Does choice of neighborhood disadvantage index matter? An application with preterm birth disparities
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Background: Epidemiologists often investigate the impacts of neighborhood disadvantage (ND) on health outcomes using indices created from publicly available data. However, it is not well known how choice of ND index can impact results. We (1) determined the most used ND indices in recent epidemiological research and (2) investigated how choice of ND index impacts the observed racial disparity in the relationship between ND and preterm birth (PTB).
Methods: We conducted a systematic scan of abstracts from 2020-2023 in 5 major epidemiology journals and conferences to determine the most used ND indices and assigned them to birth records for singleton live births with no birth defects to non-Hispanic (NH) Black and NH white birthing parents in North Carolina from 2016-2018. Linear binomial regression was used to calculate risk differences (RD) for PTB for a 1-standard deviation (SD) increase in each ND index, stratified by race.
Results: Our sample included 263,066 births (30.3% NH Black; 69.7% NH white). PTB was higher for NH Black than NH white deliveries (11.0% NH Black; 7.1% NH white). The most common ND indices were Neighborhood Deprivation Index (NDI), racial and economic Index of Concentration at the Extremes (ICE), Social Vulnerability Index (SVI), and Area Deprivation Index (ADI). Overall, the indices showed an increased risk of 13-15 more PTB per 1000 live births for a 1-SD increase in ND. RDs were higher for NH white (RD range: 8.2 – 11.2) compared to NH Black birthing parents (RD range: 8.1 – 9.0) for the NDI, ICE, SVI and ADI. As ND decreased, the PTB risk disparity between NH Black and NH white birthing parents widened with the NDI and ADI, indicating that the potential benefits of living in advantaged neighborhoods may not be equally shared; this gap was not observed with ICE or SVI.
Conclusions: The relationship between ND and health outcomes may vary depending on the index used, indicating the need for thoughtful consideration in their selection.