Malaria ecology,child mortality & fertility

The broad determinants of fertility are thought to be reasonably well identified by demographers, though the detailed quantitative drivers of fertility levels and changes are less well understood. This paper uses a novel ecological index of malaria transmission to study the effect of child mortality on fertility. We find that temporal variation in the ecology of the disease is well-correlated to mortality, and pernicious malaria conditions lead to higher fertility rates. We then argue that most of this effect occurs through child mortality, and estimate the effect of child mortality changes on fertility. Our findings add to the literature on disease and fertility, and contribute to the suggestive evidence that child mortality reductions have a causal effect on fertility changes.     

Causes and consequences of increase in child survival rates: ethnoepidemiology among the Hmong of Thailand.

The Hmong "hill tribe" minority in Thailand has much higher exposure to factors usually associated with risk of child mortality (high fertility, low status of women, low education, less use of modern medical care for births, exposure to warfare, economic and physical disruption, and poor hygienic conditions) than the rural ethnic Thai population. Nonetheless, infant mortality has declined from over 120 per 1000 to under 50 per 1000 live births among both these populations in the past 30 years. The reason for the rapid increase in child survival among the Hmong appears to be better access to and more use of modern curative and preventive medical care associated with road construction rather than major changes in social or hygienic conditions. Conventional wisdom suggests that high fertility is both a cause and a consequence of high infant and child mortality and that parents will not reduce fertility until they see that mortality has declined. Most Hmong parents recognize the decline in child mortality and attribute it to better access to modern medical care. Most Hmong parents also say that, if they were starting to have children now, they would want to have fewer children. Fear of child death is infrequently mentioned as a motive for having more children, and the perceived decline in child mortality is rarely mentioned as a reason for reduced fertility. Most Hmong parents explain their desired family size in terms of economic conditions rather than perceived risk of child mortality. Results of this study suggest that fertility and child mortality can vary independently of one another and that major reductions in child mortality can be accomplished without waiting for major social changes (e.g., improved education or status of women) or major reductions in fertility.     

The life-history trade-off between fertility and child survival

Evolutionary models of human reproduction argue that variation in fertility can be understood as the local optimization of a life-history trade-off between offspring quantity and ‘quality’. Child survival is a fundamental dimension of quality in these models as early-life mortality represents a crucial selective bottleneck in human evolution. This perspective is well-rehearsed, but current literature presents mixed evidence for a trade-off between fertility and child survival, and little empirical ground to evaluate how socioecological and individual characteristics influence the benefits of fertility limitation. By compiling demographic survey data, we demonstrate robust negative relationships between fertility and child survival across 27 sub-Saharan African countries. Our analyses suggest this relationship is primarily accounted for by offspring competition for parental investment, rather than by reverse causal mechanisms. We also find that the trade-off increases in relative magnitude as national mortality declines and maternal somatic (height) and extrasomatic (education) capital increase. This supports the idea that socioeconomic development, and associated reductions in extrinsic child mortality, favour reduced fertility by increasing the relative returns to parental investment. Observed fertility, however, falls considerably short of predicted optima for maximizing total offspring survivorship, strongly suggesting that additional unmeasured costs of reproduction ultimately constrain the evolution of human family size.     

The delineation of fertility strategies in a tribal population of India: the Koyas of Koraput District,Orissa

Demographic data collected for a tribal population of India, the Koyas of Koraput District, Orissa, were examined in light of 2 models of reproductive behavior associated with the economic value of children: the replacement effect and son survivorship motivation. Both models are united in the concept that infant/child mortality affects subsequent fertility. The database consists of retrospective fertility histories of Koya women who had completed their reproductive period. The total number was 260, with the total offspring numbering 1407. 2 distinct cohorts of women were formed for the purpose of analysis, separated only by the criterion of offspring survival: women who had experienced infant child mortality (129 women with 739 children); and women who completed their reproductive period without suffering offspring loss of this nature (132 women with 668 children). The cohort without child loss had a mean parity of 5.10, lower than the average parity of 5.73 recorded for the cohort whose reproductive histories included at least 1 infant/child death. Age specific marital fertility and birth interval analyses indicated that this differential was because of biological, not behavioral, factors. The age pattern of fertility of females suffering offspring mortality failed to demonstrate a high rate of childbearing in the later age intervals of the reproductive period, a characteristic pattern of couples attempting to "replace" lost offspring. Birth interval analysis pointed to biological "interval effect," whereby infant/child mortality caused a cessation of lactation and hence a shortening of postpartum amenorrhea. Computer simulation further indicated that the higher fertility differential of the cohort experiencing offspring loss still did not result in high son survivorship values. The findings agree with earlier studies indicating that for predemographic transitional populations, economically motivated fertility strategies are ineffectual.     

Determinants of infant and child mortality in the West Bank and Gaza Strip

Infant and child mortality in the West Bank and Gaza Strip has steadily reduced since 1967, even though fertility has remained extremely high. In this paper the determinants of infant and child mortality are discussed, with particular emphasis on the role of consanguineous marriages, short birth spacing and maternal education. It is shown that short birth spacings and type of marriage are more important determinants of infant mortality than maternal education. Moreover, the relative role of consanguineous marriages appears to increase with time.     

Child mortality, social status, and fertility in India

The incidence of child mortality in relation to the social status and fertility of Indian women was investigated on the assumptions that: 1) the higher the social status, the lower the child mortality rate; and 2) the lower the child mortality rate, the lower the family size. 311 married women in Chandigarh were grouped into 4 status categories: (1) higher educated working women (95); (2) higher educated nonworking women (75); (3) less educated nonworking women (75); and (4) less educated working women (66). The 311 women gave birth to a total of 1075 children (960 living and 115 who had died, mostly between the ages 0-5 years). Percentage of children living (89%) was different for each status category: 93% for category 1; 92% for category 2; 91% for category 3; and 81% for category 4. When analyzed by proportion of women who had lost children in each status category, the relationship between child mortality and social status confirmed the assumption that the higher the social status, the lower the mortality. In category 1, 87% had not experienced any child mortality in their family; in category 2, the figure was 77%; category 3, 72%; and category 4, 48%. The findings also confirmed the other assumption that the lower the mortality rate, the lower the fertility (Table 2).     

Determinants of infant mortality and representation in bioarchaeological samples: A review

In bioarchaeological contexts, a complex relationship exists between infant representation in the age-at-death distribution, gestational and young child mortality rates, and the total fertility rate. The representation of infants in a skeletal sample may be influenced by a range of social, biological, and archaeological factors. To better understand the interactions between representation, fertility, and mortality, this study evaluates the relationship between infant-juvenile age-at-death proportions, fertility rates, and a range of gestational and early childhood mortality measures. The statistical component of this study found the correlation between fertility rates and infant-juvenile proportions was stronger than with any mortality rate variable of interest. This suggests that the proportion of infants in a mortuary sample is a stronger indicator of fertility than it is of infant-juvenile mortality. Social, biological, and archaeological variables potentially influencing infant representation in skeletal samples are discussed and a strongly contextualized and holistic approach to infant and juvenile mortality is recommended.     

Demographic contexts and the adaptive role of mother-infant attachment

Currently much debate surrounds the significance of cross-cultural variation in mother-infant attachment. Is only one form of attachment “healthy,” or are different types of attachment adaptations to local socioecological conditions? Juvenile mortality rates have been promoted as important features of local environments that shape attachment, which in turn affects later reproductive strategies. To this we add fertility. Fertility changes the environment of a child by influencing the number of potential caregivers and competitors for care, and the cultural ethos regarding the rights of children. Different combinations of fertility and mortality will likely give rise to different attachment forms, and only under one regime (low fertility and mortality) do we expect exclusivity in attachment.     

Estimation of fertility and mortality of the Kuwaiti population

Indirect techniques are applied to estimate the current level of fertility and mortality among Kuwaiti nationals in Kuwait during 1980-85. The various methods discussed provide estimates in the vicinity of 45 per thousand for birth rate and 8 per thousand for death rate. While child spacing by birth order in Kuwait is about 2 years, the proportion of childlessness is very low (1%). As a consequence of lower mortality and stable high fertility, the Kuwaiti population remains young.     

Determinants of fertility in Nepal: applications of an aggregate model

Bongaarts aggregate model of the proximate determinants of fertility is applied to data from the 1976 National Fertility Survey in Nepal. Breastfeeding is shown to be the most important limiting factor, resulting in a reduction of about 6 children per woman. Decline in the duration of breastfeeding by 1/4 would increase fertility by 1 additional child per woman. The temporary separation of spouses due to migration is conjectured to be the 2nd most important fertility inhibiting factor, not explicitly accounted for in the standard model. Results are presented for the 3 major ecological regions, urban-rural residence and educational attainment of women. High nuptiality and virtually no contraceptive use in Nepal produce age-specific fertility rates very close to a natural fertility pattern. Total average interval between births is 36 months; about 18 months are solely due to breastfeeding, the remaining months to combined effects of gestation, waiting time to conception, intrauterine mortality and post-partum infecundability. As urbanization increases and pace of modernization becomes more pronounced, the duration of breastfeeding is susceptible to decline.     

Sex differentials in infant and child mortality in Korea

This paper reports on a study of infant and child mortality in the Republic of Korea, a country known for a strong son preference, using the 1974 World Fertility Survey data. When the age-specific probabilities of dying for ages 0 to 5 are compared for male and female children, an unusual pattern of relatively high female mortality is observed. The higher female mortality is more pronounced during childhood than during infancy. Multivariate analysis of life tables, using a hazard model, shows that covariates influencing the mortality at young ages differ for male and female children and suggests that male and female children receive unequal care by their parents. The analysis also reveals different patterns of interaction between infant and child mortality and mother's fertility control behavior depending on the sex of the child.     

Effect of infant mortality on subsequent fertility in Pakistan and Sri Lanka

This study used data from the 1975 World Fertility Surveys in Pakistan and Sri Lanka to examine the association between fertility and infant mortality. A positive association between the mean number of children ever born and the number of child deaths was found in both rural and urban areas of each country. In Pakistan, women with no child loss had 3.3 children ever born while those who lost 1 child had 4.7 children; in Sri Lanka the figures were 3.5 and 5.4 children, respectively. However, child replacement was much less marked when controls were introduced for demographic and socioeconomic factors. When deaths at specific parities were examined, and age and time since previous birth were controlled, child replacement at the 1st parity was reduced to .3 in Pakistan and .2 in Sri Lanka. Further control for a series of socioeconomic factors (e.g. husband's level of education, husband's occupation, household structure, religion, standard of living) reduced the child replacement ratio to .2 children in Pakistan and zero in Sri Lanka. Replacement was slightly more pronounced when there were fewer surviving male children. This analysis suggests that the relationship between infant mortality and fertility is complex. A possibility that could not be explored in this study is that variation in fertilitty may itself be responsible for some of the variation in infant mortality.     

Sex differentials in infant and child mortality in Korea

Abstract

This paper reports on a study of infant and child mortality in the Republic of Korea, a country known for a strong son preference, using the 1974 World Fertility Survey data. When the age‐specific probabilities of dying for ages zero to five are compared for male and female children, an unusual pattern of relatively high female mortality is observed. The higher female mortality is more pronounced during childhood than during infancy. Multivariate analysis of life tables, using a hazard model, shows that covariates influencing the mortality at young ages differ for male and female children and suggests that male and female children receive unequal care by their parents. The analysis also reveals different patterns of interaction between infant and child mortality and mother's fertility control behavior depending on the sex of the child.     

Demography and childcare in preindustrial societies

The preliminary comparison of hunter gatherers, horticulturalists, and pastoralists is based on 57 preindustrial populations with demographic and child care data out of a potential of 1264 documented cultures from the Ethnographic Atlas. The purpose of this effort is to demonstrate that the demographic characteristics of a population influence its child care practices and provides clues to understanding child care patterns. Traditional practices and provides clues to understanding child care patterns. Traditional practices including multiple caregiving, multistage play groups, and parents or siblings as cultural transmitters are reviewed in a demographic context. Other emerging practices are also discussed: the role of stepparents and differential parental investment in sons and daughters. Anthropological data published and unpublished included only those using standardized methods on total fertility, infant or child mortality, and/or sex/age distribution. Problems with the data set include limited cultural representation, small study sizes, limited time trends, and reliability. There is a concentration on the ]Kung San, Efe, Aka, Gidjingali, Yanomamo, Dusan, Semai, and Kipsigis. Only 7 of the 57 are outside the tropics. Foragers are farmers are primarily represented, because the pastoralists are primarily East African and smaller samples. Tables provide cultural specific data on total fertility rates (TRF), infant and child mortality, and sex ratios at birth and among the juvenile and adult population. Sections are devoted to methods, general patterns, traditional characteristics of childcare based on 5 hypotheses, and emergent trends with 2 more hypotheses on stepparenting and male preference. 2 patterns prevail: 1) hunter gatherers and horticulturalists/pastoralists show great intercultural variability in fertility and mortality rates, and 2) the ranges and means of both groups are very similiar. In the discussion of specific cultures, the hypothesis is proposed and then examples are drawn from the 57 studies to provide support or rejection of the hypothesis. The 1st postulated that the level of multiple care increases with the number of adult women without children increasing. The 2nd hypothesis is that the greater the density or compactness of the settlement, the greater the level of multiple care. It is reasoned in the 3rd that fertility and mortality patterns influence the nature of indulgent care of infants. The 4th hypothesis is that sex and age distributions and compactness of the camp influence the nature of the play ground and type of supervision. The 5th is that father involvement will be greater in societies with low population densities or isolated. The 6th is that a child rarely stays with natural parents throughout the dependency period. The 7th is that male biased juvenile sex ratios will exist in societies where the cost of raising males is or = that of raising families, or where males contribute more calories to the diet, or where male mortality is high.     

A phylogenetic analysis of the relationship between sub-adult mortality and mode of subsistence

The hypothesis that measures of sub-adult mortality rates in natural fertility populations are associated with subsistence practices in a selected cross-cultural sample (n = 39) was tested. After controlling for both distance from the equator and the general likelihood of cultural similarities between genetically closely related cultures using phylogenetic comparative methods, it was found that dependence on extractive modes of subsistence (hunting, gathering and fishing) was a significant positive correlated of total child mortality (15q0). Both increases in dependence on foraging and permanent settlement were associated with increases in child mortality between pairs of historically related cultures. The results indicated little association between infant mortality (1q0) and either dependence on foraging or settlement.     

Consanguinity, fertility of couples and mortality of children in the high Atlas population (commons of Anougal and Azgour, Marrakesh, Morroco)

This study analyses the relationship between consanguinity, fertility and child mortality in a rural population of two moroccan High-Atlas valleys. Among this very endogamous population, we have reconstituted, by inquiries, for each family, the totality of its reproductive life as well as the genealogic relationships that exist between the spouses on several generations. The analysis carried out on the group of families with women who are over 40 years old (438 families) has shown that the population was very strong related (28% of marriages are consanguineaous). A positive association between levels of fertility, infant mortality and consanguinity was observed.     

Did food increase fertility? Evaluation of !Kung and Herero history.

Low fertility among nomadic !Kung foragers of the northern Kalahari Desert of Botswana has been hypothesized to be an adaptation to scarcity of food. However, a comparison of !Kung fertility before and after a transition to a more sedentary lifestyle indicates that more food did not increase fertility. An examination of the fertility of neighboring sedentary Bantu-speaking Herero pastoralists during the same period also indicates that low female reproductive rates in this region are not unique to the !Kung. Herero fertility has increased dramatically in recent decades, probably in response to the control of sexually transmitted diseases in northwestern Botswana. More food appears to have substantially increased !Kung reproductive success by reducing infant and child mortality rates to levels observed among the Herero. These findings suggest that low !Kung fertility and mortality reflect contact with the Herero, who began expanding in large numbers into !Kung territory in the 1950s. This study emphasizes the need for a more rigorous comparative perspective in anthropology to understand better the significance of findings from restricted populations, and I suggest that evolutionary ecology would benefit from shifting some of its current focus on fertility to mortality.     

Human population growth and the demographic transition

The world and most regions and countries are experiencing unprecedentedly rapid demographic change. The most obvious example of this change is the huge expansion of human numbers: four billion have been added since 1950. Projections for the next half century expect a highly divergent world, with stagnation or potential decline in parts of the developed world and continued rapid growth in the least developed regions. Other demographic processes are also undergoing extraordinary change: women''s fertility has dropped rapidly and life expectancy has risen to new highs. Past trends in fertility and mortality have led to very young populations in high fertility countries in the developing world and to increasingly older populations in the developed world. Contemporary societies are now at very different stages of their demographic transitions. This paper summarizes key trends in population size, fertility and mortality, and age structures during these transitions. The focus is on the century from 1950 to 2050, which covers the period of most rapid global demographic transformation.     

Social class and fertility in metropolitan Madras

Abstract

Interviews were conducted with a random sample of 463 couples in metropolitan Madras. From these data, social class, as measured by the respondent's self‐identification, is found to be inversely correlated with the fertility and child mortality experienced by women in unbroken marriages. These class differences in fertility are not explained either by their rates of sterility or their variations in duration of marriage, i.e., exposure to the risks of conception.     

Infant and child mortality in India in the last two decades: a geospatial analysis

BACKGROUND: Studies examining the intricate interplay between poverty, female literacy, child malnutrition, and child mortality are rare in demographic literature. Given the recent focus on Millennium Development Goals 4 (child survival) and 5 (maternal health), we explored whether the geographic regions that were underprivileged in terms of wealth, female literacy, child nutrition, or safe delivery were also grappling with the elevated risk of child mortality; whether there were any spatial outliers; whether these relationships have undergone any significant change over historical time periods. METHODOLOGY: The present paper attempted to investigate these critical questions using data from household surveys like NFHS 1992-1993, NFHS 1998-1999 and DLHS 2002-2004. For the first time, we employed geo-spatial techniques like Moran's-I, univariate LISA, bivariate LISA, spatial error regression, and spatiotemporal regression to address the research problem. For carrying out the geospatial analysis, we classified India into 76 natural regions based on the agro-climatic scheme proposed by Bhat and Zavier (1999) following the Census of India Study and all estimates were generated for each of the geographic regions. RESULT/CONCLUSIONS: This study brings out the stark intra-state and inter-regional disparities in infant and under-five mortality in India over the past two decades. It further reveals, for the first time, that geographic regions that were underprivileged in child nutrition or wealth or female literacy were also likely to be disadvantaged in terms of infant and child survival irrespective of the state to which they belong. While the role of economic status in explaining child malnutrition and child survival has weakened, the effect of mother's education has actually become stronger over time.