The Effects of Internal Migration and Related Factors on Nutrient Intake and Anthropometric Status of Children Aged 1-9 Years in South Africa, 1999
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The Effects of Internal Migration and Related Factors on Nutrient Intake and Anthropometric Status of Children Aged 1-9 Years in South Africa, 1999 Elizabeth Catherina Swart (M.Phil Public Health) EXAMINATION COPY A thesis submitted in fulfilment of the requirements for the degree of Doctor Philosophiae (Public Health) in the Faculty of Community and Health Sciences, University of the Western Cape. Supervisors: Dr Debra Jackson Prof Robert Shell 2004 ii The effects of internal migration and related factors on nutrient intake and anthropometric status of children aged 1-9 years in South Africa, 1999. Elizabeth Catherina Swart Keywords Migration Residential mobility Height Weight Nutritional status Children Dietary intake Women Growth South Africa iii Abstract Migration both as a process and as an outcome of multiple factors contributes to social, economic, environmental and behavioural changes, which, in turn, affect the health and nutritional status of individuals. To best understand the association between migration, dietary intake, nutritional status and socio-economic conditions, all factors should be considered as a continuum. The differences in outcomes would depend on where the individual started off. In turn, the starting point not only influences the outcomes, but also the propensity to migrate. Children are often most susceptible to changes, but, as they are often not regarded as migrants, little is known about the impact of internal migration on the nutritional status of children in South Africa. Therefore, for the first time in South Africa, the purpose of this study is to provide a national overview on internal migration of children and to relate these migration patterns to the nutritional status of children. This study specifically investigates the internal migration that took place during the life span of the National Food Consumption Survey (NFCS) study population and relates that to their dietary intake and anthropometric status. The 1999 NFCS was a cross-sectional nationally representative sample of children aged 1-9 years in South Africa (n = 2 892; 2 505 with migration information). For 83% of the children no migration was reported and 15% moved only once. The children who moved mostly experienced intra-provincial migration within urban areas or within rural areas. Rural-to-urban migration was reported for only 1.5% of children. The highest volume of migration (both inter- and intra-provincially) was reported for children living in Gauteng and the Western Cape. For two-thirds of the children the same migration pattern was reported for their mothers. Migration was found to be an independent predictor of a higher energy and vitamin C intake as well as a lower prevalence of overweight in children who migrated. iv Children aged 1-9 years, who migrated in South Africa in the period 1990 –1999, are not the most vulnerable rural children, and migration most likely contributed to their improved dietary intake. v Declaration I declare that The effects of internal migration and related factors on nutrient intake and anthropometric status of children aged 1-9 years in South Africa, 1999 is my own work; that it has not been submitted previously for any degree or examination in any other university, and that all the sources I have used or quoted have been indicated and acknowledged by complete reference. ELIZABETH CATHERINA SWART OCTOBER 2004 SIGNED: …………………………… vi Acknowledgements This study would not have been possible without the National Food Consumption Survey (NFCS) in children aged 1-9 years: South Africa 1999, commissioned by the National Department of Health and conducted by a consortium of Heads of Departments of Dietetics at universities in South Africa. The members of the Consortium are listed below in alphabetical order. The permission given by the Consortium and the Department of Health for the use of the data, the collaboration on data collection for this study, and the support and encouragement received, is gratefully acknowledged. The study would also not have been possible without the co-ordinators and fieldworkers who worked so hard, under difficult circumstances, to ensure that the best possible quality data was collected. The families who willingly participated in the survey and organisations that provided financial support to the NFCS are also gratefully acknowledged. Statistics South Africa and Prof Louis van Tonder made access to and comparison with the 1996 Census and the University of Pretoria/Brown University Migration Study 1999 datasets possible. Dr Pieter Kok provided valuable guidance on migration and Dr Stefan Maritz provided guidance on regression analyses. NFCS Consortium directors Prof. D. Labadarios, Universities of Stellenbosch (chairperson) Prof. A. Dannhauser, University of the Free State Ms G. Gericke, University of Pretoria Ms J. Huskinson, University of Natal, Prof E Maunder, University of Natal Dr U. MacIntyre, MEDUNSA Mr E. Nesamvuni, MEDUNSA Prof. N. Steyn, University of the North Ms R. Swart, University of the Western Cape Prof. H. H. Vorster, University of Potchefstroom vii Table of contents Keywords ii Abstract iii Declaration v Acknowledgements vi Table of contents vii List of Figures xii List of Tables xx Abbreviations xxxiv Definitions of concepts xxxv Chapter 1: Introduction 1 Introduction and rationale 2 The problem: Setting and background 3 Value of the study 6 Aim of the study 7 Objectives of the study 7 Scope and Limitations of the study 7 Research hypotheses 8 Organisation of the remainder of the report 8 Chapter 2: Literature review 11 Introduction 12 viii Migration 14 Definition of migration 14 Reasons for migration 16 Direction of migration 22 Consequences of migration 23 Urbanisation 24 Poverty 27 Health and disease 31 Infectious diseases 31 Infant mortality 32 Reproductive outcomes 35 Diseases of lifestyle 39 Cancer 40 Health care access and utilization 41 Acculturation 43 Behavioural problems / Social adaptation 44 Summary 46 Impact of migration on nutritional status of children 47 Dietary intake 47 Anthropometry 51 The South African situation 57 The South African migration situation 57 The health consequences of migration for South Africans 61 The nutritional status of children in South Africa 63 Anthropometry 65 Micronutrient malnutrition 70 Nutrient intake 71 Macronutrient intake 71 Micronutrient intake 72 Summary 74 Conceptual framework for the effect of migration on the nutritional status of children in South Africa 75 Chapter 3: Methodology 79 Research methodology 80 Study design 80 Study population 80 Sample size 80 Study variables 82 Data collection 84 ix Questionnaires and measurements 85 Pilot study 89 Training of fieldworkers 89 Quality control 90 Data management and data analysis 90 Assumptions 100 Validity and reliability 101 Contribution by the researcher 101 Ethical considerations 102 Chapter 4: Results 103 Introduction 104 Missing value analysis 104 Representativeness of the data 109 Migration 113 Migration of children, their mothers and grandmothers 113 Frequency of migration 113 Direction of migration 117 Similarity of migration patterns 128 Duration of stay at current residence 129 Internal migration and socio-economic characteristics 131 Gender 135 Age 137 Language and ethnic origin 139 Caretaker 140 Household headship 140 Marital status of mother 141 Employment status of mother 142 Employment status of father 143 Type of dwelling 144 Household size 145 Household income 146 Household food expenditure 147 Source of drinking water 148 Type of toilet 148 Fuel used for cooking 149 Cold food storage 150 Cooking facilities 150 Educational level of mother 151 Radio and television 152 Adjusted association between migration and socio-economic 152 variables x Nutrient intake 156 Internal migration and nutrient intake 156 Hypothesis testing 176 Crude analyses 176 Assessment of potential confounding 177 Anthropometry 183 Internal migration and anthropometric status of children 183 Hypothesis testing 191 Crude analyses 191 Assessment of potential confounding 192 Socio-economic context of internal migration, nutrient intake and 195 anthropometric status of children Undernutrition 196 Nutrition transition 202 Summary 207 Chapter 5: Discussion 209 Introduction 210 Migration: Volume of migrants 210 Frequency of migration 211 Socio-demographics and migration 212 Direction of migration 216 Consequences of migration 219 Urbanization 220 Poverty 220 Health and disease 221 Nutrient intake 221 Anthropometric status 225 xi Socio-economic context of dietary intake and growth of migrant children 227 Conceptual framework 231 Chapter 6: Conclusions and Recommendations 233 Chapter 7: List of references 241 Appendices Appendix A: Variables and values 288 Appendix B: Consent form 293 Appendix C: Protocol 296 Appendix D: Questionnaires 319 Appendix E: Tables 339 xii List of Figures Figure 1.1: Number of people in each province by urban and non- urban place of enumeration, Census 1996……………… 3 Figure 1.2: Comparison of anthropometric status of children aged 1- 6 years in South Africa with that of children in selected countries in Africa.………………………………………… 6 Figure 2.1: De Jong’s general model of migration decision-making… 21 Figure 2.2: Conceptual framework on nutrition………………………... 64 Figure 2.3: The anthropometric status of children 1-9 years nationally and by area of residence: NFCS 1999……… 66 Figure 2.4: The anthropometric status of children 1-9 years by province: NFCS 1999……………………………………… 67 Figure 2.5: Comparison of anthropometric status of children 12-71 months