Polygynous Contexts,Family Structure,and Infant Mortality in Sub-Saharan Africa

Contextual characteristics influence infant mortality above and beyond family-level factors. The widespread practice of polygyny is one feature of many sub-Saharan African contexts that may be relevant to understanding patterns of infant mortality. Building on evidence that the prevalence of polygyny reflects broader economic, social, and cultural features and that it has implications for how families engage in the practice, we investigate whether and how the prevalence of polygyny (1) spills over to elevate infant mortality for all families, and (2) conditions the survival disadvantage for children living in polygynous families (i.e., compared with monogamous families). We use data from Demographic and Health Surveys to estimate multilevel hazard models that identify associations between infant mortality and region-level prevalence of polygyny for 236,336 children in 260 subnational regions across 29 sub-Saharan African countries. We find little evidence that the prevalence of polygyny influences mortality for infants in nonpolygynous households net of region-level socioeconomic factors and gender inequality. However, the prevalence of polygyny significantly amplifies the survival disadvantage for infants in polygynous families. Our findings demonstrate that considering the broader marital context reveals important insights into the relationship between family structure and child well-being.     

Infant Mortality and Socioeconomic Status: New Bottle,Same Old Wine

This paper presents the results of an ecological analysis of the relationship between infant mortality and economic status in metropolitan Ohio for the period 1960–2000. The data examined are centered on the five censuses undertaken during this 40-year period. The basic unit of analysis is the census tract of mother’s usual residence, with economic status being determined by the percentage of low income families living in each tract. For each of the five periods covered, census tracts were aggregated into broad income areas and three-year average infant mortality rates were computed for each area, by age, sex, race and exogenous-endogenous causes of death. The most important conclusion to be drawn from the data is that in spite of some very remarkable declines in infant mortality at all class levels since 1960, there continues to be a very clear and pronounced inverse association between income status and infant mortality. Indeed, the evidence indicates that the relationship has become stronger over the years. These observations are applicable for both sexes, for whites and nonwhites, for neonatal and postneonatal deaths, and for both major cause of death groups. It is concluded that while public health programs are important, any progress in narrowing this long-standing differential is unlikely unless ways can be found to enhance the economic well-being of the lower socioeconomic groups.     

Rural–Urban Migration and Cross-National Variation in Infant Mortality in Less Developed Countries

The relationship between migration and child health in individual countries is well known, but the cross-national variation in this relationship is largely untested. Using Demographic and Health Survey (DHS) data from 52 medium and low income countries, this study examines the effect of rural–urban migration on infant mortality and whether its effect varies cross-nationally. A secondary objective is to determine whether there is a relationship between the time a child is born in the migration process and infant mortality. Hypotheses are developed on the basis of competing theories on the relationship between migration and health. There are modest, but significant cross-national effects of rural–urban migration on infant mortality, which were better revealed in the presence of family- and child-level variables. The results also show that the unadjusted effects of rural–urban migration are quite substantial, but were largely accounted for by family- and child-level factors including education, socioeconomic status (SES), marital status, birth order, maternal age at child’s birth, and inter-births intervals. The results largely point to a selection process, which is further confirmed by results showing that the hazards of infant death increase with length of urban residence. Programs that target increasing maternal education, improving household SES, and lengthening interbirth intervals would therefore greatly benefit child survival in less developed countries.     

Polygyny and the rate of population growth

Summary The roots, motives and feasibility of practising polygyny in societies with a balanced sex structure and the effect of polygyny on the rate of population growth are considered. High demand for labour combined with limited supply over the last several centuries, had been conducive to the evolution of a polygynous nuptiality pattern. The unprecedentedly high rates of population growth during the last several decades combined with progressive economic development have led to a change in the role of the labour factor and consequently diminished its impact upon polygyny. Polygyny is feasible because of a sex-age differential at first marriage, which enables younger cohorts of women to enter the marriage market, and thus results in a very early age at first marriage and universal incidence of marriage among women. A very young pattern of nuptiality inevitably evolves under polygyny, which tends to raise the rate of population growth. No significant variation in fertility between polygynous and monogamous women was found but substantial gaps in standards of living, child mortality, and educational attainment were noted for polygynous households. The findings imply that during the transition from polygyny to monogamy family size will tend to diminish, although initially fertility may not decline concurrently with changing socio-economic status. The most important effects on the rate of population growth thus result from the increase in age at first marriage and declining proportions of ever married women.     

Polygyny as social and biological differentiation among Toposa agro-pastoralists of Southern Sudan

A demographic survey of eight Toposa villages in Southern Sudan was undertaken to delineate patterns of infant and childhood mortality. Among these predominantly egalitarian agro-pastoralists few standard socio-economic variables useful in the detection of demographic differentials were found. Instead, polygyny was used as a measure of social differentiation, hypothesizing that social differentiation induces demographic differences between polygynous and monogamous marriages. Analysis indicated social differentiation through gerontocracy, while significant differences in mortality and fertility levels were found berween monogamous and polygynous marriages, with the latter featuring higher fertility and mortality levels. Underlying rationale for these differences were sought through consideration of social and biological factors.     

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.     

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.     

Polygyny and Fertility among the Shipibo of the Peruvian Amazon

This report describes a study of the fertility experience of an Amazon Indian tribe that has shown evidence of having the highest documented fertility of any human group. The Shipibo, who live in the upper Peruvian Amazon, are experiencing rapid cultural change, including a decline in the prevalence of polygyny. This study tests the specific hypotheses that polygyny limits individual female and community fertility through the mechanism of post partum sexual abstinence and longer birth intervals. Total population counts in eight villages and reproductive histories of all females age 13+ show that mean birth interval lengths of polygynous women are four months longer than those of monogamous women. Fertility of polygynous women was lower, with 1.3 fewer term-births per reproductive span than that of monogamous women. The community general fertility rate is negatively associated with the proportion of polygynous birth intervals in the community. In this study, cultural change is strongly associated with higher fertility.     

Sustained Effects of the 1974–5 Famine on Infant and Child Mortality in a Rural Area of Bangladesh

In this paper the sustained effects of the 1974–75 famine on cohort mortality in a rural area of Bangladesh are studied. In the analysis, mortality rates for children born and conceived during the famine are compared with those from a post-famine cohort. In the famine-born cohort, mortality was higher during the first and second years of life, while in the famine-conceived cohort it was higher during the first year and lower during the second compared to the non-famine cohort. No significant differences in mortality by cohort were observed between the ages of 24 and 59 months. Using logistic regression, interactions between famine and socio-demographic characteristics were also studied. Three principal results emerged: first, a differential effect of the famine by socio-economic group was only present during the post-neonatal period for the famine-born cohort; secondly, children aged 12–23 months who were born to younger mothers were more adversely affected by the famine than those born to older mothers; and thirdly, although there was excess mortality for girls aged 24–59 months relative to boys of the same age in the non-famine and famine-conceived cohorts, there was little difference between mortality by sex for the famine-born.     

Polygyny and the breeding success of the great reed warblerAcrocephalus arundinaceus

Summary Settlement date, mating status, and breeding success of individually marked great reed warblers,Acrocephalus arundinaceus, were studied during the 1980–84 breeding seasons in Kahokugata, Ishikawa Prefecture, Japan. Twenty-five per cent of the territorial males were polygynous, of which the majority were bigamous. The settling periods of both sexes were long, extending for 65 days in males and 49 days in females. About 80% of males and females settled in the first half of the settling period, and the settlement date of 28–54% males overlapped with that of females. Many of the late settlers were bachelors and the males which mated earlier tended to be polygynous. The timing of a male's settlement is important in acquiring mates. Fifty-five per cent of eggs laid were lost before fledging, mainly due to predation. The mean number of fledglings was 3.19 per primary female, 2.41 per secondary female, and 2.80 per monogamous female. Comparison of the number of fledglings of females which mated during the same period showed that the presence of another female in the same territory did not adversely affect the breeding success of either of the polygynous females. Polygynous males have the advantage of decreasing the risk of breeding failure under high predation pressure.     

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.     

Polygyny, Partnership Concurrency, and HIV Transmission in Sub-Saharan Africa

We study the relationship between polygyny and HIV infection using nationally representative survey data with linked serostatus information from 20 African countries. Our results indicate that junior wives in polygynous unions are more likely to be HIV positive than spouses of monogamous men, but also that HIV prevalence is lower in populations with more polygyny. With these results in mind, we investigate four explanations for the contrasting individual- and ecological-level associations. These relate to (1) the adverse selection of HIV-positive women into polygynous unions, (2) the sexual network structure characteristic of polygyny, (3) the relatively low coital frequency in conjugal dyads of polygynous marriages (coital dilution), and (4) the restricted access to sexual partners for younger men in populations where polygynous men presumably monopolize the women in their community (monopolizing polygynists). We find evidence for some of these mechanisms, and together they support the proposition that polygynous marriage systems impede the spread of HIV. We relate these results to the debate about partnership concurrency as a primary behavioral driver for the fast propagation of HIV in some parts of sub-Saharan Africa.     

Socioeconomic Inequalities in Infant Mortality in Egypt: Analyzing Trends Between 1995 and 2014

This paper analyses the trend of the socioeconomic inequalities in infant mortality rates in Egypt over the period 1995–2014, using repeated cross-sectional data from the National Demographic and Health Survey. A multivariate logistic regression and concentration indices are used to examine the demographic and socioeconomic correlates of infant mortality, and how the degree of socioeconomic disparities in child mortality rates has evolved over time. We find a significant drop in infant mortality rates from 63 deaths per 1000 live births in 1995 to 22 deaths per 1000 live births in 2014. However, analyzing trends over the study period reveals no corresponding progress in narrowing the socioeconomic disparities in childhood mortality. Infant mortality rates remain higher in rural areas and among low-income families than the national average. Results show an inverse association between infant mortality rates and living standard measures, with the poor bearing the largest burden of early child mortality. Though the estimated concentration indices show a decline in the degree of socioeconomic inequality in child mortality rates over time, infant mortality rate among the poor remains twice the rate of the richest wealth quintile. Nonetheless, this decline in the degree of socioeconomic inequality in child mortality is not supported by the results of the multivariate logistic regression model. Results of the logistic model show higher odds of infant mortality among rural households, children who are twins, households with risky birth intervals. We find no statistically significant association between infant mortality and child’s sex, access to safe water, mothers’ work, and mothers’ nutritional status. Infant mortality is negatively associated with household wealth and regular health care during pregnancy. Concerted effort and targeting intervention measures are still needed to reduce the degree of socioeconomic and regional inequalities in child health, including infant mortality, in Egypt.     

Demographic transition and economic growth: Empirical evidence from Greece

Over the past decades, due to a combination of declining fertility rates and rising life expectancies, most industrialized countries have experienced aging populations and low numbers of young populations that may pose economic problems in the future. This paper investigates the relationship first between fertility rate and infant mortality rate and second among demographic changes, real wages and real output in Greece over the period 1960–96. When we control for fluctuations in overall economic activity and the labor market on the bivariate relationship between fertility and mortality rates, the evidence suggests that Granger-causation must exist in at least one direction. The results show that in the long run a decrease in infant mortality rates, taking into consideration economic performance and the labor market, causes a reduction in fertility rates. Also, employing the vector error-correction models, the variance decomposition analysis and the impulse response functions, the empirical results support the endogeneity of fertility choice to infant mortality, the labor market and the growth process. Received: 16 May 1999/Accepted: 18 September 2000     

Estimating the completeness of under-5 death registration in Egypt

To evaluate the completeness of registration of infant and child deaths in Egypt, reinterviews were conducted with families who had reported a death of a child under age 5 in the five years before the survey for two national surveys recently conducted in Egypt: the United Nations PAPCHILD survey of1990-1991 and the Egyptian Demographic and Health Survey (EDHS) of 1992. The survey instrument included questions regarding notification of the death at the local health bureau. If the family said the death had been notified, separate employees searched the health bureau records for the registration. Overall 57% of infant deaths were reported as notified and 68% of those death reports were found; the corresponding figuresfor child deaths were 89% and 74%. Using the percentage reported as notified as an estimate for completeness of registration, we adjusted upward the national infant and child mortality rates from registration data, giving values of 73 per 1,000 for infant mortality and 99 for ₅q₀ for the period 1987-1990. These values are approximately 20% above the corresponding direct estimates from the PAPCHILD and EDHS surveys.     

Birth Outcome Measures and Infant Mortality

Recent studies have proposed alternative birth outcome measures as means of assessing infant mortality risk; nevertheless, there hasn’t yet been an integrated analysis of these approaches. We review 14 strategies, including various combinations of birth weight, gestational age, fetal growth rate, and Apgar scores—as predictors of early neonatal, late neonatal, and postneonatal mortality, and infant mortality. Using the NCHS linked birth/infant death file for 2001, we construct multivariate logit models and assess the associations between each of the 14 key birth outcome measures and four mortality outcomes. We find that all evaluated birth outcome measures are strong predictors, but Apgar scores are the strongest among all models for all outcomes, independent of birth weight and gestational age. Apgar scores’ predictive power is stronger for Mexican-, white-, and female-infants than for black- and male-infants. Second, all birth outcome measures remain significantly associated with mortality, but their predictive power reduces drastically over time. These findings suggest a rule of thumb for predicting infant mortality odds: when available, Apgar scores should always be included along with birth weight (or LBW status) and gestational age. Additionally, these findings argue for the continued study of low birthweight, gestational age, and Apgar scores as independently salient health outcomes.     

The impact of breast feeding patterns on the biometric analysis of infant mortality

A major assumption of the biometric analysis of infant mortality as developed by Bourgeois-Pichat is that the age structure of infant deaths after the first month of life is virtually constant across time and cultures. Reanalysis of results from studies which compare the mortality of infants according to the type of feeding indicated that the relationship between mortality and age within the first year of life followed different patterns for breast fed and artificially fed infants. Historical data for populations with different breast feeding customs reveal similar differences in the age pattern of infant mortality. In populations where breast feeding was uncommon or of very short duration, infant mortality rises particularly steeply during the early months of the first year of life. The age structure of infant mortality in less developed countries where breast feeding is decreasing rapidly may be similarly affected. When substantial deviations from the linear relationship are evident, particular caution is required in applying the biometric technique, since in such situations the estimated endogenous mortality is very much affected by the particular set of data points within the first year of life which are chosen for the basis of the estimates.     

High-risk families: the unequal distribution of infant mortality in nineteenth-century Sweden

An analysis of infant mortality (based on 133,448 births) in two regions, Sundsvall and Skellefte?, in north-eastern Sweden during the nineteenth century shows that infant mortality was highly clustered with a relatively small number of families accounting for a large proportion of all infant deaths. Using logistic regression, two important factors were found to be associated with high-risk families: (i) a biological component evidenced by an over-representation of women who had experienced stillbirths, and (ii) a social component indicated by an increased risk among women who had remarried. The results strengthen the argument for using the family rather than the single child as the unit of analysis. The clustering of infant deaths points to the need to re-evaluate our interpretations of the causes of infant mortality in the past.     

The Effect of birth spacing on childhood mortality in Pakistan

Summary In this study retrospective data from the 1975 Pakistan Fertility Survey are used to examine the effects of birth spacing on infant and child mortality. The length of the preceding interval between live births emerges as a major determinant of mortality. The effect persists for rural and urban families, for children of uneducated and educated mothers, for both boys and girls, and for large and small families. The possibility that this relationship is the spurious consequence of data defects or of a common cause, such as early weaning, is examined but rejected. Once the length of the preceding interval is controlled, the average spacing of earlier births is found to be unrelated to survivorship. However, the length of the succeeding interval is significantly related to survivorship during the second year of life.