Racial disparities in low birthweight and the contribution of residential segregation: A multilevel analysis

This study investigates the geography of racial disparities in low birthweight in New York City by focusing on racial residential segregation and its effect on the risk of low birthweight among African-American infants and mothers. This cross-sectional multilevel analysis uses birth records at the individual level (n=96,882) and racial isolation indices at the census tract or neighborhood level (n=2095) to measure their independent and cross-level effects on low birthweight. This study found that residential segregation and neighborhood poverty operate at different scales to increase the risk of low birthweight. At the neighborhood scale residential segregation is positively and significantly associated with low birthweight, after controlling for individual-level risk factors and neighborhood poverty. Residential segregation explains neighborhood variation in low birthweight means and race effects across census tracts, which cannot be accounted for by neighborhood poverty alone. At the individual scale-increasing levels of residential segregation does not significantly reduce or exacerbate individual-level risk factors for low birthweight; whereas increasing levels of neighborhood poverty significantly eliminates the race effect and reduces the protective effect of being foreign-born on low birthweight, after controlling for other individual-level risk factors and residential segregation. These findings are contradictory to previous health research that shows protective mechanisms associated with ethnic density in local areas. It is likely that structural factors underlying residential segregation, i.e., racial isolation, impose additional stressors on African-American women that may offset or disguise positive attributes associated with ethnic density. However, as poverty is concentrated within these neighborhoods, differences between races in low birthweight cease to exist. This study demonstrates that residential segregation and neighborhood poverty are important determinants of racial disparity in low birthweight in New York City.     

Birth outcomes among urban African-American women: a multilevel analysis of the role of racial residential segregation

Residential segregation is a common aspect of the urban experiences of African-Americans in the United States (US), yet few studies have considered how segregation might influence perinatal health. Here, we develop a conceptual model of relationships between segregation and birth outcomes and test the implications of the model in a sample of 434,376 singleton births to African-American women living in 225 US Metropolitan Statistical Areas (MSAs). Data from the National Center for Health Statistics 2002 birth files were linked to data from the 2000 US Census and two distinct measures of segregation: an index of isolation (the probability that an African-American resident will encounter another African-American resident in any random neighborhood encounter) and an index of clustering (the extent to which African-Americans live in contiguous neighborhoods). Using multilevel regression models, controlling for individual- and MSA-level socioeconomic status and other covariates, we found higher isolation was associated with lower birthweight, higher rates of prematurity and higher rates of fetal growth restriction. In contrast, higher clustering was associated with more optimal outcomes. We propose that isolation reflects factors associated with segregation that are deleterious to health including poor neighborhood quality, persistent discrimination and the intra-group diffusion of harmful health behaviors. Associations with clustering may reflect factors associated with segregation that are health-promoting such as African-American political power empowerment, social support and cohesion. Declines in isolation could represent positive steps toward improving birth outcomes among African-American infants while aspects of racial contiguity appear to be mitigating or indeed beneficial. Segregation is a complex multidimensional construct with both deleterious and protective influences on birth outcomes, depending on the dimensions under consideration. Further research to understand racial/ethnic and economic health disparities could benefit from a focus on the contributory role of neighborhood attributes associated with the dimensions segregation and other social geographies.     

Mediating medical risk factors in the residential segregation and low birthweight relationship by race in New York City

This study explores mediating medical risk factors in the association between racial residential segregation (i.e., racial 'black' isolation) and low birthweight in New York City, adjusting for maternal and infant risk factors and neighborhood poverty. This race-specific cross-sectional multilevel study found that as racial isolation increased in neighborhoods, the odds of having a low birthweight infant also increased for African-American and White women living in these areas. Medical conditions that mediated the racial isolation and low birthweight relationship included chronic hypertension and pregnancy-related hypertension for African-American women and chronic hypertension and lung disease for White women. Although this study was limited by the quality of the birth certificate data, it does provide exploratory pathways by which medical risks and their sequelae are linked to neighborhood environments and reproductive vulnerability.     

Metropolitan isolation segregation and Black-White disparities in very preterm birth: a test of mediating pathways and variance explained

Residential isolation segregation (a measure of residential inter-racial exposure) has been associated with rates of preterm birth (<37 weeks gestation) experienced by Black women. Epidemiologic differences between very preterm (<32 weeks gestation) and moderately preterm births (32–36 weeks) raise questions about whether this association is similar across gestational ages, and through what pathways it might be mediated. Hierarchical Bayesian models were fit to answer three questions: is the isolation-prematurity association similar for very and moderately preterm birth; is this association mediated by maternal chronic disease, socioeconomic status, or metropolitan area crime and poverty rates; and how much of the geographic variation in Black–White very preterm birth disparities is explained by isolation segregation? Singleton births to Black and White women in 231 U.S. metropolitan statistical areas in 2000–2002 were analyzed and isolation segregation was calculated for each. We found that among Black women, isolation is associated with very preterm birth and moderately preterm birth. The association may be partially mediated by individual level socioeconomic characteristics and metropolitan level violent crime rates. There is no association between segregation and prematurity among White women. Isolation segregation explains 28% of the geographic variation in Black–White very preterm birth disparities. Our findings highlight the importance of isolation segregation for the high-burden outcome of very preterm birth, but unexplained excess risk for prematurity among Black women is substantial.     

Neighborhood influences on the association between maternal age and birthweight: a multilevel investigation of age-related disparities in health

It was hypothesized that the relationship between maternal age and infant birthweight varies significantly across neighborhoods and that such variation can be predicted by neighborhood characteristics. We analyzed 229,613 singleton births of mothers aged 20-45 years from Chicago, USA in 1997-2002. Random coefficient models were used to estimate the between-neighborhood variation in age-birthweight slopes, and both intercepts- and-slopes-as-outcomes models were used to evaluate area-level predictors of such variation. The crude maternal age-birthweight slopes for neighborhoods ranged from a decrease of 17 g to an increase of 10 g per year of maternal age. Adjustment for individual-level covariates reduced but did not eliminate this between-neighborhood variation. Concentrated poverty was a significant neighborhood-level predictor of the age-birthweight slope, explaining 44.4% of the between-neighborhood variation in slopes. Neighborhoods of higher economic disadvantage showed a more negative age-birthweight slope. The findings support the hypothesis that the relationship between maternal age and birthweight varies between neighborhoods. Indicators of neighborhood disadvantage help to explain such differences.     

A multilevel decomposition approach to estimate the role of program location and neighborhood disadvantage in racial disparities in alcohol treatment completion

Large racial disparities in completion rates from substance abuse treatment programs in urban settings remain largely unexplained, although evidence is accumulating that neighborhood conditions may influence individual substance abuse patterns and consequences. Understanding racial disparities in alcohol treatment completion, in particular, is crucial to resolving health disparities because racial/ethnic minorities bear a disproportionate burden of alcohol-related health consequences. Patient records for all non-homeless African American (N=1677), Hispanic (N=1635), and white (N=1216) alcohol outpatients, ages 18 or older, discharged during 1998-2000 from publicly funded treatment programs in Los Angeles County, the second largest system of publicly funded substance abuse treatment in the United States, were combined with census data. We tested the hypothesis that racial differences in treatment completion are related to differences in neighborhood context, particularly neighborhood-level disadvantage. Estimates from multilevel statistical models indicate that treatment neighborhood disadvantage is independently associated with treatment completion after controlling for patient characteristics and facility- and zip code-level random effects. Results of a Oaxaca decomposition of the regression estimates indicate that racial differences in treatment neighborhood disadvantage account for 32.3% of African American-white differences in treatment completion. Hispanic-white differences in completion, and the effect of home neighborhood disadvantage on completion, were non-significant. We conclude that the location of publicly funded alcohol treatment programs is related to racial disparities in treatment completion, but additional research is necessary to understand the mechanism behind this association.     

Racial disparities in the transgenerational transmission of low birthweight risk

Objective: To examine the association of maternal low birthweight (LBW) with infant LBW and infant LBW subgroups (i.e. moderate and very LBW), overall and among non-Hispanic (NH) white and NH black mothers.

Design: We conducted a population-based cohort study in Allegheny County, Pennsylvania, using linked birth record data of NH white and NH black mother-infant pairs (N?=?6,633) born in 1979–1998 and 2009–2011, respectively. The exposure of interest was maternal LBW (birthweight <2500 grams) while the outcomes were infant LBW and LBW subgroups – moderate LBW (1,500–2,499 grams) or very LBW (<1,500 grams). Logistic regression (binomial and multinomial) models were used to estimate adjusted Odds Ratios (ORs), Relative Risk Ratios (RRRs), and related 95% confidence intervals (CI). Stratified analyses were conducted to assess effect modification by mothers’ race.

Results: Maternal LBW was associated with 1.53 (95%CI: 1.15–2.02) and 1.75 (95%CI: 1.29–2.37) –fold increases in risk of infant LBW and MLBW, respectively, but not VLBW (RRR?=?0.86; 95%CI: 0.44–1.70). In race-stratified models, maternal LBW-infant LBW associations were observed among NH blacks (OR?=?1.88; 95%CI: 1.32–2.66) and not among NH whites (OR?=?1.03; 95%CI: 0.62–1.73) (P for interaction?=?0.07). Among NH blacks, maternal LBW was associated with a 2.18 (95%CI: 1.49, 3.20) –fold increase in risk of infant MLBW, but not VLBW (RRR?=?1.12; 95%CI: 0.54, 2.35). Among NH whites, LBW subgroup analyses could not be performed due to small numbers of VLBW infants among LBW mothers.

Conclusion: Mothers who were LBW at their own birth were more likely to have MLBW infants. Maternal race modified associations of maternal LBW with infant LBW, particularly infant MLBW. Further research is needed in this area to understand the potential mechanisms involved in the transgenerational transmission of LBW risk and race-specific differences in the transmission.     

Social context as an explanation for race disparities in hypertension: findings from the Exploring Health Disparities in Integrated Communities (EHDIC) Study

Disparities in hypertension between African Americans and non-Hispanic whites have been well-documented, yet an explanation for this persistent disparity remains elusive. Since African Americans and non-Hispanic white Americans tend to live in very different social environments, it is not known whether race disparities in hypertension would persist if non-Hispanic whites and African Americans were exposed to similar social environments. We compared data from the Exploring Health Disparities in Integrated Communities-SWB (EHDIC-SWB) Study with the National Health and Nutrition Examination Survey (NHANES) 1999-2004 to determine if race disparities in hypertension in the USA were attenuated in EHDIC-SWB, which is based in a racially integrated community without race differences in income. Hypertension was defined as systolic blood pressure (BP) > or = 140 mmHg (millimeters of mercury) and/or diastolic BP > or = 90 mmHg or respondent's report of taking antihypertensive medications. Of the 1408 study participants, 835 (59.3%) were African American, 628 (44.6%) were men, and the mean age was 40.6 years. After adjustment for potential confounders, various analytic models from EHDIC-SWB and NHANES 1999-2004 data, we found the race odds ratio was between 29.0% and 34% smaller in the EHDIC-SWB sample. We conclude that social and environmental exposures explained a substantial proportion of the race difference in hypertension.     

Historical redlining and food environments: A study of 102 urban areas in the United States

ObjectiveUnhealthy food environments are disproportionally concentrated in neighborhoods with clustering of racial/ethnic minorities and poverty. This disparity has been blamed, in part, on market self-regulation. This explanation risks overlooking past and current practices of racial segregation that have created and reinforced the obstacles blocking investments from food retailers in marginalized neighborhoods. We fill this gap by investigating how the long-term ramifications of redlining, discriminatory housing practices enacted by federal Home Owner Lending Corporation (HOLC) in the 1930s, has evolved generations later to disproportionally exposing neighborhoods to unhealthy food environments.MethodsWe overlaid historical redlining maps over 2010 food environment observations at the census tract level to identify areas with less healthy food environments and to assess the historical context of those areas. For 11,651 census tracts within 102 U.S. urban areas, we described the healthiness of food environments as measured by the modified retail food environment index (mRFEI). Using hurdle models with random effects, we further examined the association between redlining housing practice and food environments.ResultsThe results indicate that historically redlined neighborhoods show a higher likelihood for unhealthy retail food environments even for census tracts with present-day economic and racial privilege.ConclusionThe current evidence shows how structural discrimination manifested by unjust housing practices and racial residential segregation fueled an uneven food environment where minority neighborhoods disproportionally bore the brunt of restrictive food access. It highlights an urgent need to ameliorate patterns of housing inequality as a fix to unequal food environments.     

A multilevel analysis of race, community disadvantage, and body mass index among adults in the US

This study examined the contributions of both individual socioeconomic status (SES) and community disadvantage in explaining the higher body mass index (BMI) of black adults in the US. Data from a national survey of adults (1986 American's Changing Lives Study) were combined with tract-level community data from the 1980 census. Results of multilevel regression analyses showed that black women had an age-adjusted BMI score three points higher than non-black women. Individual SES (income, education, assets) was negatively associated with BMI in women, but it only reduced the association between race and BMI from 2.99 to 2.50. Adding community socioeconomic disadvantage index further reduced the race coefficient slightly from 2.50 to 2.21. Nevertheless, living in communities with higher socioeconomic disadvantage was associated with higher BMI net of age, race, individual SES, smoking, physical activity, stress, and social support. Community income inequality (Gini) had an independent positive association with BMI, but did not substantially reduce racial differences among women. Community percent black was not associated with BMI. Results for men demonstrated no statistically significant racial differences in BMI, and no association between BMI and either individual SES or community disadvantage. Although individual SES and community socioeconomic disadvantage each partly explained the higher average BMI among black women, clear racial disparities persisted. Moreover, race, individual SES, community socioeconomic disadvantage, and individual health behaviors were each independent predictors of BMI among women. Unexplained within- and between-community variance in BMI remained among both women and men, with most unexplained variation due to within-community variance. Because our evidence for women suggests that the determinants of obesity are multiple and multilevel, attempts to address this growing social problem will similarly require a multi-faceted and multilevel approach.     

Racial and ethnic residential segregation and access to health care in rural areas

This study examined the relationship between racial/ethnic residential segregation and access to health care in rural areas. Data from the Medical Expenditure Panel Survey were merged with the American Community Survey and the Area Health Resources Files. Segregation was operationalized using the isolation index separately for African Americans and Hispanics. Multi-level logistic regression with random intercepts estimated four outcomes. In rural areas, segregation contributed to worse access to a usual source of health care but higher reports of health care needs being met among African Americans (Adjusted Odds Ratio [AOR]: 1.42, CI: 0.96-2.10) and Hispanics (AOR: 1.25, CI: 1.05-1.49). By broadening the spatial scale of segregation beyond urban areas, findings showed the complex interaction between social and spatial factors in rural areas.     

Racial/ethnic minority segregation and low birth weight: a comparative study of Chicago and Toronto community-level indicators

We examined the association between racial/ethnic minority segregation and low birth weight (LBW) in Chicago and Toronto communities. While previous work has documented the importance of contextual effects on LBW, these studies have usually been conducted within a single city. We used Pearson correlation coefficients and OLS regression models to examine potential variability in the association between racial/ethnic minority segregation and LBW in Chicago (N = 77 communities) and Toronto (N = 140 communities). Results indicate that racial/ethnic minority segregation, unemployment, and low educational attainment are not associated with LBW in Toronto, while these indicators have strong and significant associations with LBW in Chicago. In a combined model with data from both cities, a 10% increase in minority composition is associated with a 0.5% increase in LBW, controlling for the effects of unemployment and low educational attainment. Stratified models show that this effect is only significant in Chicago, and subsequent models revealed opposite effects for percentage non-Hispanic Black and percentage Hispanic. Future research should consider additional cities for comparative analysis. Such work could test the notion that Chicago and Toronto represent opposite sides of a spectrum, reflecting variability in how social determinants map on to public health outcomes. Future research should also examine the significant heterogeneity observed in highly segregated communities, particularly in Chicago.     

Racial residential segregation: a fundamental cause of racial disparities in health

Racial residential segregation is a fundamental cause of racial disparities in health. The physical separation of the races by enforced residence in certain areas is an institutional mechanism of racism that was designed to protect whites from social interaction with blacks. Despite the absence of supportive legal statutes, the degree of residential segregation remains extremely high for most African Americans in the United States. The authors review evidence that suggests that segregation is a primary cause of racial differences in socioeconomic status (SES) by determining access to education and employment opportunities. SES in turn remains a fundamental cause of racial differences in health. Segregation also creates conditions inimical to health in the social and physical environment. The authors conclude that effective efforts to eliminate racial disparities in health must seriously confront segregation and its pervasive consequences.     

The application of intersectional multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) to examine birthweight inequities in New York City

Exploring the intersection of dimensions of social identity is critical for understanding drivers of health inequities. We used multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) to examine the intersection of age, race/ethnicity, education, and nativity status on infant birthweight among singleton births in New York City from 2012 to 2018 (N = 725,875). We found evidence of intersectional effects of various systems of oppression on birthweight inequities and identified U.S.-born Black women as having infants of lower-than-expected birthweights. The MAIHDA approach should be used to identify intersectional causes of health inequities and individuals affected most to develop policies and interventions redressing inequities.     

Neighborhood residential segregation and mental health: A multilevel analysis on Hispanic Americans in Chicago

Compared with the relationship between neighborhood-level residential segregation and physical health of Hispanic Americans, less is known about how neighborhood residential segregation affects mental health. This study examines if, and how, neighborhood residential segregation is associated with the mental health of Puerto Rican and Mexican Americans in Chicago. Multilevel analyses reveal that neighborhood residential segregation is positively associated with depressive symptoms and anxiety in both groups. Neighborhood segregation, however, has more salient effects on the mental health of Mexican Americans. For Puerto Rican Americans, the effects of neighborhood segregation on mental health become nonsignificant after controlling for neighborhood-level income and individual-level covariates, whereas neighborhood segregation is strongly associated with the mental health of Mexican Americans even after controlling for other covariates. These findings show that living in a Mexican American-dominated community is not beneficial to mental health, in contrast to findings for physical health shown in previous studies.     

Racial/ethnic minority segregation and low birth weight in five North American cities

ABSTRACT

Comparisons of communities across cities are rare in social epidemiology. Our prior work exploring racial/ethnic segregation and the prevalence of low birth weight (LBW) in communities from two large urban cities showed a strong relationship in Chicago and a very weak relationship in Toronto. This study extends that work by examining the association between racial/ethnic minority segregation and LBW in total of 307 communities in five North American cities: Baltimore, Boston, Chicago, Philadelphia, and Toronto. We used Pearson correlation coefficients and OLS regression models to examine potential variability in the association between racial/ethnic minority segregation and LBW, controlling for community-level unemployment. In a combined model with community-level data from all cities, a 10% increase in minority composition is associated with a 0.7% increase in LBW. While racial/ethnic minority segregation and unemployment are not associated with LBW in Toronto, these social determinants have strong and significant associations with LBW across communities in the four US cities in the analysis. Subsequent models revealed opposite effects for percentage non-Hispanic Black and percentage Hispanic. Across communities in the US cities in this analysis, there is considerable similarity in the strength of the effect of racial/ethnic segregation on LBW. Future work should incorporate communities from additional cities, looking to identify community assets and public policies that allow some minority communities to thrive, while other minority communities suffer from a high prevalence of LBW. More work is also needed on the generalizability of these patterns to other health outcomes.     

Metropolitan Racial Residential Segregation and Cardiovascular Mortality: Exploring Pathways

Racial residential segregation has been associated with an increased risk for heart disease and stroke deaths. However, there has been little research into the role that candidate mediating pathways may play in the relationship between segregation and heart disease or stroke deaths. In this study, we examined the relationship between metropolitan statistical area (MSA)-level segregation and heart disease and stroke mortality rates, by age and race, and also estimated the effects of various educational, economic, social, and health-care indicators (which we refer to as pathways) on this relationship. We used Poisson mixed models to assess the relationship between the isolation index in 265 U.S. MSAs and county-level (heart disease, stroke) mortality rates. All models were stratified by race (non-Hispanic black, non-Hispanic white), age group (35–64 years, ≥65 years), and cause of death (heart disease, stroke). We included each potential pathway in the model separately to evaluate its effect on the segregation–mortality association. Among blacks, segregation was positively associated with heart disease mortality rates in both age groups but only with stroke mortality rates in the older age group. Among whites, segregation was marginally associated with heart disease mortality rates in the younger age group and was positively associated with heart disease mortality rates in the older age group. Three of the potential pathways we explored attenuated relationships between segregation and mortality rates among both blacks and whites: percentage of female-headed households, percentage of residents living in poverty, and median household income. Because the percentage of female-headed households can be seen as a proxy for the extent of social disorganization, our finding that it has the greatest attenuating effect on the relationship between racial segregation and heart disease and stroke mortality rates suggests that social disorganization may play a strong role in the elevated rates of heart disease and stroke found in racially segregated metropolitan areas.     

Racial/ethnic residential segregation: framing the context of health risk and health disparities

An increasing body of public health literature links patterns of racial/ethnic residential segregation to health status and health disparities. Despite substantial new empirical work, meaningful understanding of the pathways through which segregation operates to influence health remains elusive. The literature on segregation and health was appraised with an emphasis on select conceptual, methodological, and analytical issues. Recommendations for advancing the next generation of racial/ethnic residential segregation and health research will require closer attention to sharpening the methodology of measuring segregation, testing mediating pathways and effect modification, incorporating stronger test of causality, exploring factors of resilience in segregated areas, applying a life-course perspective, broadening the scope of the investigation of segregation to include nativity status in blacks and other racial/ethnic groups, and linking segregation measures with biological data.     

Racial and social class gradients in life expectancy in contemporary California

Life expectancy, or the estimated average age of death, is among the most basic measures of a population's health. However, monitoring differences in life expectancy among sociodemographically defined populations has been challenging, at least in the United States (US), because death certification does not include collection of markers of socioeconomic status (SES). In order to understand how SES and race/ethnicity independently and jointly affected overall health in a contemporary US population, we assigned a small-area-based measure of SES to all 689,036 deaths occurring in California during a three-year period (1999–2001) overlapping the most recent US census. Residence at death was geocoded to the smallest census area available (block group) and assigned to a quintile of a multifactorial SES index. We constructed life tables using mortality rates calculated by age, sex, race/ethnicity and neighborhood SES quintile, and produced corresponding life expectancy estimates. We found a 19.6 (±0.6) year gap in life expectancy between the sociodemographic groups with the longest life expectancy (highest SES quintile of Asian females; 84.9 years) and the shortest (lowest SES quintile of African–American males; 65.3 years). A positive SES gradient in life expectancy was observed among whites and African–Americans but not Hispanics or Asians. Age-specific mortality disparities varied among groups. Race/ethnicity and neighborhood SES had substantial and independent influences on life expectancy, underscoring the importance of monitoring health outcomes simultaneously by these factors. African–American males living in the poorest 20% of California neighborhoods had life expectancy comparable to that reported for males living in developing countries. Neighborhood SES represents a readily-available metric for ongoing surveillance of health disparities in the US.     

Racial residential segregation,racial discrimination,and diabetes: The Coronary Artery Risk Development in Young Adults study

Although racial residential segregation and interpersonal racial discrimination are associated with cardiovascular disease, few studies have examined their link with diabetes risk or management. We used longitudinal data from 2,175 black participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study to examine associations of racial residential segregation (G_i* statistic) and experiences of racial discrimination with diabetes incidence and management. Multivariable Cox models estimated associations for incident diabetes and GEE logistic regression estimated associations with diabetes management (meeting targets for HbA1c, systolic blood pressure, and LDL cholesterol). Neither segregation nor discrimination were associated with diabetes incidence or management.