Association of Food Desert Residency and Preterm Birth in the United States

Introduction: Food deserts are a major public health concern. Inadequate access to healthy food has been associated with poor nutrition and the development of dietary related chronic conditions.

Objective: To determine the association between geographic access to nutritious food and preterm birth and whether gestational hypertension mediates this relationship.

Methods: Food access data was retrieved from the U.S. Department of Agriculture Food Access Research Atlas (2019) and used to quantify the percentage of Census tracts within each county that were food deserts: low-income tracts with limited access to grocery stores, supermarkets, or other sources of healthy, nutritious foods. These data were merged with US birth records from 2018 to 2019 by using the maternal county of residence (n = 7,533,319). We fit crude and adjusted logistic regression models with generalized estimating equations to determine the association between living in a food desert and the odds of preterm birth. We conducted a secondary within-group analysis by stratifying the fully adjusted model by race for non-Hispanic White and non-Hispanic Black birthing people.

Results: In the fully adjusted model, we found a dose-response relationship. As the prevalence of tract-level food deserts within counties increased, so did the likelihood of preterm birth (mid-range: odds ratio (OR) = 1.04, 95% confidence interval (C.I.) 1.01-1.07; high: OR = 1.07, 95% C.I. 1.03-1.11). Similar results were seen in the White-Black stratified models. However, a disparity remained as Black birthing people had the highest odds for preterm birth. Lastly, gestational hypertension appears to mediate the relationship between nutritious food access and preterm birth (natural indirect effect (NIE) = 1.01, 95% CI = 1.00, 1.01).

Conclusion: It is salient, particularly for Black birthing people who experience high rates of adverse birth outcomes, that the role of food desert residency be explored within maternal and child health disparities.