Dissertations and Theses

Date of Degree


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Epidemiology and Biostatistics


Luisa N. Borrell

Committee Members

Luisa N. Borrell, DDS, PhD

Clare Evans, ScD

Mary Huynh, PhD

Heidi Jones, PhD, MPH

Subject Categories

Epidemiology | Public Health


birthweight; intersectionality; health inequities; intersectional MAIHDA; multilevel models; social epidemiology


BACKGROUND: Birthweight is an important indicator of health for infants, as low birthweight is associated with adverse health outcomes for infants and children. In the United States (U.S.), there are significant birthweight inequities by several maternal characteristics including maternal race/ethnicity, age, education, and nativity status. For example, the prevalence of low birthweight among Black infants is double the prevalence among white infants (14% vs. 6.9%, respectively). These health inequities are caused, in part, by unjust systems, policies, and practices rooted in interlocking systems of oppression, like racism. These systems of oppression affect individuals directly as well as the contexts in which they live. Inequities in birthweight by various social and geographic characteristics have been observed. Examining patterns of health outcomes at the intersection of multiple dimensions of social identity is critical for understanding drivers of such inequities. Additionally, understanding how the effects of social identity on birthweight may differ across social and geographic contexts can further elucidate pathways for intervention. Accordingly, this dissertation focused on exploring patterns of birthweight inequities in New York City (NYC) at the intersection of several dimensions of maternal social identity and position and to better understand how maternal social identity and position interact with neighborhood context to affect such inequities.

METHODS: This dissertation comprised three studies utilizing NYC birth record data from 2012-2018. This study was restricted to singleton births born between 21 and 42 weeks in NYC hospitals among women with a residential address in NYC and with non-missing, plausible values for birthweight. For Aims 1 and 2, Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy (MAIHDA) was used to explore patterns of birthweight inequities. This approach aligns with health inequities theory, in that social identity and position is considered a “clustering” that occurs due to systems of oppression and advantage in which people with similar social identities share comparable contexts that may be important in understanding patterns of health inequities. In Aim 1, observations were clustered by social strata defined by a combination of maternal race/ethnicity, age group, education, and nativity status. In Aim 2, neighborhood percent minoritized population (high; low) was added to the social strata definition. For Aim 3, multilevel linear regression models were used to explore potential effect measure modification of the effect of maternal race/ethnicity on birthweight by neighborhood percent minoritized population on the additive scale.

RESULTS: We found evidence of intersectional effects of various systems of oppression on birthweight inequities in NYC and identified specific groups that experienced higher- and lower-than expected birthweight. Aim 1 analyses found that U.S.-born Black women had infants of lower-than-expected birthweights and among the lowest predicted birthweights with the lowest among U.S.-born Black women aged 30-39 with less than a high school diploma (residual, -102.16g, predicted birthweight, 3052.4g). We also found evidence of an intersectional effect between maternal age group, race/ethnicity, education status, nativity status, and neighborhood of residence’s racial/ethnic composition on infant birthweight (Aim 2). We found that U.S.-born Black women living in neighborhoods with a high percent of minoritized population experienced the lowest predicted infant birthweights and lower-than-expected birthweights, underscoring the importance of racism, which affects both individuals and neighborhoods, as well as its generational impact, as a primary force in producing inequities in birthweight. We also found that for Latino and Asian women, the role of neighborhood percent minoritized population in patterning inequities was dependent on nativity status, with foreign-born women experiencing relatively higher birthweights when living in neighborhoods with high percent minoritized populations. Findings from Aim 3 indicate that neighborhood racial/ethnic minoritized density modifies the effect of maternal race/ethnicity on infant birthweight. Compared to white women living in neighborhoods with low percent minoritized populations, assumed to be the most privileged group, women of all other races/ethnicities experienced lower infant birthweights, regardless of neighborhood context. High neighborhood percent minoritized population was associated with decreased birthweight for women who were white, Latino, Asian, and other races/ethnicities. Black women experienced a slight increase in birthweight in neighborhoods with high percent minoritized populations.

DISCUSSION: Our findings provide evidence that systems of oppression and advantage interlock in a way that contributes to observed patterns of inequities in birthweight. We also found evidence that the effects of social identity and position, defined as a combination of maternal race/ethnicity, age group, education, and nativity status, may differ by the context of neighborhood racial/ethnic composition. While this study confirmed significant Black-white inequities in birthweight overall and across neighborhood contexts, we were able to identify specific groups that experienced lower-than expected birthweights. U.S.-born Black women aged 30-39 with less than a HS diploma had infants of lower-than-expected birthweights, which suggests this population should be prioritized for policy, programmatic, and clinical practice solutions to reducing low birthweight and existing resources should be allocated using an equity-based approach. Furthermore, the study found that the effect of social identity varies across neighborhood context, underscoring the need to consider neighborhood context when exploring health inequities. Our findings also indicate that in NYC, the percent of the population in a neighborhood that is minoritized population significantly modifies the effect of maternal race/ethnicity on infant birthweight and may be a causal partner in producing racial/ethnic inequities in birthweight, providing further evidence that racism operates at both individual and contextual levels to affect infant health. Overall, our findings highlight the effects of systems of oppression that operate at the individual and neighborhood levels, which contribute to health inequities. Additionally, this research demonstrates the importance and utility of using an intersectional approach to exploring the effects of systems of oppression and advantage on health inequities, particularly in identifying specific social groups that may be at increased risk of adverse outcomes.

Available for download on Tuesday, October 01, 2024

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