The Epidemiology and Prevention of Childhood Obesity in Tehran, Iran
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The epidemiology and prevention of childhood obesity in Tehran, Iran By Behnoush Mohammadpour-Ahranjani A thesis submitted to The University of Birmingham for the degree of DOCTOR OF PHILOSOPHY Unit of Public Health, Epidemiology and Biostatistics School of Health and Population Sciences College of Medical and Dental Sciences The University of Birmingham September 2010 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. Abstract Introduction The relationship between childhood obesity and later chronic diseases is evident. In Iran, whilst childhood obesity is a recognised increasing public health problem, no evidence for effective prevention strategies are available. Aim and objectives The aim was to inform the development of an obesity prevention intervention for Iranian school children, which could be later tested as part of a randomised controlled trial. Objective included: To develop and validate a semi-quantitative food ticklist to estimate energy intake in children. To examine the pattern, and factors associated with obesity in school children. To explore contextual influences on childhood obesity and to gain insights on barriers and facilitators that would help tailor the intervention. To identify and prioritise potential intervention components to help children maintain a healthy weight. Methods A dietary assessment tool was developed and compared with a 24-h semi-weighed food diary. For the second objective, a cross-sectional study of Tehrani school children (n=319) aged 6-8 yrs from a range of socio-economic backgrounds was undertaken. Participants underwent anthropometric and blood pressure measures, completed validated questionnaires to assess their body image perception and quality i of life, and their parents completed questionnaires related to socio-demographic, diet and physical activity habits. For the remaining objectives, a series of focus groups and interviews were undertaken with parents and school staff. Results There was good agreement in estimated energy intake between the food ticklist and more resource intensive 24-h food diary. Overall 28.2% of the study children were overweight or obese, with those from higher socio-economic areas being at greater risk. Body Mass Index and other measures of body fat were highly positively correlated with blood pressure. There was a tendency for increasing energy intake with higher weight status, although this was not statistically significant. There was generally accurate body size perception. Quality of life scores were generally similar by weight status. Focus group participants identified a range of obesity risk factors related to diet and physical activity at the micro and macro levels. In terms of interventions, the importance of macro level educational activities, and better provision of physical activity at school were highlighted. The importance of cooperation between schools and families and the substantial contribution of the government in providing a supportive environment were emphasised. Conclusion The study confirms that childhood obesity is an important health problem in Tehran and highlighted socio-economic variations in prevalence, which will inform the targeting of prevention interventions. Important contextual information was obtained ii to inform the development of a prevention intervention. The feasibility and acceptability of applying a range of physical and psychological outcome measures in a population setting was also demonstrated. These could be used for a future population based trial of childhood obesity prevention. iii Acknowledgments I would like to express my gratitude to my supervisors; Dr. Peymane Adab who has not only provided me with invaluable and detailed guidance and strong encouragement but also shared her brilliant insight and expertise as a friend, and Professor KK Cheng for his valuable suggestions. I wish to thank Dr. Morteza Abdollahi who has been a great friend and provided much support throughout this PhD, which would not have been completed without his outstanding contribution. For their unconditional support, I would like to thank Dr. Hubert Lam, Sheila Hirst, Ariyo Movahedi, Dr. Miranda Pallan, Saied Mowahed, and Hayfa Al-Shahristani. I would like to thank Dr. Arash Rashidi for sharing his positive thoughts and valuable input and Saloomeh Armin for her substantial contribution to “dietary intake assessment”. I am grateful to Professor Janet Cade for sharing her invaluable experience on validating the dietary intake tool, Professor Jayne Parry for her critical and valuable comments on the “qualitative study” and to Professor Jon Deeks for his statistical advice. My special thanks to Narges Djazayery, Moloud Pakravan, Maryam Amini, Anahita Houshiar-rad, Mina Esmaeili, Saeideh Nassiri, Pooneh Angoorani, Mahshid Mohammadizadegan, Zohreh Hajmirsadeghi, Hamid Sabour, Amin Salehpour, Ali iv Shafee, Soudeh Moghadam, Rezvan Ghodoussi, Mohammadreza Khoshfetrat, Telma Zoghi, Masoumeh Nazar, Mohammad Hosseini, Sepideh Alibeyk, Azadeh Aminpour, and Dr. Nasser Kalantari, who helped me to complete the field work and data entry. Their presence was precious and comforting. I would like to thank the participating children for their attendance and kindness. I also very much appreciate the participation of parents and school staff in this study. I would like to acknowledge the contribution of the Overseas Research Students Awards Scheme, UK; the National Nutrition and Food Technology Research Institute, Iran; the Unit of Public Health, Epidemiology & Biostatistics at the University of Birmingham, UK; the Education Office, Tehran; and the schools which have made my PhD and the project possible. I would like to acknowledge Dr. Hedayat Hosseini, Dr. Ahmad-Reza Dorosty, Dr. Esmat Nasseri, Dr. Tirang Neyestani, Dr. Dolly Bondarianzadeh, and Ali Parizadeh at the National Nutrition and Food Technology Research Institute who enabled me to complete my PhD as a full-time student. v I am forever grateful to my parents for their love, dedication, patience, wholehearted support, and encouragement. Thank you for everything. For their genuine affection, generous support, and pleasant company, I would like to specially thank Auntie Faezeh and Uncle Jalil who have made Birmingham my second hometown. I would also like to say a special thank you to Kian who has taught me how to enjoy my life in any situation. Finally, I would like to thank my brother, Behzad, and Pooneh for their care and inspiration and Arvin who has brought precious things into my life. vi TABLE OF CONTENTS OVERVIEW ..................................................................................................................1 1 INTRODUCTION .................................................................................................3 1.1 Tehran city......................................................................................................................................3 1.1.1 Population..............................................................................................................................3 1.1.2 Climate ..................................................................................................................................4 1.1.3 Socio-economic and nutritional status...................................................................................4 1.1.4 Geopolitical factor.................................................................................................................5 1.2 Epidemiology of obesity.................................................................................................................6 1.2.1 Worldwide prevalence and trends of obesity.........................................................................6 1.2.2 Prevalence of overweight and obesity in Iran........................................................................6 1.2.3 Socio-economic and ethnic risk factors for obesity...............................................................8 1.2.4 Global prevalence of childhood obesity ................................................................................9 1.2.5 Prevalence of childhood overweight and obesity in Iran.....................................................10 1.2.6 Cost of obesity.....................................................................................................................12 1.2.7 Factors influencing the development of overweight and obesity ........................................12 1.2.8 Potential contributors to overweight and obesity in Iran.....................................................13 1.2.8.1 Dietary factors ...........................................................................................................13 1.2.8.2 Physical activity pattern.............................................................................................13 1.2.8.3 Environmental and social contributors ......................................................................14 1.2.9 Consequences and morbidity