Rainfall variations and child mortality in the Sahel: results from a comparative event history analysis in Burkina Faso and Mali

Over the last 40 years, the Sahel has seen a long-term downward trend in rainfall. The importance of ecological variables as factors affecting child survival in rural subsistence societies has already been emphasized, but little empirical evidence has been gathered to support this. This paper presents a comparative event history analysis aimed at understanding how rainfall variations may influence child mortality in two neighbouring countries, Burkina Faso and Mali. These countries are similar in terms of population dynamics, economy, livelihood, child mortality and rainfall conditions (i.e. strong south–north decreasing rainfall gradient). Individual data for both countries came from two detailed nationally representative retrospective surveys conducted in 2000. Rainfall data for the 1960–1998 time period were obtained from the Climatic Research Unit. This study shows that child survival in each country is related to specific patterns of rainfall variation across livelihood regions, highlighting the complex nature of environmental causality of child mortality.     

Is There an Urban Advantage in Child Survival in Sub-Saharan Africa? Evidence From 18 Countries in the 1990s

Evidence of higher child mortality of rural-to-urban migrants compared with urban nonmigrants is growing. However, less attention has been paid to comparing the situation of the same families before and after they migrate with the situation of urban-to-rural migrants. We use DHS data from 18 African countries to compare child mortality rates of six groups based on their mothers’ migration status: rural nonmigrants; urban nonmigrants; rural-to-urban migrants before and after they migrate; and urban-to-rural migrants before and after they migrate. The results show that rural-to-urban migrants had, on average, lower child mortality before they migrated than rural nonmigrants, and that their mortality levels dropped further after they arrived in urban areas. We found no systematic evidence of higher child mortality for rural-to-urban migrants compared with urban nonmigrants. Urban-to-rural migrants had higher mortality in the urban areas, and their move to rural areas appeared advantageous because they experienced lower or similar child mortality after living in rural areas. After we control for known demographic and socioeconomic correlates of under-5 mortality, the urban advantage is greatly reduced and sometimes reversed. The results suggest that it may not be necessarily the place of residence that matters for child survival but, rather, access to services and economic opportunities.     

Health Interventions and Health Equity: The Example of Measles Vaccination in Bangladesh

Although the existence of socioeconomic differentials in infant and childhood mortality in developing countries is well established. little consensus exists as to the most effective approaches to reducing such differentials. This article utilizes longitudinal data from the Matlab study area in rural Bangladesh to investigate the impact of an efficacious child survival intervention—measles vaccination—on reductions in gender and socioeconomic differentials in childhood mortality. The article analyzes data from 16,270 vaccinated children and randomly matched controls, and evaluates their subsequent mortality risks. Proportional hazards analysis demonstrates that unvaccinated children from very poor families face more than a threefold higher risk of subsequent early child mortality, compared to vaccinated children from families of high economic status. While measles vaccination has little impact on mortality risks among children of higher economic status, the improvement in survival among children from poorer households is pronounced. The provision of measles vaccination markedly reduces mortality risks for poorer children—from over three times higher to just over 1.5 times higher relative to vaccinated children from wealthier families. The findings of this study are evaluated in terms of the potential of child survival interventions such as measles vaccination to promote greater health equity.     

Data on survival of recent births as a source of child mortality estimates in the developing world: An assessment of census data

In many less developed countries, household surveys collect full and summary birth histories to provide estimates of child mortality. However, full birth histories are expensive to collect and cannot provide precise estimates for small areas, and summary birth histories only provide past child mortality trends. A simple method that provides estimates for the most recent past uses questions about the survival of recent births in censuses or large household surveys. This study examines such data collected by 45 censuses and shows that on average they tend to underestimate under-5 mortality in comparison with alternative estimates, albeit with wide variations. In addition, the high non-sampling uncertainty in this approach precludes its use in providing robust estimates of child mortality at the country level. Given these findings, we suggest that questions about the survival of recent births to collect data on child mortality not be included in census questionnaires.     

Parental survival data: Some results of the application of Ledermann's model life tables

Summary Ledermann's one- and two-parameter model life tables are used in order to summarize and compare adult mortality estimates derived from parental survival data, and also to link parental survival with child survival data. The Ledermann models provide an alternative to the logit model used by Brass and Hill. Examination of life tables derived from actual child and adult mortality estimates reveals that although the two types of models yield similar overall levels of mortality, they show marked differences in the estimated patterns by sex and age. It has not been possible to disentangle completely how much of this divergence is due to the models themselves and how much to inadequacies in the data available. Finally, we question whether it is always wise to establish a full life table from child and adult mortality estimates when these are based on data which refer to different periods of exposure to the risk of dying, without allowance for possible distortions resulting from mortality change.     

Polygyny and child survival in Nigeria: Age-dependent effects

Mortality risks under age five are estimated using data from the 1990 Nigerian Demographic and Health Survey for children in monogamous and polygynous families. Integrating existing theories on polygyny’s relationship with infant and child mortality and some demographic concepts, the study shows that polygyny has different effects on infant and child mortality at different ages. The results indicate that polygyny does not have a significant effect on neonatal mortality (age less than one month). In contrast to the results of previous research, polygyny is significantly associated with lower child mortality during the post-neonatal period (1–11 months), but not during childhood (12–59 months). The study found socio-economic factors to be important confounders of the relationship between polygyny and mortality during the neonatal and post-neonatal periods. The protective effect of polygyny during the post-neonatal period suggests the need to further investigate circumstances that may favour post-neonatal child survival in polygynous families including availability of childcare.     

Maternal Reading Skills and Child Mortality in Nigeria: A Reassessment of Why Education Matters

Mother’s formal schooling—even at the primary level—is associated with lower risk of child mortality, although the reasons why remain unclear. This study examines whether mother’s reading skills help to explain the association in Nigeria. Using data from the Demographic and Health Survey, the analysis demonstrates that women’s reading skills increase linearly with years of primary school; however, many women with several years of formal school are unable to read at all. The results further show that mother’s reading skills help to explain the relationship between mother’s formal schooling and child mortality, and that mother’s reading skills are highly associated with child mortality. The study highlights the need for more data on literacy and for more research on whether and how mother’s reading skills lower child mortality in other contexts.     

Siblings’ neonatal mortality risks and birth spacing in Bangladesh

This paper studies the familial association of neonatal mortality in Matlab, Bangladesh and its relationship to birth-spacing effects on mortality. Findings show that familial association is strongest for siblings of adjacent birth orders. Moreover, birth-spacing effects on neonatal mortality are stronger when the preceding child has survived the neonatal period than when it has died. Transitional (Markov), random-effects, and marginal models for correlated data are introduced, and are contrasted in interpretation and technique. Familial association of neonatal mortality can be approximated well by a first-order Markov model using generalized estimating equations (GEE) to allow for higher-order correlation.     

Approaches to the measurement of childhood mortality: a comparative review

"In the developing world, measures of child mortality are needed for a variety of purposes, and estimates of child mortality can be obtained by a variety of approaches. In this paper, the author reviews the characteristics that child mortality measures should have for particular purposes, and then examines the available measurement approaches to determine the extent to which they provide accurate measures with the required characteristics. Particular emphasis is put on the comparative performance of different approaches in different settings to produce estimates of recent levels and trends in child mortality. He concludes that no single approach can satisfy all measurement purposes and that all approaches are sensitive to the quality of data collection, but that many needs can be met by relatively inexpensive data collection and analysis methods."     

Child mortality in India: the community-level effect of education

When assessing the health benefits of increased education in less developed countries, many researchers have been concerned about the omission of important determinants of an individual's education from the models. The study presented here shows that one should also be concerned about the limitations of the individual-level perspective. According to a multilevel discrete-time hazard model estimated with data from the National Family Health Survey II, the average education of women in a census enumeration area has a strong impact on child mortality, in addition to the effect of the mother's own education. The lower child mortality associated with women's autonomy is taken into account in this estimation. Results from similar models for various health and health-care variables suggest that the effect of community education, like that of individual education, operates through the use of maternity services and other preventive health services, the child's nutrition, and the mother's care for a sick child.     

Effects of Childhood Mortality and Morbidity on the Fertility Transition in sub‐Saharan Africa

Child mortality rates have fallen substantially in developing countries since 1960. The expected fertility decline has followed only weakly in sub‐Saharan Africa compared to other recent and historic demographic transitions. Disease and anthropometric data suggest that morbidity remains prevalent in Africa despite child survival improvements. The uniquely high infectious disease burden among children in Africa reduces population health and diminishes the returns to human capital investment, thwarting the quantity–quality tradeoff for children that typically accompanies the mortality transition. Individual‐level data from the Demographic and Health Surveys are used to show that persistent morbidity has weakened the positive relationship between child mortality and total fertility rates throughout the region, slowing Africa's demographic transition.     

Household income and child survival in Egypt

This article uses household-level economic and fertility survey data to examine the relationship between household income and child survival in Egypt. Income has little effect on infant mortality but is inversely related to mortality in early childhood. The relationship persists with other associated socioeconomic variables controlled. The mechanisms underlying the income effects are not evident from this analysis: income differentials in sources of household drinking water, type of toilet facilities, and maternal demographic characteristics do not explain the net impact of income on child mortality. The absence of effects on child survival of the size of the place of residence and the relatively weak effects of maternal schooling are also notable.     

The impact of childhood mortality on Fertility in six rural Thanas of Bangladesh

In this article, we examine the relationship between child mortality and subsequent fertility using prospective longitudinal data on births and childhood deaths occurring to nearly 8000 Bangladeshi mothers observed over the 1982-1993 period, a time of rapid fertility decline. Generalized hazard-regression analyses are employed to assess the effect of infant and child mortality on the hazard of conception, with controls for birth order and maternal age and educational attainment. Results show that childhood mortality reduces the time to subsequent conception if the death occurs within a given interval, representing the combined effect of biological and volitional replacement. The time to conception is also reduced if a childhood death occurs during a prior birth interval, a finding that signifies an effect of volitional replacement of the child that died. Moreover, mortality effects in prior birth intervals are consistent with hypothesized insurance (or hoarding) effects. Interaction of replacement with elapsed time suggests that the volitional impact of child mortality increases as the demographic transition progresses. This volitional effect interacts with sex of index child. Investigation of higher-order interactions suggests that this gender-replacement effect has not changed over time.     

New evidence about effects of reproductive variables on child mortality in sub-Saharan Africa

There is still considerable uncertainty about how reproductive factors affect child mortality. This study, based on Demographic and Health Survey data from 28 countries in sub-Saharan Africa, shows that mortality is highest for firstborn children with very young mothers. Other children with young mothers, or of high birth order, also experience high mortality. Net of maternal age and birth order, a short preceding birth interval is associated with above average mortality. These patterns change, however, if time-invariant unobserved mother-level characteristics of importance for both mortality and fertility are controlled for in a multilevel–multiprocess model. Most importantly, there are smaller advantages associated with longer birth intervals and being older at first birth. The implications of alternative reproductive ‘strategies’ are discussed, taking into account that if the mother is older at birth, the child will also be born in a later calendar year, when mortality may be lower.     

The effects of infant mortality on fertility revisited: new evidence from latin america

In this paper, we examine empirical evidence for a relation between infant and child mortality and fertility in Latin American countries from 1920 to 1990. We investigate the relation at several levels of aggregation and evaluate the extent to which evidence at one level is consistent with evidence at other levels. We first examine aggregate cross-country information over several decades, a type of data typically used in past research on the topic. We also examine yearly series of births, deaths, infant deaths, and socioeconomic indicators for selected countries to track the association between short-term fluctuations in fertility and infant mortality. Finally, we use micro-level data from the Demographic and Health Surveys (DHS) to assess the relation between fertility and child mortality from individual reproductive histories. The evidence we assemble from these different data sets is remarkably consistent and suggests small positive effects of infant mortality on fertility. These effects, however, may be too small to support the hypothesis that changes in child mortality are of more than modest importance in the process of fertility decline in Latin America in the late twentieth century.     

The child survival hypothesis

Summary Because of current interest in the child survival hypothesis, we have reviewed available evidence bearing upon the relationships of infant and child mortality to fertility and contraceptive behaviour. The evidence is drawn from time series data for local and national vital events, from special in-depth studies of the infant mortality-fertility relationships in family formation, and from service statistics from health and family planning programmes. As a result of this review, we suggest five clarifications which should be made in redefining the child survival hypothesis and assessing its potential programme implications. The child survival hypothesis states that improved child survival will contribute to increased family planning motivation and consequent fertility decline. The evidence presented here suggests that the effect is not automatic and probably not a necessary pre-condition for fertility decline. There is certainly not a reflexive one-to-one replacement, but a partial effect may still be important. In the clearly demonstrated reduction in inter-pregnancy intervals after a child death, the major component is undoubtedly the removal of the biological protection of lactational amenorrhoea. A separate but somewhat smaller effect has been demonstrated in situations where lactation did not seem to have been the explanation. It is expected that increased child survival will contribute to fertility decline mainly in countries experiencing rapid mortality decline and population growth. The replacement of children who die is probably not so much 'volitional' as a result of alterations in sub-conscious expectations. It is apparent that in traditional agrarian populations, few direct and manipulable means of influencing motivation for fertility limitation are available, and, therefore, it must be stressed that integrated health and family planning programmes do provide opportunities for immediate programme development. By making parents aware of improved changes of survival through health services in which they develop confidence, the spontaneous linkages between mortality and fertility can presumably be reinforced. Family planning services must be provided as an essential initial step in programme development, but they can be made more effective, as well as politically more acceptable if appropriately integrated with maternal and child health and nutrition services.     

The First Fifty Years – A Tribute to E. Grebenik

India is a country with a pervasive preference for sons and one of the highest levels of excess child mortality for girls in the world (child mortality for girls exceeds child mortality for boys by 43 per cent). In this article, data from the National Family Health Survey are used to examine the effect of son preference on parity progression and ultimately on child mortality. The demographic effects of family composition are estimated with hazard models. The analysis indicates that son preference fundamentally affects demographic behaviour in India. Family composition affects fertility behaviour in every state examined and son preference is the predominant influence in all but one of these states. The effects of family composition on excess child mortality for girls are more complex, but girls with older sisters are often subject to the highest risk of mortality.     

Infant mortality in the Marshall Islands

Levy and Booth present previously unpublished infant mortality rates for the Marshall Islands. They use an indirect method to estimate infant mortality from the 1973 and 1980 censuses, then apply indirect and direct methods of estimation to data from the Marshall Islands Women's Health Survey of 1985. Comparing the results with estimates of infant mortality obtained from vital registration data enables them to estimate the extent of underregistration of infant deaths. The authors conclude that 1973 census appears to be the most valid information source. Direct estimates from the Women's Health Survey data suggest that infant mortality has increased since 1970-1974, whereas the indirect estimates indicate a decreasing trend in infant mortality rates, converging with the direct estimates in more recent years. In view of increased efforts to improve maternal and child health in the mid-1970s, the decreasing trend is plausible. It is impossible to estimate accurately infant mortality in the Marshall Islands during 1980-1984 from the available data. Estimates based on registration data for 1975-1979 are at least 40% too low. The authors speculate that the estimate of 33 deaths per 1000 live births obtained from registration data for 1984 is 40-50% too low. In round figures, a value of 60 deaths per 1000 may be taken as the final estimate for 1980-1984.     

The relative effects of shocks in early- and later-life conditions on mortality

The relative importance of cohorts' early-life conditions, compared to later period conditions, on adult and old-age mortality is not known. This article studies how cohort-level mortality depends on shocks in cohorts' early- and later-life (period) conditions. I use cohorts' own mortality as a proxy for the early-life conditions, and define shocks as deviations from trend. Using historical data for five European Countries i find that shocks in early-life conditions are only weakly associated with cohorts' later mortality. This may be because individual-level health is robust to early-life conditions, or because at the cohort level scarring, selection, and immunity cancel each other. Shocks in period conditions, measured as deviations from trend in period child mortality, are strongly and positively correlated with mortality at all older ages. The results suggest that at the cohort level changing period conditions drive mortality variation and change.     

The effect of child mortality experience on subsequent fertility: in Pakistan and Bangladesh

Summary This paper presents an empirical analysis of the effects, behavioural and biological, of child mortality experience on subsequent fertility in two South Asian Islamic nations. Data for the investigation came from retrospective pregnancy histories of 2,910 currently married women interviewed in the Pakistan National Impact Survey (1968-69) and from longitudinal vital registration data (1966-2070) of 5,236 women residing in a rural area of Bangladesh collected by the Cholera Research Laboratory. The aim of this study was to assess the importance of the child-replacement motivational response to child death experience after biological effects have been controlled adequately. A common approach employed previously has been to examine cumulative fertility according to child death experience. In Pakistan and Bangladesh, a consistently positive relationship was demonstrated between the number of children ever born and the number of child deaths. This method, however, did not exclude the inverse relationship, the influence of fertility on mortality, nor did it dissect out behavioural from biological effects. Utilizing a measure of subsequent fertility, live-birth-to-live-birth intervals, the study further illustrated another common pitfall. Since the risk of infant death, which leads to shorter birth intervals, is associated with the mother's reproductive history, women with child mortality experience are more likely to experience shorter intervals because of the biological effect of subsequent infant death. Behavioural influences may, therefore, be observed by considering only those birth intervals in which the first-born child survives to the end of the interval. With these limitations controlled, very few, if any, behavioural influences were noted in the Pakistan and Bangladesh data. Median birth intervals in Pakistan varied between 35-43 and 41-42 months, increasing with parity. Within each parity group, no consistent difference was observed between women with and without previous child loss. In Bangladesh, the median birth interval for all women with a surviving infant was 37-2 months. This was shortened to 24-31 months by an infant death. When intervals with infant deaths were excluded, little or no behavioural influence was detected among women of the same parity, but with varying levels of previous child loss. Even without behavioural effects, elimination of infant mortality in Bangladesh would reduce fertility by prolonging the average period of post-partum sterility. In the Bangladesh setting, however, the size of the effect was only about four per cent. This modest effect, more-over, was counterbalanced by an overall increase of net reproduction by seven per cent due to better survivorship of infants.