, and lower prevalence of cannabis use. After adjusting for relevant covariates, the "inactive+sedentary" group was more likely to report overweight/obesity than the "active+not sedentary" group (odds ratio [OR] = 1.71, 95% confidence interval [CI] = 1.26-2.32). The "inactive+not sedentary" group was also more likely to report overweight/obesity (OR = 1.54, 95% CI 1.20-1.97) while the "active+sedentary" group was not significantly associated with overweight/obesity (OR = 1.27, 95% CI 0.88-1.83). Children meeting both the physical activity and screen time recommendations are less likely to be classified as overweight/obese compared with any other combination. Future efforts are needed to target both MVPA and sedentary behaviour to address public health concerns such as excess weight.