Racial Disparities In Infant Mortality Research Articles

Systemic racism and Non-Hispanic Black to Non-Hispanic White disparities in infant mortality at the county level.

To use a novel measure of systemic racism to examine its relationship with Non-Hispanic Black (NHB) to Non-Hispanic White (NHW) racial disparities in infant mortality across U.S. counties. In this cross-sectional study, a composite, multi-dimensional measure of systemic racism at the county level was developed using confirmatory factor analysis based on indicators across five dimensions of systemic racism. Using linear regression analysis, we examined the relationship between the systemic racism factor scores and the NHB to NHW racial disparities in county-level infant mortality rates. Additionally, we performed a multi-level analysis of infant mortality, with births nested within counties by running a random intercept model that controlled for factors at both the individual and county levels to take into account the clustered nature of the data. There were 325 counties that met inclusion criteria for the county level analysis and 1181 counties for the individual level analysis. Each one standard deviation increase in the Systemic Racism Index was associated with an increase of 10.4% in the Non-Hispanic Black to Non-Hispanic White infant mortality rate ratio at the county level (aOR 1.104, 95% CI [1.061-1.148]). After controlling for individual level clinical factors and county level factors, each one standard deviation increase in the systemic racism index score was associated with a decrease of 3.5% in the NHW infant mortality rate (aOR 0.965, 95% CI [0.943-0.988]). Systemic racism is significantly associated with differences between counties in the magnitude of their Non-Hispanic Black to Non-Hispanic White racial disparities in infant mortality rates.

Medical Misadventures as Errors and Mistakes and Motor Vehicular Accidents in the Disproportionate Burden of Childhood Mortality among Blacks/African Americans in the United States: CDC Dataset, 1968-2015.

Racial disparities in infant mortality in the United States persist after adjustment for known confounders of race and mortality association, as well as heterogeneity assessment. Epidemiologic and clinical data continue to show the survival disadvantages of Black/AA children: when Black/AAs are compared to whites, they are three times as likely to die from all-cause mortality. The persistent inability to remove the variance in race-mortality association is partly due to unobserved, unmeasured, and residual confounding, as well as implicit biases in public health and clinical medicine in health equity transformation. This current epidemiologic-perspective explanatory model study aimed to examine the possible explanation of racial differences in U.S. infant mortality using medical misadventures as errors and mistakes, and infants' involvement in motor vehicular traffic accidents. Using CDC WONDER ecologic data from 1968 to 2015, we assessed the infant mortality-rate ratio and percent change associated with medical misadventures as well as motor vehicular accidents or trauma. The rate ratio and percent change were estimated using stratification analysis and trend homogeneity, respectively. There was a Black-white racial difference in medical misadventures during the study period. Relative to the years 1968-1978 (rate ratio [RR], 1.43), there was a steady increase in the mortality-rate ratio in 1979-1998 (52%, RR = 1.52), and mortality was more than two times as likely in 1999-2015 (RR = 2.37). However, with respect to motor vehicular accident/trauma mortality, the mortality ratio, although lower among Blacks in 1968-1978 (RR, 0.92), increased in 1979-1998 by 27% (RR = 1.27) but decreased in 1999-2015 (RR, 1.17), though there was still an excess of 17% mortality among Black/AAs. The percent change for medical misadventures indicated an increasing trend from 9.3% in 1998 to 52% in 2015. However, motor vehicular-related mortality indicated a positive trend in 1998 (38.5%) but a negative trend in 2015 (-8.4%). There were substantial race differentials or variances in infant mortality associated with medical misadventures compared to traffic accidents, and Black/AA children relative to whites experienced a survival disadvantage. These comparative findings are suggestive of medical misadventures and motor vehicular trauma as potential explanations for some of the persistent Black-white disparities in overall infant mortality in the U.S. From these findings, we recommend a national effort to address these issues, thus narrowing the observed disparities in the U.S. infant mortality burden among Black/AAs.

The Effects of Race, Ethnicity, and Maternal Education on Infant Mortality.

The state of New Jersey has a large Black/African American (AA) versus White racial disparity in infant mortality and educational level at childbirth. This disparity, measured by rate ratio, increases with greater maternal education among varied racial-ethnic groups. The nature of this disparity measured by rate differences has not been explored. Infant birth and mortality data were used to examine whether racial or ethnic disparities in infant mortality increased with greater maternal education, comparing rate differences and rate ratios. Racial and ethnic variations in the association between maternal education and infant mortality were examined. Data were from the New Jersey State Health Assessment Data for all New Jersey births between 2014 and 2018 stratified by race and ethnicity, maternal education, and infant mortality ( n = 481,333). R software was used to create a data set and estimate additive and multiplicative interactions, rate differences, and rate ratios for infant mortality by maternal race/ethnicity and educational levels among four racial-ethnic groups. Infant mortality was significantly greater for Black/AA and Hispanic mothers than for White mothers. At all educational levels, Black/AA mothers had the highest prevalence of infant mortality compared to other racial or ethnic groups. Rate differences in infant mortality showed a decrease in Black/AA-White differences for mothers with a high school education or less compared to mothers with a college degree. However, rate ratios showed an increase in Black/AA-White ratio with increasing education levels for mothers with high school education or less than mothers with a college degree. Risk ratios comparing infant mortality for Black/AA versus Hispanic or Asian mothers showed more than a twofold greater risk at all education levels for Black/AA infants. Finally, college-educated Black/AA mothers had significantly higher rates of infant mortality than White or Hispanic mothers with a high school education or less. Black/AA mothers with a college degree had a higher infant mortality rate than White, Hispanic, or Asian mothers with a high school education or less. Future research should address contextual/systemic contributors to this disparity.

A Review of Racial Disparities in Infant Mortality in the US.

Racial disparities in infant mortality have persisted, despite the overall decline in the United States’ overall infant mortality rate (IMR). The overall IMR of the entire United States (5.58 per 1000 live births) population masks significant disparities by race and ethnicity: the non-Hispanic Black population experienced an IMR of 10.8 followed by people from Native Hawaiian or Other Pacific Islander populations at 9.4 and American Indians at 8.2. The non-Hispanic White and Asian populations in the United States have the lowest IMR at 4.6 and 3.6, respectively, as of 2018. A variety of factors that characterize minority populations, including experiences of racial discrimination, low income and education levels, poor residential environments, lack of medical insurance, and treatment at low-quality hospitals, demonstrate strong correlations with high infant mortality rates. Identifying, acknowledging, and addressing these disparities must be performed before engaging in strategies to mitigate them. Social determinants of health play a major role in health disparities, including in infant mortality. The study and implementation of programs to address neighborhood factors, education, healthcare access and quality, economic stability, and other personal and societal contexts will help us work towards a common goal of achieving health equity, regardless of racial/ethnic background.

Addressing Black Infant Mortality Through Harnessing the Power of Community.

In Hamilton County, Ohio, the infant mortality rate is above the national average and the Black infant mortality rate is more than 3 times the white infant mortality rate. These racial disparities in infant mortality cannot be explained through other socio-economic characteristics like education, income, housing, or medical insurance. Research has shown that racism, not race itself, is the driving force behind the high disparity in infant mortality rates in Hamilton County and the nation as well. The World Health Organization (WHO) and the Institute of Medicine have long cited institutional/structural racism and cultural racism as a key factor in health disparity. A paradigm shift needed to occur to address the consequences of racism within the lives of Black women, namely disempowerment and agency. The Commission on Social Determinants of Health (CSDH) model was which engaged Black women and positioned them as an asset, to share in the process of strategizing, creating, and implementing a plan. Queens Village was founded to implement the CSDH model and address the upstream determinants of infant mortality through cultivating a sense of community.

"They Make You Feel Less of a Human Being": Understanding and Responding to Milwaukee's Racial Disparity in Infant Mortality.

Black infants die three times as often as white and Hispanic infants before their first birthday in Milwaukee, WI. Prematurity is the major cause of infant mortality, and social determinants of health contribute to this disparity. To understand how socioeconomic factors and racism create barriers to healthy pregnancies and birth outcomes for Black women, and identify practices necessary for overcoming these barriers. Thirteen collaborators (four women, four support group leaders, and five health professionals) were recruited from church support groups, a family medicine residency clinic, and the health department. Data were collected through field observations, six one-on-one interviews, one small group interview, and one focus group. Thematic analysis identified six key themes related to socioeconomic factors and racism in women's and infant health: Public Apathy; Violence and Stress; Discrimination; Mistrust; Spiritual and Social Support; Reproductive Justice. These themes point out failures in health care, social services, and policy initiatives that do not meet women's and infant needs, in addition to some opportunities to implement successful practices. Recommendations are made for policymakers, social services, health systems, and health professionals to implement systemic changes that support Black women and their families. Future applications of this work include implementing and measuring the impact of systems change to benefit Black women and families.

Reconsidering upstream approaches to improving population health

Racial and socioeconomic disparities in health outcomes have been well documented. 1 Blumenshine P Egerter S Barclay CJ Cubbin C Braveman PA Socioeconomic disparities in adverse birth outcomes: a systematic review. Am J Prev Med. 2010; 39: 263-272 Summary Full Text Full Text PDF PubMed Scopus (477) Google Scholar , 2 Matoba N Collins Jr, JW Racial disparity in infant mortality. Semin Perinatol. 2017; 41: 354-359 Crossref PubMed Scopus (43) Google Scholar Although overall global rates of poor birth outcomes have decreased, decades of research and interventions have not eliminated disparities. However, much intervention research has focused on individual-level risk factors and groups at high risk. In The Lancet, Jennifer Jardine and colleagues 3 Jardine J Walker K Gurol-Urganci I et al. Adverse pregnancy outcomes attributable to socioeconomic and ethnic inequalities in England: a national cohort study. Lancet. 2021; (published online Nov 1.)https://doi.org/10.1016/S0140-6736(21)01595-6 Summary Full Text Full Text PDF PubMed Scopus (7) Google Scholar report on population attributable fractions, which indicate the proportion of a particular outcome that would be removed if a risk factor did not exist or was more similar to a reference population. The use of population attributable fractions is an important contribution because it demonstrates the excess risk of poor outcomes that can be attributed to population-level factors. The authors provide a potential roadmap for future interventions, emphasising the role of widespread health promotion in improving population-level health metrics over targeted, individual-level interventions that have less population impact. 4 Rose G Sick individuals and sick populations. Int J Epidemiol. 1985; 14: 32-38 Crossref PubMed Scopus (2188) Google Scholar This study 3 Jardine J Walker K Gurol-Urganci I et al. Adverse pregnancy outcomes attributable to socioeconomic and ethnic inequalities in England: a national cohort study. Lancet. 2021; (published online Nov 1.)https://doi.org/10.1016/S0140-6736(21)01595-6 Summary Full Text Full Text PDF PubMed Scopus (7) Google Scholar included 1·16 million singleton births in England, which represented 94% of England's births obtained from administrative hospital data linked to the National Maternity and Perinatal Audit between 2015 and 2017. The authors report that 24% of stillbirths, 19% of preterm births, and 31% of fetal growth restriction could be attributed to socioeconomic inequality. The women included in the sample were 77·2% White, 11·9% south Asian, 4·9% Black, 1·8% mixed ethnicity, and 4·2% other ethnicity. Perhaps most striking were the authors’ findings on the intersection of race and socioeconomic disadvantage, describing that more than half of stillbirths, a third of preterm births, and nearly two-thirds of fetal growth restriction among south Asian and Black women could be eliminated if their risk factors were equal to the least socioeconomically deprived White women. The authors suggest that this finding supports a combination of population-based and risk-based approaches, but does not consider the inextricable link between ethnic background and socioeconomic deprivation. 5 Kane JB Miles G Yourkavitch J King K Neighborhood context and birth outcomes: going beyond neighborhood disadvantage, incorporating affluence. SSM Popul Health. 2017; 3: 699-712 Crossref PubMed Scopus (17) Google Scholar Additionally, the association between race or socioeconomic inequality and birth outcomes might vary because of factors like social support and experiences of racism and discrimination. In combination with the limitation of using an area-level index of deprivation, the authors acknowledge potential inaccuracies and bias in the population attributable fractions. 6 Mansournia MA Altman DG Population attributable fraction. BMJ. 2018; 360: k757 Crossref PubMed Scopus (114) Google Scholar They rightfully note that more detailed causal mediation analysis is a research priority. Moreover, because the definition of fetal growth restriction varies by the reference used, which itself varies by ethnic mix in the index population, 7 Grantz KL Fetal growth curves: is there a universal reference?. Obstet Gynecol Clin North Am. 2021; 48: 281-296 Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar interpretations of this outcome are unclear. Indeed, the authors may be capturing small-for-gestational age rather than fetal growth restriction, which may not indicate pathology. Adverse pregnancy outcomes attributable to socioeconomic and ethnic inequalities in England: a national cohort studyOur results indicate that socioeconomic and ethnic inequalities were responsible for a substantial proportion of stillbirths, preterm births, and births with FGR in England. The largest inequalities were seen in Black and South Asian women in the most socioeconomically deprived quintile. Prevention should target the entire population as well as specific minority ethnic groups at high risk of adverse pregnancy outcomes, to address risk factors and wider determinants of health. Full-Text PDF

Racial Inequalities in Mortality from Coronavirus: The Tip of the Iceberg

Racial Inequalities in Mortality from Coronavirus: The Tip of the Iceberg

Differential relationship between state-level minimum wage and infant mortality risk among US infants born to white and black mothers

BackgroundCompared to other Organisation for Economic Co-operation and Development (OECD) nations, US infant mortality rates (IMRs) are particularly high. These differences are partially driven by racial disparities, with non-Hispanic black...

What Matters More, Maternal Characteristics or Differential Returns for Having Them? Using Decomposition Analysis to Explain Black-White Racial Disparities in Infant Mortality in the United States

Studies have found that socioeconomic factors alone cannot explain the high incidence of infant deaths among black Americans, and structural racism may be producing these differences in IMR across racial groups. Using data from the 1988 National Maternal and Infant Health Survey, we applied decomposition analysis to test how much of the black-white differences in IMR were determined by racial differences in (1) characteristics (e.g., socioeconomic, demographic and geographic) versus (2) rates of return on those characteristics (e.g., ability to translate the characteristics into healthy infants), with the latter indicative of racism. The black IMR was found to be over twice as high as the white IMR. Differences in socio-demographic characteristics did not explain gap. Instead, the differential returns on the characteristics of black mothers and their inability to translate their characteristics to produce healthy infants, accounted for a larger part of the black-white IMR inequality, providing evidence of institutional racism. Attention must be paid to broader structural factors that may be creating and contributing to the maintenance of racial disparities in IMR.

A Case Study on A University-Community Partnership to Eliminate Racial Disparities in Infant Mortality: Effective Strategies and Lessons Learned

ABSTRACTThis case study discusses the implementation framework, effective strategies, and lessons learned of a university-community partnership addressing racial disparities in infant mortality. The partnership was successful at enhancing coordination within service delivery systems for maternal and child health programs. Results: the elimination of waiting list for services, maximizing federal and state reimbursement, the adoption of culturally-appropriate intervention practices, increasing racial diversity in the workforce, diffusing silos, and facilitating healthier relationships among service providers. Key lessons: activating the collective strengths among a network of diverse community stakeholders with shared interests, prioritizing black voices in the change process, and capacity building opportunities.

The promise and pitfalls of precision medicine to resolve black-white racial disparities in preterm birth.

Differences in preterm birth rates between black and white women are the largest contributor to racial disparities in infant mortality. In today's age of precision medicine, analysis of the genome, epigenome, metabolome, and microbiome has generated interest in determining whether these biomarkers can help explain racial disparities. We propose that there are pitfalls as well as opportunities when using precision medicine analyses to interrogate disparities in health. To conclude that racial disparities in complex conditions are genetic in origin ignores robust evidence that social and environmental factors that track with race are major contributors to disparities. Biomarkers measured in omic assays that may be more environmentally responsive than genomics, such as the epigenome or metabolome, may be on the causal pathway of race and preterm birth, but omic observational studies suffer from the same limitations as traditional cohort studies. Confounding can lead to false conclusions about the causal relationship between omics and preterm birth. Methodological strategies (including stratification and causal mediation analyses) may help to ensure that associations between biomarkers and exposures, as well as between biomarkers and outcomes, are valid signals. These epidemiologic strategies present opportunities to assess whether precision medicine biomarkers can uncover biology underlying perinatal health disparities.

Reimagining Solidarity to Confront Infant Mortality

Background: In Milwaukee, black babies die nearly three times as often as white babies, and black women experience stillbirth two and a half times more often than white women. There are many contributors to this reality. While parental responsibility is one factor, deeper, more systemic issues related to racial inequality and class privilege are also at play. Even among groups with similar socioeconomic status, racial disparities in infant mortality persist.

Contribution of Previable Births to Racial Disparity in Infant Mortality Rates the United States [22D

INTRODUCTION: All live births that occur <20weeks contribute to Infant Mortality Rates (IMRs) as all result in death. We aim to describe racial variation in US IMRs attributed to infant deaths among previable (<20week) live born infants. METHODS: Population-based retrospective cohort study of all US live births from 2007-2014, using CDC WONDER database’s Linked Birth/Infant Death Records. Data were stratified by maternal race and gestational age (GA) at birth. We compared the proportion of infant deaths within previable and periviable/viable (≥20weeksGA) categories. The US reported IMR (births at all GAs including <20weeks) was compared to an adjusted IMR (≥20weeks), and the difference (≥IMR) was calculated for each race/ethnicity. RESULTS: Previable infant deaths represented 4.12%, 7.69%, and 4.99% of total deaths for non-Hispanic White, non-Hispanic Black, and Hispanic groups, respectively. The contribution of previable deaths to the total IMR of these racial/ethnic groups are .21, .89, and .26 per 1000 live births, respectively, P<.0001. Adjusted IMRs of the groups are 4.98, 10.85, and 4.69 deaths per 1000 live births. CONCLUSION: There are significant racial/ethnic differences in the relative contribution of previable births to each group’s IMR in the US. Non-Hispanic Black mothers had the largest number of previable births and the largest IMR if a lower GA cutoff of 20 weeks is considered. One potential method of standardizing IMR on the regional, national, and international levels is to impose a minimum gestational age for infant mortality calculations. However, this approach may obscure the disproportionate contribution of previable births to IMRs among the non-Hispanic black population.

Childhood stress and birth timing among African American women: Cortisol as biological mediator

Preterm birth (PTB) occurs among 1:11U.S. white women and 1:7.5 African American women and is a significant driver of racial disparities in infant mortality. Maternal stress is the most common clinical phenotype underlying spontaneous PTB. Specific patterns of stress and biological mediators driving PTB remain unclear. We examined the effect of childhood stress on birth timing among African American women and evaluated maternal cortisol elevation as a biological mediator. A prospective observational design was employed, with a single study visit at 28–32 weeks gestation and medical record review. The Stress and Adversity Inventory was administered, which provides a comprehensive estimate of childhood stress, stress in adulthood, and five core characteristic subscales (interpersonal loss, physical danger, humiliation, entrapment, role disruption). Venipuncture was performed between 11:00am and 4:00pm and plasma cortisol quantified by ELISA. Analyses controlled for stress in adulthood. Among a final sample of 89, cumulative childhood stress predicted birth timing (p=0.01). The association was driven by stress related to interpersonal loss and physical danger, with support for maternal cortisol as a biological mediator (ab=0.02, 95% CI [0.001, 0.045]; ab=0.02, 95% CI [0.001, 0.043], respectively). Results were similar, overall, in sub-group analyses among spontaneously laboring women (n=53); however, role disruption arose as an additional predictor, as mediated by cortisol elevations (ab=0.03, 95% CI [0.005, 0.074]). Of note, cortisol was no longer supported as a mediator linking physical danger to birth timing after adjusting for sleep quality and hours awake prior to venipuncture (ab=0.02, 95% CI [−0.0001, 0.046]). We provide preliminary evidence that, independent of stress in adulthood, childhood stress of specific core characteristics may shape birth timing, with cortisol elevation as a biological mediator. Further investigation is warranted and may bolster the development of biologically-informed screening tools for the prediction and targeted prevention of stress-related PTB.

State-Level Progress in Reducing the Black-White Infant Mortality Gap, United States, 1999-2013.

To assess state-level progress on eliminating racial disparities in infant mortality. Using linked infant birth-death files from 1999 to 2013, we calculated state-level 3-year rolling average infant mortality rates (IMRs) and Black-White IMR ratios. We also calculated percentage improvement and a projected year for achieving equality if current trend lines are sustained. We found substantial state-level variation in Black IMRs (range = 6.6-13.8) and Black-White rate ratios (1.5-2.7), and also in percentage relative improvement in IMR (range = 2.7% to 36.5% improvement) and in Black-White rate ratios (from 11.7% relative worsening to 24.0% improvement). Thirteen states achieved statistically significant reductions in Black-White IMR disparities. Eliminating the Black-White IMR gap would have saved 64 876 babies during these 15 years. Eighteen states would achieve IMR racial equality by the year 2050 if current trends are sustained. States are achieving varying levels of progress in reducing Black infant mortality and Black-White IMR disparities. Public Health Implications. Racial equality in infant survival is achievable, but will require shifting our focus to determinants of progress and strategies for success.

African-American:White Disparity in Infant Mortality due to Congenital Heart Disease

To determine the importance of infant factors, maternal prenatal care use, and demographic characteristics in explaining the racial disparity in infant (age <365 days) mortality due to congenital heart defects (CHD). In this cross-sectional population-based study, stratified and multivariable logistic regression analyses were performed on the 2003-2004 National Center for Health Statistics linked live birth-infant death cohort files of term infants with non-Hispanic white (n = 3 684 569) and African-American (n = 782 452) US-born mothers. Infant mortality rate, including its neonatal (<28 day) and postneonatal (28-364 day) components, due to CHD was the outcome measured. The infant mortality rate due to CHD for African-American infants (296 deaths; 3.78 per 10 000 live births) exceeded that of white infants (1025 deaths; 2.78 per 10 000 live births) (relative risk [RR], 1.36; 95% CI, 1.20-1.55). The racial disparity was wider in the postneonatal period (2.08 per 10 000 vs 1.42 per 10 000; RR, 1.53; 95% CI, 1.29-1.83) compared with the neonatal period (1.70 per 10 000 vs 1.44 per 10 000; RR, 1.20; 95% CI, 0.99-1.45). Compared with white mothers, African-American mothers had a higher percentage of high-risk characteristics. In multivariable logistic regression models, the adjusted OR of postneonatal and neonatal mortality due to CHD for African-American mothers compared with white mothers was 1.20 (95% CI, 0.98-1.48) and 0.95 (95% CI, 0.77-1.19), respectively. The racial disparity in infant mortality rate due to CHD among term infants with US-born mothers is driven predominately by the postneonatal survival disadvantage of African-American infants. Commonly cited individual-level risk factors partly explain this phenomenon. The study is limited by the lack of information on neighborhood factors.

Mediation Analysis for Health Disparities Research.

Social epidemiologists often seek to determine the mechanisms that underlie health disparities. This work is typically based on mediation procedures that may not be justified with exposures of common interest in social epidemiology. In this analysis, we explored the consequences of using standard approaches, referred to as the difference and generalized product methods, when mediator-outcome confounders are associated with the exposure. We compared these with inverse probability-weighted marginal structural models, the structural transformation method, doubly robust g-estimation of a structural nested model, and doubly robust targeted minimum loss-based estimation. We used data on 900,726 births from 2003 to 2007 in the Penn Moms study, conducted in Pennsylvania, to assess the extent to which breastfeeding prior to hospital discharge explained the racial disparity in infant mortality. Overall, for every 1,000 births, 3.36 more infant deaths occurred among non-Hispanic black women relative to all other women (95% confidence interval: 2.78, 3.93). Using the difference and generalized product methods to assess the disparity that would remain if everyone breastfed prior to discharge suggested a complete elimination of the disparity (risk difference = -0.87 per 1,000 births; 95% confidence interval: -1.39, -0.35). In contrast, doubly robust methods suggested a reduction in the disparity to 2.45 (95% confidence interval: 2.20, 2.71) more infant deaths per 1,000 births among non-Hispanic black women. Standard approaches for mediation analysis in health disparities research can yield misleading results.

Racial disparity in previable birth

Extremely preterm birth of a live newborn before the limit of viability is rare but contributes uniformly to the infant mortality rate because essentially all cases result in neonatal death. The objective of the study was to quantify racial differences in previable birth and their contribution to infant mortality and to estimate the relative influence of factors associated with live birth occurring before the threshold of viability. This was a population-based retrospective cohort of all live births in Ohio over a 7 year period, 2006-2012. Demographic, pregnancy, and delivery characteristics of previable live births at 16 0/7 to 22 6/7 weeks of gestation were compared with a referent group of live births at 37 0/7 to 42 6/7 weeks. Rates of birth at each week of gestation were compared between black and white mothers, and relative risk ratios were calculated. Logistic regression estimated the relative risk of factors associated with previable birth, with adjustment for concomitant risk factors. Of 1,034,552 live births in Ohio during the study period, 2607 (0.25% of all live births) occurred during the previable period of 16-22 weeks. There is a significant racial disparity in the rate and relative risk of previable birth, with a 3- to 6-fold relative risk increase in black mothers at each week of previable gestational age. The incidence of previable birth for white mothers was 1.8 per 1000 and for black mothers, 6.9 per 1000. Factors most strongly associated with previable birth, presented as adjusted relative risk ratio (95% confidence interval [CI]), were maternal characteristics of black race adjusted relative risk 2.9 (95% CI, 2.6-3.2), age ≥ 35 years 1.3 (95% CI, 1.1-1.6), and unmarried 2.1 (95% CI, 1.8-2.3); fetal characteristics including congenital anomaly, 5.4 (95% CI, 3.4-8.1) and genetic disorder, 5.1 (95% CI, 2.5-10.1); and pregnancy characteristics including prior preterm birth 4.4 (95% CI, 3.7-5.2) and multifetal gestation, twin, 16.9 (95% CI, 14.4-19.8) or triplet, 65.4 (95% CI, 32.9-130.2). The majority, 80%, of previable births (16-22 weeks) were spontaneous in nature, compared with 73% in early preterm births (23-33 weeks), 72% in late preterm births (34-36 weeks), and 65% of term births (37-42 weeks) (P < .001). Previable births constituted approximately 28% of total infant mortalities in white newborns and 45% of infant mortalities in black infants in Ohio during the study period. There is a significant racial disparity in previable preterm births, with black mothers incurring a 3- to 6-fold increased relative risk compared with white mothers, most of which are spontaneous in nature. This may explain much of the racial disparity in infant mortality because all live-born previable preterm births result in death. Focused efforts on the prevention of spontaneous previable preterm birth may help to reduce the racial disparity in infant mortality.

Social Environments, Genetics, and Black–White Disparities in Infant Mortality

Genes and environments often interplay to produce population health. However, in some instances, the scientific literature has favoured one explanation, underplaying the other, even in the absence of rigorous support. We examine parental race disparity on the risk of infant mortality to see if such an analysis might provide clues to understanding the extent to which genes and environment may shape perinatal risks. We assessed parental racial disparities in infant mortality among singletons by analysing the risk of infant mortality among racially consonant vs. dissonant couples over time between 1989-1997 and 1998-2006 in the state of Michigan (n = 1 428 199). We calculated the degree of modification of the relation between maternal race and infant mortality by paternal race dynamically across the two time periods. Infant mortality among interracial couples decreased with time relative to white-white couples, while infant mortality among black-black couples increased with time after adjusting for socio-economic, demographic, and prenatal care differences. The degree to which paternal black race strengthened the relation between maternal black race and higher infant mortality risk relative to white mothers increased with time throughout our study. Evidence from these data suggests that environmental factors likely play the greater role in explaining the parental race disparity and risk of infant mortality.