The Independent and Interactive Associations of Screen Time and Physical Activity on Mental Health, School Connectedness and Academic Achievement among a Population-Based Sample of Youth.
OBJECTIVE
Few studies have addressed the links between sedentary behaviour (SED) and mental health in youth. Most studies on physical activity (PA) and SED examine their independent effects on mental health, or fail to account for PA in this relationship. The purpose of this study is to examine the independent effects of PA and screen time on mental health, school connectedness and academic achievement, and potential interactions between PA and screen time in such associations.


METHODS
Data was obtained through 2,660 adolescents who completed the self-administered Ontario Student Drug Use and Health Survey (OSDUHS) in 2009. Self-reported variables of demographics, PA, screen time, and mental health indicators were also collected.


RESULTS
Using logistic regression, screen time was inversely associated with all mental health indicators (p<.05). Although meeting PA guidelines was associated with lower school disconnectedness in males, the effects of high screen time were greater than the independent associations of PA among mental health indicators. An interaction between screen time and PA with low self-esteem was found only in males. Higher screen time was associated with lower self-esteem in males, independent of PA (p<.001).


CONCLUSIONS
High screen time was associated with poorer mental health and academic outcomes. Being physically active did not result in higher self-esteem in the presence of high screen time among males. These results confirm the value in distinguishing the independent and interactive effects of PA and SED on mental health. Future research should promote PA and reduce screen time to improve mental health outcomes among youth.
Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario.
Linda
L
Trinh
Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario.
Bonny
B
Wong
Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario.
Guy E
GE
Faulkner
mental health; physical activity; screen time; youth