Retirement, Cardiovascular Disease and Its Risk Factors in China

Retirement, Cardiovascular Disease and its Risk Factors in China Baowen Xue Thesis submitted for the degree of Doctor of Philosophy UCL 2017 1 Declaration I, Baowen Xue, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Signature: ……………………………………………… Baowen Xue Date: ……………………………………………… 2 Abstract Population ageing and proposals for delaying retirement in many countries have led to greater interest in understanding the potential long-term associations between retirement and cardiovascular disease (CVD) and CVD risk factors. Most relevant studies were conducted in Western countries. The cross-national comparison between China and England conducted by this thesis revealed that China has a much earlier retirement age than England, and the cross-sectional associations of retirement and CVD and CVD risk factors are different in the Chinese context, and these associations are moderated by personal and family characteristics in both countries. It is important to consider reverse causality when investigating the health effects of retirement. Thus, this thesis assessed the longitudinal associations between retirement and CVD risk factors over a 17-year period both before and after retirement among 1,084 people who participated in the China Health and Nutrition Survey at least once prior to and once after the year in which they retired. Piecewise models, centred at the year of retirement, were applied. Retirement was accompanied by a reduction in diastolic blood pressure, a slowdown in the increase of both systolic blood pressure and waist circumference, and a reduction in the probability of being a heavy drinker. Results for heavy smoking mirrored those for heavy drinking, but only reached borderline statistical significance. The association between retirement and blood pressure was stronger for men, for urban dwellers, and for those who have a non-working spouse. No significant association with body mass index was found. The reduced probability of being a heavy drinker after retirement explained some of the association between retirement and blood pressure. This study suggests that retirement may be beneficial in the Chinese context. Better working environment and flexible schedules are needed for an ageing workforce, given plans to raise the retirement age in China. 3 Acknowledgements I would like to express my deepest gratitude to my supervisors Dr. Anne McMunn and Professor Jenny Head for their outstanding guidance, encouragement, and support. I could not have imagined having better advisors and mentors for my PhD study. I am grateful to Dr Elizabeth Breeze for giving me advice, ideas and detailed comments on my upgrade reports. I wish to thank staff in the International Centre for Lifecourse Studies in Society and Health for their help throughout my studies. I would also like to thank the staff of the Department of Epidemiology and Public Health at UCL for their friendly support. I owe my thanks to my beloved families; for their understanding and endless love, through the duration of my studies. 4 Contents Declaration ........................................................................................................................ 2 Abstract ............................................................................................................................. 3 Acknowledgements ........................................................................................................... 4 Contents ............................................................................................................................ 5 Tables .............................................................................................................................. 10 Figures ............................................................................................................................. 12 Map ................................................................................................................................. 14 Abbreviations .................................................................................................................. 14 Chapter 1: Introduction and Background ....................................................................... 16 1.1 Introduction .............................................................................................................. 17 1.2 Aims and objectives .................................................................................................. 18 1.3. The pension system and retirement behaviour in China ......................................... 21 1.3.1 Development of the pension system in China ............................................................................. 21 1.3.2 Retirement behaviour in China .................................................................................................... 22 1.3.3 Determinants of retirement in China .......................................................................................... 24 1.4 CVD and its risk factors in China ............................................................................... 28 1.4.1 The epidemiology of CVD ............................................................................................................ 28 1.4.2 The epidemiology of CVD risk factors .......................................................................................... 30 Chapter 2: Literature and Systematic Reviews ............................................................... 36 2.1 Introduction .............................................................................................................. 37 2.2 Theoretical perspectives on the health effects of retirement .................................. 37 2.2.1 Role theory .................................................................................................................................. 37 2.2.2 Continuity theory ......................................................................................................................... 38 2.2.3 Stage theory................................................................................................................................. 39 5 2.2.4 The life course perspective .......................................................................................................... 40 2.2.5 Discussion .................................................................................................................................... 43 2.3 Life course theoretical framework of retirement and CVD ...................................... 44 2.4 Empirical studies on the association between retirement and non-CVD health outcomes ......................................................................................................................... 49 2.4.1 Comparing study designs in investigating associations between retirement and non-CVD health outcomes ................................................................................................................................. 49 2.4.2 Retirement and mental health .................................................................................................. 51 2.4.3 Retirement and cognitive function ........................................................................................... 52 2.4.4 Retirement and physical functioning ....................................................................................... 53 2.4.5 Retirement and self-rated health .............................................................................................. 54 2.4.6 Summary .................................................................................................................................... 55 2.5 Systematic review of the associations between retirement and CVD and CVD risk factors ............................................................................................................................. 57 2.5.1 Search method ............................................................................................................................ 57 2.5.2 Results ......................................................................................................................................... 58 2.5.3 Key findings of the systematic review ......................................................................................... 59 2.5.4. Discussion of the systematic review and identifying gaps in current evidence ......................... 75 Chapter 3: Retirement and its Cross-sectional Associations with CVD and CVD Risk Factors in China and England .......................................................................................... 80 3.1 Introduction of the chapter ...................................................................................... 81 3.2 Data and analytic sample .......................................................................................... 82 3.2.1 Data ............................................................................................................................................. 82 3.2.2 Analytic sample ............................................................................................................................ 85 3.3 Measures ................................................................................................................... 86 3.3.1 Exposure variable: retirement status .........................................................................................

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