Mortality in transitional Vietnam

CHAPTER I: INTRODUCTION

1.1. The importance of mortality data in public health systems

Mortality data represent essential elements for the quantification of health problems. It is one of the most important health indicators for measuring a country’s health development. Information on cause-specific mortality is crucial for summarizing the total burden of disease in different settings. Understanding mortality patterns is very useful, and is considered to be an essential pre-requisite for guiding public health action and for supporting development of evidence-based policy. Commonly, mortality statistics are used to [1]: (a) establish the public health importance of different causes of death; (b) help in identifying priorities and appropriate interventions for avoidable causes of death; (c) study the trend in cause-specific mortality over time, which is especially valuable in a longitudinal surveillance system; (d) make comparisons of cause-specific mortality between groups (regions, countries) or between individuals (by gender, age group, etc); and (e) evaluate the effect of interventions on cause- specific mortality. Moreover, it has also been suggested that mortality can be measured more easily than morbidity (sickness). The assumption is that morbidity changes in parallel with mortality, even if not at the same rate, although this may not always be true, especially for older people [2, 3].

Mortality data have also received special attention by policy makers. Mortality measures are expressed in two targets of the Millennium Development Goals and in one out of three components of the Human Development Index [4]. In 2006, the World Health Organization (WHO) showed its interest in mortality information by issuing a special WHO Bulletin theme issue on mortality surveillance, confirming that “counting the dead is essential for health” [5]. This issue focused on the importance of mortality data in measuring health status of people all around the world as well as different efforts in collecting data and making effective use of them for policy makers.

1.2. The change in mortality patterns during epidemiological transition

The epidemiological transition theory was conceived by Omran in early 1970s [6]. It encompasses changing patterns of disease and health (health transition), changing fertility and population age structures (parts of demographic transition), changing lifestyles, changing health care patterns, medical and technological evolutions (technological transition), and environmental and ecological changes (ecological transition). In his work, Omran originally defined three stages of epidemiological transition: 1 – the “age of pestilence and famine”, 2 – the “age of receding pandemics”, 3 – the “age of degenerative and manmade disease” [6]. Thirty years later, Omran proposed two more stages for the western model: 4 – the “age of delayed degenerative diseases” and 5- the “age of aspired quality of life, with paradoxical longevity and persistent inequities” [7]. Some other authors also suggested a new fifth stage of the epidemiological transition – the re-emergence of infectious and parasitic diseases stage, which had happened in some population subgroups [8].

Within the complex dynamics of epidemiological transition, mortality is a most fundamental force exerting its influence through rises in pre-modern societies or through declines in modern times. The pattern of mortality changes over the different stages of epidemiological transition, from predominant infectious diseases, malnutrition and maternal complications in stage 1 and 2, to increasing cases from cardiovascular disease (CVD), cancer, and other man- made diseases in stage 3, and aging in stage 4 (Table 1). At some points in the process of transition, there may be a “double burden” of disease in which non-communicable diseases (NCD) increase while pre-existing infectious diseases still remain.

While the epidemiological transition progressed slowly over a century in the developed world, it appears to be moving faster in some developing countries. The epidemiological transitions in “non-western societies” occur with different acceleration, timing and magnitude of changes; thus they can be differentiated into rapid, intermediate and slow transition models. “Non¬western societies” have experienced prolonged pestilence and famine (stage 1) as well as the stage of receding epidemics (stage 2). Omran later proposed a different third stage for non¬western countries, “the age of triple health burden”, i.e. the unfinished old set of health problems, a rising new set of health problems, and ill-prepared health systems to cope with the prevention and care of chronic diseases [7].

TABLE OF CONTENTS

ABSTRACT i

ABBREVIATIONS ii

ORIGINAL PAPERS iii

CHAPTER I: INTRODUCTION 1

1.1. The importance of mortality data in public health systems 1

1.2. The change in mortality patterns during epidemiological transition 1

1.3. Certifying cause of death: an overview 3

1.4. Verbal autopsy (VA): an alternative method for determining cause of death 5

1.5. Collecting mortality data: the current situation in developing countries 6

1.6. Quantifying burdens of premature mortality 9

1.7. Vietnam 11

1.8. Study objectives 19

1.9. Outline of publications 20

CHAPTER II: MATERIALS AND METHODS 21

2.1. Study setting 21

2.2. Study base 23

2.3. Collection of mortality data and the verbal autopsy performance 26

2.4. Measuring premature mortality and calculating life expectancy 31

2.5. Statistical methods 31

2.6. Main definitions and variables 32

2.7. Ethical considerations 32

CHAPTER III. RESULTS 33

3.1. Verbal autopsy method application 33

3.2. The pattern of mortality in transitional Vietnam 35

3.3. Measuring premature mortality 39

3.4. The association between cause specific mortality and socio-economic status 40

CHAPTER IV: DISCUSSIONS 42

4.1. Methodological issues 42

4.2. The double burden of mortality in transitional Vietnam 49

4.3. Premature mortality: a public health concern 52

4.4. Socio-economic situation inequality and mortality 54

CHAPTER V: CONCLUSIONS AND RECOMMENDATIONS 56

ACKNOWLEDGEMENTS 58

REFERENCES 62