Introduction:
Higher levels of residential segregation have been associated with poorer cardiometabolic health profiles among women. Still, it remains unclear whether segregation may differentially impact the development of gestational hypertension (gHTN) among an ethnically-diverse cohort of pregnant women. We used birth record data from 2003-2009 and data from the 2000 US Census to determine whether racial and economic segregation are associated with gHTN among a diverse cohort of child-bearing women in the greater Philadelphia area.
Methods:
We quantified racial and economic segregation using sociodemographic data from the US Census and the local Getis-Ord (Gi*) spatial statistic. The Gi* produces a spatially-weighted z-score for each census tract reflecting the degree of clustering of racially-similar neighborhoods in an area relative to the surrounding Philadelphia region. We categorized each type of segregation as low (Gi*<0), moderate (Gi*0-1.96), or high (Gi*>1.96), and assigned these to each woman by her census tract of residence. Gestational hypertension was defined in the birth record data as the development of pregnancy-induced hypertension or preeclampsia. We used hierarchical generalized linear mixed effect models to obtain risk ratios and differences (per 1000 women) for the relationships between each form of residential segregation and gHTN. All models were stratified by maternal race/ethnicity, and sequentially adjusted for maternal sociodemographics, health behaviors, medical histories, and neighborhood-level characteristics.
Results:
Our sample consisted of 220,897 Non-Hispanic (NH) Black (26%), NH White (64%), and Hispanic (10%) women, of whom 4% developed gHTN. However, a much greater proportion of NH Black women both developed gHTN and lived in high segregation neighborhoods compared to NH Whites and Hispanics. After adjustment, NH Black women in moderate and high economic segregation areas had 16% higher risk (RR=1.16, 95% CI: 1.03-1.31) and 23% higher risk (RR=1.23, 95% CI: 1.08-1.39) of gHTN, respectively, compared to NH Black women living in low segregation areas. NH Black women in highly racially segregated neighborhoods saw an additional 9 cases of gHTN (per 1000 women) compared to NH Black women living in more racially integrated neighborhoods (RD=8.47, 95% CI: 3.14-13.80). Among NH White and Hispanic women, economic segregation was not associated with gHTN, and only marginally significant findings were observed for racial segregation.
Conclusions:
In our diverse sample of child-bearing women from the greater Philadelphia area, higher levels of racial and economic segregation were associated with greater risk of gHTN among NH Black women. Future work should seek to delineate the specific pathways by which neighborhoods differentially impact individual level cardiovascular health based upon race.
Estimating Income Statistics from Grouped Data: Mean-constrained Integration over Brackets
