Erin R. Hamilton

Racial and Ethnic Disparities in Low Birthweight Among Urban Unmarried Mothers

ObjectivesWe examined racial and ethnic disparities in low birthweight (LBW) among unmarried mothers and the extent to which demographic, economic, psychosocial, health, health care, and behavioral factors explain those disparities.MethodsUsing a sample of 2,412 non-marital births from a national urban birth cohort study, we estimated multiple logistic regression models to examine disparities in LBW between non-Hispanic white (NHW), non-Hispanic black (NHB), U.S.-born Mexican-origin (USMO), and foreign-born Mexican-origin (FBMO) mothers.ResultsNHW mothers were almost as likely as NHB mothers to have LBW infants. USMO mothers had 60% lower odds and FBMO mothers had 57% lower odds than NHW mothers of having LBW infants. FBMO mothers had no advantage compared to USMO mothers. Controlling for prenatal health and behaviors substantially reduced the LBW advantages for USMO and FBMO mothers. The odds of LBW for NHB mothers relative to NHW mothers increased with the addition of the same covariates.ConclusionsRacial and ethnic disparities in LBW among unmarried mothers—an economically disadvantaged population—do not mirror those in the general population. Prenatal health and behaviors are strongly associated with LBW in this group and explain a sizable portion of the Mexican-origin advantage. The lack of a significant black-white disparity in this group suggests that poverty plays an important role in shaping racial disparities in the general population. The finding that controlling for prenatal health and behaviors widens rather than narrows the racial disparity suggests that efforts to ameliorate black-white disparities in LBW should focus on social and health risks throughout the life course.

Effects of neighborhood racial composition on birthweight

We employed multilevel models to estimate the effects of neighborhood racial composition on birthweight, using a national urban sample of 1871 births to unmarried black mothers from the Fragile Families and Child Wellbeing birth cohort study. The mothers lived in 1181 census tracts with substantial variability in racial composition and poverty. Controlling for individual characteristics, census tract poverty, and city characteristics, the proportion black in the mothers census tract had no linear association with infant birthweight. There was an observed non-linear association, but the pattern was inconsistent with prevailing theories of how neighborhoods affect health. The results were robust to alternative measures, covariates, and sample restrictions and when accounting for the length of time the mother resided in her neighborhood.

Mexican American Birthweight and Child Overweight Unraveling a Possible Early Life Course Health Transition

Mexican American children have a weight distribution that categorizes them as relatively healthy at birth but relatively unhealthy by age 3. This early life course transition in health based on weight raises the question of whether Mexican American children “outgrow” the epidemiologic paradox of favorable birth outcomes despite social disadvantage or whether their birthweight distribution places them on trajectory for overweight in childhood. We address this question using newly available 9-year follow-up data from the Fragile Families and Child Wellbeing birth cohort study linked to pre-natal medical records. We systematically investigate the roles of birthweight, pre-natal factors, and childhood factors in explaining racial/ethnic differences in childhood overweight. Our main finding is that Mexican American children do outgrow the paradox: Their rates of childhood overweight are higher than expected given their birthweight distribution. Observed pre-natal and childhood factors do not explain the elevated rates of overweight among Mexican American children.

Deporting Fathers: Involuntary Transnational Families and Intent to Remigrate among Salvadoran Deportees

One-fourth of deportees from the United States are parents of US-citizen children. We do not know how separation from families affects remigration among deportees, who face high penalties given unlawful reentry. We examined how family separation affects intent to remigrate among Salvadoran deportees. The majority of deportees with children in the United States were also separated from their spouse, and the vast majority had US-citizen children. Family separation was the single most important factor affecting intent to remigrate. We interpret these findings in light of immigration policy debates.

Two Sources of Error in Data on Migration From Mexico to the United States in Mexican Household-Based Surveys

We examine the nature and degree of two sources of error in data on migration from Mexico to the United States in Mexican household-based surveys: (1) sampling error that results when whole households migrate and no one is left behind to report their migration; and (2) reporting errors that result when migrants are not identified by survey respondents. Using data from the first two waves of the Mexican Family Life Survey, which tracked Mexican migrants to the United States from 2002 to 2005, we find that one-half of migrants from Mexico to the United States are not counted as a result of these two sources of error. Misreporting is the larger source of error, accounting for more than one-third of all migrants. Those who are not counted, especially whole-household migrants, are a unique group. Their omission results in an underestimate of female migrants, child migrants, and migrants from the Mexican border region, and an overestimate of migrants from the periphery region.

The mixed effects of migration: Community-level migration and birthweight in Mexico

Research on the relationship between migration and infant health in Mexico finds that migration has mixed impacts on the risk of low birthweight (LBW). Whereas the departure and absence of household and community members are harmful, remittances are beneficial. We extend this work by considering a different measure of infant health in addition to LBW: macrosomia (i.e., heavy birthweight), which is associated with infant, child, and maternal morbidities but has a different social risk profile from LBW. We link the 2008 and 2009 Mexican birth certificates with community data from the 2000 Mexican census to analyze the association between various dimensions of community-level migration (i.e., rates of out-migration, receipt of remittances, and return migration) and the risk of LBW and macrosomia. We examine this association using two sets of models which differ in the extent to which they account for endogeneity. We find that the health impacts of migration differ depending not only on the dimension of migration, but also on the measure of health, and that they are robust to potential sources of endogeneity. Whereas community remittances and return migration are associated with lower risk of LBW, they are associated with increased risk of macrosomia. By contrast, out-migration is associated with increased risk of LBW and lower risk of macrosomia. Our analysis of endogeneity suggests that bias resulting from unmeasured differences between communities with different levels of migration may result in an underestimate of the impacts of community migration on birthweight.

Residential Segregation in the Mexico City Metropolitan Area, 1990–2000

The concentration of poverty in large U.S. cities is an issue of great public and academic concern. Understood as the outcome of various processes, including the restructuring of the economy and loss of employment among low-skilled workers (Wilson, 1997), the movement of manufacturing firms away from the city centers (Kain, 1968), and discriminatory housing policies restricting the location of low-income minority groups, concentrated poverty in inner-cities is considered an important social problem facing many large urban centers in the United States. Neighborhood poverty has been associated with a broad range of negative social outcomes such as high school dropout rates and teenage pregnancy (Harding, 2003), adult depression (Ross, 2000), and domestic violence (Cunradi et al., 2000), among others.