Ethnic density and preterm birth in African-, Caribbean-, and US-born non-Hispanic black populations in New York City

Risk of Adverse Perinatal Outcomes Among African-born Black Women in California, 2011-2020

BACKGROUND

African-born women have a lower risk of preterm birth and small for gestational age (SGA) birth compared with United States-born Black women, however variation by country of origin is overlooked. Additionally, the extent that nativity disparities in adverse perinatal outcomes to Black women are explained by individual-level factors remains unclear.

METHODS

We conducted a population-based study of nonanomalous singleton live births to United States- and African-born Black women in California from 2011 to 2020 (n = 194,320). We used age-adjusted Poisson regression models to estimate the risk of preterm birth and SGA and reported risk ratios (RR) and 95% confidence intervals (CI). Decomposition using Monte Carlo integration of the g-formula computed the percentage of disparities in adverse outcomes between United States- and African-born women explained by individual-level factors.

RESULTS

Eritrean women (RR = 0.4; 95% CI = 0.3, 0.5) had the largest differences in risk of preterm birth and Cameroonian women (RR = 0.5; 95% CI = 0.3, 0.6) in SGA birth, compared with United States-born Black women. Ghanaian women had smaller differences in risk of preterm birth (RR = 0.8; 95% CI = 0.7, 1.0) and SGA (RR = 0.9; 95% CI = 0.8, 1.1) compared with United States-born women. Overall, we estimate that absolute differences in socio-demographic and clinical factors contributed to 32% of nativity-based disparities in the risk of preterm birth and 26% of disparities in SGA.

CONCLUSIONS

We observed heterogeneity in risk of adverse perinatal outcomes for African- compared with United States-born Black women, suggesting that nativity disparities in adverse perinatal outcomes were not fully explained by differences in individual-level factors.

African immigrants' favorable preterm birth rates challenge genetic etiology of the Black-White disparity in preterm birth

Background

We examined over a million California birth records for 2010 through 2021 to investigate whether disparities in preterm birth (PTB) by nativity and race support the widely held but hitherto unsubstantiated belief that genetic differences explain the persistent Black-White disparity in PTB.

Methods

We examined PTB rates and risk ratios among African-, Caribbean-, and U.S.-born Black women compared to U.S.-born White women. Multivariate analyses adjusted for maternal age, education, number of live births, delivery payer, trimester of prenatal care initiation, pre-pregnancy BMI, smoking, and prevalence of poverty in a woman's residence census tract; and for paternal education.

Results

In adjusted analyses, African-born Black women's PTB rates were no different from those of U.S.-born White women.

Discussion

The results add to prior evidence making a genetic etiology for the racial disparity in PTB unlikely. If genetic differences tied to "race" explained the Black-White disparity in PTB among U.S.-born women, the African immigrants in this study would have had higher rates of PTB, not the lower rates observed. Multiple explanations for the observed patterns and their implications are discussed. Failure to distinguish causes of PTB from causes of the racial disparity in PTB have likely contributed to erroneous attribution of the racial disparity to genetic differences. Based on the literature, unmeasured experiences of racism, including racism-related stress and adverse environmental exposures, are plausible explanations for the PTB disparity between Black and White U.S.-born women. The favorable birth outcomes of African-born Black immigrants may reflect less exposure to racism during sensitive life periods, e.g., childhood, when they were in African countries, where Black people are in the racial majority.

Structural racism, nativity and risk of adverse perinatal outcomes among Black women

BACKGROUND

Black women in the United States (US) have the highest risk of preterm birth (PTB) and small for gestational age (SGA) births, compared to women of other racial groups. Among Black women, there are disparities by nativity whereby foreign-born women have a lower risk of PTB and SGA compared to US-born women. Differential exposure to racism may confer nativity-based differences in adverse perinatal outcomes between US- and foreign-born Black women. This remains unexplored among US- and African-born women in California.

OBJECTIVES

Evaluate the relationship between structural racism, nativity, PTB and SGA among US- and African-born Black women in California.

METHODS

We conducted a population-based study of singleton births to US- and African-born Black women in California from 2011 to 2017 (n = 131,424). We examined the risk of PTB and SGA by nativity and neighbourhoods with differing levels of structural racism, as measured by the Index of Concentration at the Extremes. We fit crude and age-adjusted Poisson regression models, estimated using generalized estimating equations, with risk ratios (RR) and 95% confidence intervals (CI) as the effect measure.

RESULTS

The proportions of PTB and SGA were 9.7% and 14.5%, respectively, for US-born women, while 5.6% and 8.3% for African-born women. US-born women (n = 24,782; 20.8%) were more likely to live in neighbourhoods with high structural racism compared to African-born women (n = 1474; 11.6%). Structural racism was associated with an elevated risk of PTB (RR 1.19, 95% CI 1.12, 1.26) and SGA (RR 1.19, 95% CI 1.13, 1.25) for all Black women, however, there was heterogeneity by nativity, with US-born women experiencing a higher magnitude of effect than African-born women.

CONCLUSIONS

Among Black women in California, exposure to structural racism and the impacts of structural racism on the risk of PTB and SGA varied by nativity.

Transition in vaginal Lactobacillus species during pregnancy and prediction of preterm birth in Korean women

The predominance of vaginal Lactobacillus species, specifically L. crispatus, is important for pregnancy maintenance, but varies by race. The composition of the vaginal microbiome can affect susceptibility to adverse pregnancy outcomes. We performed 16S rRNA gene amplicon sequencing on vaginal swabs taken from Korean pregnant women. Here, we report the transition of Lactobacillus spp. in samples of full-term birth (FTB) collected longitudinally in the second and third trimesters of pregnancy in a cohort study (n = 23) and their association with Lactobacillus abundance and preterm birth (PTB) in a case-control study (n = 200). Lactobacillus species, which was dominant in FTB samples including those that received interventions in the second trimester, did not change until 37 weeks of gestation. However, L. crispatus was replaced by other Lactobacillus species after 37 weeks. The PTB risk showed a closer association with the Lactobacillus abundance than with community state type determined by Lactobacillus species. PTB was associated with less than 90% of Lactobacillus abundance and an increase in Ureplasma parvum in the second trimester. Thus, the vaginal microbiome may change in preparation for childbirth in response to multiple intrinsic factors after 37 weeks of gestation. Monitoring the Lactobacillus abundance may help improve the reliability of microbial PTB biomarkers.

A Comprehensive Review on Social Inequalities and Pregnancy Outcome-Identification of Relevant Pathways and Mechanisms

Scientific literature tends to support the idea that the pregnancy and health status of fetuses and newborns can be affected by maternal, parental, and contextual characteristics. In addition, a growing body of evidence reports that social determinants, measured at individual and/or aggregated level(s), play a crucial role in fetal and newborn health. Numerous studies have found social factors (including maternal age and education, marital status, pregnancy intention, and socioeconomic status) to be linked to poor birth outcomes. Several have also suggested that beyond individual and contextual social characteristics, living environment and conditions (or "neighborhood") emerge as important determinants in health inequalities, particularly for pregnant women. Using a comprehensive review, we present a conceptual framework based on the work of both the Commission on Social Determinants of Health and the World Health Organization (WHO), aimed at describing the various pathways through which social characteristics can affect both pregnancy and fetal health, with a focus on the structural social determinants (such as socioeconomic and political context) that influence social position, as well as on intermediary determinants. We also suggest that social position may influence more specific intermediary health determinants; individuals may, on the basis of their social position, experience differences in environmental exposure and vulnerability to health-compromising living conditions. Our model highlights the fact that adverse birth outcomes, which inevitably lead to health inequity, may, in turn, affect the individual social position. In order to address both the inequalities that begin in utero and the disparities observed at birth, it is important for interventions to target various unhealthy behaviors and psychosocial conditions in early pregnancy. Health policy must, then, support: (i) midwifery availability and accessibility and (ii) enhanced multidisciplinary support for deprived pregnant women.

Adverse birth outcomes in New York City women: Revisiting the Hispanic Paradox

In the United States, African American or non-Hispanic Black infants experienced worst birth outcomes whereas Hispanic and Asian infants have intermediate or similar outcomes compared with non-Hispanic white infants. The findings of better birth outcomes for Hispanic women have been coined the "Hispanic Paradox" given their low education, income, and access to care. New York City (NYC) has a great racial/ethnic diversity with implications for neighborhood racial/ethnic composition on birth outcomes by protecting women from psychosocial stress via social support that may buffer against racial/ethnic discrimination and/or racism. Data from 2012 to 2018 were used to examine the association of NYC women's race/ethnicity and neighborhood racial/ethnic minority composition with adverse birth outcomes (low birthweight [LBW], small for gestational age [SGA], preterm birth and infant mortality); and whether the association between mother's race/ethnicity and each birth outcome differed by neighborhood racial/ethnic composition. Multilevel logistic regression was used to control for the clustering of outcomes within neighborhoods. Black, Asian, and American Indian women have poorer birth outcomes than white women. Infants of Mexican American, Central American, and South American women were less likely to be of LBW whereas the opposite was true for infants of Cuban and other Hispanic women compared with infants of white women. When compared with white women, Mexican American, and South American women were less likely to have an SGA infant whereas Puerto Rican and other Hispanic women were more likely to have an SGA infant. All Hispanic women were more likely to have a preterm birth than white women whereas for infant mortality, greater odds of dying were observed for infants of Puerto Rican, Dominican, and other Hispanic women. Higher neighborhood racial/ethnic minority composition was associated with greater odds of having an adverse outcome. Finally, we observed heterogeneity of the associations between mother's race/ethnicity and birth outcomes by neighborhood racial/ethnic minority composition.

Black Nativity and Health Disparities: A Research Paradigm for Understanding the Social Determinants of Health

After more than a century of research and debate, the scientific community has yet to reach agreement on the principal causes of racialized disparities in population health. This debate currently centers on the degree to which "race residuals" are a result of unobserved differences in the social context or unobserved differences in population characteristics. The comparative study of native and foreign-born Black populations represents a quasi-experimental design where race is "held constant". Such studies present a unique opportunity to improve our understanding of the social determinants of population health disparities. Since native and foreign-born Black populations occupy different sociocultural locations, and since populations with greater African ancestry have greater genetic diversity, comparative studies of these populations will advance our understanding of the complex relationship between sociocultural context, population characteristics and health outcomes. Therefore, we offer a conceptual framing for the comparative study of native and foreign-born Blacks along with a review of 208 studies that compare the mental and physical health of these populations. Although there is some complexity, especially with respect to mental health, the overall pattern is that foreign-born Blacks have better health outcomes than native-born Blacks. After reviewing these studies, we conclude with suggestions for future studies in this promising area of social and medical research.

Multidimensional structural racism predicts birth outcomes for Black and White Minnesotans

Objective

The objective of this study is to determine the linkage between multidimensional structural racism typologies and preterm birth (PTB), low birthweight (LBW), and small‐for‐gestational‐age (SGA) birth among infants of White, US‐born Black, and foreign‐born Black pregnant people in Minnesota.

Data Sources

The measures of structural racism were based on the 2017 American Community Survey 5‐year estimates and the 2017 jail incarceration data from the Vera Institute of Justice. Birth outcomes of infants born in 2018 were based on birth records from the Minnesota Department of Health.

Study Design

We conducted a latent class analysis to identify multidimensional structural racism typologies in 2017 and related these typologies to birth outcomes of pregnant people who gave birth in Minnesota in 2018 using Vermunt's 3‐step approach. Racial group‐specific age‐adjusted risks of PTB, LBW, and SGA by structural racism typologies were estimated.

Data Collection

Study data were from public sources.

Principal Findings

Our analysis identified three multidimensional structural racism typologies in Minnesota in 2017. These typologies can have high structural racism in some dimensions but low in others. The interactive patterns among various dimensions cannot simply be classified as “high” (i.e., high structural racism in all dimensions), “medium,” or “low.” The risks of PTB, LBW, and SGA for US‐born Black pregnant Minnesotans were always higher than for their White counterparts regardless of the typologies in which they lived during pregnancy. Furthermore, these excess risks among US‐born Black pregnant people did not vary significantly across the typologies. We did not find clear patterns when comparing the predicted risks for infants of US‐ and foreign‐born Black pregnant people.

Conclusion

Multidimensional structural racism increases the risks of adverse birth outcomes for US‐born Black Minnesotans. Policy interventions to dismantle structural racism and eliminate birth inequities must be multi‐sectoral as changes in one or a few dimensions, but not all, will unlikely reduce birth inequities.

Where are the labor markets?: Examining the association between structural racism in labor markets and infant birth weight

Racist policies and practices that restrict Black, as compared to white workers, from employment may drive racial inequities in birth outcomes among workers. This study examined the association between structural racism in labor markets, measured at a commuting zone where workers live and commute to work, and low-birthweight birth. We found the deleterious effect of structural racism in labor markets among US-born Southern Black pregnant people of working age, but not among African- or Caribbean-born counterparts in any US region. Our analysis highlights the intersections of structural racism, culture, migration, and history of racial oppression that vary across regions and birth outcomes of Black workers.

Preterm Birth Among US and Foreign-Born Non-Hispanic Black Birthing Parents in Massachusetts: Variation by Nativity, Region, and Country of Origin

INTRODUCTION

Foreign-born non-Hispanic Black (NHB) birthing parents are less likely to have a preterm birth (PTB) than US-born NHBs. There is further variation by region and country of origin. We update previous studies by examining PTB rates by nativity, region and country of origin among NHBs in Massachusetts, a state with a heterogeneous population of foreign-born NHBs, including communities excluded from previous studies.

METHODS

Using 2011-2015 natality data from the three largest metropolitan areas in Massachusetts, we documented associations between nativity, region, and 18 individual countries of origin and PTB, using multivariable logistic regression to adjust for individual-level risk factors.

RESULTS

PTB was highest among US-born NHBs (9.4%) and lowest among those from Sub-Saharan Africa (SSA) (6.6%). Country-specific rates ranged from 4.0% among Angolans to 12.6% among those from Barbados and Trinidad and Tobago. While NHBs from SSA had significantly lower odds of PTB, risk among those from the Caribbean and Brazil was not different from US-born NHBs. The significantly lower risk among foreign-born NHBs and SSAs, in particular, remained robust in adjusted models.

DISCUSSION

Individual-level factors do not explain observed variation among NHB birthing parents. Future research should investigate explanations for lower PTB risk among SSAs, and congruent risk among foreign-born Caribbeans, Brazilians and US-born NHBs. Exposure to racism, a known risk factor for PTB, likely contributes to these inequities in PTB and merits further exploration. Prenatal care providers should assess place of birth among foreign-born NHBs, as well as exposure to racial discrimination among all NLB birthing parents.

Maternal nativity and risk of adverse perinatal outcomes among Black women residing in California, 2011-2017

OBJECTIVE

Examine the risk of adverse perinatal outcomes among the United States (US)-born and foreign-born Black women in California.

STUDY DESIGN

The study comprised all singleton live births to Black women in California between 2011 and 2017. We defined maternal nativity as US-born or foreign-born. Using Poisson regression, we computed risk ratios (RR) and 95% confidence intervals (CI) for three adverse perinatal outcomes: preterm birth, small for gestational age deliveries, and infant mortality.

RESULTS

Rates of adverse perinatal outcomes were significantly higher among US-born Black women. In adjusted models, US-born Black women experienced an increased risk of preterm birth (RR 1.51, 95% CI 1.39, 1.65) and small for gestational age deliveries (RR 1.52, 95% CI 1.41, 1.64), compared to foreign-born Black women.

CONCLUSIONS

Future studies should consider experiences of racism across the life course when exploring heterogeneity in the risk of adverse perinatal outcomes by nativity among Black women in the US.

Neighborhood Context and the Nativity Advantage in Preterm Birth among Black Women in California, USA

Non-Hispanic Black women remain at increased risk for adverse birth outcomes, yet Black immigrant women are at lower risk than their US-born counterparts. This study examines whether neighborhood context contributes to the nativity advantage in preterm birth (PTB, < 37 weeks) among Black women in California. A sample of live singleton births to non-Hispanic US-born (n = 83,169), African-born (n = 7151), and Caribbean-born (n = 943) Black women was drawn from 2007 to 2010 California birth records and geocoded to urban census tracts. We used 2010 American Community Survey data to measure tract-level Black immigrant density, Black racial concentration, and a neighborhood deprivation index. Risk ratios (RR) and 95% confidence intervals (95%CI) were estimated using log-binomial regression to assess whether neighborhood context partially explained nativity differences in PTB risk. Compared to US-born Black women, African-born Black women had lower PTB risk (RR = 0.65, 95%CI: 0.60-0.71). The difference in PTB risk between US- and Caribbean-born women did not reach statistical significance (RR = 0.87, 95%CI: 0.71-1.05). The nativity advantage in PTB risk was robust to neighborhood social conditions and maternal factors for African-born women (RR = 0.59, 95%CI: 0.51-0.67). This study is one of few that considers area-level explanations of the nativity advantage among Black immigrants and makes a significant contribution by showing that the neighborhood context does not explain the nativity advantage in PTB among Black women in California. This could be due to many factors that should be examined in future research.

Complex species and strain ecology of the vaginal microbiome from pregnancy to postpartum and association with preterm birth

Background

Lactobacillus was described as a keystone bacterial taxon in the human vagina over 100 years ago. Using metagenomics, we and others have characterized lactobacilli and other vaginal taxa across health and disease states, including pregnancy. While shifts in community membership have been resolved at the genus/species level, strain dynamics remain poorly characterized.

Methods

We performed a metagenomic analysis of the complex ecology of the vaginal econiche during and after pregnancy in a large U.S. based longitudinal cohort of women who were initially sampled in the third trimester of pregnancy, then validated key findings in a second cohort of women initially sampled in the second trimester of pregnancy.

Findings

First, we resolved microbial species and strains, interrogated their co-occurrence patterns, and probed the relationship between keystone species and preterm birth outcomes. Second, to determine the role of human heredity in shaping vaginal microbial ecology in relation to preterm birth, we performed a mtDNA-bacterial species association analysis. Finally, we explored the clinical utility of metagenomics in detection and co-occurrence patterns for the pathobiont Group B Streptococcus (causative bacterium of invasive neonatal sepsis).

Conclusions

Our highly refined resolutions of the vaginal ecology during and post-pregnancy provide insights into not only structural and functional community dynamics, but highlight the capacity of metagenomics to reveal finer aspects of the vaginal microbial ecologic framework.

Funding

NIH-NINR R01NR014792, NIH-NICHD R01HD091731, NIH National Children's Study Formative Research, Burroughs Wellcome Fund Preterm Birth Initiative, March of Dimes Preterm Birth Research Initiative, NIH-NIGMS (K12GM084897, T32GM007330, T32GM088129).

Interracial/ethnic marriage and adverse birth outcomes: The effect of neighborhood racial/ethnic composition

Race/ethnicity is associated with adverse birth outcomes in the United States. However, mostly mother's race/ethnicity has been considered. We examined the associations of mother's and parents' race/ethnicity with low birth weight, small for gestational age, preterm birth and infant mortality among New York City women between 2012 and 2017. We also examined the independent and joint effects of neighborhood racial/ethnic composition. We found that mother's and parents' race/ethnicity are associated with adverse birth outcomes; these associations are outcome-specific; and neighborhood racial/ethnic composition is not only associated with such outcomes but also modifies the association of mother's and parents' race/ethnicity with these outcomes. Our findings underscore the need to consider the race/ethnicity of women's partners and their neighborhoods calling attention to the role of context where individuals reside, and their daily interactions take place. These findings may have implications beyond New York City as our society becomes more racial/ethnic diverse and interracial/ethnic marriage becomes more common in the United States.

The Muslim Ban and preterm birth: Analysis of U.S. vital statistics data from 2009 to 2018

Anti-immigrant stigma or xenophobia is increasingly pervasive globally. Racism is a determinant of adverse health outcomes, but the epidemiological implications of the recent wave of xenophobic policies have not been well studied. The 2017 travel ban on individuals from Muslim majority countries is an example of such policy efforts in the United States. Using the 2009-2018 National Center for Health Statistics period linked infant birth-death data, we used time series methods to compare the monthly odds of preterm births to women from travel ban countries (Iran, Iraq, Libya, Somalia, Sudan, Syria, and Yemen) after the January 2017 travel ban to the number expected had the ban not been implemented. We estimated our counterfactual from the history of preterm birth among women born in countries included in the ban as well as trends in preterm birth among native-born non-Hispanic (NH) White women. Among the 18,945,795 singleton live births included in our study period (including 191,121 born to women from banned countries), the average monthly rate of births that were preterm birth was 8.5% (range: 6.8%, 10.6%) among women born in the countries affected by the ban and 8.6% (range: 7.7%, 9.8%) among native-born NH White women. Our results show an increase in the odds of preterm birth among infants born to women from travel ban countries in September 2017 and persisting through the cohort born in August 2018. The coefficient for exposed infants born in these months suggests that the odds of preterm birth increased by 6.8% among women from banned countries (p < 0.001). Our results suggest that the first U.S. Executive Order (#13769) of the travel ban targeting individuals from Muslim majority countries may be associated with preterm births. We therefore conclude that structurally xenophobic and racist policies in the U.S. may have a harmful effect on birth outcomes and early life indicators of life-long health outcomes.

Neighborhood Racial/Ethnic Composition Trajectories and Black-White Differences in Preterm Birth among Women in Texas

The black-white disparity in preterm birth has been well documented in the USA. The racial/ethnic composition of a neighborhood, as a marker of segregation, has been considered as an underlying cause of the racial difference in preterm birth. However, past literature using cross-sectional measures of neighborhood racial/ethnic composition has shown mixed results. Neighborhoods with static racial/ethnic compositions over time may have different social, political, economic, and service environments compared to neighborhoods undergoing changing racial/ethnic compositions, which may affect maternal health. We extend the past work by examining the contribution of neighborhood racial/ethnic composition trajectories over 20 years to the black-white difference in preterm birth. We used natality files (N = 477,652) from birth certificates for all live singleton births to non-Hispanic black and non-Hispanic white women in Texas from 2009 to 2011 linked to the Neighborhood Change Database. We measured neighborhood racial/ethnic trajectories over 20 years. Hierarchical generalized linear models examined relationships between neighborhood racial/ethnic trajectories and preterm birth, overall and by mother's race. Findings showed that overall, living in neighborhoods with a steady high proportion non-Hispanic black was associated with higher odds of preterm birth, compared with neighborhoods with a steady low proportion non-Hispanic black. Furthermore, while black women's odds of preterm birth was relatively unaffected by neighborhood proportions of the Latinx or non-Hispanic white population, white women had the highest odds of preterm birth in neighborhoods characterized by a steady high proportion Latinx or a steady low proportion non-Hispanic white. Black-white differences were the highest in neighborhoods characterized by a steady high proportion white. Findings suggest that white women are most protected from preterm birth when living in neighborhoods with a steady high concentration of whites or in neighborhoods with a steady low concentration of Latinxs, whereas black women experience high rates of preterm birth regardless of proportion white or Latinx.

An Examination of Preterm Birth and Residential Social Context among Black Immigrant Women in California, 2007-2010

The foreign-born black population contributes a considerable amount of heterogeneity to the US black population. In 2005, black immigrants accounted for 20% of the US black population. Compared to native-born black women, black immigrant women are at lower risk for adverse birth outcomes, including preterm birth. Some scholars posit that differential exposures to socioeconomic disadvantage and structural racism in the residential context may account for this advantage. However, to date, few studies offer comprehensive examinations of the black immigrant residential social context, particularly in settlement regions beyond predominantly black and historically segregated regions. Further, studies examining the black immigrant residential context typically use a single indicator, which limits discussion of the intersecting domains that simultaneously increase or decrease risk among black immigrants. We addressed these gaps by examining black immigrant neighborhoods in the state of California, where racial residential segregation of the black population is low. We operationalized the residential context of black immigrant women using three distinct attributes: immigrant co-ethnic density, black racial concentration, and neighborhood deprivation. We linked 2007-2010 California birth records of black immigrant women and 2010 census data on tract-level social attributes (N = 6930). OLS regression analyses showed that immigrant co-ethnic density, black racial concentration and neighborhood deprivation were not associated with preterm birth among black immigrants. Our findings indicate that in California, residential social context has little relation to black immigrant preterm birth-a finding that is unique compared to residential settings of other settlement contexts.

Neighborhood ethnic density and self-rated health: Investigating the mechanisms through social capital and health behaviors

While living with co-ethnics benefits minorities' health, the so-called ethnic density effect, little is known about the mechanisms through which neighborhood ethnic density influences self-rated health. We examine two pathways, namely neighborhood social capital and health behaviors, with a 2010 survey collected in Philadelphia (2297 blacks and 492 Hispanics). The mediation analysis indicates that (1) living with co-ethnics is beneficial to both blacks' and Hispanics' self-rated health, (2) neighborhood social capital and health behaviors mediate almost 15% of the ethnic density effect for blacks, and (3) the two mechanisms do not explain why living with co-ethnics improves Hispanics' health.

Ethnic enclaves and birth outcomes of immigrants from India in a diverse U.S. state

Sociological theory suggests that ethnic enclaves promote immigrant health. Existing studies of ethnic enclaves and immigrant birth outcomes have generally focused on blacks and Hispanics, while few have focused on immigrants from India - the second largest immigrant group in the U.S., after Mexicans. Paradoxically, this group generally exhibits worse birth outcomes than non-Hispanic whites, despite their high levels of education. This study investigates associations between residence in South Central Asian ethnic enclaves and both birth outcomes and prenatal behaviors of immigrant mothers from India, using population-level birth record data from the state of New Jersey in the U.S. (1999-2012; n = 64,375). Results indicate that residence in a South Central Asian enclave is associated with less prenatal smoking and earlier prenatal care, but not with birthweight- or gestational-age related outcomes, among immigrant mothers from India. These findings are consistent with theory suggesting that social support, social capital, and social norms transmitted through the social networks present in ethnic enclaves foster health-promoting behaviors. Notably, the prenatal behaviors of non-Hispanic white mothers were not associated to a large degree with living in South Central Asian enclaves, which is also consistent with theory and bolsters our confidence that the observed associations for immigrant mothers from India are not spurious.

Racial residential segregation and adverse birth outcomes: A systematic review and meta-analysis

RATIONALE

Persistent racial disparities in adverse birth outcomes are not fully explained by individual-level risk factors. Racial residential segregation-degree to which two or more groups live apart from one another-may contribute to the etiology of these birth outcome disparities. Our aim was to assess associations between segregation and adverse birth outcomes by race. This review focused on formal measures of segregation, using Massey and Denton's framework (1998) that identifies five distinct operationalizations of segregation, in addition to proxy measures of segregation such as racial composition, in order to gain a deeper understanding of the operationalizations of segregation most salient for birth outcomes.

METHOD

Review and meta-analyses were conducted using PubMed, PsycINFO and Web of Science and included articles from inception through April 30, 2017.

RESULTS

Forty-two articles examined associations between segregation and adverse birth outcomes among Black and White mothers separately. Meta-analyses showed that among Black mothers, exposure was associated with increased risk of preterm birth (OR = 1.17, 95% CI = 1.10, 1.26), and low birth weight (OR = 1.13, 95% CI=1.06, 1.21), and Black racial composition was associated with increased risk of preterm birth (OR = 1.20, 95% CI=1.05, 1.37), among those living in most- compared to least-segregated neighborhoods. Few studies were conducted among White mothers and only exposure was associated with increased risk of preterm birth and low birth weight. Qualitative analyses indicated that among Black mothers, exposure and hypersegregation were associated with multiple adverse birth outcomes; findings were mixed for evenness and clustering.

CONCLUSIONS AND FUTURE DIRECTIONS

Associations between segregation and adverse birth outcomes differ by race. Methodological heterogeneity between studies may obscure true associations. Research can be advanced through use of multilevel frameworks and by examining mechanistic pathways between segregation and adverse birth outcomes. Elucidation of pathways may provide opportunities to intervene to reduce seemingly intractable racial disparities in adverse birth outcomes.

Residential segregation, political representation, and preterm birth among U.S.- and foreign-born Black women in the U.S. 2008-2010

Although racial residential segregation is associated with preterm birth (PTB) among non-Hispanic black (NHB) women in the U.S., prior work suggests that increased black political power arising from segregation may be protective for infant health. We examined associations between residential segregation, black political representation, and preterm birth (PTB) among U.S- and foreign-born NHB women in major U.S. cities using birth certificate data from 2008 to 2010 (n=861,450). Each 10-unit increase in segregation was associated with 3-6% increases in odds of PTB for both U.S.- and foreign-born NHB women. Black political representation was not associated with PTB and did not moderate the association between residential segregation and PTB.

Neighborhood racial composition and poverty in association with pre-pregnancy weight and gestational weight gain

BACKGROUND

Studies of neighborhood racial composition or neighborhood poverty in association with pregnancy-related weight are limited. Prior studies of neighborhood racial density and poverty has been in association with adverse birth outcomes and suggest that neighborhoods with high rates of poverty and racial composition of black residents are typically segregated and systematically isolated from opportunities and resources. These neighborhood factors may help explain the racial disparities in pre-pregnancy weight and inadequate weight gain. This study examined whether neighborhood racial composition and neighborhood poverty was associated with weight before pregnancy and weight gain during pregnancy and if this association differed by race.

METHODS

We used vital birth records of singleton births of 73,061 non-Hispanic black and white women in Allegheny County, PA (2003-2010). Maternal race and ethnicity, pre-pregnancy body-mass-index (BMI), gestational weight gain and other individual-level characteristics were derived from vital birth record data, and measures of neighborhood racial composition (percentage of black residents in the neighborhood) and poverty (percentage of households in the neighborhood below the federal poverty) were derived using US Census data. Multilevel log binomial regression models were performed to estimate neighborhood racial composition and poverty in association with pre-pregnancy weight (i.e., overweight/obese) and gestational weight gain (i.e., inadequate and excessive).

RESULTS

Black women as compared to white women were more likely to be overweight/obese before pregnancy and to have inadequate gestational weight gain (53.6% vs. 38.8%; 22.5% vs. 14.75 respectively). Black women living in predominately black neighborhoods were slightly more likely to be obese prior to pregnancy compared to black women living in predominately white neighborhoods (PR 1.10; 95% CI: 1.03, 1.16). Black and white women living in high poverty areas compared with women living in lower poverty areas were more likely to be obese prior to pregnancy; while only white women living in high poverty areas compared to low poverty areas were more likely gain an inadequate amount of weight during pregnancy.

CONCLUSIONS

Neighborhood racial composition and poverty may be important in understanding racial differences in weight among childbearing women.

Association of neighborhood context with offspring risk of preterm birth and low birthweight: A systematic review and meta-analysis of population-based studies

Findings from studies investigating associations of residential environment with poor birth outcomes have been inconsistent. In a systematic review and meta-analysis, we examined associations of neighborhood disadvantage with preterm birth (PTB) and low birthweight (LBW), and explored differences in relationships among racial groups. Two reviewers searched English language articles in electronic databases of published literature. We used random effects logistic regression to calculate odds ratios (and 95% confidence intervals) relating neighborhood disadvantage with PTB and LBW. Neighborhood disadvantage, most disadvantaged versus least disadvantaged neighborhoods, was defined by researchers of included studies, and comprised of poverty, deprivation, racial residential segregation or racial composition, and crime. We identified 1314 citations in the systematic review. The meta-analyses included 7 PTB and 14 LBW cross-sectional studies conducted in the United States (U.S.). Overall, we found 27% [95%CI: 1.16, 1.39] and 11% [95%CI: 1.07, 1.14] higher risk for PTB and LBW among the most disadvantaged compared with least disadvantaged neighborhoods. No statistically significant association was found in meta-analyses of studies that adjusted for race. In race-stratified meta-analyses models, we found 48% [95%CI: 1.25, 1.75] and 61% [95%CI: 1.30, 2.00] higher odds of PTB and LBW among non-Hispanic white mothers living in most disadvantaged neighborhoods compared with those living in least disadvantaged neighborhoods. Similar, but less strong, associations were observed for PTB (15% [95%CI: 1.09, 1.21]) and LBW (17% [95%CI: 1.10, 1.25]) among non-Hispanic black mothers. Neighborhood disadvantage is associated with PTB and LBW, however, associations may differ by race. Future studies evaluating causal mechanisms underlying the associations, and racial/ethnic differences in associations, are warranted.

Comparison of black-white disparities in preterm birth between Canada and the United States

BACKGROUND

A higher risk of preterm birth among black women than among white women is well established in the United States. We compared differences in preterm birth between non-Hispanic black and white women in Canada and the US, hypothesizing that disparities would be less extreme in Canada given the different historical experiences of black populations and Canada's universal health care system.

METHODS

Using data on singleton live births in Canada and the US for 2004-2006, we estimated crude and adjusted risk ratios and risk differences in preterm birth (< 37 wk) and very preterm birth (< 32 wk) among non-Hispanic black versus non-Hispanic white women in each country. Adjusted models for the US were standardized to the covariate distribution of the Canadian cohort.

RESULTS

In Canada, 8.9% and 5.9% of infants born to black and white mothers, respectively, were preterm; the corresponding figures in the US were 12.7% and 8.0%. Crude risk ratios for preterm birth among black women relative to white women were 1.49 (95% confidence interval [CI] 1.32 to 1.66) in Canada and 1.57 (95% CI 1.56 to 1.58) in the US (p value for heterogeneity [pH] = 0.3). The crude risk differences for preterm birth were 2.94 (95% CI 1.91 to 3.96) in Canada and 4.63 (95% CI 4.56 to 4.70) in the US (pH = 0.003). Adjusted risk ratios for preterm birth (pH = 0.1) were slightly higher in Canada than in the US, whereas adjusted risk differences were similar in both countries. Similar patterns were observed for racial disparities in very preterm birth.

INTERPRETATION

Relative disparities in preterm birth and very preterm birth between non-Hispanic black and white women were similar in magnitude in Canada and the US. Absolute disparities were smaller in Canada, which reflects a lower overall risk of preterm birth in Canada than in the US in both black and white populations.

A Comparison of Birth Outcomes Among Black, Hispanic, and Black Hispanic Women

BACKGROUND

While non-Hispanic Black populations tend to be disproportionately affected by adverse reproductive outcomes, Hispanic populations tend to demonstrate healthier birth outcomes, regardless of socioeconomic background. Little is known about birth outcomes for women who are both Black and Hispanic. We examined whether birth outcomes and risk factors for women who are both Black and Hispanic most closely resemble those of women who are only Black or Hispanic and also compared these outcomes to those for Whites.

METHODS

Using the 2013 US natality files, we examined 2,970,315 singleton births to Black Hispanic, Hispanic, Black, and White mothers. We used logistic regression to calculate predicted probabilities of low birth weight (LBW), preterm birth (PTB), or small for gestational age (SGA). Race-stratified regression analysis was used to identify the factors that significantly predicted risk for each outcome for each racial/ethnic group.

RESULTS

Black mothers had the highest prevalence and predicted probabilities of experiencing all three outcomes. Black Hispanic mothers were less likely than Black mothers and more likely than Hispanic mothers to experience each of the adverse outcomes. We also found support for racial variation in risk and protective factors for mothers in the different groups. Factors like age and education inconsistently predicted risk of experiencing the birth outcomes for all groups. Overall, Black Hispanic mothers had birth outcomes and risk factor profiles like Hispanic mothers, although they had sociodemographic characteristics and health behaviors like Black mothers.

CONCLUSIONS

Patterning of birth outcomes among Black Hispanic women suggest an intersection of risk and protective factors associated with their respective racial and ethnic identities. Additional information about sociodemographic context is needed to develop a more complete picture of how factors related to race and ethnic group membership influence Black Hispanic women's birth outcomes.

Does maternal race influence the short-term variation of the fetal heart rate? An historical cohort study

OBJECTIVES

The main aim of this article was to analyze short-term variation (STV) of the fetal heart rate according to maternal race. The secondary aim was to study the baseline fetal heart rate according to this factor.

STUDY DESIGN

This single-center historical cohort study covered the period from November 2008 through December 2011 (n=182). The inclusion criteria were: black women from sub-Saharan Africa or white European women, with a singleton pregnancy ≥34 weeks and fetal heart rate recorded by computerized analysis (Oxford Sonicaid System 8002) at a prenatal visit. The exclusion criteria were: medication likely to modify fetal heart rate, abnormal fetal heart rate tracing, and being in labor. A multiple linear regression analysis was used to study the association between maternal race and STV.

RESULTS

STV was lower by 2.6ms in fetuses of black women (n=55) compared to those of white women (n=127) (8.9±2.1ms vs. 11.4±3.4ms) (p<0.001). The basal fetal heart rate was higher (p=0.001), and the recording criteria were met less often for the black women (p=0.04). After adjustment for maternal age, body mass index at the beginning of pregnancy, maternal cigarette smoking, parity, gestational diabetes, gestational age at the time of the fetal heart rate recording, and the time between the last meal and the recording, mean STV was lower by 3.1±0.6ms in fetuses of black compared with white women (p<0.001).

CONCLUSION

STV is lower in fetuses of black women compared to those of white women in a low-risk population. A study of black and white women with high-risk pregnancies is necessary to assess the impact of medical practices on perinatal outcome after STV analysis.

Is ethnic density associated with health in a context of social disadvantage? Findings from the Born in Bradford cohort

OBJECTIVES

In this study we aimed to test the associations between area-level ethnic density and health for Pakistani and White British residents of Bradford, England.

DESIGN

The sample consisted of 8610 mothers and infant taking part in the Born in Bradford cohort. Ethnic density was measured as the percentage of Pakistani, White British or South Asian residents living in a Lower Super Output Area. Health outcomes included birth weight, preterm birth and smoking during pregnancy. Associations between ethnic density and health were tested in multilevel regression models, adjusted for individual covariates and area deprivation.

RESULTS

In the Pakistani sample, higher own ethnic density was associated with lower birth weight (β = -0.82, 95% CI: -1.63, -0.02), and higher South Asian density was associated with a lower probability of smoking during pregnancy (OR = 0.99, 95% CI: 0.98, 1.00). Pakistani women in areas with 50-70% South Asian residents were less likely to smoke than those living in areas with less than 10% South Asian residents (OR = 0.39, 95% CI: 0.16, 0.97). In the White British sample, neither birth weight nor preterm birth was associated with own ethnic density. The probability of smoking during pregnancy was lower in areas with 10-29.99% compared to <10% South Asian density (OR = 0.79, 95% CI: 0.64, 0.98).

CONCLUSION

In this sample, ethnic density was associated with lower odds of smoking during pregnancy but not with higher birth weight or lower odds of preterm birth. Possibly, high levels of social disadvantage inhibit positive effects of ethnic density on health.

Improvement in Perinatal HIV Status Documentation in a Massachusetts Birth Hospital, 2009-2013

BACKGROUND AND OBJECTIVES

Despite recommendations for universal HIV testing during routine prenatal care, maternal HIV status is not always available at the time of delivery, which may lead to missed opportunities for antiretroviral prophylaxis. We completed a quality improvement project focused on increasing the availability of maternal HIV status documentation at our perinatal facility. Our primary aim was to improve documentation rates from 50% to 100% between 2009 and 2013. Our secondary aim was to identify predictors of documentation.

METHODS

After an initial needs assessment, we performed a multidisciplinary quality improvement effort to address lack of HIV documentation in perinatal charts. The interventions included a switch to a verbal-only consent process, a rapid HIV testing protocol, and a simplified newborn admission document. To assess the impact of our intervention, we audited 100 charts per month and formally analyzed a second random sample of 200 charts in the postimplementation phase.

RESULTS

Rates of HIV status documentation improved between 2009 and 2013, from 55.5% to 96.5%. Multivariable models revealed that before our interventions, mothers receiving care at freestanding offices (versus community-based outreach clinics) and those privately insured (versus publicly) were less likely to have HIV status documented. In 2013, neither ambulatory site nor insurance type predicted documentation.

CONCLUSIONS

We demonstrated improvement in maternal HIV status documentation on admission to labor and delivery after implementation of a 3-pronged intervention. Next steps include investigating persistent barriers to achieving universal screening and documentation.

The role of socioeconomic factors in Black-White disparities in preterm birth

OBJECTIVES

We investigated the role of socioeconomic factors in Black-White disparities in preterm birth (PTB).

METHODS

We used the population-based California Maternal and Infant Health Assessment survey and birth certificate data on 10 400 US-born Black and White California residents who gave birth during 2003 to 2010 to examine rates and relative likelihoods of PTB among Black versus White women, with adjustment for multiple socioeconomic factors and covariables.

RESULTS

Greater socioeconomic advantage was generally associated with lower PTB rates among White but not Black women. There were no significant Black-White disparities within the most socioeconomically disadvantaged subgroups; Black-White disparities were seen only within more advantaged subgroups.

CONCLUSIONS

Socioeconomic factors play an important but complex role in PTB disparities. The absence of Black-White disparities in PTB within certain socioeconomic subgroups, alongside substantial disparities within others, suggests that social factors moderate the disparity. Further research should explore social factors suggested by the literature-including life course socioeconomic experiences and racism-related stress, and the biological pathways through which they operate-as potential contributors to PTB among Black and White women with different levels of social advantage.

Variation in birth outcomes by mother's country of birth among non-Hispanic black women in the United States

Rates of prematurity (PTB) and small-for-gestational age (SGA) were compared between US-born and foreign-born non-Hispanic black women. Comparisons were also made between Sub-Saharan African-born and Caribbean-born black women and by maternal country of birth within the two regions. Comparisons were adjusted for sociodemographic, health behavioral and medical risk factors available on the birth record. Birth record data (2008) from all states (n = 27) where mother's country of birth was recorded were used. These data comprised 58 % of all singleton births to non-Hispanic black women in that year. Pearson Chi square and logistic regression were used to investigate variation in the rates of PTB and SGA by maternal nativity. Foreign-born non-Hispanic black women had significantly lower rates of PTB (OR 0.727; CI 0. 726, 0.727) and SGA (OR 0.742; CI 0.739-0.745) compared to US-born non-Hispanic black women in a fully adjusted model. Sub-Saharan African-born black women compared to Caribbean-born black women had significantly lower rates of PTB and SGA. Within each region, the rates of PTB and SGA varied by mother's country of birth. These differences could not be explained by adjustment for known risk factors obtained from vital records. Considerable heterogeneity in rates of PTB and SGA among non-Hispanic black women in the US by maternal nativity was documented and remained unexplained after adjustment for known risk factors.

Ethnic enclaves and gestational diabetes among immigrant women in New York City

Previous research has shown that immigrants living in their own ethnic enclave are at decreased risk of poor health outcomes, but this question has not been studied in relation to gestational diabetes, an important early marker of lifecourse cardiovascular health. We ascertained gestational diabetes, census tract of residence, and individual-level covariates for Sub-Saharan African, Chinese, South Central Asian, Non-Hispanic Caribbean, Dominican, Puerto Rican, Mexican, and Central and South American migrant women using linked birth-hospital discharge data for 89,703 singleton live births in New York City for the years 2001-2002. Using 2000 census data, for each immigrant group we defined a given census tract as part of an ethnic enclave based on the population distribution for the corresponding ethnic group. We estimated odds ratios for associations between living in an ethnic enclave and risk of gestational diabetes adjusted for neighborhood deprivation, percent commercial space, education, age, parity, and insurance status, using multilevel logistic regression. Overall, we found no effect of ethnic enclave residence on gestational diabetes in most immigrant groups. Among South Central Asian and Mexican women, living in a residential ethnic enclave was associated with an increased odds of gestational diabetes. Several explanations are proposed for these findings. Mechanisms explaining an increased risk of gestational diabetes in South Central Asian and Mexican ethnic enclaves should be examined.

Ethnic density and depressive symptoms among African Americans: threshold and differential effects across social and demographic subgroups

OBJECTIVES

We examined the association between Black ethnic density and depressive symptoms among African Americans. We sought to ascertain whether a threshold exists in the association between Black ethnic density and an important mental health outcome, and to identify differential effects of this association across social, economic, and demographic subpopulations.

METHODS

We analyzed the African American sample (n = 3570) from the National Survey of American Life, which we geocoded to the 2000 US Census. We determined the threshold with a multivariable regression spline model. We examined differential effects of ethnic density with random-effects multilevel linear regressions stratified by sociodemographic characteristics.

RESULTS

The protective association between Black ethnic density and depressive symptoms changed direction, becoming a detrimental effect, when ethnic density reached 85%. Black ethnic density was protective for lower socioeconomic positions and detrimental for the better-off categories. The masking effects of area deprivation were stronger in the highest levels of Black ethnic density.

CONCLUSIONS

Addressing racism, racial discrimination, economic deprivation, and poor services-the main drivers differentiating ethnic density from residential segregation-will help to ensure that the racial/ethnic composition of a neighborhood is not a risk factor for poor mental health.

Maternal mercury exposure, season of conception and adverse birth outcomes in an urban immigrant community in Brooklyn, New York, U.S.A

Adverse birth outcomes including preterm birth (PTB: <37 weeks gestation) and low birth weight (LBW: <2500 g) can result in severe infant morbidity and mortality. In the United States, there are racial and ethnic differences in the prevalence of PTB and LBW. We investigated the association between PTB and LBW with prenatal mercury (Hg) exposure and season of conception in an urban immigrant community in Brooklyn, New York. We recruited 191 pregnant women aged 18-45 in a Brooklyn Prenatal Clinic and followed them until delivery. Urine specimens were collected from the participants during the 6th to 9th month of pregnancy. Cord blood specimens and neonate anthropometric data were collected at birth. We used multivariate logistic regression models to investigate the odds of LBW or PTB with either maternal urinary mercury or neonate cord blood mercury. We used linear regression models to investigate the association between continuous anthropometric outcomes and maternal urinary mercury or neonate cord blood mercury. We also examined the association between LBW and PTB and the season that pregnancy began. Results showed higher rates of PTB and LBW in this cohort of women compared to other studies. Pregnancies beginning in winter (December, January, February) were at increased odds of LBW births compared with births from pregnancies that began in all other months (OR7.52 [95% CI 1.65, 34.29]). We observed no association between maternal exposure to Hg, and either LBW or PTB. The apparent lack of association is consistent with other studies. Further examination of seasonal association with LBW is warranted.

Border health in the shadow of the Hispanic paradox: issues in the conceptualization of health disparities in older Mexican Americans living in the Southwest

Mexican Americans have demonstrated lower than what would be expected mortality rates and disease prevalence, given their overrepresentation among those living in poverty. However, Mexican Americans living along the US-Mexico border have been documented as carrying a higher burden of disease and disability that seems to contradict or at least challenge evidence in support of a "Hispanic Paradox". The purpose of this paper is to evaluate the concept of border health as it relates to the conceptualization and measurement of health outcomes in older Mexican Americans living in the Southwest United States. Data for this study comes from the Hispanic Established Populations for the Epidemiologic Studies of the Elderly (Hispanic EPESE) wave 1 and mortality files up to wave 5. Border residence was determined using La Paz Agreement county and distance from a port of entry classifications. Statistical analysis was conducted to assess border versus non-border differences in cause of death, disability, disease prevalence and premature mortality. Adjusted regression models were used to predict cause of death, disability and disease-free life expectancy and premature mortality (i.e. occurring before life expectancy). Interaction models between border/non-border and median income were also performed. Finally, distance from the US-Mexico border was used to determine the effect of distance to the US-Mexico border in border-residing participants. The findings from this study indicate that participants in the HEPESE were more likely to be alive at Wave 5 if they resided in a border county, however more likely to transition into ADL disability status. These findings were not explained by behaviors, duration in the US or sociocultural characteristics of where they lived. Additionally, Hispanic EPESE subjects that lived in the border region were more likely to have died from old age and were less likely to be lost to follow up. Interaction models revealed significant effects for diabetes as a cause of death. Moreover, distance from a US-Mexico port of entry was significant for being alive at wave 5 for border-residing participants. Relative to non-border residing participants, border residing Mexican Americans in the Hispanic EPESE did not carry a uniformly higher burden of disease, however had a significantly greater odds of 10 year survival. These findings bring up issues of measurement and the importance of geographic location when it comes to evaluating disease burden and mortality in Mexican Americans.

Exploring the health consequences of majority-minority neighborhoods: minority diversity and birthweight among native-born and foreign-born blacks

We examined the association between neighborhood minority diversity and infant birthweight among non-Hispanic US-born black women and foreign-born black women from Sub-Saharan Africa and the non-Spanish speaking Caribbean using 2002-2006 vital statistics birth record data from the state of New Jersey (n = 73,907). We used a standardized entropy score to measure the degree of minority diversity (i.e., non-white multiethnic racial heterogeneity) for each census tract where women lived. We distinguished between four levels of minority diversity, with the highest level representing majority-minority neighborhoods. We estimated mean birthweight for singleton births over this 5-year period using linear regression with robust standard errors to correct for clustering of mothers within census tracts. We found significant differences in mean birthweight by mother's country of origin such that infants of US-born black mothers weighed significantly less than the infants of African and Caribbean immigrants (3130 g vs. 3299 g and 3212 g; p < 0.001). Adjustments for neighborhood deprivation, residential instability, individual-level sociodemographics, maternal health behaviors and conditions, and gestational age did not reduce these origin differences. Minority diversity had a protective effect on black infant health. Women living in low and moderately diverse tracts as well as those in majority-minority neighborhoods had heavier babies (β = 26.5, 29.8 and 61.2, respectively, p < 0.001) on average than women in the least diverse tracts. The results for majority-minority neighborhoods were robust when we controlled for neighborhood- and individual-level covariates.

Contextualizing nativity status, Latino social ties, and ethnic enclaves: an examination of the 'immigrant social ties hypothesis'

OBJECTIVES

Researchers have posited that one potential explanation for the better-than-expected health outcomes observed among some Latino immigrants, vis-à-vis their US-born counterparts, may be the strength of social ties and social support among immigrants.

METHODS

We examined the association between nativity status and social ties using data from the Chicago Community Adult Health Study's Latino subsample, which includes Mexicans, Puerto Ricans, and other Latinos. First, we used ordinary least squares (OLS) regression methods to model the effect of nativity status on five outcomes: informal social integration; social network diversity; network size; instrumental support; and informational support. Using multilevel mixed-effects regression models, we estimated the association between Latino/immigrant neighborhood composition and our outcomes, and whether these relationships varied by nativity status. Lastly, we examined the relationship between social ties and immigrants' length of time in the USA.

RESULTS

After controlling for individual-level characteristics, immigrant Latinos had significantly lower levels of social ties than their US-born counterparts for all the outcomes, except informational support. Latino/immigrant neighborhood composition was positively associated with being socially integrated and having larger and more diverse social networks. The associations between two of our outcomes (informal social integration and network size) and living in a neighborhood with greater concentrations of Latinos and immigrants were stronger for US-born Latinos than for immigrant Latinos. US-born Latinos maintained a significant social ties advantage over immigrants - regardless of length of time in the USA - for informal social integration, network diversity, and network size.

CONCLUSION

At the individual level, our findings challenge the assumption that Latino immigrants would have larger networks and/or higher levels of support and social integration than their US-born counterparts. Our study underscores the importance of understanding the contexts that promote the development of social ties. We discuss the implications of these findings for understanding Latino and immigrant social ties and health outcomes.

Ethnic density effects on physical morbidity, mortality, and health behaviors: a systematic review of the literature

It has been suggested that people in racial/ethnic minority groups are healthier when they live in areas with a higher concentration of people from their own ethnic group, a so-called ethnic density effect. Ethnic density effects are still contested, and the pathways by which ethnic density operates are poorly understood. The aim of this study was to systematically review the literature examining the ethnic density effect on physical health, mortality, and health behaviors. Most studies report a null association between ethnic density and health. Protective ethnic density effects are more common than adverse associations, particularly for health behaviors and among Hispanic people. Limitations of the literature include inadequate adjustment for area deprivation and limited statistical power across ethnic density measures and study samples.

Ethnic density effects on health and experienced racism among Caribbean people in the US and England: a cross-national comparison

Studies indicate an ethnic density effect, whereby an increase in the proportion of racial/ethnic minority people in an area is associated with reduced morbidity among its residents, though evidence is varied. Discrepancies may arise due to differences in the reasons for and periods of migration, and socioeconomic profiles of the racial/ethnic groups and the places where they live. It is important to increase our understanding of how these factors might promote or mitigate ethnic density effects. Cross-national comparative analyses might help in this respect, as they provide greater heterogeneity in historical and contemporary characteristics in the populations of interest, and it is when we consider this heterogeneity in the contexts of peoples' lives that we can more fully understand how social conditions and neighbourhood environments influence the health of migrant and racial/ethnic minority populations. This study analysed two cross-sectional nationally representative surveys, in the US and in England, to explore and contrast the association between two ethnic density measures (black and Caribbean ethnic density) and health and experienced racism among Caribbean people. Results of multilevel logistic regressions show that nominally similar measures of ethnic density perform differently across health outcomes and measures of experienced racism in the two countries. In the US, increased Caribbean ethnic density was associated with improved health and decreased experienced racism, but the opposite was observed in England. On the other hand, increased black ethnic density was associated with improved health and decreased experienced racism of Caribbean English (results not statistically significant), but not of Caribbean Americans. By comparing mutually adjusted Caribbean and black ethnic density effects in the US and England, this study examined the social construction of race and ethnicity as it depends on the racialised and stigmatised meaning attributed to it, and the association that these different racialised identities have on health.

Biracial couples and adverse birth outcomes: a systematic review and meta-analyses

BACKGROUND

Differences in birth outcomes such as low birthweight (LBW), preterm births (PTB), stillbirth, differences in birthweight in Black vs. White race are well known. Infants born to biracial parents (mother and father from either Black or White races) also experience higher adverse birth outcomes.

OBJECTIVE

To systematically review and meta-analyze birth outcomes among parents of mixed racial background compared to parents of same race.

SEARCH STRATEGY

Medline, Embase, CINAHL and bibliographies of identified articles were searched for English language studies.

SELECTION CRITERIA

Studies reporting association between parental mixed racial status and LBW, PTB, or small-for-gestational age (SGA) outcomes were included. DATA COLLECTION AND ANALYSES: After exclusion of duplicate cohorts in different publications, data from White mother-Black father (WMBF), Black mother-White father (BMWF) and Black mother-Black father (BMBF) groups were compared with the White mother-White father (WMWF) group.

RESULTS

Eight English language studies from of 26 335 596 singleton births were included and reviewed. Compared to the WMWF group, the adjusted odds ratio (95% confidence intervals) were: (a) low birthweight; 1.21 (1.10-1.33) for WMBF, 1.75(1.64-1.87) for BMWF, and 2.08 (1.81-2.38) for BMBF; (b) preterm births; 1.17 (1.05-1.31) for WMBF, 1.37 (1.18-1.59) for BMWF, and 1.78 (1.59-2.00) for BMBF; and (c) stillbirths; 1.43 (0.92-2.21) for WMBF, 1.51 (1.09-2.08) for BMWF, and 1.85 (1.47-2.32) for BMBF.

CONCLUSION

Biracial status of parents was associated with higher risk for adverse pregnancy outcomes than both White parents but lower than both Black parents, with maternal race having a greater influence than paternal race on pregnancy outcomes.

Risk factors for preterm birth in an international prospective cohort of nulliparous women

OBJECTIVES

To identify risk factors for spontaneous preterm birth (birth <37 weeks gestation) with intact membranes (SPTB-IM) and SPTB after prelabour rupture of the membranes (SPTB-PPROM) for nulliparous pregnant women.

DESIGN

Prospective international multicentre cohort.

PARTICIPANTS

3234 healthy nulliparous women with a singleton pregnancy, follow up was complete in 3184 of participants (98.5%).

RESULTS

Of the 3184 women, 156 (4.9%) had their pregnancy complicated by SPTB; 96 (3.0%) and 60 (1.9%) in the SPTB-IM and SPTB-PPROM categories, respectively. Independent risk factors for SPTB-IM were shorter cervical length, abnormal uterine Doppler flow, use of marijuana pre-pregnancy, lack of overall feeling of well being, being of Caucasian ethnicity, having a mother with diabetes and/or a history of preeclampsia, and a family history of low birth weight babies. Independent risk factors for SPTB-PPROM were shorter cervical length, short stature, participant's not being the first born in the family, longer time to conceive, not waking up at night, hormonal fertility treatment (excluding clomiphene), mild hypertension, family history of recurrent gestational diabetes, and maternal family history of any miscarriage (risk reduction). Low BMI (<20) nearly doubled the risk for SPTB-PPROM (odds ratio 2.64; 95% CI 1.07-6.51). The area under the receiver operating characteristics curve (AUC), after internal validation, was 0.69 for SPTB-IM and 0.79 for SPTB-PPROM.

CONCLUSION

The ability to predict PTB in healthy nulliparous women using clinical characteristics is modest. The dissimilarity of risk factors for SPTB-IM compared with SPTB-PPROM indicates different pathophysiological pathways underlie these distinct phenotypes.

TRIAL REGISTRATION

ACTR.org.au ACTRN12607000551493.

Are associations between neighborhood socioeconomic characteristics and body mass index or waist circumference based on model extrapolations?

BACKGROUND

We investigated whether neighborhood socioeconomic characteristics, measured within person-centered areas (ie, centered on individuals' residences) are associated with body mass index (BMI [kg/m²]) and waist circumference. We used propensity-score matching as a diagnostic and validation tool to examine whether socio-spatial segregation (and related structural confounding) allowed us to estimate neighborhood socioeconomic effects adjusted for individual socioeconomic characteristics without excessive model extrapolations.

METHODS

Using the RECORD (Residential Environment and CORonary heart Disease) Cohort Study, we conducted cross-sectional analyses of 7230 adults from the Paris region. We first estimated the relationships of 3 neighborhood socioeconomic indicators (education, income, real estate prices) with BMI and waist circumference using traditional multilevel regression models adjusted for individual covariates. Second, we examined whether these associations persisted when estimated among participants exchangeable based on their probability of living in low-socioeconomic-status neighborhoods (propensity-score matched samples).

RESULTS

After adjustment for covariates, BMI/waist circumference increased with decreasing neighborhood socioeconomic status, especially with neighborhood education measured within 500-m radius buffers around residences; associations were stronger for women. With propensity-score matching techniques, there was some overlap in the odds of exposure between exposed and unexposed populations. As a function of socio-spatial segregation and an indicator of whether the data support inferences, sample size decreased by 17%-59% from the initial to the propensity-score matched samples. Propensity-score matched models confirmed relationships obtained from models in the entire sample.

CONCLUSIONS

Overall, adjusted associations between neighborhood socioeconomic variables and BMI/waist circumference were empirically estimable in the French context, without excessive model extrapolations, despite the extent of socio-spatial segregation.

More than culture: structural racism, intersectionality theory, and immigrant health

Explanations for immigrant health outcomes often invoke culture through the use of the concept of acculturation. The over reliance on cultural explanations for immigrant health outcomes has been the topic of growing debate, with the critics' main concern being that such explanations obscure the impact of structural factors on immigrant health disparities. In this paper, we highlight the shortcomings of cultural explanations as currently employed in the health literature, and argue for a shift from individual culture-based frameworks, to perspectives that address how multiple dimensions of inequality intersect to impact health outcomes. Based on our review of the literature, we suggest specific lines of inquiry regarding immigrants' experiences with day-to-day discrimination, as well as on the roles that place and immigration policies play in shaping immigrant health outcomes. The paper concludes with suggestions for integrating intersectionality theory in future research on immigrant health.