DETERMINANTS OF BODY COMPOSITION IN UNDERGRADUATE STUDENTS IDENTIFYING DETERMINANTS OF BODY COMPOSITION IN UNDERGRADUATE STUDENTS: A SYSTEMATIC REVIEW AND PROTOCOL FOR A PROSPECTIVE OBSERVATIONAL STUDY By: RITA E. MORASSUT, B.Sc.H. A thesis submitted to the School of Graduate Studies in partial fulfillment of the requirements for the degree Master of Science McMaster University © Copyright by Rita E. Morassut, May 2018 M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology Master of Science (2018) McMaster University (Health Research Methodology) Hamilton, Ontario Title: Identifying determinants of body composition in undergraduate students: a systematic review and protocol for a prospective observational study Author: Rita E. Morassut, B.Sc.H. (Queen’s University) Supervisor: Dr. David Meyre Number of pages: xviii, 121 ii M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology Abstract Young adulthood is an important period in the development of obesity. Undergraduate students are particularly at-risk since they gain more weight than those not attending university. As students transition from high school to university, they often adopt unhealthy lifestyle behaviours which are thought to lead to weight gain. On average, students gain three to five pounds (1.4-2.3 kg) during their first year of undergraduate education. However, less is known about how body composition changes throughout the four-year course of undergraduate education and what causes these changes. We thus conducted a systematic review to synthesize a comprehensive list of factors associated with obesity traits (e.g. body mass index, body fat percentage, muscle mass) in undergraduate students. Two hundred thirty-eight studies were included (175 cross-sectional, 49 cohort, 11 interventional, 3 qualitative). We identified age, sex, ethnicity, socioeconomic status, religion, diet, eating habits, physical activity, sedentary activity, sleep, stress, university campus life, alcohol use, smoking, psychiatric disorders, body image, eating attitude, eating regulation, personality, and social/cultural influences as factors which are associated with obesity traits. These factors guided the design of the Genetic and EnviroNmental Effects on weight in University Students (GENEiUS) study, a prospective observational study which investigates the genetic and environmental determinants of body composition in undergraduate students over four years. The GENEiUS study will recruit 2500 multiethnic first- year undergraduates aged 17–25 years and will follow them every six months for four years. Primary outcomes are body mass index, waist circumference, waist-to-hip ratio, body fat mass and body fat percentage. This study will help design obesity prevention programs in universities. iii M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology Acknowledgements I would like to thank my supervisor Dr. David Meyre for this valuable guidance and overwhelming support over the past two years. I came into graduate studies with little experience in clinical science and he was a patient teacher who challenged me to produce my best work. Without his belief in me and kind encouragement, this thesis would not be possible. I would also like to extend my sincere gratitude to my wonderful thesis committee members, Dr. Andrew Mente and Dr. Constantine Samaan, and external reviewer, Dr. Andrea Josse-Obar, for their expertise and constructive feedback in the development of my thesis. Thank you to Dr. Stephanie Atkinson for her amazing support and guidance as I worked on the BHIP study. I am grateful for the help and support of all my colleagues. From the Meyre lab, thank you sincerely to Akram Alyass helping me get over my fear of R; Christine Langlois for patiently answering all my GENEiUS questions when I first joined the lab; and Anila Qasim and Adeola Ishola for their friendship. A special thank you to the undergraduate volunteers who have helped make the GENEiUS study a reality. I would like to thank Laura Banfield for teaching me how to search databases. To the ladies of the BHIP team, I am so grateful to have worked with and learned from you. I would also like to thank my fellow graduate students in the Department of Health Research Methods, Evidence, and Impact and for their kind friendship and unwavering support. Finally, I would like to express my sincerest gratitude to my loving family and friends who have been by side and supported me unconditionally throughout my studies, even at a distance. iv M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology Table of contents Abstract iii Acknowledgements iv Table of contents v Glossary of abbreviations ix Glossary of anthropometric terms xvi Declaration of academic achievement xvii Preface xviii Chapter 1: Introduction 1 1.1 Measurement of obesity 1 1.2 Genetic epidemiology of obesity 2 1.3 Environmental determinants of obesity 4 1.4 Why the undergraduate population is important 4 1.5 Rationale for further study 5 1.6 References 7 Chapter 2: Factors associated with obesity traits in undergraduate students: a systematic review 10 2.1 Summary 11 2.2 Introduction 11 2.3 Methods 13 2.3.1 Literature search 13 2.3.2 Article review 14 2.3.3 Data extraction and analysis 15 2.4 Results 15 2.4.1 Literature flow 15 2.4.2 Overview of studies 16 2.4.3 Factors associated with BMI level 17 2.4.4 Factors associated with BMI change 19 2.4.5 Factors associated with weight 19 2.4.6 Factors associated with adiposity measures 21 2.4.7 Factors associated with lean/muscle mass measures 22 2.4.8 Factors associated with other obesity traits 22 v M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology 2.5 Discussion 23 2.5.1 Strengths and limitations 25 2.5.2 Implications 26 2.6 Figures and tables 27 Figure 1. PRISMA literature flow diagram of eligible studies 27 Table 1. Factors associated with body mass index change 28 Table S1. Full search queries 29 Table S2. Factors associated with body mass index level 32 Table S3. Factors associated with weight 41 Table S4. Factors associated with weight change 42 Table S5. Factors associated with body adiposity index 45 Table S6. Factors associated with body fat mass 46 Table S7. Factors associated with body fat percentage level 46 Table S8. Factors associated with body fat percentage change 48 Table S9. Factors associated with fat mass index 48 Table S10. Factors associated with skinfold thickness 48 Table S11. Factors associated with visceral fat 49 Table S12. Factors associated with conicity index 49 Table S13. Factors associated with muscle mass 49 Table S14. Factors associated with muscle mass percentage 49 Table S15. Factors associated with fat-free mass 49 Table S16. Factors associated with fat-free mass index 50 Table S17. Factors associated with fat-free mass percentage 50 Table S18. Factors associated with waist circumference 50 Table S19. Factors associated with hip circumference 52 Table S20. Factors associated with waist-to-hip ratio 52 Table S21. Factors associated with corpulence index 52 Table S22. Factors associated with body surface area 52 2.7 References 53 Chapter 3: Rationale and design of GENEiUS: a prospective observational study on the genetic and environmental determinants of body mass index evolution in Canadian undergraduate students 73 3.1 Abstract 74 3.2 Strengths and limitations of this study 75 3.3 Introduction 75 3.3.1 Obesity in young adulthood 75 3.3.2 Predictors of undergraduate weight change 77 3.3.3 Study objectives 80 vi M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology 3.4 Methods and study design 80 3.4.1 Participant selection and recruitment 80 3.4.2 Data collection 81 3.4.3 Outcomes 82 3.4.4 Predictor variables 83 3.4.4.1 DNA extraction, whole-genome genotyping and whole-exome sequencing 83 3.4.4.2 Energy intake 84 3.4.4.3 Alcohol consumption 84 3.4.4.4 Physical activity 85 3.4.4.5 Exercise motivation 85 3.4.4.6 Sleep 85 3.4.4.7 Stress 86 3.4.4.8 History of abuse 86 3.4.4.9 Impulsivity 86 3.4.4.10 Eating disorders 87 3.4.4.11 Body dissatisfaction 87 3.4.4.12 Self-esteem 88 3.4.4.13 Depression 88 3.4.4.14 Anxiety 88 3.4.4.15 Religiosity 89 3.4.5 Sample size calculation 89 3.4.6 Statistical methods 90 3.4.6.1 Analysis of environmental risk factors 90 3.4.6.2 Analysis of genetic risk factors 91 3.4.6.3 Prediction models of weight change 93 3.5 Discussion 93 3.5.1 Ethics and dissemination 96 3.6 Figures and tables 98 Table 1. Study timeline, outcomes risk factor variables, and measurements 98 Table 2. Sample size estimates for BMI level 100 Table 3. Sample size estimates for BMI change 100 Table S1. Sample size estimates for BMI level by GWAS 101 Table S2. Sample size estimates for BMI level by exome-wide association study 102 Table S3. Sample size estimates for environmental traits with BMI level 102 Table S4. Sample size estimates for BMI change by GWAS 103 Table S5. Sample size estimates for BMI change by exome-wide association study 104 Table S6. Sample size estimates for environmental traits with BMI change 105 3.7 References 106 Chapter 4: Conclusion 114 vii M.Sc. Thesis — R.E. Morassut; McMaster University — Health Research Methodology 4.1 Summary of conclusions and methodological limitations 114 4.2 Sources of bias 115 4.2.1 Factors associated with obesity traits in undergraduate students: a systematic review 115 4.2.2 Rationale and design of GENEiUS: a prospective observational study on the genetic and environmental determinants of body mass index evolution in Canadian undergraduate students 116 4.3 Feasibility of the GENEiUS study and practical considerations 117 4.4 Ethical considerations with the GENEiUS study 118 4.5 Future directions 120 4.6 References 121 viii M.Sc.