Demographic models of birth outcomes and infant mortality: An alternative measurement approach

Most demographic studies use 2,500 grams of birth weight and 37 weeks of gestation as cutpoints for evaluating the effects of adverse birth outcomes on infant mortality. We propose an alternative strategy, which relies on continuous measures of birth outcomes, identifies an optimal combination of birth weight and gestational age for infant survival, and estimates the effects of adverse birth outcomes in terms of their departure from this "optimal point." We illustrate the advantages of this approach by estimating a logistic model using data from the 1989-1991 NCHS linked birth/infant death files. Finally, we discuss future applications and methodological issues to be resolved in subsequent research.     

Urban determinants of racial differentiation in infant mortality

This study relates differential socioeconomic status between blacks and whites to racial differentiation in infant mortality rates. The basic assumption is that decreases in socioeconomic differentiation and related variables lead to decreases in the black—white infant mortality differential. A comparative approach based on aggregate measures of socioeconomic differentiation is utilized to compare sixty-one United States urban places. Path analysis shows that neonatal mortality differentiation is virtually unaffected by socioeconomic differentials while decreased racial differences in hospital births tend to increase neonatal mortality differentiation. In contrast, postneonatal differentiation is affected by socioeconomic differentiation, especially along the dimensions of income, education, and regional location. It is concluded that despite some suggestions that infant mortality is no longer responsive to socioeconomic factors, postneonatal differentation is affected by socioeconomic differentials when comparison is based on city units.     

An investigation of racial and ethnic disparities in birth weight in Chicago neighborhoods

We examine differences in the mean birth weights of infants born to non-Hispanic black, non-Hispanic white, and Mexican-origin Hispanic mothers (of any race) in Chicago in 1990 using linear regression models with neighborhood fixed effects. Our pooled models accounted for 64% of the black-white difference and 57% of the black/Mexican-origin Hispanic difference. Differences in the relationship between measured characteristics and birth weight accounted for around half the birth-weight gap between non-Hispanic black and other infants. Efforts to close this gap must go beyond programs that aim to reduce the level of risk factors among black women to address the causes of differences in the effects of risk factors.     

Fertility among ethnic groups in the USSR

Thirty-six ethnie groups in the USSR are analyzed as to fertility differentials. The analysis is based on data from the 1959 nationwide census. To explain the fertility differentials found, ethnographic and sociological features of these groups are traced as a possible contributing factor. One of the poignant observations of the study is the fact that almost all ethnic groups with fertility above the median are those belonging to Moslem and Buddhist traditions. They are primarily located in the Central Asian republics, the Caucasus, and some parts of southern Siberia. Low fertility levels are by and large associated with the Eastern Orthodox Slavs and the Protestant Balts.Ratios of the number of children aged 0-9 to the number of women in the 20-49 age group are related to independent variables in the following order of importance: traditional religion, percentage of married women in the 20-49 age group, degree of literacy, male-female literacy differential, and sex ratio. The multiple correlation of 0.911 was obtained between the child-woman ratio and the first four of the most important independent variables. Sex ratio appeared significant only after the influence of the percentage of married women was eliminated from the analysis of multiple and partial correlations.The data suggest that the urban-rural differential is a non-linear function of the urban-rural migration. A more complete explanation of the divergence between urban and rural child-woman fertility ratios should be made the subject of separate studies.     

The increasing racial disparity in infant mortality: Respiratory distress syndrome and other causes

Although substantial declines in infant mortality rates have occurred across racial/ethnic groups, there has been a marked increase in relative black-white disparity in the risk of infant death over the past two decades. The objective of our analysis was to gain insight into the reasons for this growing inequality on the basis of data from linked cohort files for 1989-1990 and 1995-1998. We found a nationwide reversal from a survival advantage to a survival disadvantage for blacks with respect to respiratory distress syndrome over this period. The results are consistent with the view that the potential for a widening of the relative racial gap in infant mortality is high when innovations in health care occur in a continuing context of social inequality. As expected, the results for other causes of infant mortality, although similar, are less striking. Models of absolute change demonstrate that among low-weight births, absolute declines in mortality were greater for white infants than for black infants.     

The neighborhood context of racial and ethnic disparities in arrest

This study assesses the role of social context in explaining racial and ethnic disparities in arrest, with afocus on how distinct neighborhood contexts in which different racial and ethnic groups reside explain variations in criminal outcomes. To do so, I utilize a multilevel, longitudinal research design, combining individual-level data with contextual data from the Project on Human Development in Chicago Neighborhoods (PHDCN). Findings reveal that black youths face multiple layers of disadvantage relative to other racial and ethnic groups, and these layers work to create differences in arrest. At the family level, results show that disadvantages in the form of unstable family structures explain much of the disparities in arrest across race and ethnicity. At the neighborhood level, black youths tend to reside in areas with both significantly higher levels of concentrated poverty than other youths as well as lower levels of collective efficacy than white youths. Variations in neighborhood tolerance of deviance across groups explain little of the arrest disparities, yet tolerance of deviance does influence the frequency with which a crime ultimately ends in an arrest. Even after accounting for relevant demographic, family, and neighborhood-level predictors, substantial residual arrest differences remain between black youths and youths of other racial and ethnic groups.     

Infant mortality and birth intervals

Summary In the course of a demographic inquiry which also offered medical advice to the respondent women, information was obtained on the reproductive life and child mortality of women in three regions of Upper Volta. Foetal mortality rates are inversely correlated with fertility rates, whereas the opposite holds true of the mortality of children aged up to four years. An explanation of this phenomenon is attempted, showing how large variations in mortality rates continue to exist in developing countries. The second section of the paper deals with spontaneous abortions which happen much more frequently than is believed in Black Africa and with the effect of pathological sterility on birth intervals. Account is taken of the taboo on sexual relations after children have been born, a taboo which continues to be kept in the region studied and which as an important effect on inter-birth intervals.     

High foetal mortality and birth intervals

Abstract Studies of birth intervals have generally separated the process into: (1) the period of infertility following a pregnancy termination; (2) the length ofthe interval from the end of the infertile period to the next conception (which reflects the probability of conception), and (3) the average duration of pregnancy for both live births and foetal deaths.(1) Empirically derived intervals between successive live births average from 19 to 30 lunar months(2) (Table 1), depending upon the population studied and the birth order.(3) Estimates of conception rates using birth intervals data require some estimate of the extent to which foetal wastage increases the birth interval.     

Shifting racial hierarchies: An analysis of residential segregation among multi-racial and mono-racial groups in the United States

Multi-racial (mixed-race) people constitute a growing percentage of the United States (US) population. The study reported in this paper used residential segregation measures as a proxy for social distance, to examine whether segregation levels of multi-racial groups differ from those of mono-racial groups in the US in 2010. First, we find that all multi-racial groups considered in the study experience lower levels of segregation at county level than their mono-racial counterparts. However, black-whites and Hispanic-whites experience higher levels of segregation than other multi-racial groups. Second, we find region and minority composition of counties are associated significantly with segregation levels for multi-racial groups, but relative income is not.     

Racial differences in infant mortality by cause of death: The impact of birth weight and maternal age

This research examines racial disparities in infant mortality, overall and separately according to cause of death. Using linked birth and death records for the 1975 cohort of live births in Florida, racial differences are initially described and then explained statistically as a product of the distribution of births by birth weight and maternal age. The impact of birth weight is more pronounced than is the effect of maternal age. The analysis suggests the potential utility of examining infant mortality separately by cause of death. Based on the findings, we argue for systematic research focused on factors affecting birth weight.     

Estimating infant and childhood mortality under conditions of changing mortality

Summary It is well known that estimates of infant mortality obtained using Brass's technique are very accurate. Biases are introduced, however, when one or more of the assumptions on which it relies are violated. Departures from the assumption of constant fertility may be handled by using a variant of the technique which depends on information on the age distribution of surviving children, rather than on indexes of the fertility function. Violations of the assumption of constant mortality - an increasingly common situation in most developing societies - produce upward biases in the estimates. The amount of bias is a function of the speed of mortality decline, the characteristics of the fertility pattern and, finally, of the age of the mother. This paper presents a simple technique which corrects these biases, and in addition, generates estimates of the parameters of the mortality trend. It differs from others in that it uses a cohort definition of mortality decline and relies on knowledge of the age structure of surviving children rather than on indexes of the fertility pattern.     

The racial crossover in comorbidity, disability, and mortality

This study analyzed one respondent per household who was age 70 or more at the time of the household's inclusion in Wave 1 (1993-1994) and whose survival status was determinable at Wave 2 (1995-1996) of the Survey on Asset and Health Dynamics Among the Oldest Old (AHEAD Survey). At age 76 at Wave 1, there was a racial crossover in the cumulative number of six potentially fatal diagnoses (chronic lung disease, cancer, heart disease, hypertension, diabetes, and stroke) from a higher cumulative average number for blacks to a higher average number for whites. Also, there was a racial crossover at age 86 in the cumulative average number of disabilities in the Advanced Activities of Daily Living (AADLs), from a higher average for blacks to a higher average for whites. Between Waves 1 and 2, there was a racial crossover in the odds of mortality from higher odds for blacks to higher odds for whites; this occurred at about age 81. The results are consistent with the interpretation that the racial crossover in comorbidity (but not the crossover in AADL disability) propelled the racial crossover in mortality.     

Relationship of infant mortality and community development

A researcher applied indirect estimation techniques to data from 352 rural villages from the 1978 Republic of the Philippines Fertility Survey to determine if community factors affect mortality of children 5 years old. Children with the highest mortality risks included those of the poor and least educated parents. For example, infant and child mortality stood at 203 among mothers with no education compared to 42 among those with at least a college education. In addition, infant and child mortality among husbands who were farmers was 111 whereas it was 28 among husbands who worked in professional and clerical jobs. Low cost health services and midwives were the health factors that had the greatest effect ion the probability of survival for children 5 years old, especially among the poor and least educated. For example, the probability of dying fell from 123-80 among the poor and 152-79 among the least educated if a dispensary was accessible and from 131-88 among the poor and 154-96 among the least educated if a midwife was accessible. Furthermore, adequate nutrition, better housing conditions, safe water, and sanitation also played a key role in reducing the probability of death. In terms of community development, only accessibility to a newspaper outlet the families were. On the other hand, the presence of electricity was significant only when education of the mother, occupation of the father, and region of residence were used as control variables. Thus the government should expand health care services to the rural population. Further, it should integrate health components in social and economic development programs     

Low birth weight,social factors,and developmental outcomes among children in the United States

We used six waves of the National Longitudinal Survey of Youth-Child Data (1986-1996) to assess the relative impact of adverse birth outcomes vis-à-vis social risk factors on children's developmental outcomes. Using the Peabody Individual Achievement Tests of Mathematics and Reading Recognition as our outcome variables, we also evaluated the dynamic nature of biological and social risk factors from ages 6 to 14. We found the following: (1) birth weight is significantly related to developmental outcomes, net of important social and economic controls; (2) the effect associated with adverse birth outcomes is significantly more pronounced at very low birth weights (< 1,500 grams) than at moderately low birth weights (1,500-2,499 grams); (3) whereas the relative effect of very low-birth-weight status is large, the effect of moderately low weight status, when compared with race/ethnicity and mother's education, is small; and (4) the observed differentials between moderately low-birth-weight and normal-birth-weight children are substantially smaller among older children in comparison with younger children.     

Registration completeness and international comparisons of infant mortality

The physical development of the live born infant is the single most important variable governing its survival: infant mortality among those weighing 2,500 grams (5 1/2 pounds) or less at birth is 17 times the mortality among those weighing more than 2,500 grams at birth. The variation in mortality according to birth weight (or gestation) is greater than for subclasses of color, sex, maternal age, or birth order. Infant mortality in the United States is significantly higher than in a number of other countries e.g., Sweden, Netherlands, Norway. The difference is thought, by some, to be due to underregistration of low birth weight infants in other countries. In this paper, distributions of live births by birth weight for Denmark, England and Wales, New Zealand, and the United States, and infant mortality data for Denmark and the United States are examined. The data do not support a hypothesis of gross underregistration of live born infants in other countries. The results indicate that some index of physical development (birth weight, gestation, or a combination of both) should be included in any appraisal of infant mortality.