On the theory and measurement of the determinants of mortality

This article develops a model of mortality that shows how biological, demographic, and environmental factors interact to affect an individual's probability of dying. To illustrate the usefulness of the model, we derive from it (as special cases) the Brass system of model life tables and the proportional-hazard mortality model and apply a logit version of the model to analyze the determinants of child mortality in Sri Lanka.     

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.     

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.     

Population studies of mortality

Population Studies has become the principal outlet for demographic research on mortality. Many of the advances in the measurement of mortality in data-poor countries were reported in its pages. It has also published most of the influential articles which attempted to make a broad-scale assessment of the sources of mortality change. These include special attention to developments in England and Wales and Sri Lanka. Capitalizing on the widespread availability of demographic surveys, articles in the 1980s featured careful analyses of the demographic correlates of child mortality. Such studies have passed the point of diminishing returns, and declines in child mortality have focused increased attention on conditions among adults. Unfortunately, demography has not developed the means for measuring and analysing adult mortality in underdeveloped countries that are equivalent in their power to methods for studying child mortality.     

Maternal Smoking and Infant Low Birth Weight: Exploring the Biological Mechanism Through the Mother’s Pre-pregnancy Weight Status

Maternal smoking has been found to adversely affect birth outcomes, such as increasing the odds of having low birth weight infants. However, the mechanisms explaining how a mother’s smoking is linked to a child’s low birth weight status are underexplored. This study merged two nationally representative datasets in the United States (US)—the National Longitudinal Survey of Youth 1979 (NLSY79) and the NLSY79 Child and Young Adult (NLSYCYA)—to examine whether maternal weight status before pregnancy serves as a biological mechanism. We applied a recently developed mediation analysis technique to a data sample of 6550 mother–child pairs, and we compared the estimated coefficients across nested probability models. We found that maternal body mass index (BMI) (in kg/m²), a widely used measure of weight status, reduces the odds of delivering a low birth weight infant, and this mechanism explains about 10.2% of the adverse impact of maternal smoking on having a low birth weight child. Moreover, when categorizing maternal pre-pregnancy BMI into four weight statuses (i.e., underweight, normal weight, overweight, and obese), we found that, in contrast to mothers with normal weight status, underweight mothers are 70% more likely to have a low birth weight child. Our findings suggest that maternal weight status plays a role in understanding how maternal smoking affects low birth weight outcome, indicating that maintaining a proper weight status for women who plan to give birth may be a possible policy to promote infant health.

     

Population Studies of Mortality

Population Studies has become the principal outlet for demographic research on mortality. Many of the advances in the measurement of mortality in data-poor countries were reported in its pages. It has also published most of the influential articles which attempted to make a broad-scale assessment of the sources of mortality change. These include special attention to developments in England and Wales and Sri Lanka. Capitalizing on the widespread availability of demographic surveys, articles in the 1980s featured careful analyses of the demographic correlates of child mortality. Such studies have passed the point of diminishing returns, and declines in child mortality have focused increased attention on conditions among adults. Unfortunately, demography has not developed the means for measuring and analysing adult mortality in underdeveloped countries that are equivalent in their power to methods for studying child mortality.     

Single Motherhood and Child Mortality in Sub-Saharan Africa: A Life Course Perspective

Single motherhood in sub-Saharan Africa has received surprisingly little attention, although it is widespread and has critical implications for children’s well-being. Using survival analysis techniques, we estimate the probability of becoming a single mother over women’s life course and investigate the relationship between single motherhood and child mortality in 11 countries in sub-Saharan Africa. Although a mere 5 % of women in Ethiopia have a premarital birth, one in three women in Liberia will become mothers before first marriage. Compared with children whose parents were married, children born to never-married single mothers were significantly more likely to die before age 5 in six countries (odds ratios range from 1.36 in Nigeria to 2.61 in Zimbabwe). In addition, up to 50 % of women will become single mothers as a consequence of divorce or widowhood. In nine countries, having a formerly married mother was associated with a significantly higher risk of dying (odds ratios range from 1.29 in Zambia to 1.75 in Kenya) relative to having married parents. Children of divorced women typically had the poorest outcomes. These results highlight the vulnerability of children with single mothers and suggest that policies aimed at supporting single mothers could help to further reduce child mortality in sub-Saharan Africa.     

Soap operas,women, and the nation: Sri Lankan women’s interpretations of home-grown mega teledramas

This essay examines the place of home-grown soap operas, known as mega teledramas, in the lives of women in the South Asian island nation of Sri Lanka. While female audiences are often vilified for their consumption of mega teledramas in Sri Lanka, this study finds that these narratives have assumed a social role in women’s friendship networks, becoming a shared cultural source in their everyday lives. The representations in the mega teledramas were offering a range of diverse meanings to the women and their readings of women protagonists, central to the narratives, were intrinsically linked with nationally constructed notions of womanhood.     

Demographic and Health Survey--1993

The author briefly outlines some of the major findings of the 1993 Sri Lanka Demographic and Health Survey. Information is provided on fertility, family planning, infant and child mortality, maternal and child health, breast-feeding, and nutritional status of children.     

A flexible two-dimensional mortality model for use in indirect estimation

Mortality estimates for many populations are derived using model life tables, which describe typical age patterns of human mortality. We propose a new system of model life tables as a means of improving the quality and transparency of such estimates. A flexible two-dimensional model was fitted to a collection of life tables from the Human Mortality Database. The model can be used to estimate full life tables given one or two pieces of information: child mortality only, or child and adult mortality. Using life tables from a variety of sources, we have compared the performance of new and old methods. The new model outperforms the Coale-Demeny and UN model life tables. Estimation errors are similar to those produced by the modified Brass logit procedure. The proposed model is better suited to the practical needs of mortality estimation, since both input parameters are continuous yet the second one is optional.     

Estimating the incidence and prevalence of birth orders: A technique using census data

Although birth order is recognized as an important social variable, the incidence of various birth orders is often difficult to assess using vital statistics. A technique is described whereby the incidence of birth orders in a population may be estimated directly from census data on the number of children ever born to post-menopausal women. The technique has the advantages of allowing ready utilization of existing and widely available data, based on very large samples on which considerable supplementary information is available. In addition, it draws attention to a relatively neglected aspect of differential fertility, namely, the child’s perspective as opposed to the mother’s view. Limitations of the technique relating to quality of data, to multiple births, and to differentials in infant and maternal mortality are discussed, and possible applications in demography and sociology are suggested.     

Some aspects of the relationship between the levels of infant mortality and fertility in the ESCAP region

The death of a child within the first year of life is a crucial factor in fertility decisions in a developing country. The infant mortality rate gives a close, inverse indication of the socioeconomic conditions of a country. This paper presents studies by Brass, Rutherford, Chowdhury, Khan and Chen, Agrawal, Iskander and Jones, in summary/abstract form. It concludes that the probabilities of survival are poorer for births of older women and/or higher parities. Early child deaths may increase the total period of exposure to the risk of conception. A lower infant and child mortality norm calls for fewer births to meet the needs for survivors. Child replacement motivational response seems to be strongest with the birth immediately following a death event. Agrawal analyzed the interval between successive births of 1107 women of Patna, Pakistan, according to the age of mother and sex and fate of the previous child. He observed that if a child died shortly after its birth, often a new pregnancy began within a short interval. The interval between 2 consecutive live births when the previous child was male and alive was greater than when the previous child was female and alive. The interval between 2 births was reduced if the child died in infancy and specially if this was a male child.     

Family formation and the life cycle

Mathematical expressions are developed for certain life cycles when only the age-specific birth and death rates are known. The probability at birth that a woman will have a specified number of children and the expected length of time spent before the first birth, between the first and the last child, and between the last child and the time of the woman's death are shown to be calculable. Expressions for the probability of at least one child outliving the mother and for the expected number of children outliving the mother are also developed and are evaluated for three selected countries with different birth and death rates to show how these life cycles depend on birth and death rates.     

Parental underinvestment: A link in the fertility-mortality continuum

Selective parental investment in siblings has been used to describe differential mortality rates. Using data from 986 Filipino women who had an average of 4.8 live births, a LISREL and six sets of regression models support the hypothesis that fertility is linked to underinvestment and that mortality, as a consequence, is linked to high birth order. The analysis also identifies intervening factors associated with this relationship. Age of mother at childbirth showed a strong influence on the relationship of birth order and infant and child mortality; correlations are stronger among older than youger mothers. However, even after the effect of age of mother at childbirth was partialled out, the effect of birth order on infant and child mortality remained significant and substantial. The conclusion is that parental underinvestment represents a link between fertility and mortality during infancy and early childhood that has not been described previously. Policy makers appear to have overlooked parental underinvestment in favor of more obvious economic and health mediators.     

Bayesian population reconstruction of female populations for less developed and more developed countries

We show that Bayesian population reconstruction, a recent method for estimating past populations by age, works for data of widely varying quality. Bayesian reconstruction simultaneously estimates age-specific population counts, fertility rates, mortality rates, and net international migration flows from fragmentary data, while formally accounting for measurement error. As inputs, Bayesian reconstruction uses initial bias-reduced estimates of standard demographic variables. We reconstruct the female populations of three countries: Laos, a country with little vital registration data where population estimation depends largely on surveys; Sri Lanka, a country with some vital registration data; and New Zealand, a country with a highly developed statistical system and good quality vital registration data. In addition, we extend the method to countries without censuses at regular intervals. We also use it to assess the consistency of results between model life tables and available census data, and hence to compare different model life table systems.     

Sri Lankan female domestic workers overseas: mothering their children from a distance

Sri Lanka is one of three countries in Asia, along with the Philippines and Indonesia, where women migrants constitute between 60 and 70% of legal migrants; these female migrants are mainly employed overseas as domestic workers. Since the 1980s, the out-migration of Sri Lankan females for employment abroad surpassed that of males and the major destination has been countries in the Middle East. The majority of these women are married and have at least one child; they leave their children in the care of other family members in their absence. While they usually make arrangements to accommodate the spatial separation forced by migration, their migration poses many challenges to themselves and their children left behind. Recently, the issue of children left behind by migrant mothers has attracted growing attention from policy makers in Sri Lanka. Since the social and emotional ramifications of mothering from a distance and how these mothers cope with them are inadequately investigated, this article uses data collected from a 2008 survey of 400 Sri Lankan female migrant families to examine the effects of mothers’ migration on how they are mothering their children from a distance, and how they perceive the effects on their children. The article concludes with some suggested policy recommendations.     

Demographic Determinants of Infant and Early Child Mortality: A Comparative Analysis

In this paper we examine the relative importance of a number of demographic determinants of infant and early child mortality using information from 39 World Fertility Survey countries. We include sex of the child, age of the mother at the time of the birth, birth order, mother's educational level and a number of indicators of spacing of adjacent births among the correlates of chances of survival for children below the age of five years. Mortality of firstborn children and of those born to teenage mothers is shown to be higher than average; that of later children and those of older mothers was not much higher than average, once other factors are controlled. Effects of poor birth-spacing persist even after other factors have been controlled, and are similar where a sib was born during the two years preceding the birth of the child, regardless of the survival status of that sib; however, mortality was higher when that sib had died, due to increased familial risks of mortality. Rapid subsequent births also raise mortality for their earlier sibs. The findings are generally remarkably consistent in a wide range of countries and associated mortality conditions, although attention is drawn to a few interesting geographically clustered exceptions which deserve further investigation. The study leaves little room for doubt that poor child-spacing is clearly linked to decreased survival chances.     

The Level and Age Pattern of Mortality in Bandafassi (Eastern Senegal): Results From a Small-Scale and Intensive Multi-Round Survey

The data collected in the Bandafassi demographic study in Eastern Senegal, a small-scale intensive and experimental follow-up survey of a population of about 7,000 in 1983, were analysed to derive an estimated life table. The use of multi-round surveys, combined with anthropological methods to estimate ages and collect genealogies, has resulted in unusually reliable data. Taking into account the uncertainty of the estimates due to the small size of the population, mortality was high, with life-expectancy at birth close to 31 years; a pattern of infant and child mortality close to that observed in other rural areas of Senegal, with a very high level or mortality between ages six months and three years; a seasonal pattern in child mortality with two high-risk periods, the rainy season and the end of the dry season; an adult mortality pattern similar to that described in model life tables for developed countries; no significant difference by sex or ethnic group. The Bandafassi population study and a few similar studies suggest that one possible way to improve demographic estimates in countries where vital registration systems are defective would be to set up a sample of population laboratories where intensive methods of data collection would continue for extended periods.     

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.     

Disparities in Children’s Family Experiences by Mother’s Socioeconomic Status: The Case of Finland

A well-known argument claims that socioeconomic differentials in children’s family structures have become increasingly important in shaping child outcomes and the resources available to children in developed societies. One assumption is that differentials are comparatively small in Nordic welfare states. Our study examines how children’s experiences of family structures and family dynamics vary by their mother’s educational attainment in Finland. Based on register data on the childbearing and union histories of women in Finland born from 1969 onwards, we provide life-table estimates of children’s (N?=?64,162) experiences of family dissolution, family formation, and family structure from ages 0–15 years, stratified by mother’s education level at the child’s birth. We find huge socioeconomic disparities in children’s experiences of family structures and transitions. Compared to children of highly educated mothers, children of mothers with low levels of education are almost twice as likely to be born in cohabitation and four times as likely to be born to a lone mother. They are also much more likely to experience further changes in family structure—particularly parental separation. On average, children of low-educated mothers spend just half of their childhood years living with both their parents, whereas those of high-educated mothers spend four-fifths of their childhood with both parents. The sociodemographic inequalities among children in Nordic welfare states clearly deserve more scholarly attention.