Sleep Duration, Sedentary Behaviour, Physical Activity, Depression, and Other Mental Health Outcomes Among Children and Adolescents
Creators: name: Sampasa Kanyinga, Hugues
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2021
Subjects: Depression
Mental health
Physical activity
Screen time
Sleep
Movement behaviours
Children
Adolescents

description: Mental health problems are the leading causes of disability in Canada. Nearly 70% of mental health problems have their onset during childhood or adolescence. Thus, identifying modifiable determinants of mental health problems in children and adolescents can inform future interventions intended to prevent them in this age group. Until recently, research has examined relationships of movement behaviours, including sleep, sedentary behaviour and physical activity mainly with physical health indicators (e.g., adiposity, cardiovascular disease risk factors, etc.). The few studies that have examined the relationships between movement behaviours and mental health indicators have considered the former individually and in isolation of each other, ignoring the intrinsic and empirical interactions between these behaviours. Adjusting for all these behaviours in a traditional regression model that assumes independence between variables has been shown to produce flawed and inconsistent findings. The purpose of this doctoral dissertation is to examine how the combinations of physical activity, sedentary behaviour, and sleep duration are associated with depression and other mental health outcomes in children and adolescents, through a series of five research studies (one systematic review, 3 cross-sectional studies, and one longitudinal study). Empirical studies used data from 3 large and diverse samples of children and adolescents from Canada and the United States. Conventional regression models and structural equation modelling, and novel analytical techniques, including compositional data analysis were used to analyze the data. The systematic review confirmed the paucity of existing research in this area and identified important research gaps to be filled. Collectively, the results from cross-sectional studies showed that meeting all three recommendations was associated with lower odds of depressive symptoms and other mental health outcomes. However, this association appeared to be mainly driven by meeting the sleep duration recommendation, and to a lesser extent the screen time + sleep duration recommendations. There was a dose-response gradient from meeting none of the recommendations up to meeting two recommendations. Results from the longitudinal study using compositional data analysis provided further evidence suggesting that increasing sleep duration relative to the remaining behaviours (i.e. screen time and physical activity) was associated with lower depressive symptoms among all age/sex subgroups. Results further indicated that predicted changes in depressive symptoms were strongest and most beneficial when removing screen time while adding sleep duration. Finally, results from both cross-sectional and longitudinal analyses suggest that age and sex moderate the association between movement behaviour recommendations (individual or combined) and mental health indicators, depending on the type of movement behaviour and the type of mental health indicators. The findings from this body of work have shed new light on the association between movement behaviours and mental health indicators in children and adolescents by demonstrating that meeting all three movement behaviour recommendations is associated with better mental health, and that sleep duration and screen time were more strongly associated with mental health compared with physical activity in our studies.