SLEEP DURATION, SEDENTARY BEHAVIOUR, PHYSICAL ACTIVITY, DEPRESSION, AND OTHER MENTAL HEALTH OUTCOMES AMONG CHILDREN AND ADOLESCENTS HUGUES SAMPASA KANYINGA A thesis submitted to the University of Ottawa in partial fulfillment of the requirements for the PhD Degree in Epidemiology School of Epidemiology and Public Health Faculty of Medicine University of Ottawa © Hugues Sampasa Kanyinga, Ottawa, Canada, 2021 TABLE OF CONTENTS ABSTRACT ............................................................................................................................................. iv DEDICATION ......................................................................................................................................... vi ACKNOWLEDGEMENTS .................................................................................................................... vii LIST OF FIGURES ................................................................................................................................. ix LIST OF TABLES ................................................................................................................................... xi LIST OF ABBREVIATIONS ................................................................................................................ xiii Chapter 1 ....................................................................................................................................................... 1 1.1. Physical activity ................................................................................................................................. 3 1.2. Sedentary behaviour ........................................................................................................................... 6 1.3. Sleep duration .................................................................................................................................... 9 1.4. Canadian 24-hour movement guidelines .......................................................................................... 11 1.5. Research Objectives ......................................................................................................................... 15 1.6. Dissertation Organization and Outline ............................................................................................. 16 Chapter 2 ..................................................................................................................................................... 38 ABSTRACT ............................................................................................................................................ 40 INTRODUCTION .................................................................................................................................. 42 METHODS ............................................................................................................................................. 44 RESULTS ............................................................................................................................................... 50 DISCUSSION ......................................................................................................................................... 54 CONCLUSION ....................................................................................................................................... 61 Chapter 3 ..................................................................................................................................................... 84 ABSTRACT ............................................................................................................................................ 86 INTRODUCTION .................................................................................................................................. 88 METHODS ............................................................................................................................................. 91 RESULTS ............................................................................................................................................... 95 DISCUSSION ......................................................................................................................................... 97 CONCLUSION ..................................................................................................................................... 101 Chapter 4 ................................................................................................................................................... 121 ABSTRACT .......................................................................................................................................... 123 INTRODUCTION ................................................................................................................................ 125 METHODS ........................................................................................................................................... 127 ii RESULTS ............................................................................................................................................. 131 DISCUSSION ....................................................................................................................................... 134 CONCLUSION ..................................................................................................................................... 139 Chapter 5 ................................................................................................................................................... 159 ABSTRACT .......................................................................................................................................... 161 INTRODUCTION ................................................................................................................................ 162 METHODS ........................................................................................................................................... 164 RESULTS ............................................................................................................................................. 169 DISCUSSION ....................................................................................................................................... 171 CONCLUSION ..................................................................................................................................... 176 Chapter 6 ................................................................................................................................................... 195 ABSTRACT .......................................................................................................................................... 197 INTRODUCTION ................................................................................................................................ 199 METHODS ........................................................................................................................................... 202 RESULTS ............................................................................................................................................. 208 DISCUSSION ....................................................................................................................................... 211 CONCLUSION ..................................................................................................................................... 216 Chapter 7 ................................................................................................................................................... 241 7.1 Summary of key findings ................................................................................................................ 241 7.2 Comparison with other relevant literature ...................................................................................... 244 7.3 Contributions to the literature ......................................................................................................... 248 7.4 Strengths and Limitations ............................................................................................................... 250 7.5 Implications and recommendations for practice ............................................................................. 252 7.6 Implications and future directions for research ............................................................................... 254 7.7 Conclusion ...................................................................................................................................... 255 APPENDIX 1. Search strategies for the systematic review (Chapter 2) .............................................. 267 APPENDIX 2. Research Ethics Boards Approval from the University of Ottawa ............................... 275 APPENDIX 3. Screenshot of manuscript submission letter from Plos One ......................................... 277 iii ABSTRACT 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