Residential mobility in greater Johannesburg: patterns, associations and educational outcomes amongst children in the birth to twenty cohort

The United Nations has projected that Africa’s urban population will expand from fourth largest to becoming the second largest of the world’s regions by the year 2050. Patterns of migration and urbanisation have therefore been highlighted as significant focus areas for research and policy. Movement has the potential to result in improved living conditions and well-being, but may also reinforce inequalities and conditions of vulnerability. These consequences may pose particular risks in the case of children, and understanding the patterns, drivers and outcomes associated with child mobility is therefore critical. South Africa provides an important setting in which to explore child movements. The shift within the country from politically controlled migration to movement based on choice has resulted in high levels of mobility both to and within urban areas. Children have been shown to participate in such movements either independently or in conjunction with connected adults. However, there is currently little knowledge of the patterns and consequences of child residential mobility in South Africa, particularly within the urban environment. This PhD thesis attempts to address this research gap. Data from Birth to Twenty, a cohort of South African urban children living in Greater Johannesburg, was used to investigate three central research questions concerning residential mobility of cohort children over a 14 year period. Specifically, the thesis aimed to determine the frequencies and patterns of residential mobility observed over the first 14 years of the children’s lives, to examine the associations with mobility of children over a set of domains relating to the child, the child’s primary caregiver, and the child’s household and to assess the relationships between residential and school mobility and a set of educational outcomes. Routine data collected over the course of the Birth to Twenty study was supplemented with data from a Residential Move Questionnaire, administered to children’s primary caregivers in order to validate and provide additional information concerning the children’s residential movements over the time frame. The research objectives were achieved through the use of cross-sectional and longitudinal analysis techniques applied to these data. In particular, multilevel event-history analysis was used to model the children’s residential movements over time. Of the 3273 children enrolled into the cohort in 1990, two thirds of the children (64%) had moved home at least once by the time they reached 15 years of age. Nonetheless, a third of the children had never moved, indicating stability or a lack of opportunity for movement amongst this urban child population. Mobility was found to be more likely amongst children whose primary caregivers had no formal education and who lived in households with fewer assets and less access to services, suggesting that residential movement within this group of children was more common in the context of disadvantage. Extending these findings to an exploration of children’s educational outcomes revealed some unexpected results. The analyses provided evidence of a positive association between changes in residence and numeracy and literacy scores, and school mobility was found to be associated with grade repetition, however, a negligible relationship was found between residential mobility and school progression. In conclusion, mobility is associated with opportunities for some children in the cohort and challenges or hardships for others. However, even in the instance of movement connected to disadvantage, changes of residence did not prejudice children in terms of the educational outcomes investigated. This is suggestive of children’s possible resilience and adaptability in the face of change and highlights the potential for mobility to influence children’s lives positively. The findings concerning the relationship between mobility and child well-being run counter to trends observed in high-income countries and on that basis, the need for further research into dynamics associated with child mobility in other low- and middle-income country settings is highlighted. There is justification for monitoring child mobility in South Africa; mobility trends provide a valuable indicator of children’s living situations as well as the spatial and social changes occurring in the country more broadly. Keywords: residential mobility; internal migration; urban children; South Africa; eventhistory models; school progression; numeracy and literacy; school mobilit

The dynamic role of household structure on under-5 mortality in southern and eastern sub-Saharan Africa

Background: Children are born and grow up in households, where they receive essential care, including time, socio-psychological support, and economic resources. Children's immediate environment, captured by household structure, changes over time. Objective: We evaluate the role of dynamic household structure in the risk of child death in southern and eastern Africa. Methods: We use longitudinal data from 15 Health and Demographic Surveillance Systems between 1990 and 2016, covering almost 282,000 under-5 year olds. We analyse under-5 mortality using semi-parametric Cox models accounting for time-varying household structure (household size and household typology) and controlling for maternal characteristics. Results: We find that children in smaller households have a higher risk of death than those in large households. In particular, children in households where they are the sole child with two adults of opposite sexes have the lowest chances of survival, reflecting a first-child effect. By contrast, nuclear-type households with more than one child are the most protective, while children in extended households are more vulnerable. Contribution: Our findings suggest that the (in)stability of households is important in evaluating child survival, and that it is imperative to consider households as changing entities

A training manual for event history analysis using longitudinal data

Objective This research note reports on the activities of the Multi-centre Analysis of the Dynamics of Internal Migration And Health (MADIMAH) project aimed at collating and testing of a set of tools to conduct longitudinal event history analyses applied to standardised Health and Demographic Surveillance System (HDSS) datasets. The methods are illustrated using an example of longitudinal micro-data from the Agincourt HDSS, one of a number of open access datasets available through the INDEPTH iShare2 data repository. The research note documents the experience of the MADIMAH group in analysing HDSS data and demonstrates how complex analyses can be streamlined and conducted in an accessible way. These tools are aimed at aiding analysts and researchers wishing to conduct longitudinal data analysis of demographic events. Results The methods demonstrated in this research note may successfully be applied by practitioners to longitudinal micro-data from HDSS, as well as retrospective surveys or register data. The illustrations provided are accompanied by detailed, tested computer programs, which demonstrate the full potential of longitudinal data to generate both cross-sectional and longitudinal standard descriptive estimates as well as more complex regression estimates

Dynamic household structure and composition: a manual for longitudinal analysis of living arrangements

Abstract Objective This research note introduces a set of tools to conduct analysis of household structure and composition with either limited or comprehensive longitudinal data. The data used here are from Health and Demographic Surveillance Systems in Africa, but the methods can be adapted and applied to other longitudinal micro-data such as register data. A training manual describing the procedures for creating time-varying household measures step-by-step is supplied as supplementary material to this note. Code is provided in STATA but can easily be translated for other statistical software, and the logic for each step remains the same. Results The analysis of household structure demonstrates how with limited data (such as a household identifier), it is possible to construct time-varying measures of household membership, including household size or the number of members in specific age and sex groups. The analysis of household composition demonstrates how with expanded data (including links to parents in addition to residence status in the same household), it is possible to construct time-varying measures of household membership of specific kin, i.e. mother, sibling or grandparent. The results illustrated in this research note are a taste of what can be achieved by following the training manual in the supplementary material

Modelling residential mobility: factors associated with the movement of children in Greater Johannesburg, South Africa

Conceptualisation of child residential mobility has been influenced by developed country contexts; however, trends and models for movement are likely to differ in transitional societies. This paper uses event-history analysis to model the residential movements of South African urban children in the Birth to Twenty cohort over their first 14 years of life. Associations with mobility of children are tested over a set of domains relating to the child, the child's primary caregiver, and the child's household. A methodological approach is proposed for analysing repeated moves using multi-level models, which are adapted to maximise information from children who dropped out of the study or who had long gaps in their residential histories. The results indicate mobility is associated with economic disadvantage with children whose primary caregivers had no formal education and who lived in households with fewer assets and less access to services being more likely to change residence. The study suggests potential risks for mobile children in urban environments who may be more likely to be exposed to disruption or compromised living conditions

Migrant health penalty: evidence of higher mortality risk among internal migrants in sub-Saharan Africa

Background: Despite the greater attention given to international migration, internal migration accounts for the majority of movements globally. However, research on the effects of internal migration on health is limited, with this relationship examined predominantly in urban settings among working-age adults, neglecting rural populations and younger and older ages. Objectives: Using longitudinal data from 29 mostly rural sub-Saharan African Health and Demographic Surveillance Systems (HDSS), this study aims to explore life-course differences in mortality according to migration status and duration of residence. MethodsCox proportional hazards models are employed to analyse the relationship between migration and mortality in the 29 HDSS areas. The analytical sample includes 3 836,173 people and the analysis spans 25 years, from 1990 to 2015. We examine the risk of death by sex across five broad age groups (from ages 1 to 80), and consider recent and past in- and return migrants. Results: In-migrants have a higher risk of mortality compared to permanent rural residents, with return migrants at greater risk than in-migrants across all age-groups. Female migrants have lower survival chances than males, with greater variability by age. Risk of dying is highest among recent return migrant females aged 30–59: 1.86 (95% CI 1.69–2.06) times that of permanent residents. Only among males aged 15–29 who move to urban areas is there evidence of a ‘healthy migrant’ effect (HR = 0.62, 95% CI 0.51–0.77). There is clear evidence of an adaptation effect across all ages, with the risk of mortality reducing with duration following migration. Conclusions: Findings suggest that adult internal migrants, particularly females, suffer greater health disadvantages associated with migration. Policy makers should focus on improving migrant’s interface with health services, and support the development of health education and promotion interventions to create awareness of localised health risks for migrants

The Crucial Role of Mothers and Siblings in Child Survival: Evidence from 29 Health and Demographic Surveillance Systems in Sub-Saharan Africa

There is a considerable body of research on the effects of siblings on child mortality through birth intervals. This research commonly focuses on older siblings. We argue that birth intervals with younger siblings may have equal or stronger effects on child mortality, even during a mother’s pregnancy. Moreover, we contend that birth interval effects need to be considered only when siblings are co-resident. Using longitudinal data from 29 Health and Demographic Surveillance Systems across sub-Saharan Africa, covering over 560,000 children, we examine the proximate role of siblings and mothers in child mortality. We find that a minimum 24-month birth interval is advantageous between both older and younger siblings. The effect of a younger sibling on child mortality is more pronounced and is present in addition to that of an older sibling. Moreover, child mortality is further found to be particularly low during a mother’s subsequent pregnancy, contrasting the shock resulting from a younger sibling’s birth. Further, we find that when a mother or sibling is absent from the household there is a higher risk of mortality, and the death of either reduces child survival up to six months before the death

A training manual for event history data management using Health and Demographic Surveillance System data

Objective: The objective of this research note is to introduce a training manual for event history data management. The manual provides a first comprehensive guide to longitudinal Health and Demographic Surveillance System (HDSS) data management that allows for a step-by-step description of the process of structuring and preparing a dataset for the calculation of demographic rates and event history analysis. The research note provides some background information on the INDEPTH Network, and the iShare data repository and describes the need for a manual to guide users as to how to correctly handle HDSS datasets. Results: The approach outlined in the manual is flexible and can be applied to other longitudinal data sources. It facilitates the development of standardised longitudinal data management and harmonization of datasets to produce a comparative set of results

The dynamic role of household structure on child mortality in southern and eastern sub-Saharan Africa

Households are where children are born and grow up, where they receive essential care, including time, socio-psychological support and economic resources. Households can also change over a child’s life. We consider the dynamic role of household structure in child mortality in South and Eastern Africa using longitudinal data from 16 Health and Demographic Surveillance Systems between 1990 and 2016, covering ~625,000 under-five year olds. We account for household structure as time-varying, using the number of household members by age and sex, and a typology of households, in semi-parametric Cox models estimating the risk of death among under-five year olds. We find that under-five year old children experience on average six changes in household structure. In contrast to expectations, more working aged adults in the household does not reduce the risk of child death. The presence of over 65 year olds in the household adversely affects child survival, likely because they are also dependents, competing for resources. Our findings suggest that (in)stability of households is important to consider in evaluating child survival