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.     

Compromised birth outcomes and infant mortality among racial and ethnic groups

Demography - Research based on hospital records demonstrates that many births classified as normal according to conventional demographic measurement are intrauterine growth-retarded (IUGR) when...     

Birth outcome, not pregnancy process: Reply to van der Veen

In a recent article (Frisbie. Forbes. and Pullum 1996) we documented racial/ethnic differences in birth outcomes according to a more fine-grained classification than has typically been employed in the demographic literature. In his commentary, van der Veen focuses on the measurement of one of the dimensions of that classification, maturity of the infant. as proxied by the fetal growth ratio. The crux of the critique is easily seen in van der Veen's statement that “all of my disagreements with Frisbie et al. 's method arise from their particular use of a postnatal standard for the assessment of intrauterine growth.” Our critic misunderstands our objective: He fails to realize our interest in birth outcome, not pregnancy process, and does not perceive that our intent was to extend the research extant in both the demographic and public-health literatures in which patently postnatal (i.e., ex utero) measures are taken as outcomes interesting in their own right and/or as risk factors for infant mortality and infant and childhood morbidity. Specifically, he does recognize that we purposefully expanded our focus to include moderately compromised births to determine if they were at higher risk than the normal births with whom they are conventionally categorized. Our discussion draws on research cited in the original article, on studies cited by our critic, and on a few more recent investigations. Although we have never argued that ours is the only, or even the best, approach in all cases, we try to clarify the rationale for, and adduce additional empirical evidence of, the utility of the method we used.     

Potential labor force supply and replacement in Mexico and the states of the Mexican Cession and Texas: 1980-2000

"The purpose of this article is to carry forward the examination of potential labor force supply and replacement of men in Mexico into the 1980-1990 and 1990-2000 decades so that the possible future course of international migration between that country and the United States may be better anticipated. In addition, to provide a degree of developmental perspective, trends in potential labor force supply and replacement in Mexico since 1930-40 are presented." As a contrast, "ratios of potential labor force supply and replacement in the southwestern United States--the states of the Mexican Cession and Texas, which were formerly part of Mexico--also are shown for the 1980-1990 and 1990-2000 intervals." The results suggest that "in Mexico, the projected number of males entering the labor force ages will be about 48 percent larger in the 1980s than in the 1970s.... Fertility declined significantly in Mexico in the 1970s, and therefore the number of new entrants to the labor force ages in the 1990s will decline...." The implications for international migration between Mexico and the United States are considered.     

The sociodemographic characteristics of Mexican immigrant status groups: implications for studying undocumented Mexicans

"Based on Warren and Passel's...estimate that nearly two-thirds of Mexican-born noncitizens entering the U.S. during 1975-80 and included in the 1980 Census are undocumented immigrants, this article uses the 1980 Public Use Microfiles to delineate four Mexican origin immigrant status groups--post 1975 Mexican-born noncitizens, pre-1975 Mexican-born noncitizens, self-reported naturalized citizens, and native-born Mexican-Americans." It is found that "the pattern of sociodemographic differences among these groups provides support for the idea that the first two categories contain a substantial fraction of undocumented immigrants. These two groups (especially the first) reveal characteristics that one would logically associate with undocumented immigrants--age concentration (in young adult years), high sex ratios, low education and income levels, and lack of English proficiency."     

Spanish Surname and Anglo Infant Mortality: Differentials Over a Half-Century

Using a half-century of death records from San Antonio/Bexar County, Texas, we examine the timing and cause structure of Spanish surname and Anglo infant mortality. Our findings show that despite the substantial disparities between ethnic-specific infant mortality rates in the early years of the study, there have been consistent declines in overall, neonatal, and postneonatal mortality for both groups, as well as a major convergence of mortality rates between Spanish surname and Anglo infants. Further, we demonstrate that the convergence is of relatively recent origin and is due primarily to shifts in postneonatal mortality. Finally, we examine the transition reflected in the cause structure of ethnic-specific infant mortality and show that the convergence was largely the result of reductions in deaths from exogenous causes. Implications for research into the "epidemiologic paradox" are discussed.     

“Understanding” as Support for Emerging Adults Whose Parents Have Chronic Health Conditions: A Life-Span Communication Perspective

To better understand the “chronic burden of care” in the United States, we focused on an underrepresented demographic of youth caregivers in families, emerging adults (EAs). EAs are a newly recognized population of youth, 18–25 years of age, who are developmentally between adolescence and young adulthood. Guided by the life span communication perspective, we interviewed 98 EAs (30 males and 68 females, M age = 19.09, SD = 1.72) about their experiences providing support to a parent with a chronic health condition. Many EAs in this study said they provided “understanding” and our interpretive thematic analyses uncovered two broad meanings of the word: it is a form of support that EAs both have and communicate. When EAs have understanding, they have knowledge about the health condition and how it affects their parent. They also have acceptance to some degree that the health condition is a fixture of their lives and that their parents are imperfect and fallible people. They communicate the understanding they have through reciprocating support, sacrificing, being obedient, avoiding sensitive topics, and projecting emotional strength. We discuss the findings and their implications for emerging adult development as well as parent-child relational development parallel to difficult long-term health issues in families.     

Race/Ethnicity/Nativity Differentials and Changes in Cause-Specific Infant Deaths in the Context of Declining Infant Mortality in the U.S.: 1989–2001

Using data from the national linked birth/infant death cohort files, we examined race/ethnicity/nativity disparities and changes in infant mortality due to the five leading causes of infant death between 1989 and 2001. Our results indicate substantial decreases in infant mortality from three causes (congenital anomalies, sudden infant death syndrome, and respiratory distress syndrome) for which specific perinatal health innovations emerged or were expanded. However, for these three causes, the relative disparities in infant mortality between infants born to U.S.-born black women as compared to infants of U.S.-born white women increased following the introduction (or expansion) of beneficial interventions. Among infants of U.S.-born Mexican American mothers, the findings differed. In the static comparisons, our results show the often-reported similarity in the risk of death of these babies compared to those born to non-Hispanic white mothers. However, when changes over time were modeled, there was an erosion of the relatively favorable survival chances of Mexican American infants. Our models show little change in the relative risk of death for infants of immigrant women. Regarding the other two causes (disorders relating to short gestation and unspecified low birth weight and maternal complications) for which no efficacious innovations occurred, either little change or actual increases in risks were observed. Future studies and health policy efforts should be geared toward further understanding and aggressively working to close infant mortality gaps, especially for infants of U.S.-born black mothers—an effort that will be facilitated by research focused on cause-specific infant mortality.