Prevalence of obesity and its associated risk of diabetes in a rural Bangladeshi Population Dr. Tasnima Siddiquee Supervisor: Professor Akhtar Hussain Co-supervisor: Prof A K Azad Khan University of Oslo Faculty of Medicine Institute of Health and Society Department of Community Medicine Section of International Health Thesis submitted as a part of the Master of Philosophy Degree in International Community Health May 2014 1 Table of Contents Acknowledgements…………………………………………………………………………………………………………………………….5 Abstract……………………………………………………………………………………………………………………………………………….6 List of Figures ………………………………………………………………………………………………………………………………………8 List of Tables………………………………………………………………………………………………………………………………………..9 Abbreviation……………………………………………………………………………………………………………………………………….10 Chapter 1: Introduction………………………………………………………………………………………………………………………13 1.1 Overview of Bangladesh…………………………………………………………………………………………………………….....13 1.1.1 Geography..............................................................................................................................13 1.1.2 Land and Climate…………………………………………………………………………………………………………………14 1.1.3 History………………………………………………………………………………………………………………………………..14 1.1.4 People...………………………………………………………………………………………………………………………………15 1.1.5 Economy……………………………………………………………………………………………………………………………..17 1.1.6 Life style and physical activity……………………………………………………………………………………………..18 1.1.7 Food habit…………………………………………………………………………………………………………………….......19 1.1.8 Healthcare Service……………………………………………………………………………………………………………….19 1.1.9 Urbanization………………………………………………………………………………………………………………………..20 1.1.10 Urbanization and Chronic Diseases in Bangladesh…………………………………………………………….21 1.2 Burden of Obesity..................................…………………………………………………………………………………….23 1.2.1 Burden of Obesity: Global overview…………………………………………………………………………………….23 1.2.2 Burden of Obesity in Bangladesh………………….……………………………………………………………………..24 1.3 Overview of Obesity………………….……………………………………………………………………………………………….24 1.3.1 Definition and Risk Factors of Obesity….……………………………………………………………………………..24 1.3.2 Anthropometric Indicators and Classification of Obesity ……….……………………………………………25 1.3.3 Health Hazards of Obesity……………….…………….…………………………………………………………………….27 1.4 Health Hazards of Obesity: Diabetes……….………………………………………………………………………………..28 1.4.1 Overview of Diabetes…………………………………………………….……………………..…………………………….28 1.4.2 Global Burden of Diabetes….……………………………………………………………………………………………….29 1.4.3 Burden of Diabetes in Bangladesh ………………………………..……………………………………………………29 1.5 Literature Review…………………………………………………………………………………………………………………….31 1.5.1 Adult Prevalence and Risk Factors for Obesity……………………………………………………………………31 1.5.2 Obesity as a Major Risk Factor for T2DM……………………………………………………………………………32 2 1.5.3 Comparison of General and Central Obesity for Predicting T2DM and other Cardio Metabolic Risk Factors………………………………………………………………………………………………………33 1.5.4 Optimal Cut-off Point for Anthropometric Indices for Predicting T2DM …………………………34 Chapter 2: Rationale, Research Questions and Objectives…………………………………………………………….36 2.1 Rationale………………………………………………………….…………………………………………………………………….36 2.2 Hypothesis………………………………………………………………………………………………………………………………37 2.3 Research Questions……………………………………………………………….……………………………………………….37 2.4 Objectives…………………………………………………………………………….………………………………………………..37 Chapter 3: Research methodology …………………………………………………………………………………………………38 3.1 Study Design and Study Site……….………………………………………………………………………………………….38 3.2 Study period ………………………………………………………………………………………………………………………….39 3.3 Study Population…………….………………………………………………………………………………………………………39 3.4 Inclusion Criteria……….……………………………………………………………………………………………………………39 3.5 Exclusion Criteria……………………….…………………………………………………………………………………………..39 3.6 Sample size of primary study ……….………………………………………………………………………………………..39 3.7 Study Variables………………………………………………………………………………………….……………………………40 3.7.1 Socio-demographic Variables…………………………………………………………….……………………………..40 3.7.2 Anthropometric Variables……………………………………………………………….………………………………..40 3.7.3 Biochemical Variables……….………………………………………………………………………………………………40 3.8 Data Collection……………………………………………………………………………………………………………………….40 3.8.1 Phase 1: Household Census………………………………………………………………….…………………………..40 3.8.2 Phase 2: Sample Survey and Collection of Other Data……………………………………………………….41 3.8.2.1 Sample Survey………………………………………………………………………………………………………….41 3.8.2.2 Anthropometric Measurements……………………………………….……………………………………..41 3.8.2.3 Measurement of Blood Pressure……………………………………….…………………………………….42 3.8.2.4 Blood Glucose estimation ………………….……………………………………………………………………42 3.8.2.5 Fasting Blood Lipids estimation……………………………………………………………………………….43 3.8.2.6 Methods and Specifications of the machine for the various biological tests…………..43 3.8.2.7 Food Behavior Questionnaire………...………………………………………………………………………43 3.8.2.8 Definition of Terms…………………………………………………………………………………………………44 3.9 Statistical Analysis……………………………….………………………………………………………………………………44 3.10 Ethical approval………………….………………………………………………………………………………………………45 3 Chapter 4: Results………………………………………………………………………………………………………………………….47 Chapter 5: Discussion…………………………………………………………………………………………………………………….75 5.1 Methodological Issues………………………………………………………………………………………………………….75 5.1.1 Appropriateness of Study Design…………….…………………………………………………………………….75 5.1.2 Validity of Statistical Association….………………………………………………………………………………..75 5.1.2.1 Sample Size………….……………………………………………………………………………………………….75 5.1.3 Bias………………………….…………………………………………………………………………………………………….76 5.1.3.1 Selection Bias………………….…………………………………………………………………………………… 76 5.1.3.2 Information Bias……………….…………………………………………………………………………………..76 5.1.3.3 Measurement Bias………….…………………………………………………………………………………….77 5.1.4 Confounding…………………….…………………………………………………………………………………………….77 5.1.5 Generalizability…………….………………………………………………………………………………………………..78 5.2 Strengths of the Study………….……...………………………………………………………………………………………78 5.3 Limitations of the Study……..….…………………………………………………………………………………………….79 5.4 Discussion of the Main Findings………………………….………………………………………………………………..79 Chapter 6: Conclusions, Recommendations and Future Research Implication……………………………..85 6.1 Conclusions……………………………………………………………………………………………………………………………85 6.2 Recommendations…………………………………………………………………………………………………………………86 6.3 Future Research Implication…………………………………………………………………………………………………..87 References……………………………………………………………………………………………………………………………………….89 List of Appendix………………….………………………………………………………………………………………………………….103 Appendix I: Community Awareness Leaflet……………………….………………………………………………………104 Appendix II: Personal Invitation Letter…….………………………………………………………………………………..106 Appendix III: Consent Form…….…………………………………………………………………………………………………108 Appendix IV: Questionnaire…….…………….………………………………………………………………………………….110 Appendix V: Ethical Permission………………………………………………………………………………………………….117 4 Acknowledgement Firstly, I would like to express my gratitude to Almighty Allah for His Guidance and Protection throughout this course. I would firstly like to thank the participants in the survey who took time out of their busy days to attend the camps and take part in this study. This work would never have been possible without their cooperation. I express my profound gratitude to my respected supervisor Professor Akhtar Hussain for his expert academic guidance, ideas, critical and quick comments, and valuable support as well as his encouragement throughout my study period, developing research protocol and final write up of my thesis. I express my profuse gratitude also to my other supervisor Professor A K Azad Khan, for his constructive guidance and sustained interest in my work during the years. My sincere thanks are extended to the research team members and I also express my deepest gratitude, appreciation and special thanks to my other co-supervisor Dr. Bishwajit Bhowmik for his tireless encouragement and making it possible for me to pursue further studies. Without him this thesis would not have become a reality. This study would not have been possible without the financial assistance from the Norwegian State Education Loan fund through the Quota Program and Department of International Community Health, University of Oslo. Hence, I am grateful to Statens Lånekasse for the financial support. In addition, I am grateful to the Section for International Health, as it made me have such a great experience of two-year study in Oslo. Furthermore, I would like to express cordial thanks to Prof Gunnar Bjune, Prof Johanne Sundby and all other professors who have contributed immensely to this MPhil program. Special thanks to all the administrative staffs at the department, especially, Line Low and Terese Eriksen, for always being helpful. Their passionate support and care during my course of study will be memorable. Thanks to my class fellows who have given me invaluable support by sharing with me the frustrations and prosperities of this course from the start to the end. I will never forget them for our genuine friendship. Finally, my deepest gratitude, of course, should go to my family. I am really indebted to my parents for their spiritual and moral support. Without their help and encouragement I would never have had the energy and patience required to complete this work. Oslo, May 2014 Dr. Tasnima Siddiquee 5 Abstract Background: People in the developing countries are increasingly vulnerable to the worldwide epidemic of obesity. It is a common modifiable risk factor for all the cardiometabolic diseases including type 2 diabetes (T2DM). Population-based