Association between historical redlining and preterm birth in North Carolina, 2003-2015
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Background and Aim: Starting mid-1930s, the Home Owners’ Loan Corporation (HOLC) ranked neighborhoods in cities as least to most desirable in terms of perceived mortgage stability. This racist practice, redlining, prevented minority families the opportunity to own property for wealth accumulation. Recent research suggests associations between historical redlining and adverse birth outcomes today. We investigated the association between historical redlining and preterm birth (PTB, <37 weeks gestation) in North Carolina (NC) and evaluated modification of that association by gestational parent (GP) race/ethnicity.
Methods: We assembled a retrospective, administrative cohort of singleton births in NC from 2003-2015. We linked geocoded residences at time of delivery to Mapping Inequality’s HOLC polygons. Eligible births were assigned HOLC grade A (Best), B (Still desirable), C (Declining), or D (Hazardous). We estimated odds ratios (OR (95%CI)) using logistic regression adjusting for GP age at delivery and smoking during gestation, and applying generalized estimating equations to account for clustering by city.
Results: Our analysis included 36,571 births within historically redlined cities in NC (Asheville, Charlotte, Durham, Greensboro, Winston-Salem). For births within the historically defined HOLC grades B, C, and D, respectively, the odds of PTB were 1.43 (95%CI: 1.10, 1.86), 1.77 (1.50, 2.09), and 2.10 (1.79, 2.48) compared to HOLC grade A. In stratified analyses, ORs were null and imprecise for all HOLC grades compared to HOLC grade A among non-Hispanic Black individuals (e.g. D vs A: 1.01 (0.60, 1.72)). ORs were positive but similarly imprecise among Hispanic and non-Hispanic white individuals with ORs that ranged from 1.61 (0.57, 4.54) to 1.70 (0.74, 3.93) and 1.20 (0.96, 1.50) to 1.27 (0.97, 1.67), respectively.
Conclusions: These preliminary results suggest that historical redlining is associated with poorer PTB outcomes decades later, providing additional evidence that historically racist practices continue to have lasting negative health impacts on communities today.