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Risk factors for non-communicable disease in Vietnam: estimates of prevalence, and issues in measurement by Bui Van Tan, MD, MPH Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (Medical Research) Menzies Institute for Medical Research University of Tasmania October 2015 The work presented in this thesis was supervised by: Principal supervisor Associate Professor Christopher Leigh Blizzard, PhD Menzies Institute for Medical Research University of Tasmania Hobart, Australia and Associate supervisors Professor Mark R. Nelson, PhD Menzies Institute for Medical Research University of Tasmania Hobart, Australia Associate Professor Velandai K. Srikanth, PhD Menzies Institute for Medical Research University of Tasmania Hobart, Australia Dr Seana L. Gall, PhD Menzies Institute for Medical Research University of Tasmania Hobart, Australia Declaration of originality i Declaration of originality This thesis contains no material which has been accepted for a degree or diploma by the University or any other institution, except by way of background information and duly acknowledged in the thesis, and to the best of my knowledge and belief no material previously published or written by another person except where due acknowledgement is made in the text of the thesis, nor does the thesis contain any material that infringes copyright. Signed: Date: 30 October 2015 Name: Bui Van Tan Statement of authority access ii Statement of authority access The publishers of the papers comprising Chapter 3, 4, 5, and 6 hold the copyright for that content, and access to the material should be sought from the respective journals. The remaining non published content of the thesis may be made available for loan and limited copying and communication in accordance with the Copyright Act 1968. Signed: Date: 30 October 2015 Name: Bui Van Tan Statement of ethical conduct iii Statement of ethical conduct The research associated with this thesis abides by the international and Australian codes on human and animal experimentation, the guidelines by the Australian Government's Office of the Gene Technology Regulator and the rulings of the Safety, Ethics and Institutional Biosafety Committees of the University. Signed: Date: 30 October 2015 Name: Bui Van Tan Abstract iv Abstract Background and Aims Non-communicable disease (NCD) is the leading cause of death worldwide. In Vietnam, there has been an increase in morbidity and mortality rates in recent decades, but data on NCD risk factors are limited. The principal aim of this thesis was to provide national estimates of the mean levels or prevalence of NCD risk factors. The secondary aim was to investigate issues in the measurement of these risk factors, and in the analysis and interpretation of data collected and reporting of results. Methods A population-based survey was conducted during 2009−10 using the “WHO STEPwise approach to surveillance of risk factors for NCDs” (STEPS) methodology. Participants aged 25−64 years were selected from eight provinces representing the eight ecological and geographical regions of Vietnam. Of the 22,940 eligible subjects selected by stratified multi- stage cluster sampling, 14,706 (64%) participated. National estimates of eight NCD risk factors are presented in the first of five studies, and the other four studies provide more detailed information on tobacco smoking, alcohol use, physical activity (PA) and fruit/vegetable intake. Results Study 1 provides national estimates of eight NCD risk factors. Notable findings were sex- differences in proportions of current smokers (men 57.7%, women 1.7%), binge drinkers (men 25.1%, women 0.6%), active people (men 52.0%, women 41.1%), and hypertension (men 18.5%, women 10.2%). Mean levels of fruit/vegetable intake (2.8 serves/day), BMI (21.1) and blood cholesterol (5.6 mmol/L), and prevalence of diabetes (2.6%), were similar for men and women. The correlations between the summary values for each province were generally plausible, but with some anomalous findings due to the characterisation of smoking and hypertension by STEPS protocols. More detailed information on tobacco use is presented in study 2. Male ever-smokers commenced smoking at a median age of 19 years (women 20 years) and smoked a median of 10 cigarettes/day (women 6 cigarettes/day). For men, the proportion of current daily smokers peaked in the 1965−69 birth cohort and has declined in more recent cohorts. For women, the Abstract v proportion of current daily smokers has declined in successive cohorts after the 1950−54 cohort. Study 3 provides more detailed information on alcohol use. Almost 60% of men but only 4% of women consumed alcohol during the last week. Nearly 40% of men were hazardous/harmful users. Gains in model calibration and subject discrimination from information on quantities of ‘standard drinks’ were minor after the contribution from binary responses to questions on whether or not alcohol had been consumed during the reference period. Study 4 provides more detailed information on domain-specific and overall PA. Approximately 70% met WHO recommendations for PA. Most PA was from work activity, which was higher in rural areas and varied by season. One-in-six provided unrealistically high PA values. Box-Cox transformation was the most successful method of reducing the influence of large values, but values scaled to the average Vietnamese energy intake produced the strongest correlations with pathophysiological outcomes. More detailed information on fruit/vegetable consumption is presented in study 5. Nearly 80% reported having less than five servings of fruit/vegetables daily in a typical week. The measurements were plausibly correlated with socioeconomic factors in individual-level analyses, and with provincial characteristics in aggregate analyses. Conclusions This thesis provides the first nationally-representative estimates of mean levels or prevalence of NCD risk factors in Vietnam. These data suggest that efforts to limit future growth in NCDs should be targeted at reducing tobacco smoking and binge drinking by men, encouraging physical activity, and increasing consumption of fruit and vegetables. These interventions should take account of the sex-, urban-rural and regional differences in these risk factors that were identified in this thesis. The results from this research could help to strengthen the implementation Programme of Prevention and Control of Certain Non- communicable Diseases for the Period 201020 in Vietnam. In addition, the findings from the extensive assessment of the application of the STEPS instrument in Vietnam in respect of the measurement of behavioural risk factors, and the analysis, interpretation and reporting of the results, should be of value for other investigators using the instrument and for other users of data. Acknowledgements vi Acknowledgements I would like to express my gratitude and thanks to my supervisors, colleagues, friends and family for their ongoing support and encouragement not only during the preparation of this thesis, but also during my PhD candidature. The research work presented in this thesis would not have been accomplished without their support. First and foremost, I would like to express my gratitude to my principal supervisor, Associate Professor C. Leigh Blizzard. Thank you for all your constructive guidance and statistical advice in doing this work, and constant support not only for doing this thesis, but also for the whole time I am studying in Hobart. I am very impressed with your patience with my English writing skills. Thank you for tirelessly supporting my work, no matter whether it was a week day, weekend or holiday! Without your ongoing encouragement, interest, and enthusiasm, I could not have completed this thesis. I wish to extend my great appreciation to my Associate supervisors, Professor Mark Nelson, Associate Professor Velandai Srikanth, and Dr Seana Gall. To Mark and Srikanth, thank you for your continuous support and for the valuable guidance and comments you have provided throughout my research, as well as for sharing your expertise in non-communicable diseases. To Seana, thank you for your patience and constant support, and for sharing your expertise in behavioural risk factors and analytical research skills. Again, my thesis could not have been completed without your endless encouragement and support. Sincere thanks also to The Atlantic Philanthropies Inc., participants in the surveys, the Ministry of Health of the Socialist Republic of Vietnam, provincial health authorities who provided data collection teams, Menzies consultants who trained and supervised the data collection teams, and Menzies staff including Catrina Boon and Kate Butorac who provided support for training and supervision. Thank you for giving me an opportunity to work on this project. To Kate, thanks for helping me out during my part time job at the Menzies clinic. I would like to express my thanks for the scholarship providers, the University of Tasmania and The Atlantic Philanthropies Inc. for helping me to achieve my goal. I would also like to thank Dr Phung Ngoc Hai, Dr Tran Hoang Mai and Dr Au Bich Thuy, Mr Le Phi Hai, and Mr Mark Bennett for their assistance and support. To Dr Thuy, Dr Hai and Dr Mai, thank you for your constructive comments on the drafts of our papers. Acknowledgements vii To my close friends and fellow PhD candidates at Menzies – Anitra Wilson, Harbeer Ahedi, Mithun Rajshekar, William Cuellar, Kira Patterson, Benny Antony, Hoang Phan, Tran Pham, Jing Tian, Prudence